Journal of Molecular Structure 1049 (2013) 27–35

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Journal of Molecular Structure

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Effect of deuteration: A new isotopic polymorph of glycine silver nitrate

0022-2860/$ - see front matter � 2013 Elsevier B.V. All rights reserved.http://dx.doi.org/10.1016/j.molstruc.2013.05.068

⇑ Corresponding author.E-mail address: rchitra@barc.gov.in (R. Chitra).

R. Chitra a,⇑, R.R. Choudhury a, Frederic Capet b, Pascal Roussel b, Himal Bhatt c

a Solid State Physics Division, Bhabha Atomic Research Center, Trombay, Mumbai 85, Indiab UCCS, CNRS UMR 8181, ENSC Lille UST Lille, BP 90108, 59652 Villeneuve d’Ascq Cedex, Francec High Pressure & Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Trombay, Mumbai 85, India

h i g h l i g h t s

� A new isotopic polymorph of glycine silver nitrate (GSN) has been synthesized.� The isotopic polymorph is a result of full deuteration.� The fully deuterated glycine silver (DGSN) crystallizes in P21/c space group, and forms 2-dimensional polymeric structure.� In DGSN, the silver ion is mononuclear, whereas in GSN, it is binuclear, but both of them have an oxidation state of +1� The primary reason for absence of phase transition in DGSN, is absence of coordination between Ag and Ag ions.

a r t i c l e i n f o

Article history:Received 16 April 2013Received in revised form 30 May 2013Accepted 31 May 2013Available online 15 June 2013

Keywords:Glycine silver nitrateDeuterationIsotopic polymorphSingle crystal X-ray diffractionRaman spectroscopy

a b s t r a c t

Crystallization of the completely deuterated glycine silver nitrate (DGSN) from D2O gave a new poly-morph with the crystal structure significantly differing from that of the nondeuterated form (GSN): spacegroup P21/c with polymeric two-dimensional layers parallel to the ab plane. In DGSN, the silver ions aremono-nuclear, whereas in GSN Ag–Ag dimers are present. In contrast to GSN, DGSN does not undergo anyphase transitions on cooling at least till 100 K.

� 2013 Elsevier B.V. All rights reserved.

1. Introduction

Complexes of glycine, a chiral amino acid, are interesting bothfrom biological point of view, (glycine being the simplest aminoacid), and from ferroelectricity point of view. Indeed large numberof glycine complexes, like triglycine sulphate family of crystals [1],diglycine nitrate [2], glycine phosphate [3] and glycine silver ni-trate (GSN) [4] are ferroelectric in nature. GSN was the first organo-metallic crystal with silver or nitrate ion in which ferroeclectricitywas observed [5]. The unique characteristic of GSN undergoing dis-placive phase transition makes it interesting. The infrared study[6], the proton magnetic resonance study [7] and structural studyusing X-ray powder diffraction [8] on GSN have indicated that fer-roelectricity in GSN is due to the motion of the silver ions (Ag+).This conclusion is further strengthened by the fact that on partialdeuteration (repeated recrystallization of GSN from D2O), the Curie

temperature increase only by 12 �C i.e. from about �55 �C to�43 �C. In this case the hydrogen atoms of CH2 radical have notbeen substituted by deuterium atoms [9]. Generally it is believedthat isotopic substitution does not perturb the crystal structure,but brings about change in the molecular spectroscopy vis the geo-metric isotope effect [10,11]. Attempt was made to grow fullydeuterated GSN (DGSN) crystals. Interestingly it was found thatthe grown crystals had crystallized in structure different from thatof GSN. Incidentally, only few cases of change in structure on deu-teration have been reported previously. It is also interesting tomention here that in few cases, though the deuteration does not ef-fect the structure at room temperature, but undergoes phase tran-sition at low temperature [12,13].

2. Crystallization

Colorless single crystals of the title complex were grown asthree-dimensional crystals by mixing fully deuterated a glycine

Fig. 1. Ortep [15] picture of asymmetric unit of DGSN with 50% ellipsoidalprobability.

Table 2aBond distances in DGSN.

Atoms Bond distance (Å) Atoms Bond distance (Å)

300 K 100 K 300 K 100 K

Ag1–O1g 2.2901 (9) 2.2909 (4) C1g–O1g 1.258 (1) 1.2621 (7)Ag1–O2gi 2.417 (1) 2.3878 (5) C1g–C2g 1.519 (1) 1.5220 (7)Ag1–O1n 2.534 (2) 2.4673 (6) C2g–N2g 1.468 (2) 1.4793 (7)N1–O1n 1.237 (2) 1.2501 (7) C2g–H4g 0.95 (2) 0.95 (1)N1–O3n 1.249 (2) 1.2563 (7) C2g–H5g 0.98 (2) 0.94 (1)N1–O2n 1.250 (1) 1.2578 (7) N2g–H1g 0.86 (3) 0.88 (1)C1g–O2g 1.250 (1) 1.2580 (7) N2g–H2g 0.91 (3) 0.85 (1)N2g–H3g 0.90 (3) 0.89 (1)

28 R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35

and silver nitrate in 1:1 stoichiometric ratio respectively in deuter-ated water. Repeated recrystallization yielded fully deuterated(DGSN). Under the same conditions, but with a glycine and silvernitrate in 1:1 stoichiomteric ratio respectively in aqueous solution(H2O) always yielded GSN.

