Research Article Growth and Characterization of ...downloads.hindawi.com/archive/2015/206325.pdf · F : As grown BSL crystal of dimension × × mm 3. NLO materials [ ]. e formation

Research ArticleGrowth and Characterization of Benzimidazolium SalicylateNLO Property from a Centrosymmetric Crystal

M Amudha12 R Rajkumar1 V Thayanithi1 and P Praveen Kumar1

1Department of Physics Presidency College Chennai Tamil Nadu 600005 India2Department of Physics Aalim Muhammed Salegh College of Engineering Avadi Chennai Tamil Nadu 600055 India

Correspondence should be addressed to P Praveen Kumar ppkpresidencygmailcom

Received 15 July 2015 Revised 16 September 2015 Accepted 16 September 2015

Academic Editor Giancarlo C Righini

Copyright copy 2015 M Amudha et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A new organic charge transfer molecular complex salt of benzimidazolium salicylate (BSL) single crystals was grown by the slowevaporation solution growth technique using methanol as a solvent at room temperature The grown crystals were characterisedby single crystal X-ray diffraction (XRD) which confirms that the crystal belongs to monoclinic system with the centrosymmetricspace group P2

1119888 The crystalline perfection of the grown crystal was analyzed by high resolution X-ray diffraction (HRXRD)

The presence of various functional groups was identified by FTIR spectrum UV-Vis spectral study reveals that the BSL crystal isoptically transparent in the wavelength region 342 nmndash1100 nm Dielectric measurements of the crystal at various frequencies werealso determined The mechanical properties of the grown crystal were assessed using Vickers microhardness testing Nonlinearoptical property of the crystal was confirmed using Kurtz and Perry powder technique and the SHG efficiency of the BSL crystal is07 times greater than that of the standard KDP crystal

1 Introduction

In recent years organic materials have attracted manyresearchers due to its high nonlinearities ultrafast responsein electrooptic effect large optical susceptibilities large sec-ond order molecular polarizability and higher resistance tooptical damage and they have wide applications in opticalcommunications frequencymixing optical parametric oscil-lation information storage and so forth [1ndash4] Accordingto crystal engineering second harmonic generation occursmostly in noncentrosymmetric crystals due to nonzerohyperpolarizability But some of the recent reports of organicmolecular complexes like caffenium picrate [5] picoliniummaleate [6] guanidinium trifluoroacetate and so forth havehighlighted that even centrosymmetric crystals possess SHGeffect due to the presence of delocalized 120587 electron sys-tem linking donor and acceptor groups which enhance thenecessary asymmetric polarizability [7 8] The variousorganic subnetworks enhance the thermal and mechanicalstabilities throughhydrogen bonding interactions and behaveas noncentrosymmetrymaterial in the bulk [9 10] In organicmolecular charge transfer complexes the charge transfer

interaction and molecular aggregation through intermolec-ular hydrogen bonding has been entrenched by single crystalXRD analysis [11 12]

Benzimidazole is a very good proton acceptor and in thepresence of a carboxylic acid it will always deprotonate thatgroup Hence it is widely used in the formation of organicmolecular complex salts like benzimidazolium hydrogenphenylmalonate benzimidazolium hydrogen nitrotereptha-late 2 methyl benzimidazolium picrate and so forth [13ndash15] According to Mulliken the charge transfer interactionsbetween two aromatic molecules arise due to the transfer ofan electron from Lewis base to Lewis acid and have attractedconsiderable attention on these complexes for their nonlinearoptical properties [16 17] The researchers have reportedrecently Benzimidazole based organic compounds with goodnonlinear properties such as 1H benzimidazolium hydrogenL-tartrate dihydrate [18] benzil doped Benzimidazole [19]benzimidazolium per chlorate [20] Similarly salicylic acidforms salicylate salts with various organic molecules andforms salts through hydrogen bonding interactions like Ureasalicylate Bis Guanidinium 5 sulfosalicylate and Brucinium5 sulfosalicylate trihydrate and they are reported as efficient

Hindawi Publishing CorporationAdvances in Optical TechnologiesVolume 2015 Article ID 206325 9 pageshttpdxdoiorg1011552015206325

2 Advances in Optical Technologies

N

NH

+

OHO

HO

NH

H O

HO

Benzimidazole Salicylic acid Benzimidazolium salicylate

N+

Ominus

Figure 1 Reaction scheme for BSL

Figure 2 As grown BSL crystal of dimension 19 times 9 times 4mm3

NLO materials [21ndash23] The formation of hydrogen bondingin benzimidazolium organic complex salts was reported Inthe present work the Benzimidazole molecule is protonatedthrough hydrogen transfer from the carboxylic group on the2-hydroxy benzoic acid (salicylic acid) In this paper thesynthesis crystal growth and structural spectral opticaland mechanical properties of the benzimidazolium salicylate(BSL) crystal for NLO applications are reported

2 Materials and Methods

21 Synthesis and Crystal Growth Analar grade Benzimida-zole and salicylic acid were taken in 1 1 molar ratio and dis-solved completely in methanol The mixture was stirred wellfor about 6 hrsThe reaction involved is illustrated in Figure 1Suspended impurities were removed by using Whatman 41grade filter paperThe clear filtrate so obtained was kept asidein a dust-free room for the growth of single crystalThe purityof synthesized compound BSL was improved by successiverecrystallization process and filtration Optically good trans-parent colourless crystal having dimensions 19 times 9 times 4mm3with perfect external morphology was harvested within aperiod of 1 week and the grown crystal is shown in Figure 2

