5,5'-Bis-(Alkylpyridinyl)-2,2'-Bithiophenes: Synthesis, Liquid Crystalline Behavior ... · 2013-11-22 · S1 Supporting information for 5,5'-Bis-(Alkylpyridinyl)-2,2'-Bithiophenes:

S1

Supporting information for

5,5'-Bis-(Alkylpyridinyl)-2,2'-Bithiophenes: Synthesis, Liquid Crystalline Behavior and Charge Transport

Yulia A. Getmanenko,1,3Shin-Woong Kang,2 Naresh Shakya,2 Chandra Pokhrel,2 Scott Bunge,1 Brett D. Ellman2, Robert J. Twieg1

1Chemistry Department and 2Physics Department, Kent State University, Kent, OH 44242-0001, USA

3Department of Chemistry & Biochemistry and The Center for Organic Photonics and Electronics, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, GA 30332-0400, USA

[email protected]

Table of Contents

1. Synthesis of 5,5'-bis-(5-n-alkylpyridin-2-yl)-2,2'-bithiophenes 2 ................................................................... 5

1.1. 5,5'-Bis-(5-n-hexylpyridin-2-yl)-2,2'-bithiophene (2a) .................................................................................. 5

Figure S1. DSC thermogram (2nd heating-cooling cycle) of 5,5'-bis-(5-n-hexyllpyridin-2-yl)-2,2'-bithiophene (2a).6

5,5'-Bis-(5-n-heptylpyridin-2-yl)-2,2'-bithiophene (2b) ...................................................................................... 6

Figure S2. DSC thermogram of 5,5'-bis-(5-n-heptylpyridin-2-yl)-2,2'-bithiophene (2b) with two close transitions in high temperature region: Iso to N and N to S1. ............................................................................................... 7

Figure S3. POM textures of 2b observed on the slide (image size is ca. 330 × 470 m): (a) 195.5 ºC, nematic phase (slide); (b) 193.0 ºC, mosaic texture of unidentified S1 phase (image size is ca. 330 × 470 m). ................ 8

1.2. 5,5'-Bis-(5-n-octylpyridin-2-yl)-2,2'-bithiophene (2c) ................................................................................... 8

Figure S4. DSC thermogram of 5,5'-bis-(5-n-octylpyridin-2-yl)-2,2'-bithiophene (2c) (2nd cycle, 5 ºC/min rate): 1) only one peak in the high temperature region was observed for two close transitions (Iso to N and N to S1); 2) substantial supercooling of the unidentified S1 phase was detected; 2) formation of the metastable phase from S1 on cooling with transition at 1.4 ºC followed by crystallization (exothermic peak with a maximum at ~30 ºC on heating) and melting on further heating were detected. ................................................................................ 9

Figure S5. POM texture of 2c: 186.1 ºC, nematic phase (slide) (image size is ca. 330 × 470 m). ......................... 9

1.3. 5,5'-Bis-(5-n-nonylpyridin-2-yl)-2,2'-bithiophene (2d) ............................................................................... 10

Figure S6. DSC thermogram of 5,5'-bis-(5-n-nonylpyridin-2-yl)-2,2'-bithiophene (2d) with well resolved close transitions in the region 180-190 ºC. ................................................................................................................ 11

corresponding author; [email protected], 330 672 2791 (ph); 330 672 3816 (fax)

Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry CThis journal is © The Royal Society of Chemistry 2013

mailto:[email protected]

mailto:[email protected]

http://www.novapdf.com


S2

1.4. 5,5'-Bis-(5-n-decylpyridin-2-yl)-2,2'-bithiophene (2e) ................................................................................ 11

1.5. 5,5'-Bis-(5-n-dodecylpyridin-2-yl)-2,2'-bithiophene (2f)............................................................................. 13

Figure S7. DSC thermogram of 5,5'-bis-(5-n-dodecylpyridin-2-yl)-2,2'-bithiophene (2f). .................................... 14

Figure S8. POM textures of 2f observed on the slide (image size is ca. 330 × 470 m): (a) 183.9 ºC, SmC; (b) and (c) 170.1 ºC, mosaic and “tile” textures of unidentified higher ordered phase S1/Cr1. ...................................... 14

1.6. 5,5'-Bis-(5-n-tridecylpyridin-2-yl)-2,2'-bithiophene (2g) ............................................................................ 14

Figure S9. DSC thermogram of 5,5'-bis-(5-n-tridecylpyridin-2-yl)-2,2'-bithiophene (2g). .................................... 16

Figure S10. POM textures observed for 2g on the freely suspended film (image size is ca. 330 × 470 m): (a) 173.8 ºC, growth of unidentified S1/Cr1 phase from preceding SmC phase; (b) 161.4 ºC, mosaic texture of unidentified S1/Cr1 phase. ............................................................................................................................... 16

2. Preparation of 5,5'-bis-(2-n-alkylpyridin-5-yl)-2,2'-bithiophenes 3 ............................................................. 16

2.1. 5,5'-Bis-(2-n-pentylpyridin-5-yl)-2,2'-bithiophene (3a) .............................................................................. 16

Figure S11. DSC thermogram of 5,5'-bis-(2-n-pentylpyridin-5-yl)-2,2'-bithiophene (3a)..................................... 17

2.2. 5,5'-Bis-(2-n-hexylpyridin-5-yl)-2,2'-bithiophene (3b) ................................................................................ 17

Figure S12. DSC thermogram of 5,5'-bis-(2-n-hexylpyridin-5-yl)-2,2'-bithiophene (3b) on 2nd heating-cooling cycle. 18

Figure S13. POM textures of 3b (slide, image size is ca. 330 × 470 m, the same regions are shown for a-d and e-f photographs): (a) 230.5 ºC, fan and homeotropic (black areas) textures of SmA; (b) 182.7 ºC, broken fan texture and schlieren texture of SmC, which formed from the homeotropic texture of SmA; (c) 178.8 ºC, fan and ill-defined schlieren textures of SmI phase; (d), 178.4 ºC, fan texture and schlieren-mosaic textures of SmF phase; (e) 148.8 ºC, SmF before transition to S1/Cr1 phase; (f) 145.8 ºC, unidentified S1/Cr1 phase; (g) 144.3 ºC, unidentified S1/Cr1 phase; (h) 84.0 ºC, unidentified S2/Cr2 phase. ................................................................... 20

2.3. 5,5'-Bis-(2-n-heptylpyridin-5-yl)-2,2'-bithiophene (3c) .............................................................................. 20

Figure S14. DSC thermogram of 5,5'-bis-(2-n-heptylpyridin-5-yl)-2,2'-bithiophene (3c). .................................... 21

Figure S15. POM textures of 5,5'-bis-(2-n-heptylpyridin-5-yl)-2,2'-bithiophene (3c) (slide, image size is ca. 330 × 470 m): (a) 232.4 ºC, isolation of SmA phase from isotropic liquid; (b) 207.6 ºC, SmA phase; (c) 184.9 ºC, broken fan texture of SmC phase; (d) 171.3 ºC, fan texture of SmF phase with ‘L’-shaped patterns; (e) 103.9 ºC, paramorphotic texture of unidentified S1/Cr1; (f) 93.0 ºC, Cr2 (the same area as shown in (e)). ....................... 22

2.4. 5,5'-Bis-(2-n-octylpyridin-5-yl)-2,2'-bithiophene (3d) ................................................................................ 23

Figure S16. DSC thermogram of 5,5'-bis-(2-n-octylpyridin-5-yl)-2,2'-bithiophene (3d). ...................................... 24

Figure S17. POM textures of 5,5'-bis-(2-n-octylpyridin-5-yl)-2,2'-bithiophene (3d) (slide, image size is ca. 330 × 470 m): (a) 225.1 ºC, fan texture and homeotropic texture (black area) of SmA; (b) 209.5 ºC, fan texture and schlieren texture of SmC; (c) 172.9 ºC, broken fan texture and ill-defined schlieren texture of SmI; (d) 170.7 ºC, geometrically defined fan texture and schlieren texture SmF (the latter formed from the ill-defined schlieren texture of SmI); (e) 129.7 ºC, transition from SmF to unidentified S1/Cr1 phase; (f) 67.7 ºC, Cr phase with well-defined cracks (slide) (images shown in (b)-(e) are for the same area). ............................................................. 25





S3

2.5. 5,5'-Bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e) ............................................................................... 26

Figure S18. DSC thermogram of 5,5'-bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e). ..................................... 27

Figure S19. (top) DSC thermogram of 5,5'-bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e); (bottom): (a) 215.8 ºC, focal conic texture of SmA phase; (b) 189.4 ºC, broken focal conic texture of SmC phase; (c) 181.0 ºC, schlieren texture of SmC. .................................................................................................................................. 27

Figure S20. The diffraction patterns of 5,5'-bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e): (a) 88.7 °C; Cr2 phase; (b) 28.0 °C, Cr phase. ............................................................................................................................. 28

2.6. 5,5'-Bis-(2-n-decylpyridin-5-yl)-2,2'-bithiophene (3f) ................................................................................. 28

2.7. 5,5'-Bis-(2-n-tridecylpyridin-5-yl)-2,2'-bithiophene (3g) ............................................................................ 30

Figure S21. DSC thermogram of 5,5'-bis-(2-n-tridecylpyridin-5-yl)-2,2'-bithiophene (3g). .................................. 31

Figure S22. Textures of 3g observed by polarized optical microscopy on slide (image size is ca. 330 × 470 m): (a) 172.4 ºC, fan texture of SmC phase; (b) 152.6 ºC, broken fan texture of SmI phase; (c) 159.9 ºC, fan texture and schlieren texture of SmC phase; (d) 153.5 ºC, ill-defined schlieren texture and broken fan texture of SmI (the same area as in (c)); (e) 129.3 ºC, fan texture of SmF texture with characteristic ‘L’-shaped patterns; (f) 109.1 ºC, unidentified S1/Cr1 phase. ............................................................................................................................... 32

2.8. 5-(2-n-Heptylpyridin-5-yl)-5'-(2-n-tridecylpyridin-2-yl)-2,2'-bithiophene (3h) ........................................... 33

Figure S23. DSC thermogram of 5-(2-n-heptylpyridin-5-yl)-5'-(2-n-tridecylpyridin-2-yl)-2,2'-bithiophene (3h). .. 34

Figure S24. Textures of 3h observed by polarized optical microscopy on slide (image size is ca. 330 × 470 m): (a) 214.5 ºC, isolation of SmA phase from the isotropic liquid; (b) 199.8 ºC, fan texture of the SmA phase; (c) 199.0 ºC, broken fan texture of SmC phase; (d) 128.3 ºC, fan texture of SmF phase; (e) 98.8 ºC, unidentified S1 phase; (f) 76.0 ºC, unidentified S1 phase. ......................................................................................................... 35

3. 5,5'-Bis-(5-bromopyridin-2-yl)-2,2'-bithiophene (5) .................................................................................... 35

4. 5,5'-Bis-(2-bromopyridin-5-yl)-2,2'-bithiophene (10) .................................................................................. 36

5. 2-n-Decyl-5-iodopyridine (11) ..................................................................................................................... 37

6. 5-[2,2']Bithiophenyl-5-yl-2-bromo-pyridine (13) ......................................................................................... 38

7. 5-[2,2']Bithiophenyl-5-yl-2-n-tridecyl-pyridine (14) .................................................................................... 39

8. 5-(5'-Bromo-[2,2']bithiophenyl-5-yl)-2-n-tridecyl-pyridine (15) .................................................................. 40

9. 5-(2-Bromopyridin-5-yl)-5'-(2-n-tridecylpyridin-5-yl)-2,2'-bithiophene (16) ................................................ 40

10. Single crystals X-ray analysis ..................................................................................................................... 41

Figure S25. Thermal ellipsoid structures of 2b (a), 2c (b), 2e (c), and 2f (d). Ellipsoids are drawn at the 50 % level. H atoms have been omitted for clarity. ............................................................................................................. 42

11. Computational Methodology. ................................................................................................................... 42

Figure S26. Frontier molecular orbital energies and wave-function illustrations as determined at the B3LYP/6-31G** level of theory. ...................................................................................................................................... 43





S4

Figure S27. Geometry of the molecules (B3LYP/6-31G** level of theory): (a) mesogen of type 1: dihedral angle (S2, C8, C9, C12) = 25.7º, dihedral angle (S1, C8, C15, C18) = -26.8º; (b) mesogen of type 2: dihedral angle (N2, C11, C2, S1) = -0.4º, dihedral angle (N1, C9, C8, S2) = 0.3 º; (c) mesogen of type 3: dihedral angle (S1, C2, C15, C17) = -25.8º; dihedral angle (S2, C8, C9, C12) = -27.4º, dihedral angle (S1, C4, C6, C5) = 15.1 (between the thiophene rings). .............................................................................................................................................. 44

References ....................................................................................................................................................... 44

1. Experimental Details

Solvents: tetrahydrofuran (THF) was freshly distilled from sodium benzophenone ketyl; anhydrous dimethylformamide (DMF) was purchased from Aldrich and used as received.

