Supporting Information

for

Angew. Chem. Int. Ed. Z50725

© Wiley-VCH 200369451 Weinheim, Germany

1

A New Look into an Old Pot: Syntheses and Structural Characterization of Sodium

Oligophosphandiides in the PhPCl2 / Na System

Jens Geier, Heinz Rüegger, Michael Wörle and Hansjörg Grützmacher*

[*] Prof. Dr. H. Grützmacher, Dipl.-Chem. J. Geier, Dr. H. Rüegger, Dr. M. Wörle

Department of Chemistry, HCI, ETH Hönggerberg, CH-8093 Zürich, Switzerland, Fax: int.+41 1 632 1032; E-Mail: gruetzmacher@inorg.chem.ethz.ch

The supplementary material contains

a) A description of the general techniques for the syntheses of 2a,b, 3a, 4a,b

b) A detailed description for the syntheses of 2a,b, 3a, 4a,b

c) Comments on the 31P NMR spectra of 4a

d) Ortep-plots of the structures of 2a,b, 3a, 4a,b

e) A detailed description for the X-ray structure analyses of 2a,b, 3a, 4a,b

a) Syntheses – general techniques: All reactions and manipulations of the products were done

under rigorous inert conditions using vacuum line, Schlenk-techniques and a glove box.

Argon (99.999%) was additionally purified by a copper catalyst. Glassware was flame-dried

in high vacuum prior to use. Solvents (toluene, thf, dme, tmeda, [D8]thf) were either distilled

from purple sodium-benzophenone solutions (containing tetraglyme in case of toluene) or, for

smaller scale reactions, vacuum-transferred into the reaction vessels from a suspension of

liquid sodium/potassium alloy. Phenylphosphonous acid dichloride was distilled in vacuum

prior to use. NMR spectra were recorded on Bruker DPX 250, DPX 300 and DRX 500

machines, the samples were either flame-sealed in glass tubes under high vacuum or prepared

under argon in Young PTFE tap nmr tubes. Chemical shift references are tetramethylsilane

2

or 85% aqueous H3PO4, respectively. The assignments are confirmed by two-dimensional

measurements (H,H; H,C; H,P); those which are marked with the symbols *,**, .. are

mutually interchangeable. Higher order spectra were simulated with the program MEXICO

(Version 3.0, Alex D. Bain, Main St. W., 2002). Single crystals for x-ray crystallography

were selected under Na/K-dried paraffine oil in an argon-filled glove box equipped with a

microscope and were mounted with the aid of hydrocarbon grease in Lindemann capillaries,

which were sealed by an electrically heated wire. dme = 1,2-dimethoxyethane, tmeda =

N,N,N’,N’-tetramethylethylendiamine, thf = tetrahydrofurane, app. = apparent.

i-Ct

o-Ct

m-Ct

p-Ct

P(P)x

P

i-Cco-Cc

m-Ccp-Cc

x = 0, 1, 2

- -

Figure 1. Numbering scheme for the assignment of the resonances in the NMR spectra.

b) Synthesis of [Na(dme)3]+[Na5(P2Ph2)3(dme)3]– (2a,b): Sodium metal (3.86 g, 0.168 mol; 3

equivalents) was heated in a refluxing mixture of 100 ml toluene with 15 ml tmeda and after

dispersing the liquid metal by magnetic stirring the temperature was lowered to 50°C.

Phenylphosphonous acid dichloride (10.00 g, 0.056 mol) was then added and the suspension

was heated under reflux again. The formation of solid, colourless NaCl was immediately

apparent and after 2-3 hours a yellow solid had precipitated additionally. Refluxing was

maintained 3 hours more until the metal had disappeared. The precipitate was isolated by

filtration and after drying in high vacuum there remained a yellow, pyrophoric powder

(approx. 90 %) consisting of the disodium salt of diphenyldiphosphane together with NaCl

3

and variable amounts of tmeda (corresponding to approximately [Na2(P2Ph2)(tmeda)0.5] (2a)

as determined by 1H NMR spectroscopy after extraction with [D8]thf). The orange coloured

mother liquor contains mainly the much more soluble salts Na2P3Ph3 and Na2P4Ph4 (identified

by 31P NMR spectroscopy). Extraction of this powder with dme at room temperature gave rise

to a deeply red coloured solution which after evaporation of the solvent in high vacuum

yielded an orange solid containing variable amounts of dme ([Na2(P2Ph2)(dme)0.5-1] as

determined by 1H NMR spectroscopy). Extremely air sensitive single crystals of

[Na(dme)3]+[Na5(P2Ph2)3(dme)3]– 2b were obtained by storing saturated dme-solutions in

narrow glass tubes for one day at ambient temperature. The red solutions of the

diphosphanediide in dme or thf are unstable at room temperature due to ether cleavage