3 Characterization Studies

31 Single Crystal X-Ray Diffraction Studies Single crystalX-ray diffraction analysis of the grown crystal was carriedout using ENRAF NONIUS CAD-4 X-ray diffractometer

equipped with monochromated MoK120572 radiation (120582 =

071073 A) It is found that the crystal belongs to monocliniccrystal system with space group P2

1119888 The crystal data and

the structure refinement for BSL crystal is given in Table 1The structure of the BSL crystal has been solved by directmethods and refined by full-matrix least square techniquesusing SHELXL-97 program to an 119877 value of 00481 TheORTEP diagram of the molecular structure of the grown BSLsingle crystal is shown in Figure 3 The title salt consists ofa C7H7N2

+ cation and C7H5O3

minus anion in the asymmetricunit The cation is protonated at N atom The dihedral anglebetween the benzimidazolium and benzene rings is 7588(5)∘The molecular structure is stabilized by weak O- - -H Ohydrogen bond which generates S(6) graph-set motif Inthe crystal structure the weak intermolecular N- - -H OC- - -H O hydrogen bonds link the adjacent anions andcations The crystal packing is further influenced by weakC-H Π and Π Π [Cg1 Cg1(i) distance = 34156(7) ACg1 Cg2(ii) distance = 38196(8) A (i) 2 minus 119909 2 minus 119910 minus119911(ii) 3 minus 119909 2 minus 119910 minus119911 Cg1 and Cg2 are the centroids of therings (N1C8C13N2C14) and (C8ndashC13) resp] interactionsforming a three-dimensional network

32 High-Resolution X-Ray Diffractometry (HRXRD) Analy-sis The rocking curves of the BSL crystals for the diffractionplanes (0 0 1) were recorded in symmetrical Bragg geometryusing the natural facets by performing 120596 scan with double-axis geometry [24] The monochromated X-ray beam inci-dent on the specimen was obtained using a high-resolutionfour-bounce Ge (2 2 0) monochromator A scintillationdetector was used to record the diffracted beam from thecrystal sample without using any analyzer at the receivingstage before the detector to get all the possible informationlike the individual peaks from structural grain boundariesscattered intensity from the dislocations and other defectsfrom the specimen crystal Figure 4 shows the recorded highresolution X-ray diffraction curve for a typical BSL crystalspecimen using (0 0 1) diffracting planes in symmetricalBragg geometry by employing the multicrystal X-ray diffrac-tometerwithMoK1205721 radiationTheDCcontains a single peakand indicates that the specimen is free from structural grainboundaries The FWHM (full width at half maximum) ofthe curve is 158 arcsec which is close to the perfect real lifecrystal The low values of FWHM and the low angular spreadof around 500 arcsec of the DC indicate that the crystallineperfection is reasonably good Growth conditions as well as

Advances in Optical Technologies 3

Table 1 Crystal data and structure refinement for BSL crystal

Empirical formula C14H12N2O3

Formula weight 25626Temperature 295(2) KWavelength 071073 ACrystal system MonoclinicSpace group P2

1119888

Unit cell dimensions119886 = 74776(3) A 120572 = 90∘119887 = 67002(2) A 120573 = 94445(2)∘119888 = 249017(9) A 120574 = 90∘

Volume 124386(8) A3

119885 4Density (calculated) 1368Mgm3

Absorption coefficient 0098mmminus1

119865(000) 536Crystal size 034 times 030 times 025mm3

Theta range for data collection 273 to 3935∘Index ranges minus10 le ℎ le 10 minus11 le 119896 le 9 minus35 le 119897 le 35Reflections collected 23125Independent reflections 4606 [119877(int) = 00244]Completeness to theta = 2500∘ 999Absorption correction Semiempirical from equivalentsMax and min transmission 09759 and 09674Refinement method Full-matrix least squares on 1198652

Datarestraintsparameters 46061176Goodness-of-fit on 1198652 1031Final 119877 indices [119868 gt 2sigma(119868)] 1198771 = 00481 1199081198772 = 01237119877 indices (all data) 1198771 = 00822 1199081198772 = 01422Extinction coefficient 0025(3)Largest diff peak and hole 0348 and minus0259 e Aminus3

C1

C7

N1

O1

C2

N2

O2

C3

O3

C4

C5

C6

C8C9

C10

C11 C12

C13

C14

Figure 3 ORTEP diagram of BSL crystal


158998400998400

minus1000 minus500 0 500 1000 1500minus1500

Omega (arc s)

0

5000

10000

15000

20000

25000

Diff

ract

ed X

-ray

inte

nsity

(cou

nts)

Figure 4 HRXRD curve of BSL crystal

30822988 2750

2537

1947 1860

1620

159214781451

13801353

1244

1139

1029

932

853827

796

766745

706661

612

569

458

0102030405060708090

100

T(

)

3600

3200

2800

2400

2000

1800

1600

1400

1200

1000 80

0

600

450

4000

(cmminus1)

Figure 5 FTIR Spectrum of BSL

thermodynamic considerations also result in point defects inthe crystals and are unavoidable up to some extent [25]

33 FT-IR Spectrum The FT-IR spectrum of benzimida-zolium salicylate was recorded in the range 4000ndash400 cmminus1(Figure 5) It is evident from the spectrum that the bandat 3339 cmminus1 is assigned to the OH asymmetric stretchingvibration The bands at 3082 and 2988 cmminus1 are due to aro-matic C-H asymmetric and symmetric stretching vibrationsof Benzimidazole respectively The C=O vibration of COOminusin salicylate gives its peak at 1620 cmminus1 In free salicylic acidC=O vibration occurs at 1750 cmminus1 The shift towards lowvalue therefore illustrates the transfer of carboxylic protonfrom carboxylic acid to Benzimidazole The bands at 15921478 1451 and 1380 cmminus1 are assigned to the aromatic C=Cstretching vibrations of Benzimidazole ring which once againverifies the presence of Benzimidazole in the crystal [26]The band observed at 1139 cmminus1 is assigned to C-H inplanebending vibration of benzimidazolium ring [27] The bandat 1353 cmminus1 is due to C-H bending A band at 1244 cmminus1 is