The ZnCl2 solution used for the transmetallation reactions was prepared as follows: solid ZnCl2 was dried by melting and cooling under vacuum, freshly distilled THF (an amount to prepare ~1 M solution of ZnCl2) was added, and the mixture was stirred under nitrogen until a homogenous solution was obtained.

The known compounds were prepared by literature procedures: 2,2'-bithiophene1 (4), 2-tri-n-butylstannyl-5-alkylpyridines2 8a-c, 5,5'-dibromo-2,2'-bithiophene3 (7), 2-bromo-5-iodopyridine4 (9), 2-alkyl-5-tri-n-butylstannylpyridines2 12a-f.

Both 1H and 13C NMR spectra were recorded using either a 300 MHz or a 400 MHz spectrometer (TMS as internal standard at 0.0 ppm), a FT-IR spectrometer was used to record IR-spectra, an diode array spectrophotometer was used to record UV-Vis spectra, and a ion trap mass spectrometer was used for the analysis of the synthesized materials (APCI source, drying gas temperature 300-350 ºC, APCI heater temperature 250-300 ºC). A differential scanning calorimeter (scanning rate of 5 ºC/min) and a polarizing microscope equipped with a hot stage (0.2-0.5 ºC/min cooling rate at transition temperatures determined by DSC) were used to determine the phase transitions. Phase assignments were made based on microscopic observations and images were obtained with a CCD camera using Studio Capture software (version 1.4).

For synchrotron X-ray diffraction measurements, the compounds were loaded into 1.0 mm diameter Lindéman capillaries with 10 m thick walls and placed in a homemade oven in an in-situ magnetic field of 2.5 kG strength. The sample was then exposed to synchrotron x-ray radiation of wavelength 0.7653 Å at station 6-IDB of the Midwestern Collaborative Access Team at the Advanced Photon Source of Argonne National Laboratory. The diffraction patterns were recorded at different temperatures during heating/cooling to/from the isotropic phase using a high resolution image plate area detector, MAR345, placed at a distance of 500.8 mm from samples 2c and 3d, and at 476 mm from sample 2e. The data were calibrated against a silicon standard (NIST 640C). The intensity of the incident beam was controlled using a bank of Cu and Al attenuators. Data accumulation times ranged between 1 and 60 s. The 2D diffraction patterns were analyzed using the software package FIT2D developed by A. P. Hammersley5 of the European Synchrotron Radiation Facility. The length scale corresponding to various positional orders were calculated from the position and width of the diffractions peaks





S5

1. Synthesis of 5,5'-bis-(5-n-alkylpyridin-2-yl)-2,2'-bithiophenes 2 1.1. 5,5'-Bis-(5-n-hexylpyridin-2-yl)-2,2'-bithiophene (2a)

5,5'-Dibromo-2,2'-bithiophene (7) (1.5 mmol, 0.49 g) and 2-tri-n-butylstannyl-5-n-hexylpyridine (8a)

(2.9 eq., 4.4 mmol, 1.49 g) were mixed in an oven-dried three-necked flask equipped with magnetic stirbar, nitrogen inlet, bubbler and thermometer. Anhydrous DMF (10 mL), Pd(PPh3)4 (1 mol%, 0.015 mmol, 0.017 g) and CuI (2 mol%, 0.03 mmol, 5.7 mg) were added under nitrogen atmosphere and the bright yellow suspension was heated for 2 hours (120-135 ºC internal temperature). The dark cooled mixture with orange precipitate was transferred into a beaker with 100 mL of ice water and the dark brown gummy product was separated by vacuum filtration. The crude material was washed with 75 mL of hexanes, dried and orange solid was isolated in 76.4% crude yield (0.56 g). The crude compound was dissolved in toluene-dichloromethane under heating, gravity filtered to remove an insoluble orange solid, and the dark orange solution was applied to a column (30 g of silica gel, dichloromethane as eluant). The solvent was removed from the combined fractions containing the slightly contaminated product and the resulting orange solid (0.32 g, 43.7% yield) was dissolved with heating in chloroform (15 mL), and the bright yellow solution was applied to the top of an Al2O3 column (neutral, 40 g). The column was eluted with dichloromethane to give the pure product, and then dichloromethane:ethyl acetate (15:1) to give a byproduct. Fractions containing the product were combined, treated with 1-propanol (10-15 mL), and the solution was concentrated. The title compound was isolated as a bright yellow solid (0.26 g, 81.3% recovery). 1H NMR (CDCl3, 400 MHz): δ 8.41-8.37 (dd, J = 2.0 Hz, 0.4 Hz, 2H), 7.58-7.55 (dd, J = 8.1 Hz, 0.7 Hz, 2H), 7.51-7.47 (dd, J = 8.2 Hz, 2.3 Hz, 2H), 7.45-7.42 (d, J = 3.9 Hz, 2H), 7.24-7.21 (d, J = 3.8 Hz, 2H), 2.64-2.57 (t, J = 7.7 Hz, 4H), 1.66-1.57 (m, 4H), 1.40-1.27 (m, 12H), 0.92-0.86 (t, J = 7.1 Hz, 6H); 13C{1H} NMR (CDCl3, 100 MHz): δ 149.9 (quaternary C), 149.6 (CH), 143.9 (quaternary C), 138.8 (quaternary C), 136.5 (quaternary C), 136.5 (CH), 124.7 (CH), 124.6 (CH), 118.2 (CH), 32.81 (CH2), 31.64 (CH2), 31.08 (CH2), 28.79 (CH2), 22.60 (CH2), 14.08 (CH3).





S6

Figure S1. DSC thermogram (2nd heating-cooling cycle) of 5,5'-bis-(5-n-hexyllpyridin-2-yl)-2,2'-bithiophene (2a).

5,5'-Bis-(5-n-heptylpyridin-2-yl)-2,2'-bithiophene (2b)

1-Bromoheptane (4 eq., 10.0 mmol, 1.79 g) was added dropwise to a suspension of Mg turnings (12

mmol, 0.29 g) in anhydrous THF (20 mL). The reaction mixture was refluxed until most of the magnesium dissolved. This freshly prepared Grignard reagent was added in portions to the suspension of aryl dibromide 5 (2.5 mmol, 1.19 g) and NiCl2(dppe) (7.5 mol%, 0.125 mmol, 0.10 g) in 20 mL of boiling anhydrous THF. The reaction mixture turned brown immediately after addition of the Grignard and dibromide 5 started to dissolve. The reaction was completed after addition of 12.5 mL of Grignard and reflux for an hour and a half. The contents of the flask were applied to the top of a column (40 g of basic Al2O3) and the product was eluted with dichloromethane (50 mL). The brown fractions were combined, the solvent was removed by rotary evaporation, the residue was dissolved in dichloromethane and the solution was filtered through Al2O3 one more time (30 g of basic Al2O3, dichloromethane as eluent). The combined fractions were concentrated, and the solution was chromatographed (30 g of silica gel, dichloromethane:hexanes (1:1) as eluant). The material isolated after removal of solvents from combined fractions was recrystallized from dichloromethane (~30 mL) to give bright yellow solid in 45.0% yield (0.58 g). 1H NMR (CDCl3, 400 MHz): δ 8.41-8.37 (d, J = 1.9





S7

Hz, 2H), 7.59-7.55 (d, J = 8.1 Hz, 2H), 7.52-7.47 (dd, J = 8.2 Hz, 2.2 Hz, 2H), 7.45-7.42 (d, J = 3.9 Hz, 2H), 7.24-7.21 (d, J = 3.8 Hz, 2H), 2.64-2.58 (t, J = 7.7 Hz, 4H), 1.67-1.58 (m, 4H), 1.38-1.22 (m, 16H), 0.91-0.86 (t, J = 7.0 Hz, 6H); 13C{1H} NMR (CDCl3, 100 MHz): δ 149.9 (quaternary C), 149.6 (CH), 143.9 (quaternary C), 138.8 (quaternary C), 136.5 (quaternary C), 136.5 (CH), 124.7 (CH), 124.6 (CH), 118.2 (CH), 32.81 (CH2), 31.79 (CH2), 31.12 (CH2), 29.10 (CH2), 29.08 (CH2), 22.65 (CH2), 14.10 (CH3). Analysis calculated for C32H40N2S2: C, 74.37; H, 7.80; N, 5.42; S, 12.41. Found: C, 74.42; H, 7.80; N, 5.38; S, 12.70.

Figure S2. DSC thermogram of 5,5'-bis-(5-n-heptylpyridin-2-yl)-2,2'-bithiophene (2b) with two close transitions in high temperature region: Iso to N and N to S1.

(a) (b)





S8

Figure S3. POM textures of 2b observed on the slide (image size is ca. 330 × 470 m): (a) 195.5 ºC, nematic phase (slide); (b) 193.0 ºC, mosaic texture of unidentified S1 phase (image size is ca. 330 × 470 m).

1.2. 5,5'-Bis-(5-n-octylpyridin-2-yl)-2,2'-bithiophene (2c)

The material 2c was prepared in a similar way described for 2a from 5,5'-dibromo-2,2'-bithiophene (7)

(0.5 mmol, 0.162 g), 2-tri-n-butylstannyl-5-n-octylpyridine (8b) (2 eq., 1 mmol, 0.48 g), Pd(PPh3)4 (1 mol% based on 8b, 0.01 mmol, 11.5 mg), CuI (2 mol% based on 8b, 4 mg) and anhydrous DMF (5 mL). The reaction mixture was heated for 1 hour (130 ºC internal temperature), cooled, treated with 25 mL of water, and the brown solid was separated by vacuum filtration. The crude material was rinsed with 10-15 mL of ethanol, and the sticky solid (0.37 g) was dissolved in 25 mL of dichloromethane (heating). This brown cloudy solution was chromatographed (35 g of silica gel, dichloromethane) (the solution was kept hot during the application to the column). The slightly contaminated product was isolated in 59.3% yield (0.16 g) as orange powder. The orange solid was further purified by filtration through Al2O3 column (16 g, neutral, warm dichloromethane as eluent) (0.11 g, 40.7% purified yield) and, finally, a pre-packed Biotage column and recrystallization from dichloromethane. The title compound was isolated as orange crystals (0.086 g, 78.6% recovery).

Alternatively 2c was also prepared in a similar way described for 2b from aryl dibromide 5 (1.46 mmol, 0.70 g), NiCl2(dppe) (2 mol%, 0.15 g) and an excess of n-octylmagnesium bromide, prepared from 1-bromooctane (4 eq., 5.86 mmol, 1.13 g), Mg turnings (7.03 mmol, 0.17 g) and 20 mL of anhydrous THF. The mixture was refluxed for hour and a half, cooled, treated with 50 mL of water and the organic solvents were removed by rotary evaporation. The green-brown solid was vacuum filtered, washed with ethanol (10 mL), hexanes (20 mL), dried, dissolved in dichloromethane (~25 mL) and filtered through Al2O3 (50 g, neutral, dichloromethane as eluent). The combined fractions were treated with 50 mL of 1-propanol, the solution was concentrated and the purified product was isolated as bright yellow shiny crystals (0.43 g, 53.5% yield). FT-IR (cm-1): 3075, 2950, 2917, 2848, 1592, 1564, 1533, 1470, 1294, 1249, 1180, 1068, 873, 822, 797, 784, 719, 634, 609. 1H NMR (CDCl3, 400 MHz): δ 8.40-8.37 (m, 2H), 7.59-7.55 (dd, J = 8.1 Hz, 0.7 Hz, 2H), 7.52-7.47 (dd, J = 8.2 Hz, 2.2 Hz, 2H), 7.45-7.42 (d, J = 3.9 Hz, 2H), 7.24-7.21 (d, J = 3.8 Hz, 2H), 2.64-2.57 (t, J = 7.7 Hz, 4H), 1.67-1.58 (m, 4H), 1.40-1.20 (m, 20H), 0.91-0.85 (t, J = 6.9 Hz, 6H); 13C{1H} NMR (CDCl3, 100 MHz): δ 149.9 (quaternary C), 149.6 (CH), 143.9 (quaternary C), 138.8 (quaternary C), 136.6 (quaternary C), 136.5 (CH), 124.7 (CH), 124.6 (CH), 118.2 (CH), 32.8 (CH2), 31.86 (CH2), 31.1 (CH2), 29.4 (CH2), 29.2 (CH2), 28.1 (CH2), 22.7 (CH2), 14.1 (CH3). Analysis calculated for C34H44N2S2: C, 74.95; H, 8.14; N, 5.14; S, 11.77. Found: C, 74.65; H, 8.12; N, 5.10; S, 11.37.





