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Chemical preparation and structural investigation of a new cyclohexaphosphate: (C6H5NH3)6P6O18 · 6H2O
MATERIALS CHEM;S&R’Y’Y~D ELSEVIER
Materials Chemistry and Physics 42 (1995) 225-230
Materials Science Communication
Chemical preparation and structural investigation of a new cyclohexaphosphate: ( C6H5NH3)6P601g 6H20 l
O.S.M. Elmokhtar a, S. Abid a, M. Rzaigui a, A. Durif b aLuboratoire de Chimie des MatLriauz, Faculte’ des Sciences, 7021 Znrzouna Bizerte, Tunisia b CNRS, Laboratoire de Cristallographie, associe’ ci l'llniversite'J. Fourier, BP 166, 38042 Grenoble Cedex 09, France Received 8 February 1995; revised 13 May 1995; accepted 1.5May 1995
Abstract The chemical preparation and the determination of the crystal structure of a new organic cation cyclohexaphosphate, hexa(phenylammonium) cyclohexaphosphate hexahydrate, (&H,NH 3) 6P 60 18. 6H20, is given. This new compound is triclinic, Pi, with the following unitcellparameters:a=12.353(8)~,b=11.944(8)~,c=10.154(5)~,cY=114.91(5)“,~=110.82(5)“,y=79.04(5)”,Z=2,V=1269(3) A’, and Dx= 3.00 Mg rne3. The crystal structure was solved by using 4578 independent reflections with a final R value of 0.042. The P60L8 ring is centrosymmetrical. Its main geometrical features are those commonly observed in the atomic arrangements of cyclohexaphosphate. Phenylammonium groups and water molecules through H-bonds perform the three-dimensional cohesion of this simple atomic arrangement. The hydrogen bond scheme is given. Keywords: Cyclohexaphosphate; Crystal structure
1. Introduction Following the investigations of Schiilke and Kayser [ 11 on the condensation-cyclization of LiH,PO, into Li6P601s, the crystal chemistry of cyclohexaphosphates developed rapidly but the organic cation derivatives have not yet been investigated in detail. To date, only three compounds have been accurately characterized in this field: (NH,(CH2)2NH3)3P60,8.2H20 [21,(GHsNH,),P&,~.~H~O 131, (N,Hs),(N,H,),P,O,, 131. In the present investigation we report the synthesis and the crystal structure of a new organic cation cyclohexaphosphate: ( C6HsNH3)6P6018~ 6Hz0. This compound is the first example within a systematic study on the elaboration of new materials resulting from the association of organic and inorganic entities which could have a particular interest in non-linear optics [ 4 J . Research into very efficient and highly transparent non-linear optical crystals (range: 100 nm to IR wavelengths) is a challenge in which physicists concerned with non-linear optics are nowadays engaged. The performance of optical signal-processing devices is linked to the discovery of such new materials [ 51. The design of organic-inorganic polar crystals for quadratic non-linear optical applications is nowadays orientated towards and supported by two main observations: (i) the organic molecules containing 7r-electron systems asymmetrized by electron donor-acceptor 02540584/95/$09.50
Q 1995 Elsevier Science S.A. All rights reserved
SSDI0254-0584(95)01594-K
groups are highly polarizable entities in which problems of transparency and crystal growth may arise from their molecular crystal packing, and (ii) the ionic inorganic host-matrices are able to increase the cohesion of packing, to shift the transparency of organic entities towards blue wavelengths and to induce the a-centricity of packing.
2. Experimental 2. I. Chemical preparation (C,H,NH,) 6P6018. 6H,O has been prepared in two steps. An aqueous solution of cyclohexaphosphoric acid was first prepared by passing a solution of Li6P601s through an ionexchange resin in its H-state ( Amberlite IR 120). The lithium salt was prepared according to ihe process described by Schiilke and Kayser [ 11 using purum p.a. Fluka chemicals. This solution was then added drop by drop to aniline (purum p.a. Fluka) under continuous stirring until the solution exhibits a light greenish aspect. Schematically the reaction is: Hz0 W’s%
+ GJ-WS
-
(W-W-M
J’,%
. @I20
( 1)
In order to avoid hydrolysis of the ring anion the above reaction is performed at room temperature. The so-obtained
226
O.S.M. Elmokhtar et al. /Materials
solution is then slowly evaporated until the formation of large rectangular prisms of ( C6H,NH,) 6P60,8. 6H20. The title compound is stable for months in normal conditions of temperature and relative humidity. 2.2. Crystal data Unit-cell and space-group determination A preliminary single-crystal investigation has been performed using the Weissenberg technique in order to determine symmetry and space group. The unit cell appeared to be triclinic. The determination of the structure will confirm the centro-symmetric space group Pi. The main crystallographic features of the title compound are given in Table 1. Crystal structure The intensity data collection has been performed using a Philips PW 1100 diffractometer. The experimental parameters for this measurement, the strategy used for the structure determination and its final results are given in Table 1. Final atomic coordinates and B, are given in Table 2.
3. Structure description ( C,H,NH,)6P60,8. 6H20 has a simple atomic arrangement. Figs. 1 and 2 show two different projections, one along the a-axis and the other along the c-axis. The hydrogen atoms are represented.