Table 2 The wavenumber and the assignment of vibration of BSL

Wavenumber (cmminus1) Assignment of vibration3339 O-H asymmetric stretching vibration3082 2988 Aromatic C-H stretching vibration1620 C=O vibration of Salicylate1592 1478 1451 and 1380 Aromatic C=C stretching vibration1244 C-O stretching vibration1139 C-H inplane bending vibration1029 932 C-N stretching vibration766 C-H out of plane bending

342 (nm)

426 (nm)

400 600 800 1000 1200200Wavelength (nm)

00

01

02

03

04

05

06

Abso

rptio

n (

)

Figure 6 Optical absorption spectrum of BSL crystal

assigned to the C-O stretching vibration The bands at 1029and 932 cmminus1 are assigned to C-N stretching vibration Theband at 766 cmminus1 is due to the C-H out of plane bending ofaromatic hydrogen atom The respective assignments aregiven in Table 2

34 UV-Vis Absorption Spectral Analysis The UV-Vis spec-trum relinquishes valuable information about the atomicstructure of the molecules because the absorption of UVand visible light involves the promotion of 120590 and 120587 orbitalelectrons from the ground state to higher energy stateFor device fabrication this is one of the desirable prop-erties of the crystals The electronic absorption spectrumof BSL crystal was recorded using Shimadzu 1601 UV-Visspectrophotometer in the range 200ndash1100 nm and is shownin Figure 6 The optical absorption spectrum indicates thatthe crystal has lower cut-off wavelength of about 342 nmFrom the absorption spectrum it can be observed that thereis less absorbance in the entire visible and near-infraredregion The wide transparency and lower cut-off is one ofthe requirements for having efficient NLO character Theabsorption due to electronic transitions above 300 nm is thekey requirement for frequency doubling using diode andsolid state lasers [28] The absorption peak at 342 nm isassigned to 120587 to 120587lowast transition of the compound which is


Eg = 307 eV

15 20 25 30 3510h (eV)

0

2

4

6

8

10

12

(120572h

)2

Figure 7 Optical band gap of BSL crystal

attributed to the charge transfer of the compound Absenceof absorption between 400 nm and 800 nm is the key require-ment for materials possessing SHG properties Thus BSLcrystal can be used as a potential candidate for the SHGdevice application in the visible region [29] The UV cut-offwavelength of BSL is comparable with other Benzimidazolederivatives such as benzimidazolium per chlorate (360 nm)and pure Benzimidazole (300 nm) and salicylic acid saltslike Brucinium 5 sulfosalicylate (312 nm) Urea salicylic acid(347 nm) and so forth [18ndash21 30]

35 Determination of Optical Band Gap The optical absorp-tion coefficient (120572) was calculated from the transmittanceusing 120572 = (1119889) log(1119879) where 119879 is the transmittanceand 119889 is the thickness of the crystal The plot of variationof (120572ℎ])2 versus ℎ] is shown in Figure 7 The band gapenergy 119864

119892is evaluated by the extrapolation of the linear part

The band gap was found to be 307 eV The transmittanceincreases while the band gap becomes wider The wideband gap energy confirms the good optical transparencyand dielectric behaviour of the crystal [31] It also ensuresthe crystal suitability for optoelectronic device applicationoptical harmonic generation and so forth [32]

36 Dielectric Studies The capacitance (119862) and dielectric loss(tan 120575) were measured using the conventional parallel platecapacitor connected with HIOKI-LCR Hi-Tester 3532 attemperatures 308K 318 K and 328K with frequency rangeof 50Hz to 6MHz The dielectric studies of BSL crystalwas performed with a crystal of dimension 19 times 9 times 4mm3which was coated with good quality graphite to obtain agood conductive surface layer The variation of dielectricconstant and dielectric loss as a function of log119891 at differenttemperatures are shown in Figures 8 and 9

It is observed from Figure 8 that the dielectric constantdecreases with increasing frequency and finally it becomesalmost a constant at higher frequencies for all temperaturesThe dielectric constant has a high value of 505 at 100Hz

308K318K328K

1 2 3 4 5 6 70log f

0

100

200

300

400

500

Die

lect

ric co

nsta

nt (120576

r)

Figure 8 Plot of dielectric constant and log119891

308K318K328K

2 3 4 5 6 71log f

0001020304050607080910111213141516

Die

lect

ric lo

ss (t

an 120575)

Figure 9 Plot of dielectric loss and log119891

and decreases to 23 at 6MHz The higher value of dielectricconstant at lower frequency regionmay be due to the presenceof all the four types of polarization namely space chargeorientation and ionic and electronic polarizationsThe lowervalue of dielectric constant at higher frequency was due tothe loss of significance of these polarizations gradually Spacecharge polarization is generally active at lower frequenciesand high temperatures which signifies the perfection of thecrystalThe variation of dielectric loss at different frequenciesand temperatures (Figure 9) shows the same trend as dielec-tric constant The crystal undergoes piezoelectric resonanceat 10 KHz where the frequency of the electric field matches


times10minus4

minus02

00

02

04

06

08

10

12

14

16

18

120590ac

3 4 5 62log f

308K318K328K

Figure 10 Plot of ac conductivity and log119891 for varying tempera-tures

the frequency of the vibration of the crystal [33] Also thetemperature dependence of dielectric constant and dielectricloss can be explained as being due to temperature dependenceof protonic movement and ionic polarizability [34] The con-siderable low value of dielectric constant at higher frequen-cies indicates that the crystal can be used in photonic elec-trooptic andNLOdevicesMoreover the low dielectric lossesat higher frequencies indicate that the grown BSL crystal is ofgood quality with lesser defects and is an important parame-ter for nonlinear optical material in their applications [35]