S9

Figure S4. DSC thermogram of 5,5'-bis-(5-n-octylpyridin-2-yl)-2,2'-bithiophene (2c) (2nd cycle, 5 ºC/min rate): 1) only one peak in the high temperature region was observed for two close transitions (Iso to N and N to S1); 2) substantial supercooling of the unidentified S1 phase was detected; 2) formation of the metastable phase from S1 on cooling with transition at 1.4 ºC followed by crystallization (exothermic peak with a maximum at ~30 ºC on heating) and melting on further heating were detected.

Figure S5. POM texture of 2c: 186.1 ºC, nematic phase (slide) (image size is ca. 330 × 470 m).





S10

1.3. 5,5'-Bis-(5-n-nonylpyridin-2-yl)-2,2'-bithiophene (2d)

1-Bromononane (8 eq., 12.0 mmol, 2.49 g) was added dropwise to a suspension of Mg turnings (14.4 mmol, 0.35 g, activated by heating with a crystal of iodine) in anhydrous THF (15 mL) and the reaction mixture was refluxed until most of the magnesium dissolved. This freshly prepared Grignard reagent was added in portions to the suspension of aryl dibromide 7 (1.5 mmol, 0.72 g) and NiCl2(dppe) (20 mol%, 0.3 mmol, 0.16 g) in 60 mL of anhydrous THF and the warm mixture was refluxed. The reaction was completed after refluxing for 8 hours and addition of 5 equivalents of alkyl Grignard. The reaction mixture was cooled down to room temperature and vacuum filtered to remove insoluble matter. After evaporation of the solvent under reduced pressure the residue was treated with water, and the yellow-green solid was vacuum filtered and dried. This crude material (0.72 g, 83.5% crude yield) was chromatographed (silica gel, dichloromethane:hexanes (1:1), then dichloromethane). The product was isolated as a yellow powder in 30% yield (0.25 g). Purified material (0.21 g) was dissolved in 10 mL of chloroform (heating), and the yellow solution was applied to the top of a column (basic Al2O3, 15 g), and eluted with chloroform (~70 mL). The yellow solid obtained after evaporation of solvent from combined fractions was recrystallized from ~30-40 mL of 1-propanol (0.15 g, 70% recovery). 1H NMR (CDCl3, 300 MHz): δ 8.41-8.37 (d, J = 1.5 Hz, 2H), 7.60-7.54 (d, J = 8.1 Hz, 2H), 7.53-7.46 (dd, J = 8.2 Hz, 2.1 Hz, 2H), 7.45-7.42 Hz (d, J = 3.9 Hz, 2H), 7.24-7.21 (d, J = 3.9 Hz, 2H), 2.65-2.55 (t, J = 7.6 Hz, 4H), 1.63-1.57 (m, 4H), 1.40-1.20 (m, 24H), 0.91-0.80 (t, J = 6.7 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 75 MHz): δ 150.0, 149.7, 143.9, 138.9, 136.8, 136.7, 124.9, 124.8, 118.4, 33.0, 32.0, 31.3, 29.7, 29.6, 29.5, 29.3, 22.8, 14.3. Analysis calculated for C36H48N2S2: C, 75.47; H, 8.44; N, 4.89; S, 11.19. Found: C, 75.46; H, 8.49; N, 4.84; S, 11.11.





S11

Figure S6. DSC thermogram of 5,5'-bis-(5-n-nonylpyridin-2-yl)-2,2'-bithiophene (2d) with well resolved close transitions in the region 180-190 ºC.

1.4. 5,5'-Bis-(5-n-decylpyridin-2-yl)-2,2'-bithiophene (2e)

Method 1. 1-Bromodecane (8 eq., 12.0 mmol, 2.66 g) was added dropwise to a suspension of Mg

turnings (14.4 mmol, 0.34 g, activated by heating with a crystal of iodine) in anhydrous Et2O (20 mL). The reaction mixture was refluxed for an hour, cooled to room temperature and this freshly prepared Grignard reagent was added to a suspension of aryl dibromide (5) (1.5 mmol, 0.72 g) and NiCl2(dppe) (20 mol%, 0.3 mmol, 0.16 g) in 60 mL of anhydrous THF. The reaction was completed after refluxing for 3 hours and addition of ~7 equivalents of alkyl Grignard. The reaction mixture was cooled down to room temperature and vacuum filtered to remove insoluble matter. After evaporation of the solvent the solid was dissolved in 20 mL of dichloromethane and chromatographed (silica gel, dichloromethane:hexanes (35:15) as eluant). A shiny yellow solid (0.50 g, 55.6% yield) was isolated after evaporation of the solvent from combined fractions. Most of the bright yellow-orange crystals (0.47 g) were dissolved in several mL of chloroform with heating and the solution was applied to the top of a column (10 g of basic Al2O3). The column was eluted with 100 mL of dichloromethane, the yellow





S12

solution was collected (an orange band stayed at the top of the column), and the solvent was removed under reduced pressure. The material was recrystallized from 2-propanol (0.39 g, 83% recovery).

Method 2. 2,2'-Bithiophene (4) (4.4 mmol, 0.73 g) was placed into an oven-dried three-necked flask and dissolved in 22 mL of anhydrous THF. The resulting solution was cooled down to -60 ºC (acetone/dry ice bath) and n-butyllithium (2.5 M in hexanes, 8.8 mmol, 3.52 mL) was added dropwise (-60 to -40 ºC internal temperature). A thick white precipitate formed after stirring for several minutes. The cooling bath was removed and the mixture was allowed to warm up to 0 ºC over an hour and then reaction mixture was cooled down -30 ºC, and a solution of ZnCl2 (10.56 mmol, 1.40 g) in 10 mL of anhydrous THF was added to the thick suspension (-30 to 0 ºC internal temperature). The mixture was stirred for an hour, and the cloudy solution was added to a yellow solution of 2-iodo-5-n-decylpyridine (6) and Pd(PPh3)4 (1 mol% based on 6, 0.087 mmol, 0.10 g) in 10 mL of anhydrous THF. The reaction mixture became bright yellow and cloudy. After stirring for several hours the bright yellow mixture with yellow precipitate was transferred into a round bottom flask, and the solvents were removed by rotary evaporation. The residue was treated with 50 mL water, and the yellow solid was separated by vacuum filtration. The crude material (2.92 g, slightly wet) was dissolved in 100 mL of dichloromethane, gravity filtered while hot, concentrated down to ~50 mL, and the bright yellow solution was filtered through Al2O3 (basic, 60 g). The solvent was removed from combined fractions, and the residue was recrystallized from 2-propanol (450 mL). Purified product was isolated as yellow solid in 61.3% yield (1.60 g). This material was further purified for mobility measurements by column chromatography using a Biotage column and distilled dichloromethane as eluent (1.47 g, 94.8% recovery). The traces of impurities (MS (APCI): 765.0) were partially removed by this step. The solvent was removed from combined fractions; the solid was dissolved in distilled toluene (75 mL), the bright yellow solution was refluxed with 60 mL of charcoal for several hours, gravity filtered while hot, concentrated by boiling off the solvent, and cooled. The yellow solid was dissolved in dichloromethane (heating) and chromatographed (160 g of basic Al2O3, dichloromethane:hexanes (1:1) as eluent). The material was further purified by recrystallization from distilled dichloromethane. Slow cooling produced large bright yellow crystals suitable for single crystal X-ray diffraction. MS (APCI) calculated for C38H52N2S2 600.96; found 601.0. Method 3. 5,5'-Dibromo-2,2'-bithiophene (7) (1.82 mmol, 0.59 g) and 2-tri-n-butylstannyl-5-n-decylpyridine (8c) (2.2 eq., 4.0 mmol, 2.03 g) were mixed in an oven-dried three-necked flask equipped with magnetic stirbar, nitrogen inlet, bubbler and thermometer. Anhydrous DMF (10 mL) and Pd(PPh3)4 (1 mol%, 0.02 mmol, 0.023 g) were added under a nitrogen atmosphere and the bright yellow suspension was heated for 2 hours (135 ºC internal temperature). The cooled mixture with orange precipitate was transferred into a beaker with 75 mL of ice water and orange gummy solid formed. The cloudy yellow aqueous solution was decanted off and the remaining orange gummy solid was refluxed with 400 mL of ethanol, gravity filtered to remove an insoluble orange solid, and the bright yellow solution was concentrated down to 75 mL. The yellow-orange solid formed on cooling was separated by vacuum filtration (0.29 g, 26.5% yield). This solid was further purified for a mobility measurements by a series of several chromatographic columns and recrystallizations (silica gel, dichloromethane as eluent (1st column), crystallization (1-propanol) (0.17 g, 15.5% purified yield), column chromatography (20 g





S13

of basic Al2O3, dichloromethane:hexanes (1:1) as eluant (2nd column), and Biotage column (distilled dichloromethane as eluent), recrystallization (distilled 1-propanol). FT-IR (cm-1): 3075, 3017, 2917, 2849, 1699, 1651, 1560, 1472, 1181, 1072, 822, 799, 755, 720. 1H NMR (300 MHz, CDCl3): δ 8.40-8.37 (d, J = 1.6 Hz, 2H), 7.60-7.54 (d, J = 8.2 Hz, 2H), 7.52-7.47 (dd, J = 8.1 Hz, 2.2 Hz, 2H), 7.45-7.41 Hz (d, J = 3.9 Hz, 2H), 7.24-7.20 (d, J = 3.9 Hz, 2H), 2.62-2.57 (t, J = 7.6 Hz, 4H), 1.64-1.56 (m, 4H), 1.40-1.21 (m, 28H), 0.91-0.83 (t, J = 6.7 Hz, 6H, two CH3); 13C{1H} NMR (75 MHz, CDCl3): δ 150.0, 149.8, 144.0, 138.9, 136.7, 136.7, 124.8, 124.7, 118.3, 33.0, 32.0, 31.3, 29.74, 29.72, 29.6, 29.5, 29.3, 22.8, 14.3. Analysis calculated for C38H52N2S2: C, 75.95; H, 8.72; N, 4.66; S, 10.67. Found: C, 75.61; H, 8.46; N, 4.59; S, 10.72.

1.5. 5,5'-Bis-(5-n-dodecylpyridin-2-yl)-2,2'-bithiophene (2f)

An excess of alkyl Grignard was prepared from 1-bromododecane (12 mmol, 3.0 g) and Mg turnings

(14.4 mmol, 0.35 g, activated by heating with a crystal of iodine) in anhydrous Et2O (10 mL). This freshly prepared Grignard reagent was added in portions to the suspension of aryl dibromide (5) (1.5 mmol, 0.72 g) and NiCl2(dppe) (20 mol%, 0.3 mmol, 0.16 g) in 40 mL of anhydrous THF. The reaction was completed after refluxing for several hours and addition of 6 equivalents of alkyl Grignard. The reaction mixture was cooled down to room temperature, 10 mL of water was added and the reaction mixture was vacuum filtered. After evaporation of the organic solvent the brown solid was separated by vacuum filtration (1.85 g, wet). This crude material was dissolved in dichloromethane and chromatographed (silica gel, dichloromethane:hexanes (35:15)). The bright yellow crystals (0.44 g, 44.4% yield) were isolated after evaporation of the solvent from combined fractions. The purified material was dissolved in several mL of chloroform with heating, and the solution was applied to the top of a column (basic Al2O3, 15 g). The column was eluted with chloroform, the solvent was removed under reduced pressure, and the yellow solid was recrystallized from 50 mL of 1-propanol (0.32 g, 72.7% recovery). MS (APCI) calculated for C42H60N2S2 657.07; found 657.0. FT-IR (cm-1): 3074, 3054, 3040, 3001, 2950, 2916, 2848, 1591, 1552, 1533, 1469, 1392, 1289, 1204, 1135, 1072, 1023, 978, 873, 839, 798, 721, 633, 565. 1H NMR (CDCl3, 300 MHz): δ 8.40-8.38 (d, J = 1.6 Hz, 2H), 7.60-7.55 (d, J = 8.1 Hz, 2H), 7.52-7.47 (dd, J = 8.2 Hz, 2.1 Hz, 2H), 7.44-7.40 Hz (d, J = 3.9 Hz, 2H), 7.24-7.20 (d, J = 3.9 Hz, 2H), 2.64-2.57 (t, J = 7.6 Hz, 4H), 1.70-1.57 (m, 4H), 1.40-1.14 (m, 36H), 0.90-0.84 (t, J = 6.7 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 100 MHz): δ 149.9, 149.6, 143.9, 138.8, 136.5 (2C), 124.7, 124.6, 118.2, 32.8, 31.9, 31.1, 28.7 (3C), 29.6, 29.5, 29.4, 29.1, 22.7, 14.1. Analysis calculated for C42H60N2S2: C, 76.77; H, 9.20; N, 4.26; S, 9.76. Found: C, 76.53; H, 9.29; N, 4.17; S, 9.85.





S14

Figure S7. DSC thermogram of 5,5'-bis-(5-n-dodecylpyridin-2-yl)-2,2'-bithiophene (2f).