Chemistry and Physics 42 (1995) 225-230
Table 1 Crystal data and experimental parameters used for the intensity data collection. Strategy and final results of rhe structure determination Crystal data Formula
(C&~NHdJ’dhs~6Hz0
F, Crystal system Space group o (A) b (A) c (A) a (“) P (“) Y0 Z v (A’) Refinement of unit cell parameters with pear (g cm-3
F(000) Linear absorption factor, p( MO Ka) (mm-‘) Morphology Crystal size (mm) Intensity measurements Temperature (K) Wavelength (MO Ka) (A) Diffractometer Scan mode Monochromator Scan width (“) Scan speed (“s-l) 8 Range (“) Measurement area h-9 JG-. lma. Total background measuring time (s) Total no. of scanned reflections Total no. of independent reflections Two intensity and orientation reference reflections Structure determination Lorentz and polarization Program used Computer used Determination
Thermal displacement
corrections
parameters
Unique reflections included Weighting scheme Refined parameters Residual Fourier density (e Ad3) Unweighted agreement factor R Weighted agreement factor R, Estimated standard deviation Largest shift/error
1056.66 triclinic Pi 12.353(g) 11.944(g) 10.154(5) 114.91(5) 110.82(5) 79.04(5) 2 1269(3) 15reflections(10.7<8<11.9°) 3.00 1200 0.613 triangular prism 0.40 x 0.40 x 0.32
294 0.71073 Philips PW 1100 w/2@ graphite plate 1.20 0.02 3-30 +h, k, 1 18, 18, 18 6 5655 4578 116and ii6 (no variation)
no absorption correction MolEN [6] Micro-Vax 3100 Patterson and successive Fourier syntheses H atoms from difference Fourier map isotropic for H atoms anisotropic for other atoms 4578 with I>4a(I) unitary 479 0.424 0.042 0.044 0.796 0.67
3.1. P6018 ring anion Fig. 1. Projection of the atomic arrangement of ( C,HSNH,),P,O,, 6Hz0 along the a-axis. The P,O,s ring anions are given in the tetrahedral representation. The smaller empty circles represent the hydrogen atoms. The other atoms are indicated by their symbols.
The phosphoric ring is centro-symmetrical, located around the (O,O,O) inversion centre and is built of only three inde-
221
O.S.M. Elmokhtar et al. /Materials Chemistry and Physics 42 (1995) 225-230 Table 2 Final atomic coordinates and Bq with their estimated standarddeviations in parentheses.&=4/3X,Q,b,&, Atoms
x
P(l)
-0.12115(5) -0.03639(5) -0.05965(5)
P(2) P(3) O(Ll2) O(Ll3) O(El1) O(E12) O(L23) O(E21) O(E22) O(E31)
0.1233(2) -0.0066(2) 0.1292(2) 0.7917(l) O.OOW(1) -0.0685(2) 0.1044(2) 0.1846(2)
Occupation
2
Y 0.01810(5) 0.22469(5) 0.17195(5) -0,1196(l) 0.0433(2)
0.20711(6) 0.19375(6) -0.12347(6) -0.1430(2)
2.12( 1) 1.97( 1)
-0.2194(2)
3.01(4) 3.29(4)
2.16( 1) 3.01(4)
- 0.0790( 2) -0.0717(l) 0.1775(2)
-0.3633(2) 0.0863(2) 0.0467(2)
2X5(4) 2.74(4)
-0.2148(2) -0.3425(2) -0.1568(2)
-0.3189(2) -0.2137(2) 0.1664(2)
2.60(4) 3.21(4) 3.28(4)
N(1)
0.0195(2) 0.1253(2) 0.1576(2) 0.1436(3) 0.0682(2)
0.7265(2) 0.4065(2) 0.1204(2) 0.5137(2) 0.6885(2)
0.1375(2) 0.6101(2) 0.5584(2) 0.9547(3) 0.3990(2)
3.71(4) 3.84(5) 4.20(5) 7.53(7) 2.84(4)
C(1) C(2)
0.1630(2) 0.1525(3)
0.5956(2) 0.4848( 3)
3.00(5) 4.20(7)
C(3) C(4) C(5) C(6) N(2) C(7) C(8) C(9) C(l0)
0.2346( 3) 0.3406(3) 0.3492(4) 0.2596(3)
0.3975( 3) 0.4209(3) 0.5298(4) 0.6187(3) 0.0626(2) 0.0900(2) 0.0618(5) 0.9148(5) 0.8664(4)
0.4012(3) 0.2767(3) 0.2797(4)
O(E32) O(W1) O(W2) O(W3)
C(l1) C(12) N(3) C(13) C( 14a) C( 14b) C( 15a) C( C( C( C( C( C( C(
15b) 16a) 16b) 17a) 17b) 18a) 18b)
H(lW1) H(2Wl) H( lW2) H(2W2) H( lW3) H(2W3) H( lN1) H(2Nl) H(3Nl) H( lN2) H(2N2) H(3N2) H( lN3) H(2N3) H(3N3)
0.2488(2) 0.3702(2) 0.4506(3) 0.4321(4) 0.4009(3) 0.5199(4) 0.4033(3) 0.2388(2) 0.3640(3) 0.4075(5) 0.3911(S) 0.4719(6) 0.509( 1) 0.3974(5) 0.4119(9) 0.4440(5) 0.4437(S) 0.4377(4) 0.4324(9)
0.120(3) 0.122(3) 0.125(3) 0.140(3) 0.143(3) 0.121(3) 0.089(3) 0.051(3) 0.998(3) 0.231(3) 0.203 (3) 0.228( 3) 0.224( 3) 0.201(3) 0.212(3)