(recognizable after 1-2 days, vide infra) and all spectra were measured immediately after

preparing the samples. The solid NaCl/[Na2(P2Ph2)(tmeda)n]-mixture can be stored at room

temperature for several months without decomposition. The NMR samples were prepared by

dissolving crystalline 2b; samples which were prepared by direct extraction of the solid

NaCl/[Na2(P2Ph2)(tmeda)n]-mixture with [D8]thf gave identical spectra for the Ph2P22--unit.

1H NMR (300.13 MHz, [D8]thf): δ = 3.30 (s, 6H; dme, CH3), 3.46 (s, 4H; dme, CH2), 6.42

(app. t, 1H; p-Ht), 6.71 (app. t, 2H; m-Ht), 7.24 (app. d, 2H; o-Ht); 13C NMR (62.90 MHz,

[D8]thf): δ = 59.8 (s; dme, CH3), 73.6 (s; dme, CH2), 119.0 (s; p-Ct), 127.8 (s; m-Ct), 131.1

(m; o-Ct), 160.7 (m; i-Ct); 31P NMR (121.49 MHz, [D8]thf): δ = –106.4 (s).

Solutions of 2b in dme or [D8]thf which were stored in flame-sealed glass tubes for 2 months

at room temperature no more contained the original product, instead two new phosphorus

compounds had been formed: the disodium salt of 1,2,3-triphenyltriphosphane (chemical

shifts vide infra) and the monosodium salt of phenylphosphane: 31P NMR (101.25 MHz,

dme): δ = –108.0 (s); 31P{H} NMR (101.25 MHz, dme): δ = –107.9 (d, 1JP,H = 157.5 Hz). In

case of the dme solution the presence of the ether cleavage product methylvinylether was

indicated by a 13C NMR signal (singlet) at 152.0 ppm (-O-CH=). After storing dme or thf

4

solutions of 2b for just a few days at room temperature the intermediate product NaHP2Ph2 is

observable: 31P NMR (101.25 MHz, dme): δ = –63.0 (d, 1JP,P = 375.9 Hz, PhPH), –91.8 (d,

1JP,P = 375.9 Hz; PhP-); 31P{H} NMR (101.25 MHz, dme): δ = –63.0 (dd, 1JP,P = 375.9 Hz,

1JP,H = 208.9 Hz; PhPH), –91.8 (dd, 1JP,P = 375.9 Hz, 2JP,H = 15.2 Hz; PhP-). The same three

phosphorus products are observed on protonation of 2b with substoichiometric amounts of

tert.-butanole in thf. A solution of 2b with excess [Na2(P4Ph4)(tmeda)2] 4a in thf was found to

contain only Na2P3Ph3 besides unchanged Na2P4Ph4 after storage for one day at room

temperature. Mixing 2b with excess (PhP)5 in thf solution at room temperature resulted in

formation of Na2P3Ph3 and Na2P4Ph4.

Synthesis of [Na2(P3Ph3)(tmeda)3] (3a): In the same way as in the preparation of 2b described

above phenylphosphonous acid dichloride (10.00 g, 0.056 mol) was refluxed with sodium

metal (3.43 g, 0.149 mol, 8/3 eq.) in 100 ml toluene and 15 ml tmeda until no more metal was

visible (6 hours). After cooling to room temperature the reaction mixture was filtered and

concentrated until onset of crystallisation. The product was difficult to separate from the less

soluble [Na2(P4Ph4)(tmeda)2] 4a which is also contained in the raw material. After several

recrystallisations from toluene/tmeda yellow, very airsensitive crystals (55%) containing less

then 5% of 4a were obtained. X-ray quality crystals were grown by storing saturated

toluene/tmeda solutions at room temperature. 1H NMR (250.13 MHz, [D8]thf): δ = 2.15 (s,

36H; tmeda, CH3), 2.30 (s, 12H; tmeda, CH2), 6.35 (app. t, 2H; p-Ht), 6.67 (app. t, 4H; m-