(a) (b) (c)

Figure S8. POM textures of 2f observed on the slide (image size is ca. 330 × 470 m): (a) 183.9 ºC, SmC; (b) and (c) 170.1 ºC, mosaic and “tile” textures of unidentified higher ordered phase S1/Cr1.

1.6. 5,5'-Bis-(5-n-tridecylpyridin-2-yl)-2,2'-bithiophene (2g)

An excess of alkyl Grignard was prepared from 1-bromotridecane (12.0 mmol, 3.16 g) and Mg

turnings (14.4 mmol, 0.35 g, activated by heating with a crystal of iodine) in anhydrous Et2O (10 mL). This freshly prepared Grignard reagent was added in portions to the suspension of aryl dibromide (5) (1.5 mmol, 0.72 g) and NiCl2(dppe) (20 mol%, 0.3 mmol, 0.16 g) in 40 mL of anhydrous THF. The





S15

reaction was completed after refluxing for several hours and addition of 4 equivalents of alkyl Grignard. The reaction mixture was cooled down to room temperature and 20 mL of water was added and the precipitated material was vacuum filtered. The organic solvents were evaporated under reduced pressure, and the residue was combined with the solid filtered from reaction mixture. The combined solids were dissolved in chloroform, washed with 20 mL of water, dried with brine and then over MgSO4. The solution was concentrated under reduced pressure and chromatographed (silica gel, dichloromethane:hexanes (35:15) as eluent). The bright yellow crystals (0.6 g, 56.6% yield) were isolated after evaporation of the solvent from combined fractions. The material was further purified by column chromatography (silica gel, dichloromethane:hexanes (2:1)), the yellow solid obtained after evaporation of solvent from combined fractions was dissolved in 100 mL of boiling 2-propanol, gravity filtered while hot to remove small amount of insoluble matter, and the solution was concentrated down to ~60-65 mL when crystallization started. Vacuum filtration gave bright yellow solid (0.25 g, 41.7% recovery). MS (APCI) calculated for C44H64N2S2 685.12; found 685.1. FT-IR (cm-1): 3074, 3048, 3033, 3011, 2956, 2916, 2848, 1595, 1562, 1534, 1471, 1395, 1293, 1134, 1027, 927, 875, 842, 804, 757, 721. 1H NMR (CDCl3, 300 MHz): δ 8.40-8.38 (d, J = 1.4 Hz, 2H), 7.60-7.53 (d, J = 8.1 Hz, 2H), 7.52-7.47 (dd, J = 8.1 Hz, 1.9 Hz, 2H), 7.45-7.43 Hz (d, J =3.9 Hz, 2H), 7.25-7.20 (d, J =3.9 Hz, 2H), 2.62-2.54 (t, J = 7.6 Hz, 4H), 1.68-1.57 (m, 4H), 1.39-1.13 (m, 40H), 0.90-0.83 (t, J = 6.6 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 100 MHz): δ 149.9, 149.6, 143.8, 138.8, 136.6, 136.5, 124.7, 124.6, 118.2, 32.8, 31.9, 31.1, 29.7, 29.6, 29.4, 29.4, 29.1, 22.7, 14.1 (three alkyl carbon signals are missing due to overlap). Analysis calculated for C44H64N2S2: C, 77.14; H, 9.42; N, 4.09; S, 9.36. Found: C, 76.98; H, 9.38; N, 4.02; S, 9.38.





S16

Figure S9. DSC thermogram of 5,5'-bis-(5-n-tridecylpyridin-2-yl)-2,2'-bithiophene (2g).

(a) (b)

Figure S10. POM textures observed for 2g on the freely suspended film (image size is ca. 330 × 470 m): (a) 173.8 ºC, growth of unidentified S1/Cr1 phase from preceding SmC phase; (b) 161.4 ºC, mosaic texture of unidentified S1/Cr1 phase.

2. Preparation of 5,5'-bis-(2-n-alkylpyridin-5-yl)-2,2'-bithiophenes 3

2.1. 5,5'-Bis-(2-n-pentylpyridin-5-yl)-2,2'-bithiophene (3a)

An oven-dried flask was charged with 5,5'-dibromo-2,2'-bithiophene (7) (2.0 mmol, 0.648 g) and 2-n-

pentyl-5-(tri-n-butylstannyl)-pyridine (12a) (6.0 mmol, 2.63 g). Pd(PPh3)4 (1 mol% based on 7, 0.02 mmol, 0.023 g) and anhydrous DMF (10 mL) were added under nitrogen atmosphere, and the reaction mixture was heated (140-145 ºC internal temperature) for 2 hours. The bright yellow reaction mixture turned orange and then brown. The mixture was cooled to room temperature and poured into 30 mL of ice water. The brown sticky precipitate was separated by vacuum filtration, washed with EtOH, dried and then dissolved in 30 mL of chloroform (heating). The brown cloudy solution was chromatographed (50 g of silica gel, dichloromethane, then dichloromethane:ethyl acetate (25:1, 10:1, 1:1) and the product was eluted with chloroform:ethyl acetate (4:1)). The bright yellow solution was treated with 25 mL of 1-propanol, the solution was concentrated down to ~20 mL and cooled. The bright yellow powder was isolated by vacuum filtration and dried (0.37 g, 40.2% yield). Additional amount of product was isolated as 2nd crop of crystals from mother liquor (total yield 0.41 g, 44.6%). The material was further purified by filtration of solution in 10 mL of chloroform through Al2O3 column (10 g, neutral, chloroform as eluent). The combined fractions were treated with 10 mL of 1-propanol, the resulting solution was concentrated, cooled and bright yellow solid was separated by vacuum filtration (0.22 g, 53.7% recovery). MS (APCI) calculated for C28H32N2S2 460.70, found 461.5. 1H NMR (CDCl3, 400





S17

MHz): δ 8.80-8.77 (dd, J = 2.4 Hz, 0.52 Hz, 2H), 7.79-7.74 (dd, J = 8.1 Hz, 2.45 Hz, 2H), 7.26-7.23 (d, J = 3.8 Hz, 2H), 7.21-7.18 (d, J = 3.6 Hz, 2H), 7.18-7.15 (d, J = 8.1 Hz, 2H), 2.83-2.78 (t, J = 7.8 Hz, 4H), 1.80-1.70 (m, 4H), 1.41-1.30 (m, 8H), 0.95-0.88 (t, J = 7.0 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 100 MHz): δ 161.83 (quaternary C), 146.09 (CH), 139.73 (quaternary C), 137.02 (quaternary C), 133.04 (CH), 127.32 (quaternary C), 124.80 (CH), 124.40 (CH), 122.69 (CH), 38.13, 31.60, 29.56, 22.56, 14.04. Analysis calculated for C28H32N2S2: C, 73.00; H, 7.00; N, 6.08; S, 13.92. Found: C, 73.20; H, 7.39; N, 6.01; S, 13.85.

Figure S11. DSC thermogram of 5,5'-bis-(2-n-pentylpyridin-5-yl)-2,2'-bithiophene (3a).

2.2. 5,5'-Bis-(2-n-hexylpyridin-5-yl)-2,2'-bithiophene (3b)

An oven-dried three-necked flask was charged with 5,5'-bis-(2-bromopyridin-5-yl)-2,2'-bithiophene

(10) (0.63 mmol, 0.30 g), anhydrous THF (10 mL) and NiCl2(dppe) (10 mol%, 0.063 mmol, 0.033 g). Freshly prepared n-hexylmagnesium bromide obtained by the standard method from 1-bromohexane (4 eq., 2.5 mmol, 0.41 g), Mg turnings (3.0 mmol, 0.073g) and anhydrous THF (5 mL) was added in portions to the suspension of aryl dibromide 10 which turned dark green and then dark brown after





S18

addition of Grignard. After two hours of stirring the mixture was vacuum filtered; the filtrate was poured into 100 mL of water, and the brown precipitate was vacuum filtered. The desired product was isolated after column chromatography (silica gel, dichloromethane and then Et2O as eluent). The yellow solid was recrystallized from hexanes (0.06 g, 20% yield). 1H NMR (CDCl3, 300 MHz): δ 8.79-8.75 (d, J = 1.9 Hz, 2H), 7.82-7.75 (dd, J = 8.1 Hz, 2.3 Hz, 2H), 7.32-7.25 (d, overlaps with residual chloroform signal, 2H), 7.22-7.17 (m, 4H, bithiophene protons), 2.86-2.75 (t, J = 7.8 Hz, 4H), 1.78-1.69 (m, 4H), 1.48-1.25 (m, 12H), 0.92-0.86 (t, J = 7.0 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 75 MHz): δ 161.9 (quaternary C), 146.1 (CH), 139.8 (quaternary C), 137.2 (quaternary C), 133.3 (CH), 127.5 (quaternary C), 125.0 (CH), 124.6 (CH), 122.9 (CH), 38.2 (CH2), 31.9 (CH2), 30.0 (CH2), 29.2 (CH2), 22.7 (CH2), 14.3 (CH3). Analysis calculated for C30H36N2S2: C, 73.72; H, 7.42; N, 5.73; S, 13.12. Found: C, 73.74; H, 7.12; N, 5.48; S, 13.06.

Figure S12. DSC thermogram of 5,5'-bis-(2-n-hexylpyridin-5-yl)-2,2'-bithiophene (3b) on 2nd heating-cooling cycle.





S19

(a) (b)

(c) (d)

(e) (f)

(g) (h)





S20

Figure S13. POM textures of 3b (slide, image size is ca. 330 × 470 m, the same regions are shown for a-d and e-f photographs): (a) 230.5 ºC, fan and homeotropic (black areas) textures of SmA; (b) 182.7 ºC, broken fan texture and schlieren texture of SmC, which formed from the homeotropic texture of SmA; (c) 178.8 ºC, fan and ill-defined schlieren textures of SmI phase; (d), 178.4 ºC, fan texture and schlieren-mosaic textures of SmF phase; (e) 148.8 ºC, SmF before transition to S1/Cr1 phase; (f) 145.8 ºC, unidentified S1/Cr1 phase; (g) 144.3 ºC, unidentified S1/Cr1 phase; (h) 84.0 ºC, unidentified S2/Cr2 phase.

2.3. 5,5'-Bis-(2-n-heptylpyridin-5-yl)-2,2'-bithiophene (3c)

Material (3c) was prepared in the same manner as described for 3a from 5,5'-dibromo-2,2'-bithiophene (7) (2.0 mmol, 0.648 g), 2-n-heptyl-5-(tri-n-butylstannyl)-pyridine (12b) (2.5 eq., 5.0 mmol, 2.34 g), Pd(PPh3)4 (1 mol% based on 7, 0.02 mmol, 0.023 g) and anhydrous DMF (10 mL). The bright yellow reaction mixture was heated (140-150 ºC) for 45 minutes, the dark brown mixture with orange precipitate on the sides was cooled to room temperature, and 15 mL of water was added. The precipitate was separated by vacuum filtration and rinsed with hexanes. The crude material dissolved in chloroform was chromatographed (40 g of silica gel, dichloromethane as 1st eluent, then dichloromethane:ethyl acetate (25:1, then 10:1 to elute the product). The combined fractions were concentrated and the bright yellow solution was chromatographed (basic Al2O3 (50 g), chloroform as eluent). The product obtained after removal of the solvent was recrystallized from 1-propanol (0.35 g, 34% purified yield). 1H NMR (CDCl3, 400 MHz): δ 8.80-8.76 (d, J = 2.3 Hz, 2H), 7.78-7.74 (dd, J = 8.1 Hz, 2.4 Hz, 2H), 7.26-7.24 (d, J = 3.8 Hz, 2H), 7.22-7.18 (d, J = 3.8 Hz, 2H), 7.18-7.14 (d, J = 8.1 Hz, 2H), 2.84-2.77 (t, J = 7.8 Hz, 4H), 1.79-1.67 (m, 4H), 1.43-1.23 (m, 16H), 0.92-0.85 (t, J = 6.8 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 100 MHz): δ 161.8 (quaternary C), 146.1 (CH), 139.7 (quaternary C), 137.0 (quaternary C), 133.1 (CH), 127.3 (quaternary C), 124.8 (CH), 124.4 (CH), 122.7 (CH), 38.2 (CH2), 31.8 (CH2), 29.9 (CH2), 29.4 (CH2), 29.2 (CH2), 22.7 (CH2), 14.1 (CH3). Analysis calculated for C32H40N2S2: C, 74.37; H, 7.80; N, 5.42; S, 12.41. Found: C, 74.20; H, 7.61; N, 5.34; S 12.23.





S21

Figure S14. DSC thermogram of 5,5'-bis-(2-n-heptylpyridin-5-yl)-2,2'-bithiophene (3c).





S22

(a) (b)

(c) (d)

(e) (f)

Figure S15. POM textures of 5,5'-bis-(2-n-heptylpyridin-5-yl)-2,2'-bithiophene (3c) (slide, image size is ca. 330 × 470 m): (a) 232.4 ºC, isolation of SmA phase from isotropic liquid; (b) 207.6 ºC, SmA phase; (c) 184.9 ºC, broken fan texture of SmC phase; (d) 171.3 ºC, fan texture of SmF phase with ‘L’-shaped patterns; (e) 103.9 ºC, paramorphotic texture of unidentified S1/Cr1; (f) 93.0 ºC, Cr2 (the same area as shown in (e)).