0.1552(5) 0.1335(4) 0.2788(2) 0.2926( 2) 0.3436(5) 0.4167(8) 0.6481(7) 0.436( 1) 0.6947(6) 0.651(l) 0.7528(6) 0.760( 1) 0.2385(5) 0.2177(9)
0.485(3) 0.368(3) 0.119(3) 0.052( 3) 0.556(3) 0.565 (4) 0.757( 3) 0.706(3) 0.341(3) 0.069( 3) 0.120(3) 0.975(3) 0.228( 3) 0.353(3) 0.243(3)
0.4027(6) 0.5271(7) 0.5275(4) 0.2049(2) 0.2946( 3) 0.2257(5) 0.6862(6) 0.5425(5) 0.5294(5) 0.4481(4) 0X607(2) 0.9142(3) 0X408(7) 0.056(I) 0.1152(9) 0.127( 1) 0.0059( 9) 0.925 ( 1) 0.9461(8) 0.038( 1) 0.0088(6) -0.118(l)
0.642(4) 0.517(4) 0.473(4) 0.548(4) 0.917(4) 0.030(4) 0.478( 3) 0.317(4) 0.607( 3) 0.116(4) 0.249(4) 0.180(3) 0.892(4) 0.891(3) 0.752(4)
5.90(9) 8.3( 1) 8.1(2) 5.0( 1) 3.08(5) 3.31(6) 6.7( 1) 7.7(2) 6.9( 1) 10.3( 1) 7.7( 1) 3.00(5) 3.89(7) 8.3(2) 4.3(2) 10.3(2) 5.8(3) 8.4(2) 6.0( 3) 5.7(2) 7.0(3) 4.9( 1) 5.5(3)
3.4(9) 4(l) 4(l) 3.9(9) 3.8(9) 4(l) 2.2(7) 3.4(9) 2.3(S) 3.4(9) 3.3(9) 2.5(8) 2.9(8) 2.7(S) 3.1(S)
0.759 0.346 0.706 0.329 0.753 0.342 0.598 0.384 0.675 0.365
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O.S.M. Elmokhtar et al. /Materials Chemistry and Physics 42 (1995) 225-230
Table 3 Main interatomic distances (A) and bond angles (“) in the phosphoric ring anion and the phenylammonium groups. Estimated standarddeviations are given in parentheses PaO,, ring anion (a) P(I)O, tetrahedron O(El1) 1.472(2) 2.560( 2) 2.509( 3) 2.467( 3)
O(E12) 120.0( 1) 1.48X2) 2.454( 3) 2.528(2)
O(L12) 109.9( 1) 105.8( 1) 1.593(2) 2.482(3)
O(L13) 107.2( 1) 110.4(l) 102.4( 1) 1.594(2)
O(E21) 1.485(2) 2.558(2) 2.530(2) 2.452(2)
O(E22) 119.9(l) 1.469(2) 2.482( 3) 2.531(2)
O(L12) 110.0(l) 107.9( 1) 1.602(2) 2.460(3)
O(L23) 105.5( 1) 111.3(l) 100.6( 1) I .595(2)
P(3) O(E31) O(E32) O(L13) O(L23)
O(E31) 1.472(2) 2.553( 3) 2.460( 3) 2.533(2)
O(E32) 120.1(l) 1.471(2) 2.506(2) 2.488(3)
O(L13) 106.6( 1) 109.5( 1) 1.597(2) 2.459(2)
0(L23) 110.8(l) 107.8( 1) 100.4( 1) 1.603(2)
P(l)-O(L12)-P(2) P(l)-O(L13)-P(3) P(2)-O(L23)-P(3) P( l)-P(2)-P(3) P(2)-P(l)-P(3) P( l)-P(3)-P(2)
132.8( 1) 134.5( 1) 132.3( 1) 109.22(2) 99.19(3) 107.20(2)
P(l)-P(2) P(l)-P(3) P(2)-P(3)
2.927( 1) 2.943( 1) 2.925( 1)
1.453(3) 1.381(3) 1.383(4) 1.358(5) 1.368(6) 1.380(5) 1.373(4)
N(l)-C(l)-C(2) N(lP31)~3(6) C(lPX)-c(3) C(2)43)--C(4)
118.9(2) 119.6(2) 118.4(3) 120.4(3) 120.9(4) 120.1(4) 118.8(3) 121.5(3)
N(2FX’)-C(8) N(2bWW3 12) W’)-c(8W(9) C(8)49)-c(lO)
c(l2w7)
1.467(3) 1.326(6) 1.414(5) 1.259(7) 1.346(8) 1.392(6) 1.347(5)
C(9)-C( lO)-C( 11) c(1o)-c(11)~(12) C(ll)-C(12)-C(7) C( 12)-C(7)-C(8)
120.5(3) 120.3(3) 119.8(4) 121.9(5) 118.9(4) 121.3(4) 118.8(4) 118.9(3)
( c ) C&W3~ N(3)-C(13) C( 13)-C( 14a) C( 14a)-C( 15a) C( 15a)-C( 16a) C( 16a)-C( 17a) C( 17a)-C( 18a) C( 18a)-C( 13)
1.463(4) 1.416(9) 1.41( 1) 1.41(l) 1.39( 1) 1.378(8) 1.359(6)
N(3)-C( 13)-C( 14a) N(3)-C( 13)-C( 18a) C( 13)X( 14a)X(lSa) C( 14a)-C( 15a)-C(16a) C( 15a)-C( 16a)-C(17a) C( 16a)-C( 17a)-C(18a) C( 17a)-C( 18a)-C(13) C( 18a)-C( 13)-C(14a)
117.0(3) 121.5(4) 118.1(6) 120.1(9) 119.5(6) 119.9(6) 121.4(7) 120.4(4)
H( lNl)-N( l)-H(2Nl) H( lNl)-N( l)-H(3Nl) H(2Nl)-N( l)-H(3Nl) H( lN3)-N(3)-H(2N3) H( lN3)-N(3)-H(3N3) H(2N3)-N(3)-H(3N3)
106(3) 113(3) 107(3) 113(4) 107(3) 108(3)
H( lN2)-N(2)-H(2N2) H( lN2)-N(2)-H(3N2) H(2N2)-N(2)-H(3N2)
102(3) 106(3) 113(4)
P(1) O(El1) O(E12) O(L12) O(L13) (b) P(2)0, tetrahedron P(2) O(E21) O(E22) L(L12) O(L23) (c) P(3)0, tetrahedron
Phenylammonium groups (a) C,H,N(l) N(l)-C(l) C(lK(2) c(2)-c(3) C(3)<(4) C(4)-c(5) C(5)-C(6) C(6)-C( 1) (b) C&&2) N(2)-C(7) C(7)-c(8) C(8)-c(9) C(9)-c( 10) C(lO)-C(ll) C(ll)-C(12)
C(3)-c(4)-c(5) C(4)-c(5)-C(6) C(5)-C(6)-c(l) C(6)-c( 1)-c(2)
O.S.M. Elmokhtar et al. /Maferials Table 4 Main geometrical features of the hydrogen-bond O(N)-H..