Ht)*, 6.76 (m, 1H; p-Hc), 6.88 (app. t, 2H; m-Hc)**, 7.46 (app. d, 4H; o-Ht)*, 7.72 (app. d,

2H; o-Hc)**; 13C NMR (62.90 MHz, [D8]thf): δ = 47.1 (s; tmeda, CH3), 59.8 (s; tmeda, CH2),

118.3 (s; p-Ct), 124.6 (s; p-Cc), 127.7 (m; m-Ct, m-Cc), 130.5 (m; o-Ct)*, 132.7 (m; o-Cc)*;

161.4 (m; i-Cc)**, 162.9 (m; i-Ct)**; 31P NMR (101.25 MHz, [D8]thf): 8 line - AB2 spin

system, δA = –54.0 (P-2), δB = –56.7 (P-1,3), 1JAB = 242.4 Hz.

Synthesis of [Na2(P4Ph4)(tmeda)2] (4a): Sodium metal (3.21 g, 0.140 mol, 5/2 eq.) and

phenylphosphonous acid dichloride (10.00 g, 0.056 mol) were refluxed in 100 ml of toluene

5

and 15 ml of tmeda analogous to the preparation of 3a. After 6 hours the reaction mixture was

filtered hot and on cooling of the clear red filtrate to room temperature the product separated

as bright yellow crystals (73%), which are soluble in thf with yellow colour. X-ray quality

crystals were grown by storing saturated toluene/tmeda solutions at room temperature.

Synthesis of [Na2(P4Ph4)(dme)3] (4b): Yellow, very airsensitive single crystals of 4b were

obtained by storing a saturated solution of 4a in dme in a narrow glass tube for several days at

room temperature.

c) Comments on the 31P NMR spectra of 4a. The 31P NMR spectrum shows that two different

exchanging major species A and B are present in thf solution, while on the timescale for the

1H and 13C NMR spectra only the averaged resonances are observed. The A : B ratio is

temperature dependent and increases from about 1:1 at room temperature to about 2 : 1 at T =

253 K. This holds also for a tmeda-free sample prepared by sodium-reduction of (PhP)5 in

THF. At 253 and 183 K, respectively, the signals for both compounds are sufficiently

resolved and show for A an AA’XX’ spin-system and for B an AFMX spin system (see

below). We believe that these results are best explained by an equilibrium (Scheme 1)

between a C2-symmetric, doubly bridged contact ion triple A = 4a (with tmeda likely to be

replaced by thf), giving rise to the AA’XX’ pattern, and a monocyclic contact ion pair

[Na(P4Ph4)(L)m]– (L = thf, tmeda) B with the five-membered NaP4-ring in an envelope

conformation, which is responsible for the AFMX spin system under the assumption that ring

inversion is slow on the 31P NMR time scale at T = 183 K. This interpretation is also in

accordance with the increase of the ion triple (A) concentration with decreasing temperature

since this is expected to be thermodynamically more stable than the ion pair B.

6

PhP

P NaLnLnNa

Ph

Ph

PPh

4a

PhP

PLmNa

Ph

Ph

PPh

–

A BL = tmeda, thf( )

+ [Na(L)k]+

NaLnLnNa

Ph PhP P

Scheme 1. Equilibrium between ion triple A (= 4a) and the solvent separated ion pair

1H NMR (250.13 MHz, [D8]thf): δ = 2.15 (s, 24H; tmeda, CH3), 2.30 (s, 8H; tmeda, CH2),

6.43 (app. t, 2H; p-Ht), 6.68 (app. t, 4H; m-Ht), 6.91 (app. t, 2H; p-Hc), 7.04 (app. t, 4H; m-

Hc), 7.31 (app. d, 4H; o-Ht), 7.87 (br. s, 4H; o-Hc); 13C NMR (62.90 MHz, [D8]thf): δ = 47.1

(s; tmeda, CH3), 59.8 (s; tmeda, CH2), 119.8 (s; p-Ct), 125.9 (s; p-Cc), 127.8 (s; m-Ct), 128.4

(s; m-Cc), 131.0 (m; o-Ct), 133.5 (m; o-Cc), 151.5 (br. m; i-Cc,)*, 159.4 (br. m; i-Ct)*; 31P

NMR (101.25 MHz, [D8]thf, 293 K): δ = –23.5 (m; P-2,3 [A + B]), –70.0 (br.; P-1,4 [B]), -

