- Email: [email protected]
Crystal structures, thermal analysis and IR investigations of (C4H14N2O)SO4 and (C4H14N2O)SO4·H2O
Materials Research Bulletin 42 (2007) 149–158 www.elsevier.com/locate/matresbu
Crystal structures, thermal analysis and IR investigations of (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Taha Guerfel, Amor Jouini * Laboratoire de Chimie du Solide, De´partement de Chimie, Faculte´ des Sciences de Monastir, 5019 Monastir, Tunisia Received 11 January 2006; received in revised form 17 April 2006; accepted 2 May 2006 Available online 30 May 2006
Abstract Crystals of 2(2-ammonium ethyl ammonium)ethanol sulfate monohydrate: (C4H14N2O)SO4H2O abbreviated as AEESM, and 2(2-ammonium ethyl ammonium)ethanol sulfate: (C4H14N2O)SO4 abbreviated as AEES, have been prepared and grown at room temperature. These materials have the following unit cell dimensions (C4H14N2O)SO4H2O: a = 16.116(6), b = 7.411(3), and ˚ , and b = 99.433(3)8. Their space groups are ˚ ; (C4H14N2O)SO4: a = 8.1142(2), b = 10.6632(4), c = 9.9951(4) A c = 15.750(6) A Pbca and P21/c, respectively. The structures of these compounds have been determined by single-crystal X-ray data analysis. The AEESM structure is built up from infinite inorganic chains parallel to the b axis linked via Ow–H O hydrogen bonds. These chains are interconnected by organic groups so as to build layers perpendicular to the c direction. The structure of AEES consists of a three-dimensional network of H-bonds connecting all its components. In the present work the crystal structures, thermal behavior and IR analysis of these two new compounds are described. # 2006 Published by Elsevier Ltd. Keywords: D. Crystal structure; C. Infrared spectroscopy
1. Introduction Studies of charged species have become an active research area in organic chemistry, biology and in crystal engineering. Their role as structural agents is important in molecular association processes of proteins, nucleic acids and in creation of non-centrosymmetric crystals for quadratic non-linear optics [1,2]. In this type of materials, the non-linear optical response can be explained primarily by an anharmonic distortion of the electron density distribution inside the molecules due to the intense electric field of an applied optical pulse [3]. The herringbone motif of cations in such non-centrosymmetric structures depends upon the ability of host anions to aggregate [4]. Within a systematic investigation of the environment of sulfate anion in new organic materials and in its contribution in formation of new non-linear compounds, we report here the synthesis and the crystal structures of two new organic sulfates.
* Corresponding author. Tel.: +216 97 367 230; fax: +216 73 500 278. E-mail address: [email protected] (A. Jouini). 0025-5408/$ – see front matter # 2006 Published by Elsevier Ltd. doi:10.1016/j.materresbull.2006.05.004
150
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
2. Experimental Crystals of (C4H14N2O)SO4H2O and (C4H14N2O)SO4 are easily prepared by slow evaporation at room temperature of an aqueous solution of H2SO4 with the organic molecule: 2(2-amino ethyl amino)ethanol; in the molar ratio 1:1. Schematically, the synthesis reactions are: ðH2 OÞ
H2 SO4 þ NH2 ðCH2 Þ2 NHðCH2 Þ2 OH ! ½NH3 ðCH2 Þ2 NH2 ðCH2 Þ2 OHSO4 H2 O ðH2 OÞ
! ½NH3 ðCH2 Þ2 NH2 ðCH2 ÞOHSO4
When most of the solution is evaporated, colorless and prismatic or thoughtlessly truncated crystals appear at the bottom of the vessel. The crystals obtained are stable under normal conditions of temperature and humidity. X-ray intensity data of AEES were collected on a Nonius Kappa-CCD diffractometer with monochromated Mo Ka radiation. For the crystals, 90 frames were recorded, each of 28 in w and 60 s duration. Each frame is doubled to eliminate the uncertain electronic impulses. The first 10 frames were used to index the reflections with the DENZO package and refined to obtain final cell parameters [5]. Preliminary photographs indicated monoclinic symmetry and systematically absent reflections that show the space group to be P21/c. Results obtained with thermal analysis TG/DTA show the presence of one water molecule in the asymmetric unit. The presence of water is also confirmed with IR investigation (as evidenced by one large band in the region 3200– 3700 cm1). The results obtained in these analyses, which were not in agreement with the structural resolution, which indicated absence of water in the structure, motivated us to choose another crystal, having different shape, to repeat the X-ray data collection again. The intensity data collection of AEESM was performed using a MACH3 Enraf Nonius diffractometer. Structural resolution confirm the results obtained with TG/DTA and IR analysis (presence of water in the structure), which lead to the conclusion that a mixture of two kinds of crystals form: a hydrated and anhydrous
Table 1 Crystal structure data for (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Compound Formula weight Crystal system Space group/Z Lattice parameters at 298 K Volume Density (g/cm3) Absorption coefficient m (mm1) F(000) Size/color/shape Diffractometer, scan mode Wavelength, Mo Ka Intensity and orientation control Refl. cell measurement/umin./umax. u range h, k, l range No. independent reflections Observed reflections (I > 2sI) Data reductions programs Programs used No. refined parameters Goodness-of-fit on F2 R1 (anisotropic) Rw (anisotropic) Extinction coefficient ˚ 3) Drmin./Drmax. (e/A Largest shift/error
(C4H14N2O)SO4 202.24 g mol1 Monoclinic P21/c (14)/4 ˚ , b = 10.6632(4) A ˚, a = 8.1142(2) A ˚ , b = 99.433(3) c = 9.9951(4) A ˚3 853.12(5) A 1.575 0.370 432 0.30 mm 0.35 mm 0.40 mm/ colorless/prismatic Kappa CCD Nonius, f ˚ l = 0.71073 A
6.028/25.348 0/9, 0/13, 12/12 1472 1440 Denzo [5] SHELX-97 [7] 142 1.087 0.0306 0.07034 0.05(1) 0.270/0.193 0.000
(C4H14N2)SO4H2O 220.25 g mol1 Orthorhombic Pbca (61)/8 ˚ , b = 7.411(3) A ˚, a = 16.116(6) A ˚ c = 15.750(6) A ˚3 1881.0(1) A 1.555 0.350 944 0.22 mm 0.36 mm 0.38 mm/ colorless/truncated prisms v/2u ˚ l = 0.71073 A (2¯ 4 2) and (8 2 8) 25/10.598/15.658 38/308 0/22, 2/10, 0/22 2733 2141 XCAD4 [6] SHELX-97 [7] 182 1.032 0.0376 0.0982 0.010(1) 0.348/0.438 0.000
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
151
Table 2 ˚ ) and bond angles (8) for (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Main interatomic distances (A S
O(1)
O(2)
O(3)
O(4)
SO4 tetrahedron (AEES) O(1) O(2) O(3) O(4)
1.466(1) 2.411(1) 2.411(1) 2.398(1)
110.14(6) 1.474(1) 2.395(1) 2.401(1)
109.96(7) 108.44(6) 1.478(1) 2.402(2)
109.62(6) 109.39(7) 109.28(7) 1.468(1)
SO4 tetrahedron (AEESM) O(1) O(2) O(3) O(4)
1.480(1) 2.407(2) 2.408(2) 2.401(2)
109.81(8) 1.462(1) 2.399(2) 2.397(2)
109.66(8) 110.07(8) 1.466(1) 2.394(2)
108.75(8) 109.48(9) 109.05(9) 1.474(1)
Organic group C(1)–C(2) C(1)–O(5) C(2)–N(1) N(1)–C(3) C(3)–C(4) C(4)–N(2)
AEESM
AEES
1.500(2) 1.412(2) 1.488(2) 1.484(2) 1.511(2) 1.481(2)
1.509(2) 1.413(2) 1.489(2) 1.485(2) 1.518(2) 1.480(2)
AEESM
AEES
O(5)–C(1)–C(2)
107.9(1)
112.8(1)
C(1)–C(2)–N(1) C(2)–N(1)–C(3) N(1)–C(3)–C(4) C(3)–C(4)–N(2)
110.2(1) 112.6(1) 112.5(1) 112.3(1)
110.2(1) 114.7(1) 111.5(1) 108.7(1)
crystal. The experimental conditions of data collections, the strategy followed for the structures determinations and final results are given in Table 1. Main geometrical features, bond distances and angles are reported in Table 2. Setaram thermoanalysers, TG/DTA92 and DSC92, were used to perform thermal treatment on samples. TG–DTA thermograms are registered with 24.1 mg samples in an open platinium crucible. The differential scanning calorimetry (DSC) was carried out with weighted 26.9 mg samples in open aluminum crucible. In both techniques, samples were heated in air with 3 8C/min heating rate; an empty crucible was used as reference.
Fig. 1. Stereoscopic view of the three-dimensional arrangement of (C4H14N2O)SO4.
152
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
IR spectrum was recorded in the range 4000–400 cm1 with a Biored FTS 6000 FTIR spectrophotometer using samples dispersed in spectroscopically pure KBr pellets. 3. Results and discussion 3.1. AEES structure description The structure of AEES consists of a three-dimensional network of H-bonds connecting all its components evidenced in Fig. 1. The asymmetric unit consists of one organic cation and one sulfate anion. Since the N(O) O ˚ [8,9], each organic cation is linked to five sulfate groups by six strong distances range from 2.725(2) to 2.807(2) A hydrogen bonds. The obtained thermal ellipsoids [10], as depicted in Fig. 2, show the S atom to exhibit rather isotropic thermal displacement and the oxygen atoms to undergo the greatest thermal displacements in a direction perpendicular to the S–O bond, as it would be expected in such a compound [11]. ˚ with an average of 1.472(1) A ˚ (see Table 3). Oxygen atoms The S–O distances range from 1.467(1) to 1.478(1) A O(1) and O(4), which participate respectively in one hydrogen bond, have shorter S–O distances than O(2) and O(3) which participate respectively in two hydrogen bonds. The high sensitivity of the S–O bond distances to the strength and number of the hydrogen bonds, which may be formed, has been also noted in other crystal structures [12–14]. The average values of the distortion indices, corresponding to the different angles and distances in the SO4 tetrahedron are: DI(OSO) = 0.0040, DI(SO) = 0.0030 and DI(OO) = 0.0022. This means that the distortions are more pronounced in
Fig. 2. ORTEP representation of the organic cation environment in (C4H14N2O)SO4. Hydrogen bonds are represented by dashed lines. Thermal ellipsoids are given at 50% probability.
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
153
Table 3 ˚ ) and angles (8) in the hydrogen-bonding schemea of (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Bond lengths (A N(O)–H
H O
N(O) O
N(O)–H O
(C4H14N2O)SO4 N(1)–H(1N1) O(4i) N(1)–H(2N1) O(2) N(2)–H(1N2) O(2ii) N(2)–H(2N2) O(3iii) N(2)–H(3N2) O(1iv) O(5)–H(O5) O(3)
0.88(2) 0.83(2) 0.90(2) 0.95(2) 0.94(2) 0.87(2)
1.87(2) 2.10(2) 1.86(2) 1.85(2) 1.87(2) 1.87(2)
2.751(2) 2.807(2) 2.765(2) 2.777(2) 2.797(2) 2.725(2)
173(2) 143(2) 177(2) 165(2) 168(2) 168(2)
(C4H14N2O)SO4H2O N(1)–H(1N1) O(2v) N(1)–H(2N1) O(1) N(2)–H(1N2) O(3vi) N(2)–H(2N2) O(2vii) N(2)–H(3N2) O(1) O(5)–H(O5) OWviii OW–H(1OW) O(4ii) OW–H(2OW) O(4)
0.88(2) 0.79(2) 0.94(3) 0.88(2) 0.87(3) 0.87(3) 0.77(4) 0.92(4)
2.26(2) 2.04(3) 1.96(3) 1.95(3) 2.07(3) 1.84(3) 1.96(4) 1.76(4)
2.857(2) 2.808(2) 2.859(2) 2.814(2) 2.897(2) 2.695(2) 2.732(2) 2.667(2)
124(2) 165(2) 154(2) 166(2) 157(2) 166(2) 176(4) 166(3)
a Symmetry code: (i): x 2, y, z; (ii): x, y + 0.5, z 0.5; (iii): x 1; y; z; (iv): x, y, z 1; (v): x + 0.5, y, z + 0.5; (vi) x + 0.5, y + 0.5, z; (vii) x + 1, y, z; (viii): x 0.5, y, z + 0.5.
the S–O distance than in O–O and thus the sulfate group can be viewed as a rigid regular arrangement of oxygen atoms with the S atom displaced from the centroid [15]. The main structural feature of the organic cation is its ordering in the hydrogen bonding network; this cation exhibits a gauche conformation and bond distances similar to those observed in the two compounds corresponding to the incorporation of this cation in a phosphate matrices [16] or the coordination of the neutral molecule to the transition metallic ions [17]. The structure contains six donors [(five N + one O) atoms] and four acceptors (O atoms of the SO4 group). The ˚ in length (H O) with N(O)–H O angles from hydrogen bonds, reported in Table 3, range from 1.85(2) to 2.10(2) A 143(2) to 177(2)8. These futures agree with those currently observed in inorganic salts containing the components used in this work. 3.2. AEESM structure description As can be seen in Fig. 3, which shows a projection along the b axis, the atomic arrangement can be described by layers built by all the components of the structure and centered by planes x = 1/4 and 3/4. Connection in these layers are established by N–H O and O–H O hydrogen bonds. Stability between successive layers is performed by weak interactions originating from the organic cations. The anionic arrangement, given in Fig. 4, can be described by infinite chains parallel to the b direction and linked ˚ ) [18]. The distance between two adjacent sulfur atoms in a via O–H O strong hydrogen bonds (dO O 2.73 A ˚ ˚ < c/2. These distances are chain is S–S = 5.273(2) A < b and between two coplanar chains S–S = 5.850(2) A 2 comparable to values observed in (SO4 )n polyanions of other compounds [19]. The interconnection between different chains is assured by organic groups. Each organic group links simultaneously two different chains, so as to build a two-dimensional network. Among the six hydrogen atoms of the organic cation, only one, H(O5), establishes a hydrogen bond with a water molecule (see Fig. 5); the remaining ones are connected to oxygen atoms of four anions. In ˚ this atomic arrangement, the organic cation has no internal symmetry. The mean length of the C–N bonds: 1.484(2) A ˚ ˚ is lower than one of the C–C bonds: 1.505(2) A. The N O distances range from 2.808(2) to 2.897(2) A. The ˚ in length (H O) with N(O)–H O angles from 124(2) to 176(4)8 hydrogen bonds range from 1.76(4) to 2.26(2) A (see Table 3). The structure contains eight donors [five N and three O atoms: 2O(W) + O(5)] and five acceptors [O atoms of the SO4 tetrahedron + O(W)]. The seven H donors around the sulfate anion is in agreement with the most frequently observed coordination number in the sulfate family [20]. ˚ with an average of 1.471(1) A ˚ . Slight differences in the S–O The S–O distances range from 1.462(1) to 1.480(1) A bond lengths together with the slight deformation of the anions indicate a different manner of connection of the oxygen atoms in the hydrogen bond system in the crystal structure. The SO42 groups exhibit a compact assembly of oxygen
154
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
Fig. 3. Projection of the atomic arrangement along the b axis (H-bonds are represented by dashed lines, SO4 groups are represented by tetrahedra).
atoms in which the sulfur atom shows a slightly displacement from the center of gravity of the tetrahedra. The calculated average values of the distortion indices [15], corresponding to the different angles and distances in the SO4 tetrahedron [DI(OSO) = 0.0035, DI(SO) = 0.0044, DI(OO) = 0.0018] exhibit a pronounced distortion of the OSO angles and SO distances if compared to OO distances. It is worth noting that among the four acceptors in the AEES structure, two atoms [O(2), O(3)] are twice acceptors, the other two [O(1), O(4)] are single acceptors; meanwhile the AEESM structure exhibits three atoms [O(1), O(2), O(4)] which are twice acceptors and two [O(3) and O(W)] are single acceptors. The encapsulation of a solvent molecule in the AEESM structure increases the number of hydrogen bonds and the cohesion if compared to those in AEES structure. 4. Thermal behavior From the TGA weight loss curve (Fig. 6), we deduce one molecule of water per formula unit (weight loss, calculated 8.17%, observed 7.41%). The removal of the water molecule, observed in the temperature range 84–200 8C, is related to two endothermic peaks on the DTA curve at 99 and 153 8C. The DH of the dehydration calculated from the DSC curve (Fig. 7) is 39.621 kJ/mol. The two endothermic peaks occurring at 194 and 210 8C correspond to the melting of the compound with a DH of 17.21 kJ/mol. However, the stability of the compound is not very high since it decomposes in the range 246–300 8C.
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
155
Fig. 4. Projection of the anionic arrangement along the a axis (H-bonds are represented by dashed lines, SO4 groups are represented by tetrahedra).
5. IR spectroscopy A free SO42 ion under Td symmetry has four fundamental vibrations, the non-degenerate symmetric stretching mode n1(A1), the doubly degenerate bending mode n2(E), the triply asymmetric stretching mode n3(F2), and the triply degenerate asymmetric bending mode n4(F2). All the modes are Raman active, whereas only n3 and n4 are active in the IR. The average frequencies [21], respectively observed for these modes are: 981, 451, 1104 and 614 cm1.
Fig. 5. ORTEP view of H-bonds around each organic molecule (For clarity, the Hydrogen of C atoms are omitted. H-bonds are represented by dashed lines, Thermal ellipsoids are given at 50% probability.).
156
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
Fig. 6. TG–DTA thermograms (for the mixture AEES and AEESM).
In the crystal, the SO42 ion occupies a lower site symmetry C1, as a result the IR inactive n1 and n2 modes may become active and the degeneracies of n2, n3 and n4 modes may be removed. The degenerate n2 mode of the ion is found to be split into two components around 445 and 483 cm1. The appearance of this IR inactive mode can be due to the symmetry lowering of the sulfate ion from Td to C1. The n3 mode appears as three bands at 1058, 1122 and 1165 cm1. The n4 mode is also observed as three bands at 574, 618 and 651 cm1. The non-degenerate stretching mode n1 appears as one band at 978 cm1. The lower frequency value obtained for the n1 mode than those in a free SO42 ion also confirms the distortion of SO4 tetrahedra as is evident from different S– O bond lengths determined by the X-ray diffraction study. The presence of hydrogen bonds may be the reason for the observed distortion in SO4 tetrahedra. The remaining observed bands in the spectrum can be assigned to CH2, NH3, NH2, OH, H2O and skeletal symmetric and asymmetric stretching and deformation modes [22]. The domain of high frequencies in the spectrum is characterized by N(C, O)–H stretching, combination bands and harmonics, while the lower one corresponds to the bending and to the external modes. The IR spectrum of this compound is depicted in Fig. 8.
Fig. 7. DSC thermogram (for the mixture AEES and AEESM).
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
157
Fig. 8. IR spectrum (for the mixture AEES and AEESM).
A broad band extending from 3700 to 2195 cm1 is observed in the IR spectrum. This broad band must be due to the symmetric and asymmetric stretching modes of CH2, NH3, NH2, OH and H2O. NH3 bending and rocking may occur in the ranges 1629–1591 and 901–810 cm1. The shifting of the stretching and bending vibrations of the NH3 group from the free state value confirms the formation of hydrogen bonds of varying strengths in the crystal. Skeletal vibrations may occur in the ranges 1557–1454, 1332–1258 and 776–734 cm1. Frequencies in the range 1454–1211 cm1 are attributed to v (CH2), d (CH2), r (CH2) and d (OH). Supplementary material CCDC 252446 and CCDC 252447, contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/data_request/cif, by e-mailing [email protected] or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK. Fax: +44 1223 336033. Acknowledgements The crystal data collection of (C4H14N2O)SO4 (AEES) was done in the ‘‘Laboratoire de Bioinorganique Structurale, Faculte´ des Sciences et Techniques, Saint Je´roˆme 13397 Marseille Cedex 20, France’’. We are grateful to Dr. M. Pierrot who supervised this experiment. References [1] [2] [3] [4] [5] [6]
P. Chakrabarti, J. Mol. Biol. 234 (1993) 463. R. Masse, M. Bagieu-Beucher, J. Pe´caut, J.P. Levy, J. Zyss, Nonlinear Opt. 5 (1993) 413. A. Fkyerat, A. Guelzim, F. Baert, W. Paulus, G. Heger, J. Zyss, A. Pe´rigaud, Acta Cryst. B51 (1995) 197. J. Zaccaro, M. Bagieu-Beucher, A. Ibanez, R. Masse, J. Solid State Chem. 124 (1996) 8. Z. Otwinowski, W. Minor, Methods in Enzymology, vol. 276, Academic Press, New York, 1997. XCAD4, Data Reduction Program for Bruker-Nonius Serial Diffractometers, Bruker-Nonius, Madison, WI, USA and Delft, The Netherlands, 2003. [7] .G.M. Sheldrick, SHELXS97 and SHELXL97 Program for Crystal Structure Solution and Refinement, University of Go¨ttingen, Germany, 1997 [8] B. Pirard, G. Baudoux, F. Durant, Acta Cryst. B 51 (1995) 103.
158 [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22]
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158 V. Bertolasi, P. Gilli, V. Ferretti, G. Gilli, Acta Cryst. B 51 (1995) 1004. L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565. S.M. Haile, K-D. Kreuer, K. Maier, Acta Cryst. B 51 (1995) 680. T. Guerfel, M. Bdiri, A. Jouini, J. Chem. Crystallogr. 30 (12) (2000) 799. A. Chtioui, T. Guerfel, L. Benhamada, A. Jouini, Solid State Sci. 3 (2001) 859. S. Capasso, C.A. Mattia, L. Mazzarella, A. Zagari, Acta Cryst. C 39 (1983) 281. W.H. Baur, Acta Cryst. B 30 (1974) 1195. S. Demir, V.T. Yilmaz, O. Andac, W.T.A. Harrison, Acta Cryst. C 58 (2002) O407. V.T. Yilmaz, A. Karadag, C. Thoene, J. Coord. Chem. 55 (2002) 609. I.D. Brown, Acta Cryst. A 32 (1976) 24. T. Guerfel, A. Jouini, J. Chem. Crystallogr. 31 (6) (2002) 333. L. Chertanova, C. Pascard, Acta Cryst. B 52 (1996) 677. G. Hertzberg, Infrared and Raman Spectra of Polyatomic Molecules, Van Nostrand, New York, 1966. K. Nakamoto, IR and Ra spectra of Inorganic and Coordination Compound, Wiley Interscience, 1986.
Crystal structures, thermal analysis and IR investigations of (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Taha Guerfel, Amor Jouini * Laboratoire de Chimie du Solide, De´partement de Chimie, Faculte´ des Sciences de Monastir, 5019 Monastir, Tunisia Received 11 January 2006; received in revised form 17 April 2006; accepted 2 May 2006 Available online 30 May 2006
Abstract Crystals of 2(2-ammonium ethyl ammonium)ethanol sulfate monohydrate: (C4H14N2O)SO4H2O abbreviated as AEESM, and 2(2-ammonium ethyl ammonium)ethanol sulfate: (C4H14N2O)SO4 abbreviated as AEES, have been prepared and grown at room temperature. These materials have the following unit cell dimensions (C4H14N2O)SO4H2O: a = 16.116(6), b = 7.411(3), and ˚ , and b = 99.433(3)8. Their space groups are ˚ ; (C4H14N2O)SO4: a = 8.1142(2), b = 10.6632(4), c = 9.9951(4) A c = 15.750(6) A Pbca and P21/c, respectively. The structures of these compounds have been determined by single-crystal X-ray data analysis. The AEESM structure is built up from infinite inorganic chains parallel to the b axis linked via Ow–H O hydrogen bonds. These chains are interconnected by organic groups so as to build layers perpendicular to the c direction. The structure of AEES consists of a three-dimensional network of H-bonds connecting all its components. In the present work the crystal structures, thermal behavior and IR analysis of these two new compounds are described. # 2006 Published by Elsevier Ltd. Keywords: D. Crystal structure; C. Infrared spectroscopy
1. Introduction Studies of charged species have become an active research area in organic chemistry, biology and in crystal engineering. Their role as structural agents is important in molecular association processes of proteins, nucleic acids and in creation of non-centrosymmetric crystals for quadratic non-linear optics [1,2]. In this type of materials, the non-linear optical response can be explained primarily by an anharmonic distortion of the electron density distribution inside the molecules due to the intense electric field of an applied optical pulse [3]. The herringbone motif of cations in such non-centrosymmetric structures depends upon the ability of host anions to aggregate [4]. Within a systematic investigation of the environment of sulfate anion in new organic materials and in its contribution in formation of new non-linear compounds, we report here the synthesis and the crystal structures of two new organic sulfates.
* Corresponding author. Tel.: +216 97 367 230; fax: +216 73 500 278. E-mail address: [email protected] (A. Jouini). 0025-5408/$ – see front matter # 2006 Published by Elsevier Ltd. doi:10.1016/j.materresbull.2006.05.004
150
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
2. Experimental Crystals of (C4H14N2O)SO4H2O and (C4H14N2O)SO4 are easily prepared by slow evaporation at room temperature of an aqueous solution of H2SO4 with the organic molecule: 2(2-amino ethyl amino)ethanol; in the molar ratio 1:1. Schematically, the synthesis reactions are: ðH2 OÞ
H2 SO4 þ NH2 ðCH2 Þ2 NHðCH2 Þ2 OH ! ½NH3 ðCH2 Þ2 NH2 ðCH2 Þ2 OHSO4 H2 O ðH2 OÞ
! ½NH3 ðCH2 Þ2 NH2 ðCH2 ÞOHSO4
When most of the solution is evaporated, colorless and prismatic or thoughtlessly truncated crystals appear at the bottom of the vessel. The crystals obtained are stable under normal conditions of temperature and humidity. X-ray intensity data of AEES were collected on a Nonius Kappa-CCD diffractometer with monochromated Mo Ka radiation. For the crystals, 90 frames were recorded, each of 28 in w and 60 s duration. Each frame is doubled to eliminate the uncertain electronic impulses. The first 10 frames were used to index the reflections with the DENZO package and refined to obtain final cell parameters [5]. Preliminary photographs indicated monoclinic symmetry and systematically absent reflections that show the space group to be P21/c. Results obtained with thermal analysis TG/DTA show the presence of one water molecule in the asymmetric unit. The presence of water is also confirmed with IR investigation (as evidenced by one large band in the region 3200– 3700 cm1). The results obtained in these analyses, which were not in agreement with the structural resolution, which indicated absence of water in the structure, motivated us to choose another crystal, having different shape, to repeat the X-ray data collection again. The intensity data collection of AEESM was performed using a MACH3 Enraf Nonius diffractometer. Structural resolution confirm the results obtained with TG/DTA and IR analysis (presence of water in the structure), which lead to the conclusion that a mixture of two kinds of crystals form: a hydrated and anhydrous
Table 1 Crystal structure data for (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Compound Formula weight Crystal system Space group/Z Lattice parameters at 298 K Volume Density (g/cm3) Absorption coefficient m (mm1) F(000) Size/color/shape Diffractometer, scan mode Wavelength, Mo Ka Intensity and orientation control Refl. cell measurement/umin./umax. u range h, k, l range No. independent reflections Observed reflections (I > 2sI) Data reductions programs Programs used No. refined parameters Goodness-of-fit on F2 R1 (anisotropic) Rw (anisotropic) Extinction coefficient ˚ 3) Drmin./Drmax. (e/A Largest shift/error
(C4H14N2O)SO4 202.24 g mol1 Monoclinic P21/c (14)/4 ˚ , b = 10.6632(4) A ˚, a = 8.1142(2) A ˚ , b = 99.433(3) c = 9.9951(4) A ˚3 853.12(5) A 1.575 0.370 432 0.30 mm 0.35 mm 0.40 mm/ colorless/prismatic Kappa CCD Nonius, f ˚ l = 0.71073 A
6.028/25.348 0/9, 0/13, 12/12 1472 1440 Denzo [5] SHELX-97 [7] 142 1.087 0.0306 0.07034 0.05(1) 0.270/0.193 0.000
(C4H14N2)SO4H2O 220.25 g mol1 Orthorhombic Pbca (61)/8 ˚ , b = 7.411(3) A ˚, a = 16.116(6) A ˚ c = 15.750(6) A ˚3 1881.0(1) A 1.555 0.350 944 0.22 mm 0.36 mm 0.38 mm/ colorless/truncated prisms v/2u ˚ l = 0.71073 A (2¯ 4 2) and (8 2 8) 25/10.598/15.658 38/308 0/22, 2/10, 0/22 2733 2141 XCAD4 [6] SHELX-97 [7] 182 1.032 0.0376 0.0982 0.010(1) 0.348/0.438 0.000
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
151
Table 2 ˚ ) and bond angles (8) for (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Main interatomic distances (A S
O(1)
O(2)
O(3)
O(4)
SO4 tetrahedron (AEES) O(1) O(2) O(3) O(4)
1.466(1) 2.411(1) 2.411(1) 2.398(1)
110.14(6) 1.474(1) 2.395(1) 2.401(1)
109.96(7) 108.44(6) 1.478(1) 2.402(2)
109.62(6) 109.39(7) 109.28(7) 1.468(1)
SO4 tetrahedron (AEESM) O(1) O(2) O(3) O(4)
1.480(1) 2.407(2) 2.408(2) 2.401(2)
109.81(8) 1.462(1) 2.399(2) 2.397(2)
109.66(8) 110.07(8) 1.466(1) 2.394(2)
108.75(8) 109.48(9) 109.05(9) 1.474(1)
Organic group C(1)–C(2) C(1)–O(5) C(2)–N(1) N(1)–C(3) C(3)–C(4) C(4)–N(2)
AEESM
AEES
1.500(2) 1.412(2) 1.488(2) 1.484(2) 1.511(2) 1.481(2)
1.509(2) 1.413(2) 1.489(2) 1.485(2) 1.518(2) 1.480(2)
AEESM
AEES
O(5)–C(1)–C(2)
107.9(1)
112.8(1)
C(1)–C(2)–N(1) C(2)–N(1)–C(3) N(1)–C(3)–C(4) C(3)–C(4)–N(2)
110.2(1) 112.6(1) 112.5(1) 112.3(1)
110.2(1) 114.7(1) 111.5(1) 108.7(1)
crystal. The experimental conditions of data collections, the strategy followed for the structures determinations and final results are given in Table 1. Main geometrical features, bond distances and angles are reported in Table 2. Setaram thermoanalysers, TG/DTA92 and DSC92, were used to perform thermal treatment on samples. TG–DTA thermograms are registered with 24.1 mg samples in an open platinium crucible. The differential scanning calorimetry (DSC) was carried out with weighted 26.9 mg samples in open aluminum crucible. In both techniques, samples were heated in air with 3 8C/min heating rate; an empty crucible was used as reference.
Fig. 1. Stereoscopic view of the three-dimensional arrangement of (C4H14N2O)SO4.
152
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
IR spectrum was recorded in the range 4000–400 cm1 with a Biored FTS 6000 FTIR spectrophotometer using samples dispersed in spectroscopically pure KBr pellets. 3. Results and discussion 3.1. AEES structure description The structure of AEES consists of a three-dimensional network of H-bonds connecting all its components evidenced in Fig. 1. The asymmetric unit consists of one organic cation and one sulfate anion. Since the N(O) O ˚ [8,9], each organic cation is linked to five sulfate groups by six strong distances range from 2.725(2) to 2.807(2) A hydrogen bonds. The obtained thermal ellipsoids [10], as depicted in Fig. 2, show the S atom to exhibit rather isotropic thermal displacement and the oxygen atoms to undergo the greatest thermal displacements in a direction perpendicular to the S–O bond, as it would be expected in such a compound [11]. ˚ with an average of 1.472(1) A ˚ (see Table 3). Oxygen atoms The S–O distances range from 1.467(1) to 1.478(1) A O(1) and O(4), which participate respectively in one hydrogen bond, have shorter S–O distances than O(2) and O(3) which participate respectively in two hydrogen bonds. The high sensitivity of the S–O bond distances to the strength and number of the hydrogen bonds, which may be formed, has been also noted in other crystal structures [12–14]. The average values of the distortion indices, corresponding to the different angles and distances in the SO4 tetrahedron are: DI(OSO) = 0.0040, DI(SO) = 0.0030 and DI(OO) = 0.0022. This means that the distortions are more pronounced in
Fig. 2. ORTEP representation of the organic cation environment in (C4H14N2O)SO4. Hydrogen bonds are represented by dashed lines. Thermal ellipsoids are given at 50% probability.
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
153
Table 3 ˚ ) and angles (8) in the hydrogen-bonding schemea of (C4H14N2O)SO4 and (C4H14N2O)SO4H2O Bond lengths (A N(O)–H
H O
N(O) O
N(O)–H O
(C4H14N2O)SO4 N(1)–H(1N1) O(4i) N(1)–H(2N1) O(2) N(2)–H(1N2) O(2ii) N(2)–H(2N2) O(3iii) N(2)–H(3N2) O(1iv) O(5)–H(O5) O(3)
0.88(2) 0.83(2) 0.90(2) 0.95(2) 0.94(2) 0.87(2)
1.87(2) 2.10(2) 1.86(2) 1.85(2) 1.87(2) 1.87(2)
2.751(2) 2.807(2) 2.765(2) 2.777(2) 2.797(2) 2.725(2)
173(2) 143(2) 177(2) 165(2) 168(2) 168(2)
(C4H14N2O)SO4H2O N(1)–H(1N1) O(2v) N(1)–H(2N1) O(1) N(2)–H(1N2) O(3vi) N(2)–H(2N2) O(2vii) N(2)–H(3N2) O(1) O(5)–H(O5) OWviii OW–H(1OW) O(4ii) OW–H(2OW) O(4)
0.88(2) 0.79(2) 0.94(3) 0.88(2) 0.87(3) 0.87(3) 0.77(4) 0.92(4)
2.26(2) 2.04(3) 1.96(3) 1.95(3) 2.07(3) 1.84(3) 1.96(4) 1.76(4)
2.857(2) 2.808(2) 2.859(2) 2.814(2) 2.897(2) 2.695(2) 2.732(2) 2.667(2)
124(2) 165(2) 154(2) 166(2) 157(2) 166(2) 176(4) 166(3)
a Symmetry code: (i): x 2, y, z; (ii): x, y + 0.5, z 0.5; (iii): x 1; y; z; (iv): x, y, z 1; (v): x + 0.5, y, z + 0.5; (vi) x + 0.5, y + 0.5, z; (vii) x + 1, y, z; (viii): x 0.5, y, z + 0.5.
the S–O distance than in O–O and thus the sulfate group can be viewed as a rigid regular arrangement of oxygen atoms with the S atom displaced from the centroid [15]. The main structural feature of the organic cation is its ordering in the hydrogen bonding network; this cation exhibits a gauche conformation and bond distances similar to those observed in the two compounds corresponding to the incorporation of this cation in a phosphate matrices [16] or the coordination of the neutral molecule to the transition metallic ions [17]. The structure contains six donors [(five N + one O) atoms] and four acceptors (O atoms of the SO4 group). The ˚ in length (H O) with N(O)–H O angles from hydrogen bonds, reported in Table 3, range from 1.85(2) to 2.10(2) A 143(2) to 177(2)8. These futures agree with those currently observed in inorganic salts containing the components used in this work. 3.2. AEESM structure description As can be seen in Fig. 3, which shows a projection along the b axis, the atomic arrangement can be described by layers built by all the components of the structure and centered by planes x = 1/4 and 3/4. Connection in these layers are established by N–H O and O–H O hydrogen bonds. Stability between successive layers is performed by weak interactions originating from the organic cations. The anionic arrangement, given in Fig. 4, can be described by infinite chains parallel to the b direction and linked ˚ ) [18]. The distance between two adjacent sulfur atoms in a via O–H O strong hydrogen bonds (dO O 2.73 A ˚ ˚ < c/2. These distances are chain is S–S = 5.273(2) A < b and between two coplanar chains S–S = 5.850(2) A 2 comparable to values observed in (SO4 )n polyanions of other compounds [19]. The interconnection between different chains is assured by organic groups. Each organic group links simultaneously two different chains, so as to build a two-dimensional network. Among the six hydrogen atoms of the organic cation, only one, H(O5), establishes a hydrogen bond with a water molecule (see Fig. 5); the remaining ones are connected to oxygen atoms of four anions. In ˚ this atomic arrangement, the organic cation has no internal symmetry. The mean length of the C–N bonds: 1.484(2) A ˚ ˚ is lower than one of the C–C bonds: 1.505(2) A. The N O distances range from 2.808(2) to 2.897(2) A. The ˚ in length (H O) with N(O)–H O angles from 124(2) to 176(4)8 hydrogen bonds range from 1.76(4) to 2.26(2) A (see Table 3). The structure contains eight donors [five N and three O atoms: 2O(W) + O(5)] and five acceptors [O atoms of the SO4 tetrahedron + O(W)]. The seven H donors around the sulfate anion is in agreement with the most frequently observed coordination number in the sulfate family [20]. ˚ with an average of 1.471(1) A ˚ . Slight differences in the S–O The S–O distances range from 1.462(1) to 1.480(1) A bond lengths together with the slight deformation of the anions indicate a different manner of connection of the oxygen atoms in the hydrogen bond system in the crystal structure. The SO42 groups exhibit a compact assembly of oxygen
154
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
Fig. 3. Projection of the atomic arrangement along the b axis (H-bonds are represented by dashed lines, SO4 groups are represented by tetrahedra).
atoms in which the sulfur atom shows a slightly displacement from the center of gravity of the tetrahedra. The calculated average values of the distortion indices [15], corresponding to the different angles and distances in the SO4 tetrahedron [DI(OSO) = 0.0035, DI(SO) = 0.0044, DI(OO) = 0.0018] exhibit a pronounced distortion of the OSO angles and SO distances if compared to OO distances. It is worth noting that among the four acceptors in the AEES structure, two atoms [O(2), O(3)] are twice acceptors, the other two [O(1), O(4)] are single acceptors; meanwhile the AEESM structure exhibits three atoms [O(1), O(2), O(4)] which are twice acceptors and two [O(3) and O(W)] are single acceptors. The encapsulation of a solvent molecule in the AEESM structure increases the number of hydrogen bonds and the cohesion if compared to those in AEES structure. 4. Thermal behavior From the TGA weight loss curve (Fig. 6), we deduce one molecule of water per formula unit (weight loss, calculated 8.17%, observed 7.41%). The removal of the water molecule, observed in the temperature range 84–200 8C, is related to two endothermic peaks on the DTA curve at 99 and 153 8C. The DH of the dehydration calculated from the DSC curve (Fig. 7) is 39.621 kJ/mol. The two endothermic peaks occurring at 194 and 210 8C correspond to the melting of the compound with a DH of 17.21 kJ/mol. However, the stability of the compound is not very high since it decomposes in the range 246–300 8C.
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
155
Fig. 4. Projection of the anionic arrangement along the a axis (H-bonds are represented by dashed lines, SO4 groups are represented by tetrahedra).
5. IR spectroscopy A free SO42 ion under Td symmetry has four fundamental vibrations, the non-degenerate symmetric stretching mode n1(A1), the doubly degenerate bending mode n2(E), the triply asymmetric stretching mode n3(F2), and the triply degenerate asymmetric bending mode n4(F2). All the modes are Raman active, whereas only n3 and n4 are active in the IR. The average frequencies [21], respectively observed for these modes are: 981, 451, 1104 and 614 cm1.
Fig. 5. ORTEP view of H-bonds around each organic molecule (For clarity, the Hydrogen of C atoms are omitted. H-bonds are represented by dashed lines, Thermal ellipsoids are given at 50% probability.).
156
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
Fig. 6. TG–DTA thermograms (for the mixture AEES and AEESM).
In the crystal, the SO42 ion occupies a lower site symmetry C1, as a result the IR inactive n1 and n2 modes may become active and the degeneracies of n2, n3 and n4 modes may be removed. The degenerate n2 mode of the ion is found to be split into two components around 445 and 483 cm1. The appearance of this IR inactive mode can be due to the symmetry lowering of the sulfate ion from Td to C1. The n3 mode appears as three bands at 1058, 1122 and 1165 cm1. The n4 mode is also observed as three bands at 574, 618 and 651 cm1. The non-degenerate stretching mode n1 appears as one band at 978 cm1. The lower frequency value obtained for the n1 mode than those in a free SO42 ion also confirms the distortion of SO4 tetrahedra as is evident from different S– O bond lengths determined by the X-ray diffraction study. The presence of hydrogen bonds may be the reason for the observed distortion in SO4 tetrahedra. The remaining observed bands in the spectrum can be assigned to CH2, NH3, NH2, OH, H2O and skeletal symmetric and asymmetric stretching and deformation modes [22]. The domain of high frequencies in the spectrum is characterized by N(C, O)–H stretching, combination bands and harmonics, while the lower one corresponds to the bending and to the external modes. The IR spectrum of this compound is depicted in Fig. 8.
Fig. 7. DSC thermogram (for the mixture AEES and AEESM).
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158
157
Fig. 8. IR spectrum (for the mixture AEES and AEESM).
A broad band extending from 3700 to 2195 cm1 is observed in the IR spectrum. This broad band must be due to the symmetric and asymmetric stretching modes of CH2, NH3, NH2, OH and H2O. NH3 bending and rocking may occur in the ranges 1629–1591 and 901–810 cm1. The shifting of the stretching and bending vibrations of the NH3 group from the free state value confirms the formation of hydrogen bonds of varying strengths in the crystal. Skeletal vibrations may occur in the ranges 1557–1454, 1332–1258 and 776–734 cm1. Frequencies in the range 1454–1211 cm1 are attributed to v (CH2), d (CH2), r (CH2) and d (OH). Supplementary material CCDC 252446 and CCDC 252447, contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/data_request/cif, by e-mailing [email protected] or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK. Fax: +44 1223 336033. Acknowledgements The crystal data collection of (C4H14N2O)SO4 (AEES) was done in the ‘‘Laboratoire de Bioinorganique Structurale, Faculte´ des Sciences et Techniques, Saint Je´roˆme 13397 Marseille Cedex 20, France’’. We are grateful to Dr. M. Pierrot who supervised this experiment. References [1] [2] [3] [4] [5] [6]
P. Chakrabarti, J. Mol. Biol. 234 (1993) 463. R. Masse, M. Bagieu-Beucher, J. Pe´caut, J.P. Levy, J. Zyss, Nonlinear Opt. 5 (1993) 413. A. Fkyerat, A. Guelzim, F. Baert, W. Paulus, G. Heger, J. Zyss, A. Pe´rigaud, Acta Cryst. B51 (1995) 197. J. Zaccaro, M. Bagieu-Beucher, A. Ibanez, R. Masse, J. Solid State Chem. 124 (1996) 8. Z. Otwinowski, W. Minor, Methods in Enzymology, vol. 276, Academic Press, New York, 1997. XCAD4, Data Reduction Program for Bruker-Nonius Serial Diffractometers, Bruker-Nonius, Madison, WI, USA and Delft, The Netherlands, 2003. [7] .G.M. Sheldrick, SHELXS97 and SHELXL97 Program for Crystal Structure Solution and Refinement, University of Go¨ttingen, Germany, 1997 [8] B. Pirard, G. Baudoux, F. Durant, Acta Cryst. B 51 (1995) 103.
158 [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22]
T. Guerfel, A. Jouini / Materials Research Bulletin 42 (2007) 149–158 V. Bertolasi, P. Gilli, V. Ferretti, G. Gilli, Acta Cryst. B 51 (1995) 1004. L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565. S.M. Haile, K-D. Kreuer, K. Maier, Acta Cryst. B 51 (1995) 680. T. Guerfel, M. Bdiri, A. Jouini, J. Chem. Crystallogr. 30 (12) (2000) 799. A. Chtioui, T. Guerfel, L. Benhamada, A. Jouini, Solid State Sci. 3 (2001) 859. S. Capasso, C.A. Mattia, L. Mazzarella, A. Zagari, Acta Cryst. C 39 (1983) 281. W.H. Baur, Acta Cryst. B 30 (1974) 1195. S. Demir, V.T. Yilmaz, O. Andac, W.T.A. Harrison, Acta Cryst. C 58 (2002) O407. V.T. Yilmaz, A. Karadag, C. Thoene, J. Coord. Chem. 55 (2002) 609. I.D. Brown, Acta Cryst. A 32 (1976) 24. T. Guerfel, A. Jouini, J. Chem. Crystallogr. 31 (6) (2002) 333. L. Chertanova, C. Pascard, Acta Cryst. B 52 (1996) 677. G. Hertzberg, Infrared and Raman Spectra of Polyatomic Molecules, Van Nostrand, New York, 1966. K. Nakamoto, IR and Ra spectra of Inorganic and Coordination Compound, Wiley Interscience, 1986.