3. Experimental

The room and low temperature data were collected on a BrukerX8 Apex II 4 K CCD diffractometer using Mo Ka graphite-mono-chromated radiation (k = 0.71073 Å).

Raman spectroscopic measurements were carried out on BrukerMultiRAM FT-Raman spectrometer. Liquid nitrogen cooled Gedetector was used to collect the Raman scattered light from thesample, which is excited by 1064 nm laser line of Nd:YAG laser.A total of 100 scans were co added at a resolution of 4 cm�1 to re-cord the Raman modes in the entire spectral range of interest 200–3400 cm�1. Spectral line positions were determined by a Lorentz-ian fit of the measured spectra.

4. Results and discussion

The structure was determined using direct methods as imple-mented in SHELXS [14]. The atomic parameters so obtained weresubjected to a series of isotropic and anisotropic full matrix leastsquare refinements using SHELXL97 [14]. All the reflections wereused for refinement. In the initial stages of refinement, reflectionweight (w) was taken to be 1=rðF2

oÞ, which was derived usingcounting statistics. All the hydrogen atoms were located from thedifference Fourier map and refined isotropically.

Table 1Crystallographic and refinement details.

CCDC no. 934034

Empirical formula C2H5AgN2O5

Formula weight 244.95Temperature (K) 300 KWavelength (Å) 0.71073Crystal system MonoclinicSpace group P21/cUnit cell dimensionsa (Å) 5.4372 (1)b (Å) 9.0488 (2)c (Å) 11.5456 (3)b (�) 91.926 (1)Volume (Å3) 567.72 (2)Z 4Calculated density (Mg m�3) 1.424Absorption coefficient (mm�1) 3.51Crystal size (mm3) 0.12 � 0.11 � 0.10h range for data collection (�) 2.9–45.2Limiting indices �10 6 h 6 8 �17 6 k 6 18 �Reflections collected/unique 44,545/4710 [R(int) = 0.025h max(�); Completeness to h = 45.2;99.7%Data/restraints/parameters 4710/0/112Goodness-of-fit on F2 1.03Final R indices R[F2 > 2r(F2)] R1 = 0.027 wR (F2) = 0.059

The asymmetric unit consists of glycine in the zwitter ionicform, a silver ion (Ag+) and a nitrate ion (NO�3 ) (Fig. 1). The bonddistances in the C1gO2gO1g group (C1g–O1g = 1.258(1) Å andC1g–O2g = 1.250(1) Å) of glycine indicated that the group appearsas a carboxylate, –COO� ion. Crystallographic and refinement de-tails for 300 K and 100 K are summarized in Table 1. Tables 2aand 2b gives the bond distance and bond angles at 300 K and100 K respectively.

A comparison of cell parameters at two temperatures showsthat the change in cell parameters are, Da = 0.0003(2) Å,Db = 0.0989(4) Å, Dc = 0.1818(5) Å and Db = 0.708(2)�. The de-crease in volume as we go to 100 K is 12.60(4) Å3. It is seen thatthe maximum decrease occurs along c-axis followed by b-axis.The reduction in temperature brings about closer packing of mole-cules and general shrinkage of the unit cell to the extent of 2–3%.

4.1. Molecular interaction

The zwitter ionic glycine, silver ion and nitrate ion form a lay-ered structure, with all these in one plane (ab plane). These arestacked along the c-axis, each layer slightly displaced with respectto one another. In the layer, these are connected by bifurcated N–H� � �O hydrogen bonds between the hydrogen’s of zwitter ionic gly-cine acting as donor and the oxygen’s of the nitrate ion acting asacceptors. Between the two layers, the hydrogen bonds are be-tween the hydrogen’s of zwitter ionic glycine acting as donor andboth the oxygen of the carbonyl of glycine and nitrate acting asacceptor. Apart from these N–H� � �O hydrogen bonds, there areC–H� � �O hydrogen bonds in the plane as well as between the two

934033

C2H5AgN2O5

244.95100 K0.71073MonoclinicP21/c

5.4639 (2)8.9499 (4)11.3638 (5)92.634 (2)555.12 (4)41.4793.590.12 � 0.11 � 0.102.9–45.2

23 6 l 6 23 �10 6 h 6 10 �17 6 k 6 17 �19 6 l 6 220] 27,263/4613 [R(int) = 0.022]

h = 45.2;99.8%4613/0/1121.06R1 = 0.013 wR (F2) = 0.030

Table 2bBond angles in DGSN.