The alternating current conductivity (120590ac) is calculatedusing the relation [36]

120590ac = 21205871198911205980120598119903 tan 120575 (1)

where 119891 is the frequency of the applied ac field (Hz) 1205980is the

permittivity of free space and 120598119903and tan 120575 are the measured

values of dielectric constant and dielectric loss of thematerialThe ac conductivity plot with temperature for varying fre-quency is shown in Figure 10This plot shows that the ac con-ductivity increases with frequency and temperature whichindicates the normal dielectric behaviour of BSL crystal

37 Vickers Microhardness Analysis The mechanical proper-ties of crystals are determined by mechanical testing whichenables us to study the mechanical characteristics of crystalsThe Vickers microhardness study was made on the as grownface of BSL for the static indentation test in air at roomtemperature using Leitz Wetzlar hardness tester fitted withVickers diamond pyramidal indentor The Vickers hardnessnumber was calculated using the expression

119867V = 1854 (119875

1198892) (2)

H

(kg

mm2)

20 40 60 80 1000Load P (g)

0

20

40

60

80

100

120

140

160

Figure 11 Variation of Vickers hardness number119867V with load 119875

n = 3389

10

11

12

13

14

15

log P

146 148 150 152 154 156 158144log d

Figure 12 Plot between log119875 and log 119889

where119867V is the Vickers hardness number for a given load 119875in gram and 119889 is the average diagonal length of the indenta-tion in mm For loads ranging from 25 to 100 gm the micro-hardness values of BSL were found to be increasing with loadThe plot of119867V versus load 119875 is shown in Figure 11TheMayerindex number was calculated fromMayerrsquos law which relatesthe load and indentation diagonal length Consider

119875 = 119896119889119899

log119875 = log 119896 + 119899 log 119889(3)

where 119896 is the material constant and 119899 is work-hardeningcoefficient The plot between log119875 and log 119889 is shown inFigure 12 According to Onitsch 119899 should lie between 1 and16 for hardermaterials and above 16 for softermaterials [37]Thework-hardening coefficient (119899) was calculated to be 3389from the slope of log119875 versus log 119889 Thus the BSL crystalbelongs to soft material category


Table 3 SHG efficiency of various centrosymmetric materials

Sample Space group SHG with KDPDiimidazolium dipicratemonohydrate [42] P2

1119898 02

(p-NitrophenolhexamethylenetetraminePhosphoric acid and water)supramolecular crystal [43]

P21119888 31

RS-serine [7] P21119886 002

Glycine picrate [44] P21119886 234

Guanidiniumtrifluoroacetate [45] Pbcn 087

Benzimidazolium salicylate[present work] P2

1119888 07

38 SHG Efficiency Analysis The SHG conversion efficiencyof benzimidazolium salicylate was determined by KurtzrsquosPerry technique The crystal was ground into a very finepowder and tightly packed in a microcapillary tube Then itwas mounted in the path of NdYAG laser beam of energy19mJs The output of 44mV was obtained for the grownsample When KDP crystal of the same size was used as areference material an output of 64mV was obtained Hencethe grown crystal has an efficiency of about 07 times greaterthan that of KDP

The criteria for SHG may also be satisfied by centrosym-metric molecule if they aggregate in a noncentrosymmetricmanner and there is a contribution to the bulk susceptibilityfrom intermolecular charge transfer [5] Most moleculeslike paranitro aniline have very large SHG at the molecularscale due to the charge transfer from the donor to the ac-ceptor crystallize in a centrosymmetric lattice due to predom-inating antiparallel 120587-stacking between the aromatic rings asa consequence of dipolar interactions [38 39] Even thoughthe material belongs to centrosymmetric it exhibits SHGactivity due to intermolecular hydrogen bonding and chargetransfer interactions between the donor and acceptor sys-tems The SHG in BSL crystal is due to weak interactionbetween the dipoles which is easy for the ground state toturn into the excited state as a charge separated form andgenerate the stable asymmetrical distribution of 120587 electroncloud density thus exhibiting aminimum SHG effect [40 41]The SHG efficiency of BSL crystal is compared with otherreported SHG efficiencies of centrosymmetric materials andis tabulated in Table 3

4 Conclusion

The organic molecular complex salt BSL was synthesized andgrown as single crystal by slow evaporation solution growthtechnique at room temperature with methanol as the solventThe single crystal XRD confirms that the BSL crystal belongsto monoclinic system with the centrosymmetric space groupP21119888 The functional groups present in the grown crystal

have been confirmed by FT-IR spectral analysis The UV-Visspectral analysis reveals high transparency of BSL crystal in

the entire visible region The optical band gap energy (119864119892) of

the BSL crystal is 307 eVThemechanical stability of BSL wasdetermined using Vickers microhardness analysis The highresolution X-ray diffraction (HRXRD) of the crystal showsthat the perfection of the crystal is quite good Dielectricmeasurements were carried out to analyse the dielectricconstant and dielectric loss at different frequencies and atdifferent temperature The powder SHG efficiency of BSL is07 times that of KDP The SHG effect from the centrosym-metric crystal is a remarkable experimental observation andit is concluded that BSL is a potential material for photonicdevice fabrication

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The authors thank Professor P K Das Department ofInorganic and Physical Chemistry IISC Bangalore for themeasurement of powder SHG efficiency