.O
N(l)-H(lNl)...O(Ell) N(l)-H(2Nl)...O(E32) N(I)-H(3Nl)...O(Wl) N(2)-H( lN2). .O(E12) N(2)-H(2N2). . .O(E21) N(2)-H(3N2)...O(E31) N(3)-H(lN3)..-O(E12) N(3)-H(2N3). .O(W3) N(3)-H(3N3). . .O(W2) O(Wl)-H(lWl)...O(E22) O(WI)-H(2Wl)...O(E21) O(W2)-H( lW2). .O(E21) O(W2)-H(2W2)...O(Ell) O(W3)-H( lW3). . .O(E22) O(W3)-H(2W3)...O(E32) H(lWl)-O(Wl)-H(2Wl) H(lW3)-O(W3)-H(2W3)
Chemistry and Physics 42 (1995) 225-230
229
scheme.Distances given in A, angles in decimal degrees
O(N)-H
H. . .O
O(N).
0X8(3) 0X9(4) 0.92(4) 0.88(4) 0.88( 3) 1.03(4) 0.86(4) 0.90( 3) 0.95(3) 0.85(4) 0.85(4) 0.81(4) 0.84(4) 0.74(5) 0.86(4) 116(4) lOO(4)
1.95(3)
2.822(2) 2.719(3) 2.793(4) 2.865( 3) 2.850(3) 2.713(4) 2.859(4) 2.730( 3) 2.766(2) 2.788(2) 2.812(2) 2.886(3) 2.923(4) 2.771(4) 2.970( 3) lOl(4)
1.83(4) 1.87(4) 2.00(4) 2.00(4) 1.70(4) 2.02(4) 1.84(3) 1.86(3) 1.99(3) 2.06(3) 2.15(4) 2.16(5) 2.04(S) 2.1814) H( lW2)-O(W2)-H(2W2)
pendent PO4 tetrahedra. Interatomic distances and bond angles in this ring, given in Table 3, are not significantly different from those observed in the other cyclohexaphosphates known to date. The P-O-P and P-P-P angles ranging within the values commonly observed in this kind of rings, from 132.3 to 134.5” for P-O-P and from 99.18 to 109.23” for P-P-P, while the P-P distances ranging from 2.928 to 2.942 A correspond also to values generally measured. A recent review of the various geometries observed in this kind of rings [7 ] shows that in several other P,O,s rings the distortion is much larger, with P-P-P angles ranging from 99.5 to 145.9”.
Fig. 2. Projection of the atomic arrangementof (C,HSNH,)dP,0,B.6Hz0 given.
3.2. Phenylammonium
.O
O(N)-H..
.O
173(4) 174(3) 176(3) 173(3) 165(3) 170(3) 163(3) 171(4) 158(4) 157(4) 147(5) 149(4) 152(3) 167(4) 153(4)
groups
Three independent &H,NH, groups coexist in this atomic arrangement. N-C and C-C distances and C-C-N angles in these three groups are reported in Table 3. These values show clearly that in the C,HsN( 1) group the carbon ring is very regular but slightly distorted in the two other ones, C,H,N( 2) and C6H8N( 3). In these latter groups, some carbon atoms (C,, Cg, C,,, C,l, CJ have relatively high thermal factors, while other carbon atoms (C14, C,,, &, C,, and C,,) are disordered with various occupancy rates. Unlike what can be expected this disorder does not induce, as it can be supposed
along the c-axis. The conventions are similar to those of Fig. 1. Hydrogen bonds am
230
O.S.M. Elmokhtar et al. /Materials
from interatomic bonding calculations, unusual CC distances and C-C-C angles since C-C values vary from 1.26 to 1.42 A and CC-C angles from 118.1 to 121.9” (Table 3). Among the nine H-atoms of these groups only three establish a hydrogen bond with water molecules (Table 4) ; the remaining ones are connected to the external 0 atoms of the phosphoric rings. Fig. 2 shows the phenylammonium groups intercalation between the sheets of PsO1a, parallel to the b,c-plane, in order to connect those groups by hydrogen bonds as to perform the three-dimensional cohesion. The repartition as well as the orientation of the organic rings are evidently induced by their electronic interaction. 3.3. Water molecules The O(Wl), O(W2), O(W3) water molecules are involved in the coordination of two phenylammonium groups. For the coordination of the third group intervene only oxygen atoms O(E) and O(L) belonging to the same P601s ring (Fig. 2). 0( W3) only involved in the coordination of
Chemistry and Physics 42 (1995) 225-230
the phenylammonium group, whose four carbon atoms are disordered, is less strongly bonded than the two other water molecules, a fact which can probably explain its high thermal factor (Table 2). The representation of the water molecules in Fig. 2 shows their role, through the hydrogen bonds, in the cohesion of the phosphoric rings in the atomic arrangement.
References [l] U. Schiilke and R. Kayser, Z. Anorg. A&. Chem., 531 (1985) 167. [Z] A. Durif and M.T. Averbuch-Pouchot, Acra Crystallogr., Sect. C, 45 (1989) 1884. [3] M.T. Averbuch-Pouchot and A. Durif, Acfa Crystallogr., Sect. C, 47 (1991) 1579. [4] R. Masse, M. Bagieu-Beucher, J. Pecault, J.-P. Levy and J. Zyss, Nonlinear Opt., 5 (1993) 413. [5] J. Zyss, in J.L. Bridas and R.R. Chance (eds.), Conjugated Polymeric Materials: Opportunities in Electronics. Optoelectronicsand Molecular Electronics, Kluwer, Dordrecht, 1990, p. 545. [6] Structure Determination Package MolEN, Enraf-Nonius, Delft, Netherlands, 1990. [ 71 M.T. Averbuch-Pouchot and A. Durif, Eur. J. Solid State Inorg. Chem., 28(1991)9.