Atoms Bond angle (�) Atoms Bond angle (�)

300 K 100 K 300 K 100 K

O1g–Ag1–O2gi 117.60 (3) 119.144(2) C1g–C2g–H4g 110 (2) 110.2 (7)O1g–Ag1–O1n 114.41 (4) 113.170(2) N2g–C2g–H5g 106 (1) 107.7 (7)O2gi–Ag1–O1n 127.90 (4) 127.56 (2) C1g–C2g–H5g 114 (1) 111.3 (7)O1n–N1–O3n 120.5 (1) 119.89 (5) H4g–C2g–H5g 108 (2) 108 (1)O1n–N1–O2n 120.6 (1) 120.80 (5) C2g–N2g–H1g 114 (2) 111.5 (9)O3n–N1–O2n 118.9 (1) 119.31 (5) C2g–N2g–H2g 112 (2) 110.4 (9)N1–O1n–Ag1 97.7 (1) 100.16 (4) H1g–N2g–H2g 103 (2) 107 (1)O2g–C1g–O1g 125.7 (1) 125.64 (5) C2g–N2g–H3g 110 (2) 112.0 (9)O2g–C1g–C2g 117.4 (1) 117.45 (5) H1g–N2g–H3g 108 (3) 110 (1)O1g–C1g–C2g 116.9 (1) 116.90 (5) H2g–N2g–H3g 110 (3) 106 (1)N2g–C2g–C1g 112.00 (9) 111.38 (5) C1g–O1g–Ag1 113.60 (8) 114.96 (4)N2g–C2g–H4g 107 (2) 107.7 (7) C1g–O2g–Ag1ii 121.53 (8) 121.43 (4)

Symmetry codes: (i) 1 + x, y, z (ii) �1 + x, y, z.

Table 3aHydrogen-bond parameters (Å, �) for DGSN at 300 K.

D–H H� � �A D� � �A D–H� � �A

N2G–H1G� � �O3Ni 0.86 (3) 2.19 (3) 3.046 (2) 174 (2)N2G–H1G� � �O2Ni 0.86 (3) 2.40 (3) 3.028 (2) 130 (2)N2G–H1G� � �N1i 0.86 (3) 2.64 (3) 3.447 (2) 157 (2)N2G–H2G� � �O3Nii 0.91 (3) 2.34 (3) 2.986 (2) 128 (2)N2G–H2G� � �O2Giii 0.91 (3) 2.45 (3) 3.175 (2) 136 (2)N2G–H2G� � �O1Niii 0.91 (3) 2.52 (3) 3.121 (2) 123 (2)N2G–H3G� � �O2Niv 0.90 (3) 2.02 (3) 2.907(2) 166 (3)C2G–H4G� � �O1Nv 0.95 (2) 2.43 (2) 3.222 (2) 140 (2)C2G–H4G� � �O2Gv 0.95 (2) 2.63 (2) 3.388 (2) 137 (2)C2G–H5G� � �O1Gvi 0.98 (2) 2.55 (2) 3.457 (1) 155 (2)

Table 3bHydrogen-bond parameters (Å, �) for DGSN at 100 K.

D–H H� � �A D� � �A D–H� � �A

N2G–H1G� � �O3Ni 0.88 (1) 2.08 (1) 2.9500 (7) 173 (1)N2G–H1G� � �O2Ni 0.88 (1) 2.42 (2) 3.0574 (7) 130 (1)N2G–H1G� � �N1i 0.88 (1) 2.58 (2) 3.4091 (7) 158 (1)N2G–H2G� � �O3Nii 0.85 (1) 2.42 (1) 2.9678 (7) 123 (1)N2G–H2G� � �O2Giii 0.85 (1) 2.28 (1) 3.0093 (7) 144 (1)N2G–H2G� � �O1Niii 0.85 (1) 2.60 (1) 3.1020 (7) 120 (1)N2G–H3G� � �O2Niv 0.89 (1) 2.00 (1) 2.8839 (7) 170 (1)C2G–H4G� � �O1Nv 0.95 (1) 2.43 (1) 3.1973 (8) 137.5 (9)C2G–H4G� � �O2Gv 0.95 (1) 2.54 (1) 3.3179 (7) 138.5 (9)C2G–H5G� � �O1Gvi 0.94 (1) 2.59 (1) 3.4773 (7) 157 (1)

Symmetry codes: (i) �1 + x, -1 + y, z; (ii) �x, �y, �z; (iii) �1 � x, �y, �z; (iv) x,�1 + y, z; (v) �1 � x, �1/2 + y, 1/2 � z; (vi) �1 + x, y, z.

R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35 29

planes. Tables 3a and 3b gives the hydrogen bonding at 300 K and100 K. The total crystal structure is built up from these repeatingunits to give 2-dimensional polymeric structure parallel to abplane. The geometrical arrangement in the crystal structure wasanalyzed using the program RPLUTO [16] to generate the graph

Table 4Graph set analysis.

Atoms N2GH1GO2N N2GH1GO3N N2GH2G

N2GH1GO2N C(9)N2GH1GO3N C2

2ð16Þ C(7)

R22ð8Þ

N2GH2GO3N R44ð12Þ R2

4ð8Þ R22ð14Þ

N2GH2GO2G R44ð16Þ R4

4ð12Þ R21ð4Þ

N2GH3GO2N C12ð4Þ C2

2ð6Þ R44ð12Þ

N2GH3GO1G

set shown in Table 4. Fig. 2 gives the packing diagram of DGSNlooking down a-axis.