References

[1] D S Chemla and J ZyssNonlinear Optical Properties of OrganicMolecule and Crystals Academic Press New York NY USA1987

[2] P N Prasad and D J Williams Introduction to NonlinearOptical Effects in Molecules and Polymers Wiley New York NYUSA 1991

[3] J Badan R Hierle A Perigand and J Zyss Nonlinear OpticalProperties ofOrganicMolecules andPolymericMaterials vol 233of edited by Williams American Chemical Society Washing-ton DC USA 1993

[4] C Bosshard M Bosch I Liakatas M Jager and P GunterldquoSecond-order nonlinear optical organic materials recentdevelopmentsrdquo in Nonlinear Optical Effects and Materials vol72 of Springer Series in Optical Sciences pp 163ndash299 SpringerBerlin Germany 2000

[5] A Chandramohan R Bharathikannan J Chandrasekaran PMaadeswaran R Renganathan and V Kandavelu ldquoSynthesiscrystal growth and characterization of a new organic NLOmaterial caffeinium picrate (CAFP)mdasha charge transfer molec-ular complex saltrdquo Journal of Crystal Growth vol 310 no 24 pp5409ndash5415 2008

[6] P Pandi G Peramaiyan S Sudhahar et al ldquoStudies on syn-thesis growth structural thermal linear and nonlinear opti-cal properties of organic picolinium maleate single crystalsrdquoSpectrochimica ActamdashPart A Molecular and Biomolecular Spec-troscopy vol 98 pp 7ndash13 2012

[7] K E Rieckhoff and W L Peticolas ldquoOptical second-harmonicgeneration in crystalline amino acidsrdquo Science vol 147 no 3658pp 610ndash611 1965

[8] W Guo F Guo C Wei et al ldquoSHG from centrosymmetricsupermolecular crystalrdquo Science in China Series B Chemistryvol 45 no 3 pp 267ndash274 2002


[9] A Criado M J Dianez S Perez-Garrido I M L FernandesM Belsley and E De Matos Gomes ldquo1133-tetramethylguan-idinium dihydrogenorthophosphaterdquo Acta Crystallographicavol 56 no 7 pp 888ndash889 2000

[10] J Zaccaro J P Salvastrini A Ibanez P Ney and M DJ Fontana ldquoElectric-field frequency dependence of Pockelscoefficients in 2-amino-5-nitropyridium dihydrogen phosphateorganic-inorganic crystalsrdquo Journal of the Optical Society ofAmerica B vol 17 no 3 pp 427ndash432 2000

[11] A Chandramohan R Bharathikannan M A KandhaswamyJ Chandrasekaran R Renganathan and V Kandavelu ldquoSyn-thesis spectral thermal and NLO properties of NN-dimethylanilinium picraterdquo Crystal Research and Technology vol 43 no2 pp 173ndash178 2008

[12] A Chandramohan D Gayathri D Velmurugan K Ravikumarand M A Kandhaswamy ldquo137-Trimethylxanthenium 246-trinitrophenolaterdquo Acta Crystallographica Section E vol 63 no5 pp 2495ndash2496 2007

[13] S Ueda T Fukunaga and H Ishida ldquoBenzimidazolium hydro-gen phenylmalonaterdquo Acta Crystallographica Section E vol 61pp o1845ndasho1847 2005

[14] T-T Pan J-G Liu and D-J Xu ldquoBenzimidazolium hydrogennitroterephthalaterdquo Acta Crystallographica Section E StructureReports Online vol 61 no 12 pp o3996ndasho3997 2005

[15] M Obulichetty and D Saravanabharathi ldquoInfluence of molec-ular structure on the photoluminescence of 2-methyl benzim-idazolium picrate a new fluorescent materialrdquo SpectrochimicaActamdashPart AMolecular and Biomolecular Spectroscopy vol 118pp 861ndash866 2014

[16] R Walia M Hedaitullah F S Naar K Iqbal and H S LambaldquoBenzimidazole derivativesmdashan overviewrdquo International Jour-nal of Research in Pharmacy and Chemistry vol 1 no 3 pp565ndash573 2011

[17] R S Mulliken ldquoStructures of complexes formed by halogenmolecules with aromatic andwith oxygenated solventsrdquo Journalof the American Chemical Society vol 72 no 1 pp 600ndash6081950

[18] M Rajalakshmi R Indirajith P Ramasamy and R Gopalakr-ishnan ldquoSynthesis growth and characterization of 1H-benzim-idazolium hydrogen L-tartrate dihydrate single crystalsrdquoMolec-ular Crystals and Liquid Crystals vol 548 no 1 pp 126ndash1412011

[19] R R Babu M Sukumar V Vasudevan M Shakir K Rama-murthi and G Bhagavannarayana ldquoGrowth and properties ofbenzil doped benzimidazole (BMZ) single crystalsrdquo MaterialsResearch Bulletin vol 45 no 9 pp 1197ndash1198 2010

[20] L Mariappan A Kandasamy M Rathnakumari and PSureshkumar ldquoSynthesis growth and properties of a novelorganic nonlinear optical material benzimidazolium perchlo-raterdquo Optik vol 124 no 22 pp 5707ndash5710 2013

[21] C Andal and P Murugakoothan ldquoGrowth of urea salicylic acid(USA) crystalrdquo International Journal of ChemTech Research vol6 no 3 pp 1541ndash1543 2014

[22] M Dhavamurthy G Peramaiyan K S S Babu and R MohanldquoCrystal growth morphology thermal and spectral studiesof an organosulfur nonlinear optical bis(guanidinium) 5-sul-fosalicylate (BG5SS) single crystalsrdquo Applied Physics A vol 119no 1 pp 155ndash161 2015