Materials Chemistry and Physics 42 (1995) 225-230
Materials Science Communication
Chemical preparation and structural investigation of a new cyclohexaphosphate: ( C6H5NH3)6P601g 6H20 l
O.S.M. Elmokhtar a, S. Abid a, M. Rzaigui a, A. Durif b aLuboratoire de Chimie des MatLriauz, Faculte’ des Sciences, 7021 Znrzouna Bizerte, Tunisia b CNRS, Laboratoire de Cristallographie, associe’ ci l'llniversite'J. Fourier, BP 166, 38042 Grenoble Cedex 09, France Received 8 February 1995; revised 13 May 1995; accepted 1.5May 1995
Abstract The chemical preparation and the determination of the crystal structure of a new organic cation cyclohexaphosphate, hexa(phenylammonium) cyclohexaphosphate hexahydrate, (&H,NH 3) 6P 60 18. 6H20, is given. This new compound is triclinic, Pi, with the following unitcellparameters:a=12.353(8)~,b=11.944(8)~,c=10.154(5)~,cY=114.91(5)“,~=110.82(5)“,y=79.04(5)”,Z=2,V=1269(3) A’, and Dx= 3.00 Mg rne3. The crystal structure was solved by using 4578 independent reflections with a final R value of 0.042. The P60L8 ring is centrosymmetrical. Its main geometrical features are those commonly observed in the atomic arrangements of cyclohexaphosphate. Phenylammonium groups and water molecules through H-bonds perform the three-dimensional cohesion of this simple atomic arrangement. The hydrogen bond scheme is given. Keywords: Cyclohexaphosphate; Crystal structure
1. Introduction Following the investigations of Schiilke and Kayser [ 11 on the condensation-cyclization of LiH,PO, into Li6P601s, the crystal chemistry of cyclohexaphosphates developed rapidly but the organic cation derivatives have not yet been investigated in detail. To date, only three compounds have been accurately characterized in this field: (NH,(CH2)2NH3)3P60,8.2H20 [21,(GHsNH,),P&,~.~H~O 131, (N,Hs),(N,H,),P,O,, 131. In the present investigation we report the synthesis and the crystal structure of a new organic cation cyclohexaphosphate: ( C6HsNH3)6P6018~ 6Hz0. This compound is the first example within a systematic study on the elaboration of new materials resulting from the association of organic and inorganic entities which could have a particular interest in non-linear optics [ 4 J . Research into very efficient and highly transparent non-linear optical crystals (range: 100 nm to IR wavelengths) is a challenge in which physicists concerned with non-linear optics are nowadays engaged. The performance of optical signal-processing devices is linked to the discovery of such new materials [ 51. The design of organic-inorganic polar crystals for quadratic non-linear optical applications is nowadays orientated towards and supported by two main observations: (i) the organic molecules containing 7r-electron systems asymmetrized by electron donor-acceptor 02540584/95/$09.50
Q 1995 Elsevier Science S.A. All rights reserved
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groups are highly polarizable entities in which problems of transparency and crystal growth may arise from their molecular crystal packing, and (ii) the ionic inorganic host-matrices are able to increase the cohesion of packing, to shift the transparency of organic entities towards blue wavelengths and to induce the a-centricity of packing.
2. Experimental 2. I. Chemical preparation (C,H,NH,) 6P6018. 6H,O has been prepared in two steps. An aqueous solution of cyclohexaphosphoric acid was first prepared by passing a solution of Li6P601s through an ionexchange resin in its H-state ( Amberlite IR 120). The lithium salt was prepared according to ihe process described by Schiilke and Kayser [ 11 using purum p.a. Fluka chemicals. This solution was then added drop by drop to aniline (purum p.a. Fluka) under continuous stirring until the solution exhibits a light greenish aspect. Schematically the reaction is: Hz0 W’s%
+ GJ-WS
-
(W-W-M
J’,%
. @I20
( 1)
In order to avoid hydrolysis of the ring anion the above reaction is performed at room temperature. The so-obtained
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O.S.M. Elmokhtar et al. /Materials
solution is then slowly evaporated until the formation of large rectangular prisms of ( C6H,NH,) 6P60,8. 6H20. The title compound is stable for months in normal conditions of temperature and relative humidity. 2.2. Crystal data Unit-cell and space-group determination A preliminary single-crystal investigation has been performed using the Weissenberg technique in order to determine symmetry and space group. The unit cell appeared to be triclinic. The determination of the structure will confirm the centro-symmetric space group Pi. The main crystallographic features of the title compound are given in Table 1. Crystal structure The intensity data collection has been performed using a Philips PW 1100 diffractometer. The experimental parameters for this measurement, the strategy used for the structure determination and its final results are given in Table 1. Final atomic coordinates and B, are given in Table 2.
3. Structure description ( C,H,NH,)6P60,8. 6H20 has a simple atomic arrangement. Figs. 1 and 2 show two different projections, one along the a-axis and the other along the c-axis. The hydrogen atoms are represented.