The distances of the atoms less than 3 Å to the silver atom areshown in Fig. 3. The oxidation state of silver ion is +1. Silver ionis coordinated to four oxygen’s, of which two are from the same ni-trate ion forming a bidentate coordination, and the other two areoxygen’s of the symmetry related glycine. All these four oxygen’sare in the same plane. The distances being 2.290, 2.417, 2.534and 2.651 Å. There is also a hydrogen atom, H5g in this plane ata distance of 2.809 Å. Ag ion is also coordinated to O1g and O2nat a distance of 2.732 and 2.739 Å respectively, which are aboveand below the plane. The coordination of the Ag–O bond distancesin the axial plane are longer compared to that in the equatorialplane. Since the coordination distance considered for mononuclearsilver compounds with oxygen’s is <2.62 Å [17], hence, we considerthat the four atoms O1n, O3n, O1g and O2g and Ag form a distortedtriangular coordination.

4.2. Comparison of DGSN with isomeric GSN

GSN crystallizes in P21/a space group at room temperature witha = 5.451(4) Å, b = 19.493(10) Å, c = 5.541(8) Å and b = 100.2 (0.25)�with volume = 579.5 Å3 [5]. A comparison with DGSN shows thatvolume occupied by GSN is more than that of DGSN by 11.78 Å3.A comparison of the bond parameters is given in Table 5.

A comparison of the various bond parameters between GSN andDGSN shows that bond parameters of glycine and nitrate ions do notshow a considerable difference, whereas the coordination of the sil-ver ion is very different in the two structures. In general Ag is proneto form Ag–Ag dimers in crystal structure as shown by Naumov et al[18]. In DGSN, the silver ion is mononuclear, whereas in GSN, it isbinuclear, but both of them have an oxidation state of +1.

The mean deviation from planar configuration of the atomscoordinated with Ag ion is given in Table 6. This deviation is morepronounced in the case of GSN compared to DGSN. In GSN the sil-ver ion is coordinated to Ag and oxygen’s of only glycine moiety

O3N N2GH2GO2G N2GH3GO2N N2GH3GO1N

R22ð14Þ

R44ð16Þ R4

4ð16ÞS(5)

Fig. 2. Packing diagram of DGSN looking down a axis.

Fig. 3. Coordination of AG+ ion in DGSN.

Fig. 4. Coordination of AG+ ion in GSN.

30 R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35

(Fig. 4), whereas in case of DGSN, it is coordinated to oxygen’s ofboth nitrate ions and glycine moiety (Fig. 3). The atoms of theNO�1

3 moiety in the case of GSN deviate from the plane, whereasthey are in the plane, for DGSN giving a completely planar struc-ture for the nitrate moiety. The atoms belonging to glycine in DGSN

Table 5Comparison of bond parameters (Å, �) between GSN and DGSN.

Atoms Nitrate Atoms Glyc

GSN DGSN GSN

N1–O1n 1.25 1.237(2) C1g–O1g 1.28N1–O2n 1.28 1.250(1) C1g–O2g 1.24N1–O3n 1.26 1.249(2) C1g–C2g 1.53

C2g–C1g 1.48

O1n–N1–O2n 120.5 120.6(1) O2g–C1g–O1g 124.O3n–N1–O2n 116.0 118.9(1) O1g–C1g–C2g 115.O1n–N1–O3n 122.7 120.5(1) O2g–C1g–C2g 119.

C1g–C2g–N2g 109.

O2g–C1g–C2g–N2g 166.O1–C1g–C2g–N2g 12.7

deviate more from the mean-plane as compared to that in GSN. Themaximum deviation is of C1g in both cases. The packing of GSNlooking down a-axis is shown in Fig. 5.

ine Silver

DGSN GSN DGSN

1.258(1) Ag–Ag 2.877 –1.250(1) Ag1–O2g 2.256 2.417(1)1.519(1) Ag1–O1g 2.218 2.2901(9)1.468(2) Ag–O1g (symm real) 2.372 –

Ag1–O3n – 2.651(2)Ag1–O1n – 2.534(2)

9 125.7(1) O1g–Ag–Ag 78.77 –8 116.9(1) Ag–Ag–O2g 84.66 –2 117.4(1) O1g–Ag–O1g(syy) 75.98 112.00(9) O1g(sy) Ag1–O2g 120.8 117.60(3)

O3n–Ag1–O2g 78.97(3)O3n–Ag1–O1n 49.15(4)O1n–Ag1–o1g 114.41(4)

1 161.6(1)19.6(2)

Table 6Mean deviation of atoms (Å) for planes in GSN and DGSN.