[23] K Gayathri P Krishnan P R Rajkumar and G AnbalaganldquoGrowth optical thermal and mechanical characterization ofan organic crystal brucinium 5-sulfosalicylate trihydraterdquo Bul-letin of Materials Science vol 37 no 7 pp 1589ndash1595 2014

[24] G Bhagavannarayana and S K Kushwaha ldquoEnhancement ofSHG efficiency by urea doping in ZTS single crystals and itscorrelation with crystalline perfection as revealed by Kurtzpowder and high-resolution X-ray diffraction methodsrdquo Jour-nal of Applied Crystallography vol 43 no 1 pp 154ndash162 2010

[25] G Bhagavannarayana P Rajesh and P Ramasamy ldquoInterestinggrowth features in potassium dihydrogen phosphate unravel-ling the origin and dynamics of point defects in single crystalsrdquoJournal of Applied Crystallography vol 43 pp 1372ndash1376 2010

[26] N Vijayan R Ramesh Babu R Gopalakrishnan P Ramasamyand W T A Harrison ldquoGrowth and characterization of benz-imidazole single crystals a nonlinear optical materialrdquo Journalof Crystal Growth vol 262 no 1ndash4 pp 490ndash498 2004

[27] R M Silverstein and F X Webster Spectrometric Identificationof Organic Compounds John Wiley amp Sons Quebec Canada6th edition 1998

[28] V G Dmitriev G G Gurzadyan and D N NikoyosyanHand-book of Nonlinear Optical Crystals Springer Berlin Germany1999

[29] K Kirubavathi K Selvaraju N Vijayan and S KumararamanldquoSynthesis growth and characterization of L-Valinium Picratea new nonlinear optical crystalrdquo Spectrochimica Acta Part AMolecular and Biomolecular Spectroscopy vol 71 no 1 pp 288ndash291 2008

[30] S Rajasekar M Vimalan N Vijayan and P S Joseph ldquoGrowthand dielectric studies of benzimidazole a novel organic NLOmaterialrdquo Archives of Applied Science Research vol 4 no 2 pp1022ndash1027 2012

[31] D D O Eya A J Ekpunobi and C E Okeke ldquoInfluenceof thermal annealing on the optical properties of tin oxidethin films prepared by chemical bath deposition techniquerdquoAcademic Open Internet Journal vol 17 2006

[32] P Rajesh and P Ramasamy ldquoGrowth of dl-malic acid-dopedammonium dihydrogen phosphate crystal and its characteriza-tionrdquo Journal of Crystal Growth vol 311 no 13 pp 3491ndash34972009


[34] VAHiremath andAVenkataraman ldquoDielectric electrical andinfrared studies of 120574-Fe

2O3prepared by combustion methodrdquo

Bulletin of Materials Science vol 26 no 4 pp 391ndash396 2003[35] U Charoen-In P Ramasamy and P Manyum ldquoCompara-

tive study on l-alaninium maleate single crystal grown bySankaranarayananndashRamasamy (SR) method and conventionalslow evaporation solution techniquerdquo Journal of Crystal Growthvol 312 no 16-17 pp 2369ndash2375 2010

[36] B Lal K K Bamzai P N Kotru and B M Wanklyn ldquoMicro-hardness fracture mechanism and dielectric behaviour of flux-grown GdFeO

3single crystalsrdquo Materials Chemistry and Phys-

ics vol 85 no 2-3 pp 353ndash365 2004[37] EMOnitsch ldquoMicro-hardness testingrdquoMikroscopia vol 2 pp

131ndash151 1947[38] S C Abraham and J M Robertson ldquoThe crystal structure of

p-nitroaniline NO2C6H4NH2rdquo Acta Crystallographica vol 1

pp 252ndash259 1948[39] J Donhue and K N Trueblood ldquoThe crystal structure of p-

nitroanilinerdquo Acta Crystallographica vol 9 p 960 1956[40] G J Ashwell G Jefferies D G Hamilton et al ldquoStrong second-

harmonic generation from centrosymmetric dyesrdquo Nature vol375 no 6530 pp 385ndash388 1995


[41] W Nie ldquoOptical nonlinearity phenomena applications andmaterialsrdquoAdvancedMaterials vol 5 no 7-8 pp 520ndash545 1993

[42] K Mohana Priyadharshini and A Chandramohan ldquoSynthesisgrowth crystal structure and characterization of an organicsalt single crystal diimidazolium dipicrate monohydraterdquo TheExperiment vol 25 no 4 pp 1759ndash1774 2014

[43] W Guo F Guo C Wei et al ldquoSHG from centrosymmetricsupermolecular crystalrdquo Science in China Series B Chemistryvol 45 no 3 p 276 2002

[44] M Shakir S K Kushwaha K KMauryaMArora andG Bha-gavannarayana ldquoGrowth and characterization of glycine pi-cratemdashremarkable second-harmonic generation in centrosym-metric crystalrdquo Journal of Crystal Growth vol 311 no 15 pp3871ndash3875 2009

[45] M Loganayaki V S Shankar P Ramesh M Ponnuswamyand PMurugakoothan ldquoGrowth and characterization of guani-dinium trifluoroacetatemdashsecond harmonic generation from acentrosymmetric crystalrdquo Journal ofMinerals ampMaterials Char-acterization amp Engineering vol 10 no 9 pp 843ndash853 2011

International Journal of

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Active and Passive Electronic Components

Control Scienceand Engineering

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Submit your manuscripts athttpwwwhindawicom

VLSI Design



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Civil EngineeringAdvances in