S23

2.4. 5,5'-Bis-(2-n-octylpyridin-5-yl)-2,2'-bithiophene (3d)

The title compound was prepared in a similar manner described for 3a from 5,5'-dibromo-2,2'-

bithiophene (7) (2.0 mmol, 0.65 g), 2-n-octyl-5-(tri-n-butylstannyl)-pyridine (12c) (4.2 mmol, 2.02 g), Pd(PPh3)4 (1 mol % based on 7, 0.02 mmol, 0.023 g) and 6 mL of DMF. The bright yellow reaction mixture became brown in color after heating for 1 hour (145-153 ºC internal temperature). The reaction mixture was cooled to room temperature and the contents of the flask were poured into a beaker with 50 mL of ice water. The precipitate was vacuum filtered, washed with ethanol (20 mL) and hexanes (30 mL) and dried under vacuum. The crude material isolated as dark yellow solid (0.70 g, 64.2% crude yield) was dissolved in dichloromethane:chloroform (~30 mL, heating), and the brown solution was applied to a column (neutral Al2O3, 40 g, dichloromethane as eluent). The combined yellow fractions were treated with 25 mL of 1-propanol and concentrated down to ~20-25 mL. The title compound was isolated as bright yellow solid in 47.7% yield (0.52 g). The material contained minor impurity after crystallization and was again purified by column chromatography (40 g of silica gel, dichloromethane, then dichloromethane:ethyl acetate (50:1) as eluents). First several slightly contaminated fractions were concentrated down to ~10 mL, treated with 10 mL of chloroform and left for slow evaporation for crystal growth for X-ray diffraction experiment. The rest of the fractions were combined, concentrated (down to ~10 mL), cooled and bright yellow shiny solid was isolated (0.24 g, 46.1% recovery). FT-IR (cm-1): 3092, 3070, 3034, 3017, 2957, 2916, 2848, 1595, 1469, 1425, 1386, 1204, 1180, 1146, 1074, 1026, 968, 910, 862, 834, 795, 753, 719, 638. 1H NMR (CDCl3, 400 MHz): δ 8.80-8.76 (dd, J = 2.3 Hz, 0.5 Hz, 2H), 7.79-7.74 (dd, J = 8.1 Hz, 2.4 Hz, 2H), 7.26-7.23 (d, J = 3.8 Hz, 2H), 7.21-7.18 (d, J = 3.8 Hz, 2H), 7.18-7.14 (d, J = 8.1 Hz, 2H), 2.85-2.77 (t, J = 7.8 Hz, 4H), 1.79-1.69 (m, 4H), 1.43-1.22 (m, 20H), 0.92-0.85 (t, J = 6.9 Hz, 6H, 2CH3); 13C{1H} NMR (CDCl3, 100 MHz): δ 161.9 (quaternary C), 146.1 (CH), 139.7 (quaternary C), 137.0 (quaternary C), 133.1 (CH), 127.3 (quaternary C), 124.8 (CH), 124.4 (CH), 122.7 (CH), 38.2 (CH2), 31.9 (CH2), 29.9 (CH2), 29.5 (CH2), 29.4 (CH2), 29.3 (CH2), 22.7 (CH2), 14.1 (CH3). Analysis calculated for C34H44N2S2: C, 74.95; H, 8.14; N, 5.14; S, 11.77. Found: C, 74.65; H, 8.12; N, 5.09; S 12.08.





S24

Figure S16. DSC thermogram of 5,5'-bis-(2-n-octylpyridin-5-yl)-2,2'-bithiophene (3d).





S25

(a) (b)

(c) (d)

(e) (f)

Figure S17. POM textures of 5,5'-bis-(2-n-octylpyridin-5-yl)-2,2'-bithiophene (3d) (slide, image size is ca. 330 × 470 m): (a) 225.1 ºC, fan texture and homeotropic texture (black area) of SmA; (b) 209.5 ºC, fan texture and schlieren texture of SmC; (c) 172.9 ºC, broken fan texture and ill-defined schlieren texture of SmI; (d) 170.7 ºC, geometrically defined fan texture and schlieren texture SmF (the latter formed from the ill-defined schlieren texture of SmI); (e) 129.7 ºC, transition from SmF to unidentified S1/Cr1 phase; (f) 67.7 ºC, Cr phase with well-defined cracks (slide) (images shown in (b)-(e) are for the same area).





S26

2.5. 5,5'-Bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e)

An oven-dried flask was charged with 5,5'-dibromo-2,2'-bithiophene (7) (0.5 mmol, 0.16 g) and 2-n-nonyl-5-(tri-n-butylstannyl)-pyridine (12d) (1.05 mmol, 0.52 g), Pd(PPh3)4 (1 mol%, 0.005 mmol, 0.011 g) and anhydrous DMF (5 mL) were added under a nitrogen atmosphere and the reaction mixture was heated (130-140 ºC). The light yellow reaction mixture turned bright yellow and then orange, and then after 4 hours of heating it became dark. The reaction mixture was poured into 100 mL of ice water, and the yellow-orange precipitate was vacuum filtered, and rinsed with ~10 mL of EtOH. Crude material (0.20 g, 71% yield) was chromatographed (20 g of silica gel, dichloromethane, then dichloromethane:ethyl acetate (30:1, then 20:1)). The yellow powder isolated after evaporation of the solvents from combined fractions was heated in 25 mL of 2-propanol, gravity filtered while hot to remove traces of insoluble orange powder, and the bright yellow solution was slowly cooled to room temperature to give bright yellow shiny crystals (0.12 g, 42.9% yield). The purified material (0.11 g) was dissolved in dichloromethane on heating, and bright yellow fluorescent solution was applied to the top of a column (basic Al2O3, 15 g). The column was eluted with dichloromethane (50 mL), followed by dichloromethane:ethyl acetate (25:1). The product was recrystallized from 1-propanol to give bright yellow shiny material (0.055 g, 50% recovery). MS (APCI) calculated for C36H48N2S2 572.91; found 573.1. FT-IR (cm-1): 3092, 3071, 3034, 2954, 2916, 2849, 1595, 1552, 1527, 1487, 1470, 1384, 1252, 1180, 1076, 1027, 955, 912, 870, 839, 795, 717, 682, 639. 1H NMR (CDCl3, 300 MHz): δ 8.80-8.74 (d, J = 2.3 Hz, 2H), 7.80-7.74 (dd, J = 8.1 Hz, 2.4 Hz, 2H), 7.29-7.26 (d, J = 3.8 Hz, 2H, overlaps with residual chloroform signal), 7.24-7.20 (d, J = 3.8 Hz, 2H), 7.20-7.15 (d, J = 8.2 Hz, 2H), 2.83-2.73 (t, J = 7.8 Hz, 4H), 1.80-1.68 (m, 4H), 1.40-1.20 (m, 24H), 0.92-0.82 (t, J = 6.7 Hz, 6H); 13C{1H} NMR (CDCl3, 75 MHz): δ 162.0 (quaternary C), 146.2 (CH), 139.9 (quaternary C), 137.2 (quaternary C), 133.2 (CH), 127.5 (quaternary C), 124.9 (CH), 124.6 (CH), 122.9 (CH), 38.3 (CH2), 32.0 (CH2), 30.0 (CH2), 29.7 (CH2), 29.6 (CH2), 29.5 (CH2), 29.6 (CH2), 22.9 (CH2), 14.3 (CH3). Analysis calculated for C36H48N2S2: C, 75.47; H, 8.44; N, 4.89; S, 11.19. Found: C, 75.38; H, 8.56; N, 4.92; S, 11.14.





S27

Figure S18. DSC thermogram of 5,5'-bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e).

(a) (b) (c)

Figure S19. (top) DSC thermogram of 5,5'-bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e); (bottom): (a) 215.8 ºC, focal conic texture of SmA phase; (b) 189.4 ºC, broken focal conic texture of SmC phase; (c) 181.0 ºC, schlieren texture of SmC.





S28

(a)

(b)

Figure S20. The diffraction patterns of 5,5'-bis-(2-n-nonylpyridin-5-yl)-2,2'-bithiophene (3e): (a) 88.7 °C; Cr2 phase; (b) 28.0 °C, Cr phase.

2.6. 5,5'-Bis-(2-n-decylpyridin-5-yl)-2,2'-bithiophene (3f)

Method 1. An oven-dried flask was charged with 2,2'-bithiophene (4) (1.0 mmol, 0.166 g) and

anhydrous THF (10 mL) under nitrogen atmosphere. The flask was cooled -20 ºC (acetone w/ some dry





S29

ice), and n-butyllithium (2.5 M in hexanes, 2.0 mmol, 0.8 mL) was added dropwise. The reaction mixture with precipitate was stirred for an hour at -5 ºC, cooled down -20 ºC, and ZnCl2 (2.4 mmol, 0.33 g) in 3 mL of anhydrous THF was added dropwise to the slightly green reaction mixture. After completion of addition of ZnCl2 solution the cooling bath was removed, and the reaction mixture was warmed to room temperature. Some of the precipitate present dissolved while warming. This freshly prepared arylzinc chloride was transferred into syringe, 2-n-decyl-5-iodopyridine (11) (2.0 mmol, 0.69 g) and Pd(PPh3)4 (1 mol% based on 11, 0.02 mmol, 0.023 g) were added to the same flask, and arylzinc chloride was added dropwise. After several minutes of stirring the desired product was detected by TLC. The yellow reaction mixture (no visible fluorescence) was stirred for 18 hours with mild heating (no reflux), cooled down, and the dark yellow solution was poured into 100 mL of water. Dichloromethane (50 mL) was added, and the mixture was vacuum filtered to separate some insoluble matter (residual catalyst). The organic phase was separated; the aqueous phase was extracted with dichloromethane (310 mL). The organic phases were combined (yellow bright fluorescent solution), washed with brine, and then dried over MgSO4. The solvent was removed by rotary evaporation, and the product was purified by column chromatography (30 g of silica gel, 50:1 ratio, dichloromethane as eluant first, then dichloromethane:ethyl acetate (5:1) to elute the product). The desired material was isolated as a bright yellow solid in 25% yield (0.15 g) after recrystallization from ~25 mL of 2-propanol.

Method 2. An oven-dried flask was charged with 5,5'-dibromo-2,2'-bithiophene (7) (1.0 mmol, 0.32 g) and 2-n-decyl-5-(tri-n-butylstannyl)-pyridine (12d) (2.1 mmol, 1.07 g). Catalyst Pd(PPh3)4 (5 mol% based on 7, 0.05 mmol, 0.058 g) and anhydrous DMF were added under nitrogen atmosphere and the reaction mixture was heated (130-140 ºC). The bright yellow reaction mixture turned orange with some orange-red precipitate on the sides of the flask after 4 hours of heating, and then after heating for an additional hour the mixture became dark. The cooled suspension was applied to the top of the basic aluminum oxide bath (~10 cm, 60 g), and the product was eluted with dichloromethane, then dichloromethane:ethyl acetate (30:1), then dichloromethane:ethyl acetate (3:1). First two fractions containing product were combined, the solvent was removed by rotary evaporation, and the residue was treated with 75 mL of water. The yellow solid was separated by vacuum filtration, washed with 10-15 mL of ethanol, and the recrystallized from 50 mL of 2-propanol to give purified material (yellow powder, 0.33 g, 55% yield). The NMR and DSC analyses of material 3f synthesized by the two methods matched. MS (APCI) calculated for C38H52N2S2 600.96; found 600.5. FT-IR (cm-1): 3092, 3071, 3034, 3017, 2956, 2916, 2849, 1595, 1550, 1528, 1487, 1470, 1447, 1384, 1252, 1179, 1074, 1027, 912, 871, 851, 829, 796, 717, 682, 638. 1H NMR (300 MHz, CDCl3): δ 8.82-8.75 (d, J = 2.3 Hz, 2H), 7.79-7.72 (dd, J = 8.1 Hz, 2.4 Hz, 2H), 7.26-7.23 (d, J = 3.8 Hz, 2H), 7.22-7.19 (d, J = 3.8 Hz, 2H), 7.19-7.15 (d, J = 8.2 Hz, 2H), 2.85-2.77 (t, J = 7.3 Hz, 2H), 1.82-1.67 (m, 2H), 1.43-1.22 (m, 28H), 0.91-0.82 (t, J = 6.7 Hz, 6H, two CH3); 13C{1H} NMR (75 MHz, CDCl3): δ 162.0 (quaternary C), 146.2 (CH), 139.9 (quaternary C), 137.2 (quaternary C), 133.3 (CH), 127.5 (quaternary C), 125.0 (CH), 124.6 (CH), 122.9 (CH), 38.3 (CH2), 32.1 (CH2), 30.0 (CH2), 29.8 (CH2), 29.7 (CH2), 29.7 (CH2), 29.6 (CH2), 29.5 (CH2), 22.9 (CH2), 14.3 (CH3). Analysis calculated for C38H52N2S2: C, 75.95; H, 8.72; N, 4.66; S, 10.67. Found: C, 76.02; H, 8.98; N, 4.34; S, 10.96.