Atoms Deviation of atoms from plane(Å)

Atoms Deviation of atoms from plane(Å)

Atoms Deviation of atoms from plane(Å)

Nitrate ion Glycine ion Ag coordinated

GSN DGSN GSN DGSN GSN DGSN

N1 0.055 0.0003(9) N2g 0.099 0.1322(7) AG1 0.127 0.0123(5)O1n 0.015 0.0001(3) C2g 0.118 0.164(1) O1g 0.096 0.0277(4)O2n 0.015 0.0001(3) C1g 0.025 0.018(1) O1n 0.0667(8)O3n 0.016 0.0001(3) O2g 0.083 0.1034(7) O3n 0.0729(9)

O1g 0.038 0.0530(5) O2g 0.206 0.0462(5)Ag1 0.206O1 0.225

Fig. 5. Packing diagram of GSN looking down a axis.

R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35 31

Table 7 and Figs. 6a and b gives the comparison of hydrogenbonding parameters between GSN and DGSN. Since Rao et al donot give the hydrogen positions, only the donor acceptor distanceshave been enumerated in Table 7. It is observed that the three of

Table 7Comparison of hydrogen bonding parameters in GSN and DGSN.

Atoms Distance (Å) Distance (Å)GSN DGSN

N2g� � �O1n 2.88(3)N2g� � �O2 2.93(4) 3.028(2) and 2.907(2)N2g� � �O3n 2.97(3) 3.046(2) and 2.986(2)

Fig. 6a. Hydrogen bonding in GSN.

the hydrogen bonds (O2n, O2n and O3n) in the case of DGSN arein the same plane, whereas in the case of GSN it is not so.

The DSC curve showing the melting point of DGSN is given inFig. 7. The melting point of DGSN is 428K as compared to that ofGSN, which is 415K [8]. One of the reasons of higher melting pointof DGSN may be due difference in packing and more number ofhydrogen bonds in DGSN as compared to that in GSN.

As described in the introduction, GSN is ferroelectric in natureand shows a displacive type phase transition at 218K. The ferro-electricity is attributed to the displacement of the Ag ion at lowtemperature. It is interesting to observe here that the DGSN doesnot show any phase transition till 100K. The structure at 100K re-mains the same as that of RT except for shortening of the bonds

Fig. 6b. Hydrogen bonding in DGSN.

Fig. 7. DSC curve of DGSN.

Table 8Crystal structures with Hydrogenated and deuterated counterparts with change in structu

S.no

CSD Ref.code

H/D Compond name

1 AMBONC01 H Bis(2-Amino-2-methyl-3-nickel(ii) chloride monoh

AMBONC02 Fully deuterated Pentadeutero-bis(3-aminone-oximato)-nickel(ii) chsolvate [22]

2 ENPTIP10 H Bis(Ethylenediamine)-plabis(ethylenediamine)-plaperchlorate [23]

ENPTIP04 Fully deuterated

3 FEQFEN H Bis(m5-Diphenylphosphinbis(diphenylphosphinoyl)bis(diphenylphosphinoyl)lithium benzene solvate [

FEQFEN01 Partially deuterated bis(m5-Diphenylphosphinbis(diphenylphosphinoyl)bis(diphenylphosphinoyl)lithium hexadeuterobenz

4 FUJVAH H Hexakis(Acetonitrile)-nicantimony(v)) [26]

FUJVAH01 Partially deuterated Hexakis(Trideutero-acetohexafluoroantimonate [27

5 GADGUN02 H 4-Methylpyridine pentach

GADGUN06 Fully deuterated 4-Methylpyridine pentach

6 GADGUN H 4-Methylpyridine pentach

GADGUN01 Fully deuterated 4-Methylpyridine deutero

7 HAXFER Hydrogenated 3,5-Dimethylpyridiniumdinitrobenzoic acid [31]

32 R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35

due to expected contraction of the cell with decreasing tempera-ture. This is probably the result of the coordination of the silverion to only oxygen’s in the case of DGSN. This again shows thatAg–Ag homonuclear bond is important in bringing about ferroelec-tric transition in the case of GSN.

A database research using CCDC [19] was undertaken to searchfor structures where there is a structural change due to deutera-tion, though Fisher and Helliwell [20] had mentioned about theisotope effect on the structural changes, but it was limited to thecases of O–D or an N–D bond. The ten structures where a changein crystal structure due to deuteration is observable have been tab-ulated in Table 8.

As can be seen from Table 8, there is no general trend concern-ing the expansion or contraction of the cell, since both cases areobserved. Note also that structural change can occur both for fullydeuterated and partially deuterated cases. It is known that therepulsions involving deuterium atoms are smaller than those ofhydrogen atoms at the same inter nuclear distance, resulting insmaller packing radius for deteurium as compared to hydrogen

re on deuteration.