Chemistry and Physics 42 (1995) 225-230
Table 1 Crystal data and experimental parameters used for the intensity data collection. Strategy and final results of rhe structure determination Crystal data Formula
(C&~NHdJ’dhs~6Hz0
F, Crystal system Space group o (A) b (A) c (A) a (“) P (“) Y0 Z v (A’) Refinement of unit cell parameters with pear (g cm-3
F(000) Linear absorption factor, p( MO Ka) (mm-‘) Morphology Crystal size (mm) Intensity measurements Temperature (K) Wavelength (MO Ka) (A) Diffractometer Scan mode Monochromator Scan width (“) Scan speed (“s-l) 8 Range (“) Measurement area h-9 JG-. lma. Total background measuring time (s) Total no. of scanned reflections Total no. of independent reflections Two intensity and orientation reference reflections Structure determination Lorentz and polarization Program used Computer used Determination
Thermal displacement
corrections
parameters
Unique reflections included Weighting scheme Refined parameters Residual Fourier density (e Ad3) Unweighted agreement factor R Weighted agreement factor R, Estimated standard deviation Largest shift/error
1056.66 triclinic Pi 12.353(g) 11.944(g) 10.154(5) 114.91(5) 110.82(5) 79.04(5) 2 1269(3) 15reflections(10.7<8<11.9°) 3.00 1200 0.613 triangular prism 0.40 x 0.40 x 0.32
294 0.71073 Philips PW 1100 w/2@ graphite plate 1.20 0.02 3-30 +h, k, 1 18, 18, 18 6 5655 4578 116and ii6 (no variation)
no absorption correction MolEN [6] Micro-Vax 3100 Patterson and successive Fourier syntheses H atoms from difference Fourier map isotropic for H atoms anisotropic for other atoms 4578 with I>4a(I) unitary 479 0.424 0.042 0.044 0.796 0.67
3.1. P6018 ring anion Fig. 1. Projection of the atomic arrangement of ( C,HSNH,),P,O,, 6Hz0 along the a-axis. The P,O,s ring anions are given in the tetrahedral representation. The smaller empty circles represent the hydrogen atoms. The other atoms are indicated by their symbols.
The phosphoric ring is centro-symmetrical, located around the (O,O,O) inversion centre and is built of only three inde-
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O.S.M. Elmokhtar et al. /Materials Chemistry and Physics 42 (1995) 225-230 Table 2 Final atomic coordinates and Bq with their estimated standarddeviations in parentheses.&=4/3X,Q,b,&, Atoms
x
P(l)
-0.12115(5) -0.03639(5) -0.05965(5)
P(2) P(3) O(Ll2) O(Ll3) O(El1) O(E12) O(L23) O(E21) O(E22) O(E31)
0.1233(2) -0.0066(2) 0.1292(2) 0.7917(l) O.OOW(1) -0.0685(2) 0.1044(2) 0.1846(2)
Occupation
2
Y 0.01810(5) 0.22469(5) 0.17195(5) -0,1196(l) 0.0433(2)
0.20711(6) 0.19375(6) -0.12347(6) -0.1430(2)
2.12( 1) 1.97( 1)
-0.2194(2)
3.01(4) 3.29(4)
2.16( 1) 3.01(4)
- 0.0790( 2) -0.0717(l) 0.1775(2)
-0.3633(2) 0.0863(2) 0.0467(2)
2X5(4) 2.74(4)
-0.2148(2) -0.3425(2) -0.1568(2)
-0.3189(2) -0.2137(2) 0.1664(2)
2.60(4) 3.21(4) 3.28(4)
N(1)
0.0195(2) 0.1253(2) 0.1576(2) 0.1436(3) 0.0682(2)
0.7265(2) 0.4065(2) 0.1204(2) 0.5137(2) 0.6885(2)
0.1375(2) 0.6101(2) 0.5584(2) 0.9547(3) 0.3990(2)
3.71(4) 3.84(5) 4.20(5) 7.53(7) 2.84(4)
C(1) C(2)
0.1630(2) 0.1525(3)
0.5956(2) 0.4848( 3)
3.00(5) 4.20(7)
C(3) C(4) C(5) C(6) N(2) C(7) C(8) C(9) C(l0)
0.2346( 3) 0.3406(3) 0.3492(4) 0.2596(3)
0.3975( 3) 0.4209(3) 0.5298(4) 0.6187(3) 0.0626(2) 0.0900(2) 0.0618(5) 0.9148(5) 0.8664(4)
0.4012(3) 0.2767(3) 0.2797(4)
O(E32) O(W1) O(W2) O(W3)
C(l1) C(12) N(3) C(13) C( 14a) C( 14b) C( 15a) C( C( C( C( C( C( C(
15b) 16a) 16b) 17a) 17b) 18a) 18b)
H(lW1) H(2Wl) H( lW2) H(2W2) H( lW3) H(2W3) H( lN1) H(2Nl) H(3Nl) H( lN2) H(2N2) H(3N2) H( lN3) H(2N3) H(3N3)
0.2488(2) 0.3702(2) 0.4506(3) 0.4321(4) 0.4009(3) 0.5199(4) 0.4033(3) 0.2388(2) 0.3640(3) 0.4075(5) 0.3911(S) 0.4719(6) 0.509( 1) 0.3974(5) 0.4119(9) 0.4440(5) 0.4437(S) 0.4377(4) 0.4324(9)