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



N

NH

+

OHO

HO

NH

H O

HO

Benzimidazole Salicylic acid Benzimidazolium salicylate

N+

Ominus

Figure 1 Reaction scheme for BSL

Figure 2 As grown BSL crystal of dimension 19 times 9 times 4mm3

NLO materials [21ndash23] The formation of hydrogen bondingin benzimidazolium organic complex salts was reported Inthe present work the Benzimidazole molecule is protonatedthrough hydrogen transfer from the carboxylic group on the2-hydroxy benzoic acid (salicylic acid) In this paper thesynthesis crystal growth and structural spectral opticaland mechanical properties of the benzimidazolium salicylate(BSL) crystal for NLO applications are reported

2 Materials and Methods

21 Synthesis and Crystal Growth Analar grade Benzimida-zole and salicylic acid were taken in 1 1 molar ratio and dis-solved completely in methanol The mixture was stirred wellfor about 6 hrsThe reaction involved is illustrated in Figure 1Suspended impurities were removed by using Whatman 41grade filter paperThe clear filtrate so obtained was kept asidein a dust-free room for the growth of single crystalThe purityof synthesized compound BSL was improved by successiverecrystallization process and filtration Optically good trans-parent colourless crystal having dimensions 19 times 9 times 4mm3with perfect external morphology was harvested within aperiod of 1 week and the grown crystal is shown in Figure 2

3 Characterization Studies

31 Single Crystal X-Ray Diffraction Studies Single crystalX-ray diffraction analysis of the grown crystal was carriedout using ENRAF NONIUS CAD-4 X-ray diffractometer

equipped with monochromated MoK120572 radiation (120582 =

071073 A) It is found that the crystal belongs to monocliniccrystal system with space group P2

1119888 The crystal data and

the structure refinement for BSL crystal is given in Table 1The structure of the BSL crystal has been solved by directmethods and refined by full-matrix least square techniquesusing SHELXL-97 program to an 119877 value of 00481 TheORTEP diagram of the molecular structure of the grown BSLsingle crystal is shown in Figure 3 The title salt consists ofa C7H7N2

+ cation and C7H5O3

minus anion in the asymmetricunit The cation is protonated at N atom The dihedral anglebetween the benzimidazolium and benzene rings is 7588(5)∘The molecular structure is stabilized by weak O- - -H Ohydrogen bond which generates S(6) graph-set motif Inthe crystal structure the weak intermolecular N- - -H OC- - -H O hydrogen bonds link the adjacent anions andcations The crystal packing is further influenced by weakC-H Π and Π Π [Cg1 Cg1(i) distance = 34156(7) ACg1 Cg2(ii) distance = 38196(8) A (i) 2 minus 119909 2 minus 119910 minus119911(ii) 3 minus 119909 2 minus 119910 minus119911 Cg1 and Cg2 are the centroids of therings (N1C8C13N2C14) and (C8ndashC13) resp] interactionsforming a three-dimensional network

32 High-Resolution X-Ray Diffractometry (HRXRD) Analy-sis The rocking curves of the BSL crystals for the diffractionplanes (0 0 1) were recorded in symmetrical Bragg geometryusing the natural facets by performing 120596 scan with double-axis geometry [24] The monochromated X-ray beam inci-dent on the specimen was obtained using a high-resolutionfour-bounce Ge (2 2 0) monochromator A scintillationdetector was used to record the diffracted beam from thecrystal sample without using any analyzer at the receivingstage before the detector to get all the possible informationlike the individual peaks from structural grain boundariesscattered intensity from the dislocations and other defectsfrom the specimen crystal Figure 4 shows the recorded highresolution X-ray diffraction curve for a typical BSL crystalspecimen using (0 0 1) diffracting planes in symmetricalBragg geometry by employing the multicrystal X-ray diffrac-tometerwithMoK1205721 radiationTheDCcontains a single peakand indicates that the specimen is free from structural grainboundaries The FWHM (full width at half maximum) ofthe curve is 158 arcsec which is close to the perfect real lifecrystal The low values of FWHM and the low angular spreadof around 500 arcsec of the DC indicate that the crystallineperfection is reasonably good Growth conditions as well as





1119888


Volume 124386(8) A3






C1

C7

N1

O1

C2

N2

O2

C3

O3

C4

C5

C6

C8C9

C10

C11 C12

C13

C14



158998400998400


Omega (arc s)

0

5000

10000

15000

20000

25000

Diff

ract

ed X

-ray

inte

nsity

(cou

nts)


30822988 2750

2537

1947 1860

1620

159214781451

13801353

1244

1139

1029

932

853827

796

766745

706661

612

569

458

0102030405060708090

100

T(

)

3600

3200

2800

2400

2000

1800

1600

1400

1200

1000 80

0

600

450

4000

(cmminus1)






342 (nm)

426 (nm)

400 600 800 1000 1200200Wavelength (nm)

00

01

02

03

04

05

06

Abso

rptio

n (

)





Eg = 307 eV

15 20 25 30 3510h (eV)

0

2

4

6

8

10

12

(120572h

)2








308K318K328K

1 2 3 4 5 6 70log f

0

100

200

300

400

500

Die

lect

ric co

nsta

nt (120576

r)


308K318K328K

2 3 4 5 6 71log f

0001020304050607080910111213141516

Die

lect

ric lo

ss (t

an 120575)




times10minus4

minus02

00

02

04

06

08

10

12

14

16

18

120590ac

3 4 5 62log f

308K318K328K




120590ac = 21205871198911205980120598119903 tan 120575 (1)





119867V = 1854 (119875

1198892) (2)

H

(kg

mm2)

20 40 60 80 1000Load P (g)

0

20

40

60

80

100

120

140

160


n = 3389

10

11

12

13

14

15

log P

146 148 150 152 154 156 158144log d



119875 = 119896119889119899

log119875 = log 119896 + 119899 log 119889(3)