85.6 (br.; P-1,4 [A]), ratio A/B = 1.00:0.94; 31P NMR (101.25 MHz, [D8]thf, 253 K): δ = –

24.9 (A-part of AA’XX’ system + br. m, JAA’= 310 Hz, JXX’ = 306 Hz, JAX’ = 11 Hz, JAX =

322 Hz; P-2,3 [A] + P-2,3 [B]), –70.1 (app. d; P-1,4 [B]), –89.10 (X-part of AA’XX’ system;

P-1,4 [A]), ratio A/B = 1.00:0.48; 31P NMR (202.49 MHz, [D8]thf, 183 K): δ = –16.8 (m, 1P;

P-3 [B]), –25.7 (br., A-part of AA’XX’ system; P-2,3 [A]), -30.8 (td, 1J1,2 = 340 Hz, 1J2,3 =

340 Hz, 2J2,4 = 148 Hz, 1P; P-2 [B]), –70.4 (dd, 1J3,4 = 274 Hz, 1P; P-4 [B]), –73.3 (br. d, 1P;

P-1 [B]), –89.7 (br., X-part of AA’XX’ system; P-1,4 [A]).

No new phosphorus products were formed on mixing 4a with (PhP)n in thf solution at room

temperature.

7

d) Ortep-plots of the structures of 2a,b, 3a, 4a,b. The dme molecules in 2b and 4b are shown

as ball-and-stick models, otherwise the thermal ellipsoids corresponding to 30% probability

are shown.

e) Crystal structure data for [Na(dme)3]+[Na5(P2Ph2)3(dme)3]– (2b): C60H90O12Na6P6, Mr =

1327.3 g/mol; orange hexagonal rod, crystal size 0.60 × 0.35 × 0.35 mm; hexagonal, space

8

group P6322, a = 15.04(2), c = 20.93(4) Å, V = 4102(10) Å3, Z = 2, ρber = 1.074 g/cm3, F(000)

= 1404, µ = 0.21 mm-1. The data were collected on a Bruker AXS SMART CCD

diffractometer within a hemisphere of reciprocal space in three runs with 606, 435 and 230

frames, separated by 0.3°-steps in ω-direction, at ϕ = 0°, 90° and 180°: λ(Mo-Kα) = 0.71073

Å, graphite monochromator, T = 293 K, detector distance = 60 mm, exposure time = 40 s,

2θmax = 38.22°, 2θmin = 5.76°, number of collected reflections = 10445, number of

independent reflections = 1127, Rint = 0.0695. The data reduction was performed with the

SAINT software Version 4 (Bruker AXS); for space group determination the program XPREP

(SHELXTL Version 5.1 program package; Bruker AXS) was used. The structure was solved

by direct methods (SHELXS-97; G. Sheldrick, Göttingen, Germany, 1997) and refined

against F2 with the full-matrix least-squares method (SHELXL-97; G. Sheldrick, Göttingen,

Germany, 1997). All non-hydrogen atoms were found in difference fourier synthesis and were

refined anisotropically, while the hydrogen atoms were added to the structure at calculated

positions and then refined according to a riding model (HFIX 23, 33, 43 - instructions).

Geometrical restraints/constraints were used for the disordered dme-ligands (the C-C- and C-

O-bond lengths were restrained to standard values by DFIX-instructions; refinement with split

sites was not possible) and the benzene ring (which was constrained to a regular hexagon [d =

1.39 Å] by AFIX 66 - instructions). An absorption correction was applied to the data

(SADABS; G. Sheldrick, Göttingen, Germany, 1997). All tested crystals of 2b are weakly

diffracting. The rather high R-values are considered to be a consequence of true disorder of

both types of dme-ligands contained in the structure since twin refinements (e. g. in space

group P63 with a C2-axis parallel [110] as twin symmetry element) were unsuccessful.

Measurements at lower temperatures (-40°C, -60°C) gave no improvements. In the only other

possible space group P63/m the structure cannot be solved. For the refinement all reflections

were used: data / parameters = 1127 / 116, R1 = 0.0996 for 747 reflections with I > 2σ, wR2 =

9

0.2921 for all data, GooF on F2 = 1.969, max./min. residual electron density = 0.51 / –0.29

e/Å3.