0.120(3) 0.122(3) 0.125(3) 0.140(3) 0.143(3) 0.121(3) 0.089(3) 0.051(3) 0.998(3) 0.231(3) 0.203 (3) 0.228( 3) 0.224( 3) 0.201(3) 0.212(3)
0.1552(5) 0.1335(4) 0.2788(2) 0.2926( 2) 0.3436(5) 0.4167(8) 0.6481(7) 0.436( 1) 0.6947(6) 0.651(l) 0.7528(6) 0.760( 1) 0.2385(5) 0.2177(9)
0.485(3) 0.368(3) 0.119(3) 0.052( 3) 0.556(3) 0.565 (4) 0.757( 3) 0.706(3) 0.341(3) 0.069( 3) 0.120(3) 0.975(3) 0.228( 3) 0.353(3) 0.243(3)
0.4027(6) 0.5271(7) 0.5275(4) 0.2049(2) 0.2946( 3) 0.2257(5) 0.6862(6) 0.5425(5) 0.5294(5) 0.4481(4) 0X607(2) 0.9142(3) 0X408(7) 0.056(I) 0.1152(9) 0.127( 1) 0.0059( 9) 0.925 ( 1) 0.9461(8) 0.038( 1) 0.0088(6) -0.118(l)
0.642(4) 0.517(4) 0.473(4) 0.548(4) 0.917(4) 0.030(4) 0.478( 3) 0.317(4) 0.607( 3) 0.116(4) 0.249(4) 0.180(3) 0.892(4) 0.891(3) 0.752(4)
5.90(9) 8.3( 1) 8.1(2) 5.0( 1) 3.08(5) 3.31(6) 6.7( 1) 7.7(2) 6.9( 1) 10.3( 1) 7.7( 1) 3.00(5) 3.89(7) 8.3(2) 4.3(2) 10.3(2) 5.8(3) 8.4(2) 6.0( 3) 5.7(2) 7.0(3) 4.9( 1) 5.5(3)
3.4(9) 4(l) 4(l) 3.9(9) 3.8(9) 4(l) 2.2(7) 3.4(9) 2.3(S) 3.4(9) 3.3(9) 2.5(8) 2.9(8) 2.7(S) 3.1(S)
0.759 0.346 0.706 0.329 0.753 0.342 0.598 0.384 0.675 0.365
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O.S.M. Elmokhtar et al. /Materials Chemistry and Physics 42 (1995) 225-230
Table 3 Main interatomic distances (A) and bond angles (“) in the phosphoric ring anion and the phenylammonium groups. Estimated standarddeviations are given in parentheses PaO,, ring anion (a) P(I)O, tetrahedron O(El1) 1.472(2) 2.560( 2) 2.509( 3) 2.467( 3)
O(E12) 120.0( 1) 1.48X2) 2.454( 3) 2.528(2)
O(L12) 109.9( 1) 105.8( 1) 1.593(2) 2.482(3)
O(L13) 107.2( 1) 110.4(l) 102.4( 1) 1.594(2)
O(E21) 1.485(2) 2.558(2) 2.530(2) 2.452(2)
O(E22) 119.9(l) 1.469(2) 2.482( 3) 2.531(2)
O(L12) 110.0(l) 107.9( 1) 1.602(2) 2.460(3)
O(L23) 105.5( 1) 111.3(l) 100.6( 1) I .595(2)
P(3) O(E31) O(E32) O(L13) O(L23)
O(E31) 1.472(2) 2.553( 3) 2.460( 3) 2.533(2)
O(E32) 120.1(l) 1.471(2) 2.506(2) 2.488(3)
O(L13) 106.6( 1) 109.5( 1) 1.597(2) 2.459(2)
0(L23) 110.8(l) 107.8( 1) 100.4( 1) 1.603(2)
P(l)-O(L12)-P(2) P(l)-O(L13)-P(3) P(2)-O(L23)-P(3) P( l)-P(2)-P(3) P(2)-P(l)-P(3) P( l)-P(3)-P(2)
132.8( 1) 134.5( 1) 132.3( 1) 109.22(2) 99.19(3) 107.20(2)
P(l)-P(2) P(l)-P(3) P(2)-P(3)
2.927( 1) 2.943( 1) 2.925( 1)
1.453(3) 1.381(3) 1.383(4) 1.358(5) 1.368(6) 1.380(5) 1.373(4)
N(l)-C(l)-C(2) N(lP31)~3(6) C(lPX)-c(3) C(2)43)--C(4)
118.9(2) 119.6(2) 118.4(3) 120.4(3) 120.9(4) 120.1(4) 118.8(3) 121.5(3)
N(2FX’)-C(8) N(2bWW3 12) W’)-c(8W(9) C(8)49)-c(lO)
c(l2w7)
1.467(3) 1.326(6) 1.414(5) 1.259(7) 1.346(8) 1.392(6) 1.347(5)
C(9)-C( lO)-C( 11) c(1o)-c(11)~(12) C(ll)-C(12)-C(7) C( 12)-C(7)-C(8)
120.5(3) 120.3(3) 119.8(4) 121.9(5) 118.9(4) 121.3(4) 118.8(4) 118.9(3)
( c ) C&W3~ N(3)-C(13) C( 13)-C( 14a) C( 14a)-C( 15a) C( 15a)-C( 16a) C( 16a)-C( 17a) C( 17a)-C( 18a) C( 18a)-C( 13)
1.463(4) 1.416(9) 1.41( 1) 1.41(l) 1.39( 1) 1.378(8) 1.359(6)
N(3)-C( 13)-C( 14a) N(3)-C( 13)-C( 18a) C( 13)X( 14a)X(lSa) C( 14a)-C( 15a)-C(16a) C( 15a)-C( 16a)-C(17a) C( 16a)-C( 17a)-C(18a) C( 17a)-C( 18a)-C(13) C( 18a)-C( 13)-C(14a)
117.0(3) 121.5(4) 118.1(6) 120.1(9) 119.5(6) 119.9(6) 121.4(7) 120.4(4)
H( lNl)-N( l)-H(2Nl) H( lNl)-N( l)-H(3Nl) H(2Nl)-N( l)-H(3Nl) H( lN3)-N(3)-H(2N3) H( lN3)-N(3)-H(3N3) H(2N3)-N(3)-H(3N3)
106(3) 113(3) 107(3) 113(4) 107(3) 108(3)
H( lN2)-N(2)-H(2N2) H( lN2)-N(2)-H(3N2) H(2N2)-N(2)-H(3N2)
102(3) 106(3) 113(4)
P(1) O(El1) O(E12) O(L12) O(L13) (b) P(2)0, tetrahedron P(2) O(E21) O(E22) L(L12) O(L23) (c) P(3)0, tetrahedron
Phenylammonium groups (a) C,H,N(l) N(l)-C(l) C(lK(2) c(2)-c(3) C(3)<(4) C(4)-c(5) C(5)-C(6) C(6)-C( 1) (b) C&&2) N(2)-C(7) C(7)-c(8) C(8)-c(9) C(9)-c( 10) C(lO)-C(ll) C(ll)-C(12)
C(3)-c(4)-c(5) C(4)-c(5)-C(6) C(5)-C(6)-c(l) C(6)-c( 1)-c(2)
O.S.M. Elmokhtar et al. /Maferials Table 4 Main geometrical features of the hydrogen-bond O(N)-H..