S30

2.7. 5,5'-Bis-(2-n-tridecylpyridin-5-yl)-2,2'-bithiophene (3g)

Method 1. An oven-dried flask was charged with 5,5'-dibromo-2,2'-bithiophene (7) (2 mmol, 0.64 g) and 2-n-tridecyl-5-(tri-n-butylstannyl)-pyridine (12f) (4.2 mmol, 2.31 g), Pd(PPh3)4 (1 mol%, 0.02 mmol, 0.023 g) and anhydrous DMF (10 mL), and the reaction mixture was heated for four hours (130-140 ºC). The initially light yellow reaction mixture turned bright yellow and then red with precipitate formed on the side of the flask. The reaction mixture was poured into 100 mL of ice water, the yellow precipitate was vacuum filtered, and rinsed with ~10 mL of ethanol. Crude material (1.60 g, 117% crude yield, wet) was chromatographed (75 g of silica gel, dichloromethane (200 mL), then dichloromethane:ethyl acetate (20:1) (250 mL), then chloroform:ethyl acetate (10:1)). (Note: the compound crystallized on silica gel when eluted with dichloromethane; warm solvents were used to elute the material). The yellow powder (0.86 g, 62.3% yield) isolated after evaporation of the solvents from combined fractions was recrystallized from ~15 mL of 1,4-dioxane to give 0.70 g of yellow-orange powder (0.70 g, 81.4% recovery). FT-IR (cm-1): 3092, 2072, 3037, 3000, 2954, 2916, 2849, 1595, 1550, 1528, 1471, 1252, 1178, 1027, 913, 834, 796, 717, 638. 1H NMR (CDCl3, 300 MHz): δ 8.80-8.73 (d, J = 1.9 Hz, 2H), 7.80-7.72 (dd, J = 8.1 Hz, 2.4 Hz, 2H), 7.28-7.21 (d, signal overlaps with residual chloroform, 2H), 7.22-7.18 (d, J = 3.8 Hz, 2H), 7.18-7.12 (d, J = 8.2 Hz, 2H), 2.82-2.71 (t, J = 7.8 Hz, 4H), 1.77-1.62 (m, 4H), 1.40-1.13 (m, 40H), 0.92-0.82 (t, J = 6.7 Hz, 6H, two CH3); 13C{1H} NMR (CDCl3, 75 MHz): δ 162.0 (quaternary C), 146.2 (CH), 139.9 (quaternary C), 137.2 (quaternary C), 133.2 (CH), 127.5 (quaternary C), 125.0 (CH), 124.6 (CH), 122.9 (CH), 38.3 (CH2), 32.1 (CH2), 31.0 (CH2), 29.8 (CH2), 29.7 (CH2), 29.7 (CH2), 29.5 (CH2), 22.9 (CH2), 14.3 (CH3) (five alkyl carbon signals are missing due to overlap). Analysis calculated for C44H64N2S2: C, 77.14; H, 9.42; N, 4.09; S, 9.36. Found: C, 76.77; H, 9.53; N, 3.93; S, 9.57. Method 2. Liquid crystalline material 3g was prepared by means of the method described for compound 3h using aryl bromide 16, NiCl2(dppe) (5 mol%, 4 mg), 10 mL of anhydrous THF and alkyl Grignard prepared in excess from 1-bromotridecane (2.4 mmol, 0.63 g), Mg turnings (2.88 mmol, 0.070 g) and 5 mL of anhydrous THF. After completion of the reaction the mixture was poured into cold water, Dichloromethane was added and the resulting mixture was vacuum filtered to remove insoluble matter. The organic phase was separated, and the aqueous phase was extracted with Dichloromethane (210 mL). The organic phases were combined, dried over MgSO4, and the solvent was removed by rotary evaporation. The crude material was purified by column chromatography (5 g of silica gel, dichloromethane first, then dichloromethane:ethyl acetate (50:1, then 25:1 as eluents)). After the evaporation of the solvent from combined fractions the product was recrystallized from 10-15 mL of 2-propanol. The pure material was isolated as a bright yellow solid in 25.5% yield (27 mg).





S31

Figure S21. DSC thermogram of 5,5'-bis-(2-n-tridecylpyridin-5-yl)-2,2'-bithiophene (3g).





S32

(a) (b)

(c) (d)

(e) (f)

Figure S22. Textures of 3g observed by polarized optical microscopy on slide (image size is ca. 330 × 470 m): (a) 172.4 ºC, fan texture of SmC phase; (b) 152.6 ºC, broken fan texture of SmI phase; (c) 159.9 ºC, fan texture and schlieren texture of SmC phase; (d) 153.5 ºC, ill-defined schlieren texture and broken fan texture of SmI (the same area as in (c)); (e) 129.3 ºC, fan texture of SmF texture with characteristic ‘L’-shaped patterns; (f) 109.1 ºC, unidentified S1/Cr1 phase.





S33

2.8. 5-(2-n-Heptylpyridin-5-yl)-5'-(2-n-tridecylpyridin-2-yl)-2,2'-bithiophene (3h)

Alkyl Grignard was prepared in excess from 1-bromoheptane (3.4 mmol, 0.61 g), Mg turnings (4.1 mmol, 0.10 g) and 17 mL of anhydrous THF. This freshly prepared Grignard solution was added to the flask charged with 2-bromo-5-arylpyridine 16 (0.172 mmol, 0.100 g), NiCl2(dppe) (5 mol%, 0.086 mmol, 5 mg) and 10 mL of anhydrous THF until starting material was consumed (3 mL of Grignard was used, the mixture was refluxed). During addition of Grignard the reaction mixture became brown. After reaction completion (analyzed by TLC, dichloromethane:ethyl acetate (10:1) as eluent) several drops of water were added to the reaction mixture and the organic solvents were removed by rotary evaporation. The resulting brown solid was dissolved in several mL of dichloromethane and the solution was applied to the top of a column (basic Al2O3). The column was eluted with dichloromethane:hexanes (1:1), then chloform:ethyl acetate (5:1, and then 1:1). The solvents were removed from combined fractions by rotary evaporation, and the yellow solid was recrystallized from ~30 mL of 2-propanol. The purified material was isolated in 43.1% yield (45 mg). 1H NMR (300 MHz, CDCl3): δ 8.80-8.75 (d, J = 2.4 Hz, 2H), 7.80-7.74 (dd, J = 8.1 Hz, 2.4 Hz, 2H), 7.28-7.26 (d, J = 3.9 Hz, 2H, overlaps with residual CHCl3 signal), 7.24-7.20 (d, J = 3.8 Hz, 2H), 7.20-7.15 (d, J = 8.1 Hz, 2H), 2.82-2.75 (t, J = 7.8 Hz, 4H), 1.80-1.69 (m, 4H), 1.43-1.22 (m, 28H), 0.91-0.80 (m, 6H); 13C{1H} NMR (75 MHz, CDCl3): δ 162.0 (quaternary C), 146.2 (CH), 139.9 (quaternary C), 137.2 (quaternary C), 133.2 (CH), 127.5 (quaternary C), 125.0 (CH), 124.6 (CH), 122.9 (CH), 32.1 (CH2), 31.9 (CH2), 30.0 (CH2), 29.8 (several CH2), 29.7 (CH2), 29.7 (CH2), 29.5 (several CH2), 29.3 (CH2), 22.9 (CH2), 22.8 (CH2), 14.3 (CH3), 14.3 (CH3). Analysis calculated for C38H52N2S2: C, 75.95; H, 8.72; N, 4.66; S, 10.67. Found: C, 75.60; H, 9.03; N, 4.47; S, 10.42.





S34

Figure S23. DSC thermogram of 5-(2-n-heptylpyridin-5-yl)-5'-(2-n-tridecylpyridin-2-yl)-2,2'-bithiophene (3h).

(a) (b)





S35

(c) (d)

(e) (f)

Figure S24. Textures of 3h observed by polarized optical microscopy on slide (image size is ca. 330 × 470 m): (a) 214.5 ºC, isolation of SmA phase from the isotropic liquid; (b) 199.8 ºC, fan texture of the SmA phase; (c) 199.0 ºC, broken fan texture of SmC phase; (d) 128.3 ºC, fan texture of SmF phase; (e) 98.8 ºC, unidentified S1 phase; (f) 76.0 ºC, unidentified S1 phase.

3. 5,5'-Bis-(5-bromopyridin-2-yl)-2,2'-bithiophene (5)

2,2'-Bithiophene (4) (0.02 mol, 3.32 g) was placed into an oven-dried three-necked flask and dissolved in 80 mL of anhydrous THF. The resulting solution was cooled down to -10 ºC (ethylene glycol/dry ice bath) and n-butyllithium (2.5 M in hexanes, 0.04 mol, 16 mL) was added dropwise. During dropwise addition of n-butyllithium the solution turned yellow (2 mL of n-butyllithium added), then precipitation was observed (6 mL of n-butyllithium added), and finally a white precipitate formed (8 mL of n-butyllithium added). After completion of addition the mixture was stirred for 2 hours (-5 to +5 ºC) with no changes observed. The reaction mixture was cooled down to –10 ºC, and a freshly prepared solution of ZnCl2 (0.048 mol, 6.54 g) in 40 mL of anhydrous THF was added dropwise. The temperature increased up to 0 ºC during ZnCl2 solution addition and the precipitate dissolved. The reaction mixture





S36

was allowed to warm up to room temperature and stirred for an additional 2 hours. This slightly cloudy solution was transferred via syringe into additional funnel and added dropwise to a flask charged with 2,5-dibromopyridine (0.0364 mol, 8.61 g), Pd(PPh3)4 (0.5 mol%, 0.182 mmol, 0.21 g) and anhydrous THF (30 mL). During addition the temperature increased up to 28 ºC, and then up to 33 ºC. After half an hour of stirring the reaction mixture looked like carrot juice and contained an orange precipitate. The mixture was stirred for 15 hours at room temperature and vacuum filtered to give orange solid, which was washed with dichloromethane and dried. The crude material isolated as bright orange powder in 79.1% yield (6.88 g) was recrystallized from DMF (310 mL) to provide 3.6 g of the product (42% yield) (toluene can be used as alternative to DMF). MS (APCI) calculated for C18H10Br2N2S2 478.22; found 476.6, 478.6, 480.6 (relative intensity ~1:2:1). DSC analysis (ºC): 269.8, 282.5 (on heating); 255.7, 280.5 (on cooling). POM analysis: Cr 256.6 N 276.6 Iso. 1H NMR (300 MHz, CDCl3): δ 7.26-7.24 (d, J = 3.9 Hz, 2H), 7.50-7.47 (d, J = 3.9 Hz, 2H), 7.57-7.52 (dd, J = 8.5 Hz, 0.64 Hz, 2H), 7.83-7.78 (dd, J = 8.5 Hz, 2.3 Hz, 2H), 8.61-8.58 (dd, J = 2.3 Hz, 0.50 Hz, 2H); 13C{1H} NMR (100 MHz, 1,1,2,2-tetrachloroethane-d2:CDCl3 (4:1 ratio)): δ 151.90 (CH), 151.80 (quaternary C), 144.08 (quaternary C), 140.82 (quaternary C), 140.60 (CH), 127.36 (CH), 126.60 (CH), 121.08 (CH), 119.92 (C-Br). Analysis calculated for C18H10Br2N2S2: C, 45.21; H, 2.11; N, 5.86; S, 13.41. Found: C, 44.70; H, 2.28; N, 5.75; S, 13.07.