Crystal structure data for [Na2(P3Ph3)(tmeda)3] (3a): C36H63N6Na2P3, Mr = 719.0 g/mol,

yellow cuboid, crystal size 0.62 × 0.44 × 0.42 mm, monoclinic, space group P21/c, a =

10.500(1), b = 14.914(1), c = 27.046(1) Å, β = 91.890(4)°, V = 4233.0(3) Å3, Z = 4, ρber =

1.128 g/cm3, F(000) = 1552.0, µ = 0.19 mm-1. The data were collected on a STOE IPDS II

diffractometer within a hemisphere of reciprocal space in 302 frames, λ(Mo-Kα) = 0.71073 Å,

graphite monochromator, T = 173 K, detector distance = 120 mm, exposure time = 3 min,

2θmax = 52.74°, 2θmin = 3.02°, number of collected reflections = 52111, number of

independent reflections = 8656, Rint = 0.0774. Data reduction was performed with the STOE

X-AREA software; for space group determination the program STOE X-RED was used.

Structure solution/refinement was as above. The central C-C-bond length of one of the tmeda-

ligands (C27-C28) was restrained to a standard value (DFIX-instruction). The absorption

correction was done numerically. For the refinement all reflections were used: data /

parameters = 8656 / 425, R1 = 0.0513 for 5712 reflections with I > 2σ, wR2 = 0.1621 for all

data, GooF on F2 = 1.068, max./min. residual electron density = 0.86 / –0.82 e/Å3.

Measurements at room temperature gave a rather high R1-value of 0.12 due to severe disorder

of the tmeda-ligands, which is not observed at –100°C.

Crystal structure data for [Na2(P4Ph4)(tmeda)2] (4a): C36H52N4Na2P4, Mr = 710.8 g/mol;

yellow cuboid, crystal size 0.40 × 0.20 × 0.20 mm; triclinic, space group P1, a = 10.17(1), b =

10.27(1), c = 11.94(1), α = 76.40(2), β = 71.33(2), γ = 62.14(2) Å, V = 1039(2) Å3, Z = 1, ρber

= 1.136 g/cm3, F(000) = 378.0, µ = 0.23 mm-1. The data were collected on a Bruker AXS

SMART CCD diffractometer within a hemisphere of reciprocal space in three runs with 606,

435 and 230 frames, separated by 0.3°-steps in ω-direction, at ϕ = 0°, 90° and 180°: λ(Mo-

Kα) = 0.71073 Å, graphite monochromator, T = 293 K, detector distance = 40 mm, exposure

10

time = 30 s, 2θmax = 46.62°, 2θmin = 3.62°, number of collected reflections = 4576, number of

independent reflections = 3655, Rint = 0.0304. Structure solution/refinement was as above. For

the refinement all reflections were used: data / parameters = 3655 / 425, R1 = 0.0484 for 2576

reflections with I > 2σ, wR2 = 0.1137 for all data, GooF on F2 = 1.014, max./min. residual

electron density = 0.21 / –0.18 e/Å3.

Crystal structure data for [Na2(P4Ph4)(dme)3] (4b): C36H50O6Na2P4, Mr = 748.74 g/mol,

yellow cuboid, crystal size 0.26 × 0.18 × 0.17 mm, orthorhombic, space group Pna21, a =

20.597(4), b = 12.301(3), c = 16.647(3) Ǻ, V = 4218(2) Ǻ3, Z = 4, ρber = 1.179 g/cm3, F(000)

= 1584.0, μ = 0.24 mm-1. The data were collected on a STOE IPDS I diffractometer in 220

frames separated by 1° in φ-direction: λ(Mo-Kα) = 0.71073 Å, graphite monochromator, T =

293 K, detector distance = 80 mm, exposure time = 10 min, 2θmax = 47.68°, 2θmin = 3.86°,

number of collected reflections = 21216, number of independent reflections = 5390, Rint =

0.2537. The data reduction was performed with the INTEG program (STOE & Cie GmbH).

Structure solution/refinement was as above.The rather high R-values are caused by disorder of

the dme-molecules contained in the structure, this holds especially for the central μ2-dme-

ligand. In case of the latter one the two 1,3-distances between methyl and methylen carbons

were restrained to be equal (SADI-instruction). For the refinement all reflections were used:

data / parameters = 5387 / 433, R1 = 0.0755 for 2349 reflections with I > 2σ, wR2 = 0.1806 for

all data, GooF on F2 = 0.997, max./min. residual electron density = 0.23 / –0.18 e/Å3.