1119898 02


P21119888 31

RS-serine [7] P21119886 002




1119888 07



4 Conclusion







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













1119888


Volume 124386(8) A3






C1

C7

N1

O1

C2

N2

O2

C3

O3

C4

C5

C6

C8C9

C10

C11 C12

C13

C14



158998400998400


Omega (arc s)

0

5000

10000

15000

20000

25000

Diff

ract

ed X

-ray

inte

nsity

(cou

nts)


30822988 2750

2537

1947 1860

1620

159214781451

13801353

1244

1139

1029

932

853827

796

766745

706661

612

569

458

0102030405060708090

100

T(

)

3600

3200

2800

2400

2000

1800

1600

1400

1200

1000 80

0

600

450

4000

(cmminus1)






342 (nm)

426 (nm)

400 600 800 1000 1200200Wavelength (nm)

00

01

02

03

04

05

06

Abso

rptio

n (

)





Eg = 307 eV

15 20 25 30 3510h (eV)

0

2

4

6

8

10

12

(120572h

)2








308K318K328K

1 2 3 4 5 6 70log f

0

100

200

300

400

500

Die

lect

ric co

nsta

nt (120576

r)


308K318K328K

2 3 4 5 6 71log f

0001020304050607080910111213141516

Die

lect

ric lo

ss (t

an 120575)




times10minus4

minus02

00

02

04

06

08

10

12

14

16

18

120590ac

3 4 5 62log f

308K318K328K




120590ac = 21205871198911205980120598119903 tan 120575 (1)





119867V = 1854 (119875

1198892) (2)

H

(kg

mm2)

20 40 60 80 1000Load P (g)

0

20

40

60

80

100

120

140

160


n = 3389

10

11

12

13

14

15

log P

146 148 150 152 154 156 158144log d



119875 = 119896119889119899

log119875 = log 119896 + 119899 log 119889(3)





1119898 02


P21119888 31

RS-serine [7] P21119886 002




1119888 07



4 Conclusion







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










158998400998400


Omega (arc s)

0

5000

10000

15000

20000

25000

Diff

ract

ed X

-ray

inte

nsity

(cou

nts)


30822988 2750

2537

1947 1860

1620

159214781451

13801353

1244

1139

1029

932

853827

796

766745

706661

612

569

458

0102030405060708090

100

T(

)

3600

3200

2800

2400

2000

1800

1600

1400

1200

1000 80

0

600

450

4000

(cmminus1)






342 (nm)

426 (nm)

400 600 800 1000 1200200Wavelength (nm)

00

01

02

03

04

05

06

Abso

rptio

n (

)





Eg = 307 eV

15 20 25 30 3510h (eV)

0

2

4

6

8

10

12

(120572h

)2








308K318K328K

1 2 3 4 5 6 70log f

0

100

200

300

400

500

Die

lect

ric co

nsta

nt (120576

r)


308K318K328K

2 3 4 5 6 71log f

0001020304050607080910111213141516

Die

lect

ric lo

ss (t

an 120575)




times10minus4

minus02

00

02

04

06

08

10

12

14

16

18

120590ac

3 4 5 62log f

308K318K328K




120590ac = 21205871198911205980120598119903 tan 120575 (1)





119867V = 1854 (119875

1198892) (2)

H

(kg

mm2)

20 40 60 80 1000Load P (g)

0

20

40

60

80

100

120

140

160


n = 3389

10

11

12

13

14

15

log P

146 148 150 152 154 156 158144log d



119875 = 119896119889119899

log119875 = log 119896 + 119899 log 119889(3)





1119898 02


P21119888 31

RS-serine [7] P21119886 002




1119888 07



4 Conclusion







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Eg = 307 eV

15 20 25 30 3510h (eV)

0

2

4

6

8

10

12

(120572h

)2








308K318K328K

1 2 3 4 5 6 70log f

0

100

200

300

400

500

Die

lect

ric co

nsta

nt (120576

r)


308K318K328K

2 3 4 5 6 71log f

0001020304050607080910111213141516

Die

lect

ric lo

ss (t

an 120575)




times10minus4

minus02

00

02

04

06

08

10

12

14

16

18

120590ac

3 4 5 62log f

308K318K328K




120590ac = 21205871198911205980120598119903 tan 120575 (1)





119867V = 1854 (119875

1198892) (2)

H

(kg

mm2)

20 40 60 80 1000Load P (g)

0

20

40

60

80

100

120

140

160


n = 3389

10

11

12

13

14

15

log P

146 148 150 152 154 156 158144log d



119875 = 119896119889119899

log119875 = log 119896 + 119899 log 119889(3)





1119898 02


P21119888 31

RS-serine [7] P21119886 002




1119888 07



4 Conclusion







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










times10minus4

minus02

00

02

04

06

08

10

12

14

16

18

120590ac

3 4 5 62log f

308K318K328K




120590ac = 21205871198911205980120598119903 tan 120575 (1)





119867V = 1854 (119875

1198892) (2)

H

(kg

mm2)

20 40 60 80 1000Load P (g)

0

20

40

60

80

100

120

140

160


n = 3389

10

11

12

13

14

15

log P

146 148 150 152 154 156 158144log d



119875 = 119896119889119899

log119875 = log 119896 + 119899 log 119889(3)





1119898 02


P21119888 31

RS-serine [7] P21119886 002




1119888 07



4 Conclusion







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












1119898 02


P21119888 31

RS-serine [7] P21119886 002




1119888 07



4 Conclusion







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation

















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Documents

Research Article Growth and Characterization of ...downloads.hindawi.com/archive/2015/206325.pdf · F : As grown BSL crystal of dimension × × mm 3. NLO materials [ ]. e formation