4. 5,5'-Bis-(2-bromopyridin-5-yl)-2,2'-bithiophene (10)

A solution of 2,2'-bithiophene (4) (18.0 mmol, 3.0 g) in 50 mL of anhydrous THF was cooled in down to –10 ºC and treated with n-butyllithium (2.5 M in hexanes, 36.0 mmol, 14.4 mL) (the reaction temperature during addition of n-butyllithium was -10 to -2 ºC). White precipitate formed during addition of the second half of n-butyllithium. After stirring for an hour solution of ZnCl2 (21.6 mmol, 2.95 g) in 15 mL of anhydrous THF was added to the reaction mixture (-5 to +5 ºC), the cooling bath was removed, and the mixture was stirred for an hour. This freshly prepared arylzinc chloride (prepared in excess) was slowly added via syringe to the flask charged with 2-bromo-5-iodopyridine (9) (22.6 mmol, 6.43 g) and Pd(PPh3)4 (0.7 mol%, 0.15 mmol, 0.17 g) until all 2-bromo-5-iodopyridine was consumed (TLC analysis). After addition of several mL of arylzinc chloride an orange precipitate formed and the reaction mixture was stirred for several hours and vacuum filtered. An orange solid (5.7 g, 105 % yield of the crude product) was dried under vacuum overnight. Part of the crude material (1.5 g) was recrystallized from 125 mL of DMF, and an orange powder was isolated (1.12 g, 74.5% recovery). The rest of the material was also recrystallized from DMF, and the purified title compound was isolated in 71.3% yield (3.85 g). MS (APCI) calculated for C18H10Br2N2S2 478.22; found 478.6 (with two satellites 476.6 and 480.6) (exact mass calculated for C18H10Br2N2S2 475.8652). DSC analysis: 295.0 ºC (m.p.). 1H NMR (1,1,2,2-tetrachloroethane-d2:CDCl3 (~4:1 ratio), 400 MHz): δ 7.27-7.22 (d, J = 3.9 Hz, 2H), 7.33-7.29 (d, J = 3.8 Hz, 2H), 7.54-7.50 (d, J = 3.8 Hz, 2H), 7.75-7.69 (dd, J = 8.2 Hz, 2.6 Hz, 2H), 8.57-8.60 (d, J = 2.6 Hz, 2H); 13C{1H} NMR (CDCl3, 100 MHz): δ 147.98 (CH),





S37

141.97 (quaternary C), 139.06 (quaternary C), 136.51 (CH), 130.28 (quaternary C), 129.64 (CH), 127.29 (quaternary C), 127.16 (quaternary C), 127.09 (CH), 126.80 (CH) (due to low solubility the quaternary C appeared as very weak signals, and are not certain).

5. 2-n-Decyl-5-iodopyridine (11)

The starting material for the preparation of 11, 2-n-decyl-5-bromopyridine, was prepared by an

adaptation of a literature procedure 6 using the Negishi coupling of 2,5-dibromopyridine (20.0 mmol, 4.73 g), Pd(PPh3)4 (0.5 mol%, 0.1 mmol, 0.12 g) in 10 mL of anhydrous THF with n-decylzinc chloride, which was prepared from ZnCl2 (36.0 mmol, 4.9 g) solution in 40 mL of anhydrous THF and alkyl Grignard obtained from 1-bromodecane (30.0 mmol, 6.63 g), Mg turnings (36.0 mmol, 0.87 g) and anhydrous THF (40 mL). The mixture was stirred at room temperature overnight, poured into 20 mL of water, and dichloromethane (20 mL) was added. The resulting mixture was vacuum filtered to separate a small amount of insoluble white solid, the organic phase was separated, and the aqueous phase was extracted with dichloromethane. The organic phases were combined, washed with brine and then dried over MgSO4. The solvent was removed by rotary evaporation and 2-n-decyl-5-bromopyridine was purified by Kugelrohr distillation (colorless oil, 100-105 ºC/0.10 mm Hg, 4.92 g, 82.6% yield). MS (APCI) calculated for C15H24BrN 298.26; found 298.1, 300.0 (~1:1 intensity ratio). 1H NMR (CDCl3, 300 MHz): δ 8.58-8.52 (d, J = 2.4 Hz, 1H), 7.72-7.67 (dd, J = 8.3 Hz, 2.4 Hz, 1H), 7.10-7.02 (d, J = 8.3 Hz, 1H), 2.76-2.67 (t, J = 7.8 Hz, 2H), 1.77-1.67 (m, 2H), 1.42-1.17 (m, 14H), 0.87-0.82 (t, J = 6.7 Hz, 3H, CH3); 13C{1H} NMR (CDCl3, 75 MHz): δ 161.2 (quaternary C), 150.3 (CH), 139.0 (CH), 124.2 (CH), 117.9 (C-Br), 37.9 (CH2), 32.1 (CH2), 29.9 (CH2), 29.9 (CH2), 29.7 (CH2), 29.7 (CH2), 29.6 (CH2), 29.5 (CH2), 22.8 (CH2), 14.3 (CH3).

An oven-dried three-necked flask was charged with 2-n-decyl-5-bromopyridine (7.0 mmol, 2.09 g), 65 mL of anhydrous THF and cooled in acetone/dry ice bath. Precipitation occurred on cooling (below -30 ºC) and n-butyllithium (2.5 M in hexanes, 7.0 mmol, 2.8 mL) was added dropwise to the suspension keeping the reaction temperature below -70 ºC. After completion of n-butyllithium addition the light orange reaction mixture was stirred for 10 minutes and analyzed by TLC (several drops of the reaction mixture were quenched with water, the organic component was extracted with hexanes and analyzed by TLC using dichloromethane as eluent). TLC detected no starting material, and a solution of I2 (7.7 mmol, 1.95 g) in 15 mL of anhydrous THF was added dropwise over 15 minutes. The solution remained light orange throughout the addition of most of the I2 solution. When ~2 mL was left the solution became lighter in color, and addition of next several drops changed the color to orange-reddish (excess I2). The rest of the I2 solution was added, and the mixture was warmed to room temperature. A solution of sodium thiosulfate pentahydrate (5 g in 15 mL of water) was added to the orange reaction mixture, and it became yellow after vigorous stirring. The organic solvent was removed using rotary evaporation, additional water was added (15 mL), and the product was extracted with dichloromethane (315 mL).





S38

The organic phases were combined, dried over MgSO4, the solvent was removed by rotary evaporation, and the yellow oil was chromatographed (24 g of silica gel, dichloromethane as eluent). After evaporation of the solvent from combined fractions the product was isolated in 74.3% yield (1.78 g) as yellowish oil. 1H NMR (CDCl3, 300 MHz): δ 8.74-8.70 (d, J = 2.1 Hz, 1H), 7.91-7.84 (dd, J = 8.2 Hz, 2.2 Hz, 1H), 6.99-6.94 (d, J = 8.2 Hz, 1H), 2.75-2.67 (t, J = 7.8 Hz, 2H), 1.75-1.60 (m, 2H), 1.40-1.12 (m, 14H), 0.92-0.82 (t, J = 6.7 Hz, 3H, CH3); 13C{1H} NMR (CDCl3, 75 MHz): δ 161.6 (quaternary C), 155.3 (CH), 144.6 (CH), 124.8 (CH), 89.9 (C-I), 38.0 (CH2), 32.1 (CH2), 29.9 (CH2), 29.9 (CH2), 29.7 (CH2), 29.7 (CH2), 29.6 (CH2), 29.5 (two CH2), 22.8 (CH2), 14.3 (CH3).

6. 5-[2,2']Bithiophenyl-5-yl-2-bromo-pyridine (13)

2,2'-Bithiophene (4) (38.5 mmol, 6.40 g) was placed into an oven-dried three-necked round bottom

flask, anhydrous THF (80 mL) was added, and the reaction mixture was cooled down to -35 ºC (ethylene glycol/dry ice cooling bath). n-Butyllithium (2.5 M in hexanes, 38.5 mmol, 15.4 mL) was added dropwise (-30 to -20 ºC internal temperature during addition). After addition of 14 mL of n-butyllithium the reaction mixture became cloudy, and a white precipitate formed after completion of addition of n-butyllithium. The reaction mixture was stirred for an hour, the solution was warmed up to 0 ºC, and a solution of ZnCl2 (46.2 mmol, 6.30 g) in 40 mL of anhydrous THF was added slowly (the temperature was kept at ~0 ºC). After addition of 4 mL of ZnCl2 solution the precipitate dissolved, and the reaction mixture became light yellow in color and almost clear after completion of addition of ZnCl2 solution. The cooling bath was removed, and the reaction mixture was stirred for 2 hours. Anhydrous THF (5 mL) was added to rinse the sides of the flask bringing the volume of the reaction mixture up to 150 mL.

About one third of this freshly prepared 2,2'-bithienylzinc chloride solution (50 mL, ~12.8 mmol) was added dropwise to the flask charged with 2-bromo-5-iodopyridine (9) (12.0 mmol, 3.41 g), Pd(PPh3)4 (0.5 mol%, 0.06 mmol, 0.070 g) and 10 mL of anhydrous THF. After addition of 10 mL of bithienyl dizinc dichloride the reaction mixture became cloudy yellow with blue fluorescence. After completion of addition of bithienyl dizinc dichloride the reaction mixture was stirred for an hour, vacuum filtered to separate an insoluble orange solid (0.38 g) and the solvent was removed from the filtrate under reduced pressure. The solid separated after the solvent evaporation from the filtrate was washed with 100 mL of water, vacuum filtered, and dried under vacuum for two hours. The crude material was dissolved in 40 mL of boiling dichloromethane, vacuum filtered to separate insoluble matter, concentrated and chromatographed (160 g of silica gel, dichloromethane:hexanes (1:1) as eluent). The desired product (contains 7-8% of impurities) was isolated as a fluffy yellow powder in 2.75 g (71% yield). A portion of this material (0.77 g) was further purified by column chromatography (50 g of silica gel, dichloromethane:hexanes=1:1) and recrystallization from ethanol to give a bright yellow solid (0.55 g, 71.4% recovery). DSC analysis: m.p. 112.5 ºC (decomposition above 230 ºC). FT-IR (cm-1): 3078, 2042, 3013, 2956, 2916, 2848, 1592, 1561, 1493, 1468, 1394, 1373, 1312, 1202, 1139, 1064, 955, 872,





S39

840, 792, 720, 695, 632. 1H NMR (300 MHz, CDCl3): δ 8.55-8.48 (d, J = 1.9 Hz, 1H), 7.66-7.58 (dd, J = 8.3 Hz, 2.54 Hz, 1H), 7.42-7.36 (d, J = 8.3 Hz, 1H), 7.22-7.17 (d, J = 3.8 Hz, 2H), 7.17-7.13 (d, J = 3.5 Hz, 1H), 7.12-7.07 (d, J = 3.8 Hz, 1H), 7.00-6.94 (t, J = 4.3 Hz, 1H); 13C{1H} NMR (75 MHz, CDCl3): δ 146.8 (CH), 140.5 (quaternary C), 138.8 (quaternary C), 137.5 (quaternary C), 135.1 (CH), 129.7 (quaternary C), 128.3 (CH), 128.2 (CH), 125.6 (CH), 125.3 (CH), 124.9 (CH), 124.5 (CH), 118.6 (C-Br). Analysis calculated for C13H8BrNS2: C, 48.45; H, 2.50; N, 4.35; S, 19.90. Found: C, 48.57; H, 2.49; N, 4.36; S, 19.51.

7. 5-[2,2']Bithiophenyl-5-yl-2-n-tridecyl-pyridine (14)

An oven-dried three-necked flask was charged with 5-[2,2']bithiophenyl-5-yl-2-bromopyridine (13)

(3.0 mmol, 0.97 g), NiCl2(dppe) (5 mol%, 0.15 mmol, 0.08 g) and anhydrous THF (9 mL). Alkyl Grignard prepared from 1-bromotridecane (2 eq., 6.0 mmol, 1.58 g), Mg turnings (7.2 mmol, 0.17 g) and 12 mL of anhydrous THF was added dropwise. The orange-yellow reaction mixture turned dark brown after completion of addition of the Grignard. TLC analysis (hexanes:ethyl acetate (1:1) as eluant) of the mixture after an hour of stirring showed a bit of the starting material. MS analysis (APCI) showed a peak of desired product at 426.2 (molecular weight calculated for C26H35NS2 425.69) and a minor peak of the starting material at 323.9 (molecular weight calculated for C13H8BrNS2 322.24). Additional alkyl Grignard was added (about 6 mL was used), and the mixture was stirred for 2 hours. Water (1 mL) was added to the reaction mixture, and the solvent was removed by rotary evaporation. The residue was treated with dichloromethane (55 mL) and water (20 mL), and the resulting mixture was vacuum filtered to separate insoluble matter. The organic phase was separated and the aqueous phase was extracted with dichloromethane (210 mL). The organic phases were combined, dried over MgSO4, and the solvent was removed by rotary evaporation. The product was purified by column chromatography (silica gel, dichloromethane:hexanes first, then dichloromethane). The product appeared as a bright orange band during column chromatography; the solution that came out from the column was yellow with blue fluorescence under visible light. The title compound was isolated in 63% yield as a yellow solid (0.80 g). DSC analysis: 77.7 ºC (m.p.). 1H NMR (300 MHz, CDCl3): δ 8.80-8.74 (d, J = 2.3 Hz, 1H), 7.81-7.64 (dd, J = 8.1 Hz, 2.4 Hz, 1H), 7.25-7.20 (m, 3H), 7.19-7.14 (m, 2H), 7.06-7.02 (dd, J = 5.1 Hz, 3.7 Hz, 1H), 2.82-2.75 (t, J = 7.8 Hz, 2H), 1.80-1.70 (m, 2H), 1.45-1.23 (m, 20H), 0.90-0.80 (t, J = 6.7 Hz, 3H, CH3); 13C{1H} NMR (75 MHz, CDCl3): δ 161.7 (quaternary C), 146.0 (CH), 139.4 (quaternary C), 137.7 (quaternary C), 137.2 (quaternary C), 133.4 (CH), 128.1 (CH), 127.7 (quaternary C), 124.9 (CH), 124.8 (CH), 124.5 (CH), 124.1 (CH), 123.0 (CH), 38.2 (CH2), 32.1 (CH2), 30.0 (CH2), 29.8 (four CH2 carbons), 29.7 (CH2), 29.7 (CH2), 29.5 (two CH2 carbons), 22.9 (CH2), 14.3 (CH3). Analysis calculated for C26H35NS2: C, 73.36; H, 8.29; N, 3.29. Found: C, 73.63; H, 8.29; N, 3.21.