.O
N(l)-H(lNl)...O(Ell) N(l)-H(2Nl)...O(E32) N(I)-H(3Nl)...O(Wl) N(2)-H( lN2). .O(E12) N(2)-H(2N2). . .O(E21) N(2)-H(3N2)...O(E31) N(3)-H(lN3)..-O(E12) N(3)-H(2N3). .O(W3) N(3)-H(3N3). . .O(W2) O(Wl)-H(lWl)...O(E22) O(WI)-H(2Wl)...O(E21) O(W2)-H( lW2). .O(E21) O(W2)-H(2W2)...O(Ell) O(W3)-H( lW3). . .O(E22) O(W3)-H(2W3)...O(E32) H(lWl)-O(Wl)-H(2Wl) H(lW3)-O(W3)-H(2W3)
Chemistry and Physics 42 (1995) 225-230
229
scheme.Distances given in A, angles in decimal degrees
O(N)-H
H. . .O
O(N).
0X8(3) 0X9(4) 0.92(4) 0.88(4) 0.88( 3) 1.03(4) 0.86(4) 0.90( 3) 0.95(3) 0.85(4) 0.85(4) 0.81(4) 0.84(4) 0.74(5) 0.86(4) 116(4) lOO(4)
1.95(3)
2.822(2) 2.719(3) 2.793(4) 2.865( 3) 2.850(3) 2.713(4) 2.859(4) 2.730( 3) 2.766(2) 2.788(2) 2.812(2) 2.886(3) 2.923(4) 2.771(4) 2.970( 3) lOl(4)
1.83(4) 1.87(4) 2.00(4) 2.00(4) 1.70(4) 2.02(4) 1.84(3) 1.86(3) 1.99(3) 2.06(3) 2.15(4) 2.16(5) 2.04(S) 2.1814) H( lW2)-O(W2)-H(2W2)
pendent PO4 tetrahedra. Interatomic distances and bond angles in this ring, given in Table 3, are not significantly different from those observed in the other cyclohexaphosphates known to date. The P-O-P and P-P-P angles ranging within the values commonly observed in this kind of rings, from 132.3 to 134.5” for P-O-P and from 99.18 to 109.23” for P-P-P, while the P-P distances ranging from 2.928 to 2.942 A correspond also to values generally measured. A recent review of the various geometries observed in this kind of rings [7 ] shows that in several other P,O,s rings the distortion is much larger, with P-P-P angles ranging from 99.5 to 145.9”.
Fig. 2. Projection of the atomic arrangementof (C,HSNH,)dP,0,B.6Hz0 given.
3.2. Phenylammonium
.O
O(N)-H..
.O
173(4) 174(3) 176(3) 173(3) 165(3) 170(3) 163(3) 171(4) 158(4) 157(4) 147(5) 149(4) 152(3) 167(4) 153(4)
groups
Three independent &H,NH, groups coexist in this atomic arrangement. N-C and C-C distances and C-C-N angles in these three groups are reported in Table 3. These values show clearly that in the C,HsN( 1) group the carbon ring is very regular but slightly distorted in the two other ones, C,H,N( 2) and C6H8N( 3). In these latter groups, some carbon atoms (C,, Cg, C,,, C,l, CJ have relatively high thermal factors, while other carbon atoms (C14, C,,, &, C,, and C,,) are disordered with various occupancy rates. Unlike what can be expected this disorder does not induce, as it can be supposed
along the c-axis. The conventions are similar to those of Fig. 1. Hydrogen bonds am
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O.S.M. Elmokhtar et al. /Materials
from interatomic bonding calculations, unusual CC distances and C-C-C angles since C-C values vary from 1.26 to 1.42 A and CC-C angles from 118.1 to 121.9” (Table 3). Among the nine H-atoms of these groups only three establish a hydrogen bond with water molecules (Table 4) ; the remaining ones are connected to the external 0 atoms of the phosphoric rings. Fig. 2 shows the phenylammonium groups intercalation between the sheets of PsO1a, parallel to the b,c-plane, in order to connect those groups by hydrogen bonds as to perform the three-dimensional cohesion. The repartition as well as the orientation of the organic rings are evidently induced by their electronic interaction. 3.3. Water molecules The O(Wl), O(W2), O(W3) water molecules are involved in the coordination of two phenylammonium groups. For the coordination of the third group intervene only oxygen atoms O(E) and O(L) belonging to the same P601s ring (Fig. 2). 0( W3) only involved in the coordination of
Chemistry and Physics 42 (1995) 225-230
the phenylammonium group, whose four carbon atoms are disordered, is less strongly bonded than the two other water molecules, a fact which can probably explain its high thermal factor (Table 2). The representation of the water molecules in Fig. 2 shows their role, through the hydrogen bonds, in the cohesion of the phosphoric rings in the atomic arrangement.
References [l] U. Schiilke and R. Kayser, Z. Anorg. A&. Chem., 531 (1985) 167. [Z] A. Durif and M.T. Averbuch-Pouchot, Acra Crystallogr., Sect. C, 45 (1989) 1884. [3] M.T. Averbuch-Pouchot and A. Durif, Acfa Crystallogr., Sect. C, 47 (1991) 1579. [4] R. Masse, M. Bagieu-Beucher, J. Pecault, J.-P. Levy and J. Zyss, Nonlinear Opt., 5 (1993) 413. [5] J. Zyss, in J.L. Bridas and R.R. Chance (eds.), Conjugated Polymeric Materials: Opportunities in Electronics. Optoelectronicsand Molecular Electronics, Kluwer, Dordrecht, 1990, p. 545. [6] Structure Determination Package MolEN, Enraf-Nonius, Delft, Netherlands, 1990. [ 71 M.T. Averbuch-Pouchot and A. Durif, Eur. J. Solid State Inorg. Chem., 28(1991)9.