Cell parameters (Å, �), volume (Å3) Space group

butanone oximato)ydrate [21]

a = 12.740, b = 10.790, c = 11.810,b = 92.50

P21/c

Volume = 1621.91o-3-methyl-butan-2-

loride deuterium oxidea = 11.033, b = 12.940, c = 5.862,b = 101.97

P21

Volume = 818.70tinum(ii) di-iodo-tinum(iv) tetra-

a = 7.440, b = 5.827, c = 17.031,b = 97.93

A2/m

Volume = 731.282Catena-(tetrakis(m2-Iodo)-octakis(perdeuteroethylenediamine)-tetra-platinum octaperchlorate) [24]

a = 33.828,b = 11.638,c = 7.433,b = 98.49

Volume = 2894.23 C2/mato)-bis(m3-

methanido)-bis(m2-methanido)-hexa-25]

a = 14.7823, b = 22.6115, c = 22.7105,b = 108.527

P21/n

Volume = 7197.57

ato)-bis(m3-methanido)-bis(m2-methanido)-hexa-ene solvate [25]

a = 14.2394, b = 15.2704, c = 19.5430,a = 71.727, b = 71.035, c = 69.575

P-1

Volume = 3668.84kel(ii) bis(hexafluoro- a = 8.764, b = 8.764, c = 8.764,

a = 80.92, b = 80.92, c = 80.92R-3r

Volume = 650.25nitrile)-nickel(ii)]

a = 11.346, b = 11.346, c = 17.366,a = 90, c = 90, b = 120

R-3

Volume = 1936.04lorophenol [28] a = 7.267, b = 8.966, c = 13.110,

a = 99.70, b = 118.16, c = 103.38P-1

Volume = 693.18loro-deuterophenol [28] a = 3.826, b = 27.54, c = 13.209,

b = 101.38C c

Volume = 1364.44lorophenol [29] a = 7.408, b = 8.934, c = 13.653,

a = 100.15, b = 118.50, c = 103.67P-1

volume = 726.07pentachlorophenol [30] a = 3.942, b = 27.73, c = 13.297,

b = 101.81C c

Volume = 1422.7493,5-dinitrobenzoate 3,5- a = 9.409, b = 10.813, c = 12.310,

a = 95.75, b = 108.17, c = 91.46P-1

Table 8 (continued)

S.no

CSD Ref.code

H/D Compond name Cell parameters (Å, �), volume (Å3) Space group

Volume = 1181.842HAXFER01 Fully deuterated 3,5-Dimethyl-N-deuteropyridinium 3,5-

dinitrobenzoate 3,5-dinitrodeuterobenzoic acid[32]

a = 11.680, b = 8.451, c = 24.382(9),b = 102.94(4)

P 21/c

Volume = 2345.578 HDRZHO02 Hydrogenated Hydrazinium hydrogen oxalate [32] a = 3.5792, b = 13.3228, c = 5.0965,

b = 102.600P 21/m

Volume = 237.17HDRZHO03 Fully deuterated Pentadeutero-hydrazinium deuterium oxalate [32] a = 3.5858, b = 13.3085, c = 5.1001,

b = 102.488P 21

Volume = 237.629 MSORHB10 H Tetrakis(Trifluoroacetato)-bis(dimethylsulfoxide)-

di-rhodium(ii) [33]a = 8.621, b = 9.50, c = 8.766,a = 112.68, b = 110.99, c = 87.83

P-1

Volume = 614.25MSORHB01 Fully deuteratede Tetrakis(m2-Trifluoroacetato-O,O0)-

bis(hexadeutero-dimethylsulfoxide)-di-rhodium(ii) [33]

a = 9.699, b = 14.664, c = 8.614,a = 91.42, b = 91.24, c = 83.32

P-1

Volume = 1216.22810 NOVSIA H Acridine 1-(naphthyl)acetic acid [34] a = 10.001, b = 23.584, c = 8.115,

b = 101.654P 21/c

Volume = 1874.57NOVSIA01 Partially deuterated Acridine 1-(naphthyl)deuteroacetic acid [34] a = 9.354, b = 13.333, c = 8.244,

a = 106.85, b = 104.44, c = 81.86Volume: 950.26 P-1

11 PYRDNA01 H Pyridine [35] a = 17.524, b = 8.969, c = 11.352Volume:1784.22 P n a 21

PYRDNA02 Fully deuterated Perdeuteropyridine [36] a = 5.5960, b = 6.961, c = 11.493Volume = 447.69 P 21 21 21

Fig. 8. Raman spectra of DGSN.

R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35 33

[37–39], and hence leading to smaller unit cell volume which hasbeen the basis of Kinetic isotope effect. The lower zero-point en-ergy of deuterium implies lower vibration amplitude, as a resultsmaller Van der Waals radii compared to that of hydrogen, butthe effect of temperature is to expand the effective size of deute-rium faster than that of hydrogen. This temperature effect may re-sult in inverse kinetic effect [40], which explains the increase of theunit cell volume on deuteration. In DGSN, there is reduction in thecell volume, and hence it is the kinetic isotope effect which ischanging the structure on deuteration, also it is basically the coor-dination of Ag ion which brings about a change in the structure. Itis also necessary to mention here that, it is the fully deuteratedDGSN which produces a new isotopic polymorph of GSN, whereaspartially deuterated GSN does not result in a new polymorph [9].

4.3. Spectroscopic results

Since the X-ray does not directly show the deuteration in thecompound, Raman scattering experiments were carried out in

DGSN, Raman spectra of the DGSN is given in Fig. 8. The assign-ment of the internal modes (Table 9) was achieved by comparingthe Raman frequencies of the title compound with those observedin the parent molecules, i.e. AgNO3 [41] and deuterated a Glycine[42–44] and GSN [8], as one expects close correspondence betweenthe internal frequencies of these molecules.

From Table 9 it is observed that most of the modes are not verydifferent from the parent compounds (deuterated a-glycine, silvernitrate or GSN). The bands at 132 and 191 in DGSN and 151, 195and 210 in GSN cm�1 corresponds to vibrational modes of Ag�O[45,46]. The CO�2 modes of zwitter ionic glycine in (CO2 rock, CO2

wag, CO2 bend) deuterated a Glycine and in DGSN have very littledifference, even though they are coordinated in DGSN to Ag andalso form weaker hydrogen bonds, and in deuterated a Glycine,they form only N–H� � �O hydrogen bonds. This indicates that thestrength of the Ag–O coordination bond in GSN and N–H� � �Ohydrogen bond in deuterated a Glycine are comparable, a casesimilar to that observed in GSN and a Glycine [8]. Most of the Ra-man modes except ND3 deformation and ND symmetric stretch in

Table 9Raman modes in DGSN.

Mode GSN [8] (cm�1) DGSN(this study) (cm�1) Deuterated a- Glycine [40,41] (cm�1) AGNO3 [38,39] (cm�1) mh/md

109 114Ag–O vibrational modes 151 132Ag–O vibrational modes 195 191Ag–O vibrational modes 210CO2 rock 465 456CO2 wag 599 529 527CO2 bend 692 634 643m4 NO�3 ion 706 715 709m4 NO�3 ion 722 725 734ND3 rock/NH3 rock 1093 799 807 1.36m2 NO�3 ion 825 825 807ND3 rock/NH3 rock 1107 873 870 1.26C–C str. 898 930 930C–N str. 1031 952 950CD2 twist 1013 1015m1 NO�3 ion 1051 1047 1045CD2 bend 1069 1078CD2 wag/CH2 wag 1330 1127 1130 1.18ND3 a def./NH3 a Def. 1508 1144 1172 1.318ND3 s def./NH3 s def 1556 1167 1193 1.340ND3 a def./ND3 a def 1600 1183 1207 1.352NO�3 ion 1306 1336 1320NO�3 ion 1350 1362 1350CO2 sym str. 1384 1389CO2 sym str. 1415 1410 1406CO2 asym. str. 1554 1545ND3 m(S) sym. str. 2123 2134CD2 m(S) sym. str./CH2 v(S) str. 2973 2179 2184 1.36ND3 m(S) sym. str./NH3 m(S) sym. str. 3093 2228 2333 1.39CD2 m(A) sym str./CH2 m(A) sym str. 3011 2267 2262 1.32ND3 m(S) sym. str./ND3 ma(S) sym. str. 3165 2360 2371 1.34

34 R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35

DGSN and deuterated a Glycine are similar indicating similar nat-ure of molecular conformation and also indicating difference in thestrength of N–H� � �O hydrogen bonds in DGSN and deuterated aGlycine.

Deuterium substitution in GSN leads to an isotopic ratio of1.18–1.41 for the frequencies corresponding to the hydrogen/deu-terium vibrations. This ratio between the GSN and DGSN has alsobeen enumerated in the table, which further validates the assign-ment of the various modes. The Raman pattern also shows the fulldeutreration of the complex.

5. Conclusion

As a result of full deuteration, a new isotopic polymorph of GSN,DGSN was synthesized. DGSN crystallizes in P21/n space group.This new complex does not show any phase transition till 100K,unlike GSN, probably because absence of Ag–Ag interaction inthe crystal structure. The reduction in temperature brings aboutcloser packing of molecules and general shrinkage of the unit cellto the extent of 2–3%. Raman spectroscopic measurements showedthe full deuteration of the compound.

Acknowledgment

The author R.C wishes to thank Dr. Lata Panicker of SSPD, BARCfor carrying out the DSC measurements.

References

[1] F. Jona, G. Shirane, Ferroelectric Crystals, Pergamon Press, Oxford London, 1962(Chapter 2).

[2] R. Pepinsky, K. Vedam, S. Hoshino, Y. Okaya, Phys. Rev. 111 (1958) 430–432.[3] S. Launer, M. Le Maire, G. Schaack, S. Haussuhl, Ferroelectrics 132 (1992) 257.[4] R. Pepinsky, Y. Okaya, D.P. Eastman, T. Mitsui, Phys. Rev. 107 (1957) 1538.[5] J.K.M. Rao, M.A. Viswamitra, Acta Cryst. B 28 (1972) 1481–1495.

[6] A.V.R. Warrier, P.S. Narayanan, Proc. Ind. Acad. Sci. 66A (1967) 46–54.[7] K.R.K. Easwaran, J. Phys. Soc. Jpn. 21 (1966) 1614.[8] Rajul Ranjan Choudhury, Lata Panicker, R. Chitra, T. Sakuntala, Solid State

Communications. 145 (2008) 407–412.[9] K. Gesi, K. ozawa, . Phys. Soc. Jpn. 42 (1977) 923.

[10] J. Zhou, Y.S. Kye, G.S. Harbison, J. Am. Chem. Soc. 126 (2004) 8392.[11] M.J. Ichikawa, Mol. Struct. 552 (2000) 63.[12] J.M. De Souza, P.T.C. Freire, D.N. Argyriou, J.A. Stride, M. Barthès, W. Kalceff,

H.N. Bordallo, ChemPhysChem 10 (2009) 3337–3343.[13] J.M. De Souza, P.T.C. Freire, H.N. Bordallo, D.N. Argyriou, J. Phys. Chem. B 111

(2007) 5034–5039.[14] G.M. Sheldrick, SHELXS97 and SHELXL97, University of GoÈ ttingen, Germany,

1997.[15] L.J. Farrugia, Appl. Cryst. 30 (1997) 565.[16] W.D. Motherwell, P.G. Shields, F.H. Allen, Acta Cryst. B56 (2000) 466.[17] C.E. Holloway, M. Malnik, W.A. Nevin, W. Liu, J. Coordin. Chem. 35 (1995) 85.[18] D. Yu, E.V. Naumov, N.V. Boldyreva, J.A.K. Podberezskaya, Solid State Ionics

101–103 (1997) 1315–1320.[19] F.H. Allen, Acta Cryst. B58 (2002) 380.[20] S.J. Fisher, J.R. Helliwell, Acta Cryst. A 64 (2008) 359.[21] E.O. Schlemper, W.C. Hamilton, S.J. La Placa, J. Chem. Phys. 34 (1971) 3990.[22] B. Hsu, E.O. Schlemper, C.K. Fair, Acta Cryst. B36 (1980) 1387.[23] H. Endres, H.J. Keller, R. Martin, H.N. Gung, U. Traeger, Acta Cryst. B35 (1979)

1885.[24] B. Scott, B.L. Bracewell, S.R. Johnson, B.I. Swanson, J.F. Bardeau, A. Bulou, B.

Hennion, Chem. Mater. 8 (1996) 321.[25] R. Nassar, B.C. Noll, K.W. Henderson, Polyhedron 23 (2004) 2499.[26] I. Leban, D. Gantar, B. Frlec, D.R. Russell, J.H. Holloway, Acta Cryst. C 43 (1987)

1888.[27] R. Bougon, P. Charpin, K.O. Christe, J. Isabey, M. Lance, M. Nierlich, J. Vigner,

W.W. Wilson, Inorg. Chem. 27 (1988) 1389.[28] Z. Malarski, I. Majerz, J. Mol. Struct. 380 (1996) 249.[29] Z. Malarski, I. Majerz, T. Lis, J. Mol. Struct. 158 (1996) 369.[30] I. Majerz, Z. Malarski, T. Lis, J. Mol. Struct. 240 (1990) 47.[31] L.B. Jerzykiewicz, T. Lis, Z. Malarski, E. Grech, J. Crystallogr. Spectrosc. Res. 23

(1993) 805.[32] J.O. Thomas, Acta Crystallogr. Sect. B 29 (1973) 1767.[33] F.A. Cotton, T.R. Felthouse, Inorg. Chem. 21 (1982) 431.[34] H. Koshima, K. Ding, Y. Chisaka, T. Matsuura, I. Miyahara, K. Hirotsu, J. Am.

Chem. Soc. 119 (1997) 10317.[35] D. Mootz, H.-G. Wussow, J. Chem. Phys. 75 (1981) 1517.[36] S. Crawford, M.T. Kirchner, D. Blaser, R. Boese, W.I.F. David, A. Dawson, A.

Gehrke, W.G. Marshall, S. Parsons, O. Yamamuro, Angew. Chem. Int. Ed. 48(2009) 755.

R. Chitra et al. / Journal of Molecular Structure 1049 (2013) 27–35 35

[37] A.R. Ubbelhode, Trans. Faraday Soc. 32 (1936) 525.[38] L.S. Bartell, J. Chem. Phys. 35 (1961) 1211.[39] L.S. Bartell, R.R. Roskos, J. Chem. Phys. 44 (1966) 457.[40] J.D. Dunitz, R.M. Ibberson, Angew. Chem. Int. Ed. 47 (2008) 4208.[41] K. Balasubrbhrahmanyam, G.J. Janz, J. Am. Chem. Soc. 92 (1970) 4189.[42] Z.X. Shen, W.F. Sherman, M.H. Kuok, S.H. Tang, J. Raman Spectrosc. 23 (1992)

509.

[43] K. Machida, A. Kagayama, Y. Saito, J. Raman Spectrosc. 8 (1979) 133.[44] M. Takeda, R.E.S. Izvazzo, D. Garfinkel, I.H. Scheinberg, J.T. Edsall, J. Am. Chem.

Soc. 80 (1958) 3813.[45] N. Ravi Chandra Raju, K. Jagadeesh Kumar, A. Subrahmanyam, AIP Conf. Proc.

1267 (2010) 1005 doi: 10.1063/1.3482261.[46] N.R. Raju, K.J. Kumar, A. Subrahmanyam, J. Phys. D: Appl. Phys. 42 (2009)

135411.