S40

8. 5-(5'-Bromo-[2,2']bithiophenyl-5-yl)-2-n-tridecyl-pyridine (15)

5-[2,2']Bithiophenyl-5-yl-2-n-tridecylpyridine (14) (1.87 mmol, 0.80 g) was dissolved in 15 mL of

anhydrous DMF under nitrogen atmosphere and the solution of N-bromosuccinimide (1.1 eq., 2.067 mmol, 0.36 g) in 4 mL of anhydrous DMF was added dropwise to the slightly cloudy bright yellow solution of the starting material. Precipitation took place after fifteen minutes of stirring and after half an hour the reaction mixture was analyzed by TLC. A new darker spot was observed (the starting material gives blue spot under 254 nm lamp). MS (APCI) analysis showed major peaks at 504.1 and 505.9 (1:1 ratio, molecular weight calculated for C26H34BrNS2 504.59) and a minor peak of the starting material at 426.2 (molecular weight of the starting material calculated for C26H35NS2 425.69). An additional amount of N-bromosuccinimide (10 mol%, 0.041 g) was added, and the mixture was stirred for two hours. The reaction mixture was poured into 100 mL of ice water, and vacuum filtered overnight (very slow filtration, fine particles). The crude material was isolated in 74.5% yield (0.70 g) as yellow fluffy solid. The product was purified by recrystallization from 2-propanol, and the desired material was isolated in 0.68 g (97% recovery, 72.3% yield). DSC analysis (2nd cycle): 77.1 ºC, 86.4 ºC, 120.0 ºC (on heating), 71.5 ºC, 76.9 ºC, 118.5 ºC (on cooling). Polarized optical microscopy observations on cooling: Cr 71.0 ºC SmA 121.1 ºC Iso. 1H NMR (400 MHz, CDCl3): δ 8.78-8.75 (dd, J = 2.3 Hz, 0.4 Hz, 1H), 7.76-7.73 (dd, J = 8.1 Hz, 2.4 Hz, 1H), 7.23-7.20 (d, J = 3.8 Hz, 1H), 7.17-7.14 (d, J = 8.0 Hz, 1H), 7.10-7.08 (d, J = 3.8 Hz, 1H), 7.00-6.98 (d, J = 3.8 Hz, 1H), 6.97-6.94 (d, J = 3.9 Hz, 1H), 2.83-2.74 (t, J = 7.8 Hz, 2H), 1.77-1.68 (m, 2H), 1.40-1.13 (m, 20H), 0.90-0.85 (t, J = 5.2 Hz, 3H, CH3); 13C{1H} NMR (100 MHz, CDCl3): δ 161.9 (quaternary C), 146.1 (CH), 140.0 (quaternary C), 138.3 (quaternary C), 136.6 (quaternary C), 133.1 (CH), 130.7 (CH), 127.2 (quaternary C), 124.9 (CH), 124.3 (CH), 124.0 (CH), 122.7 (CH), 111.3 (C-Br), 38.2 (CH2), 31.9 (CH2), 29.9 (CH2), 29.7 (several CH2), 29.6 (CH2), 29.5 (CH2), 29.4 (CH2), 29.4 (CH2), 22.7 (CH2), 14.1 (CH3). Analysis calculated for C26H34BrNS2: C, 61.89; H, 6.79; N, 2.78; S, 12.71. Found: C, 62.21; H, 7.12; N, 2.80; S, 12.31.

9. 5-(2-Bromopyridin-5-yl)-5'-(2-n-tridecylpyridin-5-yl)-2,2'-bithiophene (16)

An oven-dried three-necked flask equipped with magnetic stirrer, bubbler, and thermometer was

charged with 5-(5'-bromo-[2,2']bithiophenyl-5-yl)-2-tridecyl-pyridine (15) (1.35 mmol, 0.68 g) and 20 mL of anhydrous THF. The reaction mixture was cooled in acetone/dry ice bath down (-65 ºC internal temperature) and n-butyllithium (2.5 M in hexanes, 0.54 mL) was added dropwise to the suspension of the yellow powder of the starting bromide 15 (the temperature was kept at -62 to -52 ºC during addition). After completion of addition of n-butyllithium the reaction mixture turned dark red. After 5 minutes of stirring, several drops of the reaction mixture were quenched with water and the organic





S41

matter was extracted and analyzed by TLC. No starting material was detected by TLC, and a solution of ZnCl2 (1.62 mmol, 0.22 g) in 2 mL of anhydrous THF was added dropwise to the very dark red reaction mixture (the temperature was kept at -70 to -60 ºC during the addition of ZnCl2 solution). After completion of addition of ZnCl2 solution the mixture became clear and yellow-brown in color. The cooling bath was removed, and the mixture was allowed to warm up to room temperature (at -20 ºC the mixture was clear yellow). Total volume of arylzinc chloride was 25 mL and 18.5 mL (1 mmol) was used for the reaction with 2-bromo-5-iodopyridine (9). Part of this freshly prepared arylzinc chloride solution (18.5 mL, 1 mmol) was transferred to a syringe and added dropwise over half an hour period to the solution of 2-bromo-5-iodopyridine (9) (1.0 mmol, 0.28 g) and Pd(PPh3)4 (1 mol%, 0.01 mmol, 12 mg) in 10 mL of anhydrous THF. The yellow cloudy mixture was stirred for an hour and poured into 100 mL of water. The orange-yellow precipitate was filtered and dried under vacuum. This solid was dissolved in 20 mL of boiling chloroform, vacuum filtered to separate some insoluble yellow solid and the volume of the solution was reduced down to 4-5 mL. This hot solution was applied to the silica gel column (30 g of silica gel, dichloromethane:ethyl acetate (25:1) as eluant; several more mL of chloroform was used to apply the material since crystallization started). The purified material was obtained as a bright yellow solid in 0.30 g (51.7% yield) and a portion (50 mg) was recrystallized from 2-propanol (~20 mL) to get the sample for NMR and DSC analysis. DSC analysis, ºC (2nd cycle): 133.4, 236.3 (on heating); 109.5, 131.2, 235.1 (on cooling). 1H NMR (300 MHz, CDCl3): δ 8.75-8.68 (d, J = 1.8 Hz, 1H), 8.59-8.50 (dd, J = 2.5 Hz, 0.5 Hz, 1H), 7.75-7.67 (dd, J = 8.1 Hz, 2.4 Hz, 1H), 7.67-7.60 (dd, J = 8.3 Hz, 2.6 Hz, 1H), 7.46-7.40 (dd, J = 8.3 Hz, 0.5 Hz, 1H), 7.24-7.21 (d, J = 3.8 Hz, 1H), 7.21-7.17 (d, J = 3.6 Hz, 1H), 7.16-7.12 (m, 3H), 2.80-2.70 (t, J = 7.8 Hz, 2H), 1.75-1.63 (m, 2H), 1.35-1.10 (m, 20H), 0.80-0.73 (t, J = 6.6 Hz, 3H, CH3); 13C{1H} NMR (75 MHz, CDCl3): δ 161.9 (quaternary C), 146.8 (CH), 145.9 (CH), 140.7 (quaternary C), 140.1 (quaternary C), 138.3 (quaternary C), 137.8 (quaternary C), 136.8 (quaternary C), 135.2 (CH), 133.5 (CH), 129.6 (quaternary C), 128.6 (CH), 127.5 (quaternary C), 125.7 (CH), 125.4 (CH), 125.1 (CH), 124.8 (CH), 123.1 (CH), 38.1 (CH2), 32.1 (CH2), 30.0 (CH2), 29.8 (four CH2 carbons), 29.7 (CH2), 29.7 (CH2), 29.5 (two CH2 carbons), 22.9 (CH2), 14.3 (CH3). Analysis calculated for C31H37BrN2S2: C, 64.01; H, 6.41; N, 4.82, S, 11.03. Found: C, 63.76, H, 6.18; N, 4.83; S, 10.79.

10. Single crystals X-ray analysis X-Ray crystallography was performed by mounting each crystal onto a thin glass fiber from a pool of

Fluorolube™ and immediately placing it under a liquid N2 stream, on a Bruker AXS diffractometer. The radiation used was graphite monochromatized Mo K radiation ( = 0.7107 Å). The lattice parameters were optimized from a least-squares calculation on carefully centered reflections. Lattice determination, data collection, structure refinement, scaling, and data reduction were carried out using APEX2 version 1.0-27 software package. Each structure was solved using direct methods. This procedure yielded a number of the C, N, and O atoms. Subsequent Fourier synthesis yielded the remaining atom positions. The hydrogen atoms were fixed in positions of ideal geometry and refined within the XSHELL software. These idealized hydrogen atoms had their isotropic temperature factors fixed at 1.2 or 1.5





S42

times the equivalent isotropic U of the C atoms to which they were bonded. The final refinement of each compound included anisotropic thermal parameters on all non-hydrogen atoms.

(a)

(b)

(c)

(d)

Figure S25. Thermal ellipsoid structures of 2b (a), 2c (b), 2e (c), and 2f (d). Ellipsoids are drawn at the 50 % level. H atoms have been omitted for clarity.

11. Computational Methodology. Calculations for the neutral (gas-phase) ground states were carried out at the density functional theory (DFT) level using generalized gradient approximation functional B3LYP in conjunction with a 6-31G**





S43

basis set; the alkyl groups were replaced with methyl groups to reduce the computational cost. All calculations were performed using the Spartan 10 software.

Figure S26. Frontier molecular orbital energies and wave-function illustrations as determined at the B3LYP/6-31G** level of theory.

(a)





S44

(b)

(c)

Figure S27. Geometry of the molecules (B3LYP/6-31G** level of theory): (a) mesogen of type 1: dihedral angle (S2, C8, C9, C12) = 25.7º, dihedral angle (S1, C8, C15, C18) = -26.8º; (b) mesogen of type 2: dihedral angle (N2, C11, C2, S1) = -0.4º, dihedral angle (N1, C9, C8, S2) = 0.3 º; (c) mesogen of type 3: dihedral angle (S1, C2, C15, C17) = -25.8º; dihedral angle (S2, C8, C9, C12) = -27.4º, dihedral angle (S1, C4, C6, C5) = 15.1 (between the thiophene rings).

References 1. Tamao, K.; Kodama, S.; Nakajima, I.; Kumada, M.; Minato, A.; Suzuki, K., Nickel-Phosphine Complex-Catalyzed Grignard Coupling .2. Grignard Coupling of Heterocyclic-Compounds. Tetrahedron 1982, 38 (22), 3347-3354. 2. Getmanenko, Y. A.; Twieg, R. J., Unprecedented Negishi coupling at C-Br in the presence of a stannyl group as a convenient approach to pyridinylstannanes and their application in liquid crystal synthesis. Journal of Organic Chemistry 2008, 73 (3), 830-839. 3. Chaloner, P. A.; Gunatunga, S. R.; Hitchcock, P. B., Synthesis of substituted oligothiophenes and x-ray crystal structures of 3'-methyl-2,2':5',2''-terthiophene, 3,3''-dimethyl-2,2':5',2''-terthiophene and 5'-(2-thienyl)-2,2':3',2''-terthiophene. Journal of the Chemical Society-Perkin Transactions 2 1997, (8), 1597-1604. 4. Trecourt, F.; Breton, G.; Bonnet, V.; Mongin, F.; Marsais, F.; Queguiner, G., New syntheses of substituted pyridines via bromine-magnesium exchange. Tetrahedron 2000, 56 (10), 1349-1360. 5. Hammersley, A. P.; Svensson, S. O.; Hanfland, M.; Fitch, A. N.; Hausermann, D., Two-dimensional detector software: From real detector to idealised image or two-theta scan. High Pressure Research 1996, 14 (4-6), 235-248. 6. Getmanenko, Y. A.; Twieg, R. J.; Ellman, B. D., 2,5-dibromopyridine as a key building block in the synthesis of 2,5-disubstituted pyridine-based liquid crystals. Liquid Crystals 2006, 33 (3), 267-288.





Documents

5,5'-Bis-(Alkylpyridinyl)-2,2'-Bithiophenes: Synthesis, Liquid Crystalline Behavior ... · 2013-11-22 · S1 Supporting information for 5,5'-Bis-(Alkylpyridinyl)-2,2'-Bithiophenes: