- Email: [email protected]
Crystal structure, thermal analysis and IR spectrometric investigation of bis(o-anisidinium) sulfate (C7H10NO)2SO4
Materials Research Bulletin 44 (2009) 560–565
Contents lists available at ScienceDirect
Materials Research Bulletin journal homepage: www.elsevier.com/locate/matresbu
Crystal structure, thermal analysis and IR spectrometric investigation of bis(o-anisidinium) sulfate (C7H10NO)2SO4 Ahlem Chtioui, Latifa BenHamada, Amor Jouini * Laboratoire de Chimie du Solide, De´partement de chimie, Faculte´ des Sciences de Monastir, Universite´ du centre, 5019 Monastir, Tunisia
A R T I C L E I N F O
A B S T R A C T
Article history: Received 30 June 2007 Received in revised form 16 June 2008 Accepted 15 July 2008 Available online 3 August 2008
Chemical preparation, X-ray single-crystal, thermal behaviour, and IR spectroscopy investigations are given for a new organic cation sulfate (C7H10NO)2SO4 (denoted BOAS) in the solid state. This compound crystallizes in the monoclinic space group P21/c. The unit cell dimensions are: a = 7.010(3) A˚, b = 11.142(5) A˚, c = 20.770(8) A˚, b = 95.27(3)8 with y = 1615.4(12) A˚3 and Z = 4. The structure has been solved using a direct method and refined to a reliability R factor of 0.047. The title compound consists of a framework of isolated SO4 tetrahedral interleaved with organic molecules, so as to build isolated ribbons parallel to a-axis. In the present work, we describe the crystal structure, thermal behaviour and IR analysis of this new compound. ß 2008 Elsevier Ltd. All rights reserved.
Keywords: B. Chemical synthesis C. X-ray diffraction C. Infrared spectroscopy
1. Introduction The description of the recognition of an anionic group by its environment requires knowledge of its binding stereochemistry. Due to its small size and its ability to become surrounded closely and strongly by H donors the sulfate anion can play a very important role in the molecular aggregation. The family of compounds which combine the cohesion of sulfate anions with enhanced polarizability of organic molecules was clearly illustrated. The most striking result is the high number of hydrogen bonds to the sulfate, which results in the sulfate being surrounded by a cloud of hydrogen donors [1]. The title compound (BOAS) is an additional example illustrating the templating effect of organic molecules on sulfate. In the present work we describe the synthesis and crystal structure of the bis(o-anisidinium)sulfate. Thermal behaviour and IR analysis are given. 2. Experimental Crystals of BOAS are easily prepared by slow evaporation at room temperature of an aqueous solution of H2SO4 and the organic molecule: bis(o-anisidinium); in the molar ratio 1:2. Schematically the synthesis reaction is ðH2 OÞ
H2 SO4 þ 2C7 H9 NO ! ðC7 H10 NOÞ2 SO4
* Corresponding author. Tel.: +216 73 500 280; fax: +216 73 500 278. E-mail addresses: [email protected], [email protected] (A. Jouini). 0025-5408/$ – see front matter ß 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.materresbull.2008.07.012
When most of the solution is evaporated, prismatic crystals appear deep down the vessels. The crystals are stable under normal conditions of temperature and humidity. X-ray intensity data of BOAS were collected on a Nonius KappaCCD diffractometer using monochromated Mo Ka radiation. For the crystal, 90 frames were recorded, each being of 28 in w and 60 s duration. Each frame is doubled to eliminate the uncertain electronic impulses. The first 10 frames were used for indexing reflections using the DENZO package and refined to obtain final cell parameters [2]. Preliminary photographs indicated monoclinic symmetry and systematically absent reflections showed the space group to be P21/c. The structure was solved with a direct method, from the SHELXS-97 programs, which permitted the location of the SO4 groups. The remaining non-hydrogen atoms were located by the successive difference Fourier maps using the SHELXL-97 programs [3]. In the final least-squares refinement of atomic parameters with isotropic thermal factors of the H atoms, R decreased to 4.47% (Rw = 11.50%) for BOAS. Setaram TG–DTA92 Thermoanalyzer was used to perform thermal treatment on samples of BOAS. The TG–DTA thermograms were obtained with 15.20 mg. Samples were placed in an open platinum crucible and heated in air with 3 8C/min heating rate; an empty crucible was used as reference. IR spectrum of BOAS was recorded at room temperature with a Biored FTS 6000 FTIR spectrometer over the wave number range of 4000–400 cm1 with a resolution of about 4 cm1. Thin, transparent pellet was made by compacting an intimate mixture obtained by shaking 2 mg of the samples in 100 mg of KBr.
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565 Table 1 Crystal structure data for (C7H10NO)2SO4 I. Crystal data Formula/formula weight (g/mol) Crystal system Space group/Z Lattice parameters
Table 3 Main interatomic distances (A˚) and bond angles (8) for (C7H10NO)2SO4 (C7H10NO)2SO4/344.38 monoclinic P21/c(14)/4 a = 7.010(3) A˚ b = 11.142(5) A˚; b = 95.27(3)8 c = 20.770(8) A˚ 1615.4(12) A˚3
Volume Density(calculated) (g/cm3) Absorption coefficient m (mm1) F(0 0 0) Size (mm3)/color
561
1.416 0.233 728 0.45 0.40 0.35/colorless
II. Intensity measurment Diffractometer, Wavelength, Mo Ka Temperature Theta range h k l range Completness to theta = 26.978 The total data collected Number of independent reflections
Kappa-CCD Nonius, f l = 0.71073 A˚ 293 2.088/26.978 8/8, 0/14, 2/26 99.5% 4088 3494 (Rint = 0.0494)
III: Structure determination Unic reflections included: I > 2sI) Programs used Number of refined parameters Goodness-of-fit on F2 R Rw Extinction coefficient Drmin/Drmax (e/A˚3) Largest shift/error
2389 SHELX-97 [3] 289 1.041 0.0447 0.1149 0.008(2) 0.389/0.410 0.000
S
O(1)
SO4 tetrahedron O(1) 1.480(2) O(2) 2.393(2) O(3) 2.390(2) O(4) 2.380(2)
O(2)
O(3)
O(4)
109.0(1) 1.460(2) 2.396(3) 2.407(2)
108.3(2) 109.8(2) 1.468(2) 2.420(3)
107.8(1) 110.7(1) 111.3(1) 1.466(2)
Organic groups [C7H10N(1)O(5)]+ O(5)–C(1) O(5)–C(7) N(1)–C(2) C(2)–C(1) C(1)–C(6) C(2)–C(3) C(3)–C(4) C(4)–C(5) C(5)–C(6)
1.361(4) 1.429(4) 1.464(3) 1.394(4) 1.385(4) 1.370(4) 1.388(4) 1.378(5) 1.387(5)
C(7)–O(5)–C(1) C(2)–C(1)–C(6) O(5)–C(1)–C(2) O(5)–C(1)–C(6) C(1)–C(2)–N(1) C(1)–C(2)–C(3) N(1)–C(2)–C(3) C(2)–C(3)–C(4) C(3)–C(4)–C(5) C(4)–C(5)–C(6) C(5)–C(6)–C(1)
118.3(3) 119.3(2) 114.6(2) 126.1(3) 118.1(2) 121.5(3) 120.4(2) 119.2(3) 119.7(3) 121.4(3) 118.9(3)
[C7H10N(2)O(6)]+ O(6)–C(8) O(6)–C(14) N(2)–C(9) C(9)–C(8) C(8)–C(13) C(9)–C(10) C(10)–C(11) C(11)–C(12) C(12)–C(13)
1.362(4) 1.426(5) 1.459(3) 1.395(3) 1.386(4) 1.374(4) 1.390(4) 1.380(5) 1.373(5)
C(14)–O(6)–C(8) C(9)–C(8)–C(13) O(6)–C(8)–C(9) O(6)–C(8)–C(13) C(8)–C(9)–N(2) C(8)–C(9)–C(10) N(2)–C(9)–C(10) C(9)–C(10)–C(11) C(10)–C(11)–C(12) C(11)–C(12)–C(13) C(12)–C(13)–C(8)
118.9(3) 119.2(2) 115.0(2) 125.8(3) 118.1(2) 121.2(2) 120.7(2) 119.0(3) 119.9(3) 121.2(3) 119.5(3)
3. Results and discussion 3.1. BOAS structure description The structural determination shows that the BOAS compound crystallizes in the monoclinic system; crystal data are given in Table 1. Final atomic coordinates and thermal parameters are given in Table 2. Those of hydrogen atoms were also determined but are
Table 2 The final atomic coordinates and equivalent temperature factors for (C7H10NO)2SO4
S(1) O(1) O(2) O(3) O(4) O(5) O(6) N(1) N(2) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14)
x/a
y/b
z/c
Ueq
0.23877(7) 0.0685(2) 0.3975(2) 0.1916(3) 0.2857(3) 0.0719(3) 0.2019(3) 0.0416(3) 0.2841(3) 0.1068(3) 0.1703(3) 0.3468(3) 0.4643(4) 0.4022(4) 0.2249(4) 0.1437(5) 0.2879(3) 0.2442(3) 0.2471(4) 0.2950(4) 0.3403(4) 0.3375(3) 0.1573(5)
0.61704(4) 0.6143(1) 0.6730(1) 0.6880(2) 0.4929(2) 0.7534(2) 0.8996(2) 0.8798(2) 0.6952(1) 0.8007(2) 0.8672(2) 0.9211(2) 0.9097(3) 0.8446(3) 0.7883(3) 0.6780(3) 0.8072(2) 0.9133(2) 1.0210(2) 1.0216(2) 0.9167(3) 0.8080(2) 1.0035(3)
0.06375(2) 0.1010(1) 0.1032(1) 0.0049(1) 0.0480(1) 0.2855(1) 0.0991(1) 0.3902(1) 0.0369(1) 0.2844(1) 0.3390(1) 0.3447(1) 0.2949(2) 0.2405(1) 0.2348(1) 0.2332(2) 0.0004(1) 0.0342(1) 0.0007(2) 0.0649(2) 0.0982(2) 0.0652(1) 0.1377(2)
0.028 0.041 0.040 0.065 0.055 0.055 0.056 0.040 0.033 0.040 0.034 0.046 0.056 0.056 0.051 0.061 0.032 0.040 0.052 0.060 0.058 0.043 0.072
Torsion angles for the two NH3 groups C(1) C(2) N(1) C(1) C(2) N(1) C(1) C(2) N(1) C(3) C(2) N(1) C(3) C(2) N(1) C(3) C(2) N(1) C(9) C(8) N(2) C(9) C(8) N(2) C(9) C(8) N(2) C(13) C(8) N(2) C(13) C(8) N(2) C(13) C(8) N(2)
H(1N1) H(2N1) H(3N1) H(1N1) H(2N1) H(3N1) H(1N2) H(2N2) H(3N2) H(1N2) H(2N2) H(3N2)
124.10(3) 1.38(4) 113.75(3) 56.70(4) 179.42(3) 65.44(4) 69.99(3) 50.61(4) 169.66(3) 108.53(3) 130.87(3) 11.82(4)
S–S = 4.837(2).
not given, in order to shorten the table. The main geometrical features of different entities are indicated in Table 3. A view of the structure projected along the c direction is reported in Fig. 1. This projection shows that the atomic arrangement can be described by ribbons built by all the components of the structure and spreading parallel to a-axis. These ribbons are not connected in the two other directions (Fig. 2). Connection between SO42 anions and (C7H10NO)+cations inside the same ribbon is established by N–H O hydrogen bonds; stability between successive ribbons is performed by weak interactions between the organic cations. The asymmetric unit of the crystal structure consists of one sulfate anion and two organic cations. The S–O distances range from 1.460(2) to 1.480(2) A˚ with an average of 1.468 A˚. Slight differences in the S–O 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 BOAS crystal structure. The high sensitivity of the S–O bond
562
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565
Fig. 1. Projection along the c-axis of the atomic arrangement in (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
distances to the number of the hydrogen bonds which may be formed has also been noted in other crystal structures [4–6]. O(1) which participates in two N–H O hydrogen bonds, has the longest S–O distance of 1.480(2) A˚. Consequently, it is possible to use differences in bond lengths to identify which O in the N–H O bonds is more highly associated. The very short direct hydrogen bond between O(3) and H(1N1) would have a very short internuclear H O distance of under 1.66 A˚, which is even shorter than in some di-acid dimmers [7]. Note that in this structure the less distance between two adjacent sulfur atoms is S– S = 4.837(2) A˚ as would be expected in such a compound [8]. The calculated average values of distortion indices corresponding to the different angles and distances in the SO4 tetrahedral [9] [DI(OSO) = 0.010, DI(SO) = 0.004, and DI(OO) = 0.004], exhibit a pronounced distortion of the OSO angles if compared to SO and OO distances. Each sulfate anion is linked to five neighbor organic groups via five hydrogen bonds: two from two N(1)H3 groups and three from three N(2)H3 groups (Fig. 3), with N O distances ranging from 2.844(3) to 2.625(3) A˚. The hydrogen bonds range from 2.07(3) to 1.66(3) A˚ in length (H O) with N–H O angles from 179(3)8 to 115(2)8 (Table 4). Two crystallographically independent (C7H10NO)+ groups exist also in this atomic arrangement. They are organized in opposition; this situation is favourable to a centro symmetric arrangement. In the first cation [C7H10N(1)O(5)]+, location of H(2N1) in the cyclobenzene favors an intramolecular hydrogen bond with the oxygen of methoxy group. The N(1)H3 group is the 1808 rotational isomer of the second cation [C7H10N(2)O(6)]+. The geometrical features measured in o-anisidinium are similar to
intramolecular bond distances and angles for o-anisidinium dihydrogenomonophosphate [10] and 3-ammonio-4-methoxybenzesulfonate [11]. Interatomic distances and angles in these two organic groups spread within the respective ranges: 1.361(4)–1.464(3) A˚ and 114.6(2)–126.1(3)8 (Table 3). The first organic group is bridged to two SO42 anions via three N–H O bonds, whereas the second group is linked to three SO42 anions. The determined bonding angles in the NH3+ groups spread in the range 106.7(3)–111.6(3)8. The reason why the expected tetrahedral symmetry of these groups is somewhat disturbed is probably owing to the intense participation of the protons in the hydrogen bond system. The bond angles in the phenyl group deviate from the idealized value of 1208 (Table 3). Domenicano and Murray-Rust [12] have, among others, shown that the angular deformations of phenyl groups can be described as the sum of the effects of the different substitutents. 3.2. Thermal analysis Two curves, corresponding to DTA and TGA analysis in open air, are reported in Fig. 4. From these curves we were able to deduce that the anhydrous compound is stable in the range 25–130 8C. Its decomposition begins at 130 8C with evolution of ammonia represented by a set of endothermic peaks. Above this temperature the product undergoes a decomposition of the C7H9NO groups over a wide temperature range (170–350 8C). The TGA curve shows an important weight loss corresponding to the progressive pyrolysis of organic molecule in this temperature range.
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565
563
Fig. 2. Projection along the a-axis of the atomic arrangement in (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
3.3. IR spectroscopic investigation
Table 4 Bond lengths (A˚) and angles (8) in the hydrogen-bonding schemea of (C7H10NO)2SO4 (C7H10NO)2SO4 i
N(1)—H(1N1) O(3 ) N(1)—H(2N1) O(5) N(1)—H(3N1) O(1ii) N(2)—H(1N2) O(2iii) N(2)—H(2N2) O(1) N(2)—H(3N2) O(4iv)
N—H
H O
N O
N—H O
0.97 0.99 0.92 0.96 0.96 0.93
1.66(3) 2.07(3) 1.81(4) 1.78(3) 1.92(3) 1.82(3)
2.625(3) 2.651(3) 2.736(3) 2.740(3) 2.844(3) 2.737(3)
178(3) 115(2) 179(3) 171(3) 159(3) 174(3)
(4) (4) (4) (3) (4) (3)
a Symmetry code: (i) x, y + 3/2, z + 1/2; (ii) x, y + 1/2, z + 1/2; (iii) x1, y, z; (iv) x, y + 1, z.
A free regular XO4 tetrahedron has four fundamental vibrations, the no degenerate symmetric stretching mode n1(A1), the doubly degenerate bending mode n2(E), the triply asymmetric stretching mode n3(F2) and 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 observed for these modes are, respectively: 981, 451, 1104 and 614 cm1, when X = S [13]. In the crystal, the SO42 ion occupies lower site symmetry C1, as a result the IR inactive n1 and n2 modes may become active and the degeneracy 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 411 and 446 cm1. Appearance of this IR inactive mode can be due to the symmetry lowering of the sulfate ion from Td to C1. The n3 mode
564
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565 Table 5 Spectral data and band assignment
Fig. 3. Representation of the SO42 environment in (C7H10NO)2SO4. Hydrogen bonds are represented by dashed lines.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
Fig. 4. TG–DTA thermograms of (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
appears as three bands at 1018, 1043 and 1118 cm1. The n4 mode is also observed as three bands at 554, 585 and 620 cm1. The no degenerate stretching mode n1 appears as one band at 970 cm1. The lower frequency value obtained for the n1 mode than those in a free SO42 ion also confirms the distortion of SO4 tetrahedral 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 observed distortion in the SO4 tetrahedral.
The remaining observed bands in the spectrum can be assigned to CH3, CH, CO, NH3 and skeletal symmetric and asymmetric stretching and deformation modes [14]. The domain of high frequencies in the spectrum is characterized by N(C)–H stretching, combination bands and harmonics, while the lower one corresponds to the bending and to the external modes [15]. The IR spectrum of the compound is depicted in Fig. 5. The valence vibrations of the N–H and O–H groups interconnected by a system of hydrogen bonds of the crystal appear in the IR spectrum as broad bands in the 3200–1800 cm1 region [16]. As can be seen from Table 4, these consist of hydrogen bonds of N–H O type with a length of approximately 2.625(3) to 2.844(3) A˚. The presence of strong bands at 1294 and 1324 cm1 is assigned to the stretching vibration modes of C–O groups. A broad band extending from 3287 to 1741 cm1 is observed in the IR spectrum. This broad band must be due to the symmetric and asymmetric stretching modes of NH3, CH and CH3 groups. NH3 bending, rocking and torsion may occur in the ranges 1627–1530, 935–860 and 500 cm1. The shifting of stretching and bending vibrations of the NH3 group from the free state value confirms the formation of hydrogen bonds of varying strengths in the structure. The presence of the strong band at 749 cm1 corresponds to the stretching vibration modes of C C groups. The frequencies and assignments of the observed bands are given in Table 5. 4. Main conclusion
Fig. 5. IR spectrum of (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
Single crystals of the bis(o-anisidinium)sulfate were grown for the first time, using a classical method of aqueous chemistry. The crystal structure is resolved, with final R(F2) = 0.0447and Rw(F2) =
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565
0.1149 for 3494 independent reflections. It is shown that (C7H10NO)2SO4 crystallizes in the monoclinic system with P21/c space group. The structure of this organic-cation sulfate is organized as a succession of ribbons. The structural cohesion is established by weak interactions originating from the organic cations. It is to be noted that no thermal feature is observed in the DTA/TGA analysis, the stability of the compound is not very high since it decomposes at 130 8C. IR spectroscopic investigation, confirmed the symmetry lowering of the sulfate ion from Td to C1. References [1] L. Chertanova, C. Pascard, Acta Cryst. B 52 (1996) 677. [2] Z. Otwinowski, W. Minor, Methods in Enzymology, vol.276, Academic Press, New York, 1997.
565
[3] G.M. Sheldrick, SHELXS97 and SHELXL97, in: Program for Crystal Structure Solution and Refinement, University of Go¨ttingen, Germany, 1997. [4] T. Guerfel, A. Jouini, J. Chem. Crystallogr. 30 (2000) 95. [5] S. Capasso, C.A. Mattia, L. Mazzarella, A. Zagari, Acta Crystallogr: Sect. C 39 (1983) 281. [6] S.M. Haile, P.M. Calkins, D. Boysen, J. Solid State Chem. 139 (1998) 373. [7] L. Benhamada, A. Jouini, Mater. Res. Bull. 41 (2006) 1917. [8] T. Guerfel, A. Jouini, J. Chem. Crystallogr. 31 (6) (2002) 333. [9] W.H. Baur, Acta Cryst. B30 (1974) 1195. [10] M.O. Abdellahi, T. Jouini, Acta Crystallogr. Sect. C: Cryst. Struct. Commun. 51 (1995) 922. [11] S. Gao, L.H. Huo, S.W. Ng, Acta Crystallogr. Sect. E: Struct. Rep. Online 61 (2005) 539. [12] A. Domenicano, P. Murray-Rust, Tetrahedron Lett. 24 (1979) 2283. [13] G. Hertzberg, Infrared and Raman Spectra of Polyatomic Molecules, Van Nostrand, New York, 1966. [14] K. Nakamoto, IR and Ra Spectra of Inorganic and Coordinating Compounds, Wiley Interscience, 1986. [15] A. Chtioui, T. Guerfel, L. Benhamada, A. Jouini, J. Solid State Sci. 3 (2001) 859. [16] I. Ne˘mec, I. Cı´sarˇova´, Z. Micˇka, J. Solid State Chem. 71 (1998) 140.
Contents lists available at ScienceDirect
Materials Research Bulletin journal homepage: www.elsevier.com/locate/matresbu
Crystal structure, thermal analysis and IR spectrometric investigation of bis(o-anisidinium) sulfate (C7H10NO)2SO4 Ahlem Chtioui, Latifa BenHamada, Amor Jouini * Laboratoire de Chimie du Solide, De´partement de chimie, Faculte´ des Sciences de Monastir, Universite´ du centre, 5019 Monastir, Tunisia
A R T I C L E I N F O
A B S T R A C T
Article history: Received 30 June 2007 Received in revised form 16 June 2008 Accepted 15 July 2008 Available online 3 August 2008
Chemical preparation, X-ray single-crystal, thermal behaviour, and IR spectroscopy investigations are given for a new organic cation sulfate (C7H10NO)2SO4 (denoted BOAS) in the solid state. This compound crystallizes in the monoclinic space group P21/c. The unit cell dimensions are: a = 7.010(3) A˚, b = 11.142(5) A˚, c = 20.770(8) A˚, b = 95.27(3)8 with y = 1615.4(12) A˚3 and Z = 4. The structure has been solved using a direct method and refined to a reliability R factor of 0.047. The title compound consists of a framework of isolated SO4 tetrahedral interleaved with organic molecules, so as to build isolated ribbons parallel to a-axis. In the present work, we describe the crystal structure, thermal behaviour and IR analysis of this new compound. ß 2008 Elsevier Ltd. All rights reserved.
Keywords: B. Chemical synthesis C. X-ray diffraction C. Infrared spectroscopy
1. Introduction The description of the recognition of an anionic group by its environment requires knowledge of its binding stereochemistry. Due to its small size and its ability to become surrounded closely and strongly by H donors the sulfate anion can play a very important role in the molecular aggregation. The family of compounds which combine the cohesion of sulfate anions with enhanced polarizability of organic molecules was clearly illustrated. The most striking result is the high number of hydrogen bonds to the sulfate, which results in the sulfate being surrounded by a cloud of hydrogen donors [1]. The title compound (BOAS) is an additional example illustrating the templating effect of organic molecules on sulfate. In the present work we describe the synthesis and crystal structure of the bis(o-anisidinium)sulfate. Thermal behaviour and IR analysis are given. 2. Experimental Crystals of BOAS are easily prepared by slow evaporation at room temperature of an aqueous solution of H2SO4 and the organic molecule: bis(o-anisidinium); in the molar ratio 1:2. Schematically the synthesis reaction is ðH2 OÞ
H2 SO4 þ 2C7 H9 NO ! ðC7 H10 NOÞ2 SO4
* Corresponding author. Tel.: +216 73 500 280; fax: +216 73 500 278. E-mail addresses: [email protected], [email protected] (A. Jouini). 0025-5408/$ – see front matter ß 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.materresbull.2008.07.012
When most of the solution is evaporated, prismatic crystals appear deep down the vessels. The crystals are stable under normal conditions of temperature and humidity. X-ray intensity data of BOAS were collected on a Nonius KappaCCD diffractometer using monochromated Mo Ka radiation. For the crystal, 90 frames were recorded, each being of 28 in w and 60 s duration. Each frame is doubled to eliminate the uncertain electronic impulses. The first 10 frames were used for indexing reflections using the DENZO package and refined to obtain final cell parameters [2]. Preliminary photographs indicated monoclinic symmetry and systematically absent reflections showed the space group to be P21/c. The structure was solved with a direct method, from the SHELXS-97 programs, which permitted the location of the SO4 groups. The remaining non-hydrogen atoms were located by the successive difference Fourier maps using the SHELXL-97 programs [3]. In the final least-squares refinement of atomic parameters with isotropic thermal factors of the H atoms, R decreased to 4.47% (Rw = 11.50%) for BOAS. Setaram TG–DTA92 Thermoanalyzer was used to perform thermal treatment on samples of BOAS. The TG–DTA thermograms were obtained with 15.20 mg. Samples were placed in an open platinum crucible and heated in air with 3 8C/min heating rate; an empty crucible was used as reference. IR spectrum of BOAS was recorded at room temperature with a Biored FTS 6000 FTIR spectrometer over the wave number range of 4000–400 cm1 with a resolution of about 4 cm1. Thin, transparent pellet was made by compacting an intimate mixture obtained by shaking 2 mg of the samples in 100 mg of KBr.
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565 Table 1 Crystal structure data for (C7H10NO)2SO4 I. Crystal data Formula/formula weight (g/mol) Crystal system Space group/Z Lattice parameters
Table 3 Main interatomic distances (A˚) and bond angles (8) for (C7H10NO)2SO4 (C7H10NO)2SO4/344.38 monoclinic P21/c(14)/4 a = 7.010(3) A˚ b = 11.142(5) A˚; b = 95.27(3)8 c = 20.770(8) A˚ 1615.4(12) A˚3
Volume Density(calculated) (g/cm3) Absorption coefficient m (mm1) F(0 0 0) Size (mm3)/color
561
1.416 0.233 728 0.45 0.40 0.35/colorless
II. Intensity measurment Diffractometer, Wavelength, Mo Ka Temperature Theta range h k l range Completness to theta = 26.978 The total data collected Number of independent reflections
Kappa-CCD Nonius, f l = 0.71073 A˚ 293 2.088/26.978 8/8, 0/14, 2/26 99.5% 4088 3494 (Rint = 0.0494)
III: Structure determination Unic reflections included: I > 2sI) Programs used Number of refined parameters Goodness-of-fit on F2 R Rw Extinction coefficient Drmin/Drmax (e/A˚3) Largest shift/error
2389 SHELX-97 [3] 289 1.041 0.0447 0.1149 0.008(2) 0.389/0.410 0.000
S
O(1)
SO4 tetrahedron O(1) 1.480(2) O(2) 2.393(2) O(3) 2.390(2) O(4) 2.380(2)
O(2)
O(3)
O(4)
109.0(1) 1.460(2) 2.396(3) 2.407(2)
108.3(2) 109.8(2) 1.468(2) 2.420(3)
107.8(1) 110.7(1) 111.3(1) 1.466(2)
Organic groups [C7H10N(1)O(5)]+ O(5)–C(1) O(5)–C(7) N(1)–C(2) C(2)–C(1) C(1)–C(6) C(2)–C(3) C(3)–C(4) C(4)–C(5) C(5)–C(6)
1.361(4) 1.429(4) 1.464(3) 1.394(4) 1.385(4) 1.370(4) 1.388(4) 1.378(5) 1.387(5)
C(7)–O(5)–C(1) C(2)–C(1)–C(6) O(5)–C(1)–C(2) O(5)–C(1)–C(6) C(1)–C(2)–N(1) C(1)–C(2)–C(3) N(1)–C(2)–C(3) C(2)–C(3)–C(4) C(3)–C(4)–C(5) C(4)–C(5)–C(6) C(5)–C(6)–C(1)
118.3(3) 119.3(2) 114.6(2) 126.1(3) 118.1(2) 121.5(3) 120.4(2) 119.2(3) 119.7(3) 121.4(3) 118.9(3)
[C7H10N(2)O(6)]+ O(6)–C(8) O(6)–C(14) N(2)–C(9) C(9)–C(8) C(8)–C(13) C(9)–C(10) C(10)–C(11) C(11)–C(12) C(12)–C(13)
1.362(4) 1.426(5) 1.459(3) 1.395(3) 1.386(4) 1.374(4) 1.390(4) 1.380(5) 1.373(5)
C(14)–O(6)–C(8) C(9)–C(8)–C(13) O(6)–C(8)–C(9) O(6)–C(8)–C(13) C(8)–C(9)–N(2) C(8)–C(9)–C(10) N(2)–C(9)–C(10) C(9)–C(10)–C(11) C(10)–C(11)–C(12) C(11)–C(12)–C(13) C(12)–C(13)–C(8)
118.9(3) 119.2(2) 115.0(2) 125.8(3) 118.1(2) 121.2(2) 120.7(2) 119.0(3) 119.9(3) 121.2(3) 119.5(3)
3. Results and discussion 3.1. BOAS structure description The structural determination shows that the BOAS compound crystallizes in the monoclinic system; crystal data are given in Table 1. Final atomic coordinates and thermal parameters are given in Table 2. Those of hydrogen atoms were also determined but are
Table 2 The final atomic coordinates and equivalent temperature factors for (C7H10NO)2SO4
S(1) O(1) O(2) O(3) O(4) O(5) O(6) N(1) N(2) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14)
x/a
y/b
z/c
Ueq
0.23877(7) 0.0685(2) 0.3975(2) 0.1916(3) 0.2857(3) 0.0719(3) 0.2019(3) 0.0416(3) 0.2841(3) 0.1068(3) 0.1703(3) 0.3468(3) 0.4643(4) 0.4022(4) 0.2249(4) 0.1437(5) 0.2879(3) 0.2442(3) 0.2471(4) 0.2950(4) 0.3403(4) 0.3375(3) 0.1573(5)
0.61704(4) 0.6143(1) 0.6730(1) 0.6880(2) 0.4929(2) 0.7534(2) 0.8996(2) 0.8798(2) 0.6952(1) 0.8007(2) 0.8672(2) 0.9211(2) 0.9097(3) 0.8446(3) 0.7883(3) 0.6780(3) 0.8072(2) 0.9133(2) 1.0210(2) 1.0216(2) 0.9167(3) 0.8080(2) 1.0035(3)
0.06375(2) 0.1010(1) 0.1032(1) 0.0049(1) 0.0480(1) 0.2855(1) 0.0991(1) 0.3902(1) 0.0369(1) 0.2844(1) 0.3390(1) 0.3447(1) 0.2949(2) 0.2405(1) 0.2348(1) 0.2332(2) 0.0004(1) 0.0342(1) 0.0007(2) 0.0649(2) 0.0982(2) 0.0652(1) 0.1377(2)
0.028 0.041 0.040 0.065 0.055 0.055 0.056 0.040 0.033 0.040 0.034 0.046 0.056 0.056 0.051 0.061 0.032 0.040 0.052 0.060 0.058 0.043 0.072
Torsion angles for the two NH3 groups C(1) C(2) N(1) C(1) C(2) N(1) C(1) C(2) N(1) C(3) C(2) N(1) C(3) C(2) N(1) C(3) C(2) N(1) C(9) C(8) N(2) C(9) C(8) N(2) C(9) C(8) N(2) C(13) C(8) N(2) C(13) C(8) N(2) C(13) C(8) N(2)
H(1N1) H(2N1) H(3N1) H(1N1) H(2N1) H(3N1) H(1N2) H(2N2) H(3N2) H(1N2) H(2N2) H(3N2)
124.10(3) 1.38(4) 113.75(3) 56.70(4) 179.42(3) 65.44(4) 69.99(3) 50.61(4) 169.66(3) 108.53(3) 130.87(3) 11.82(4)
S–S = 4.837(2).
not given, in order to shorten the table. The main geometrical features of different entities are indicated in Table 3. A view of the structure projected along the c direction is reported in Fig. 1. This projection shows that the atomic arrangement can be described by ribbons built by all the components of the structure and spreading parallel to a-axis. These ribbons are not connected in the two other directions (Fig. 2). Connection between SO42 anions and (C7H10NO)+cations inside the same ribbon is established by N–H O hydrogen bonds; stability between successive ribbons is performed by weak interactions between the organic cations. The asymmetric unit of the crystal structure consists of one sulfate anion and two organic cations. The S–O distances range from 1.460(2) to 1.480(2) A˚ with an average of 1.468 A˚. Slight differences in the S–O 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 BOAS crystal structure. The high sensitivity of the S–O bond
562
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565
Fig. 1. Projection along the c-axis of the atomic arrangement in (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
distances to the number of the hydrogen bonds which may be formed has also been noted in other crystal structures [4–6]. O(1) which participates in two N–H O hydrogen bonds, has the longest S–O distance of 1.480(2) A˚. Consequently, it is possible to use differences in bond lengths to identify which O in the N–H O bonds is more highly associated. The very short direct hydrogen bond between O(3) and H(1N1) would have a very short internuclear H O distance of under 1.66 A˚, which is even shorter than in some di-acid dimmers [7]. Note that in this structure the less distance between two adjacent sulfur atoms is S– S = 4.837(2) A˚ as would be expected in such a compound [8]. The calculated average values of distortion indices corresponding to the different angles and distances in the SO4 tetrahedral [9] [DI(OSO) = 0.010, DI(SO) = 0.004, and DI(OO) = 0.004], exhibit a pronounced distortion of the OSO angles if compared to SO and OO distances. Each sulfate anion is linked to five neighbor organic groups via five hydrogen bonds: two from two N(1)H3 groups and three from three N(2)H3 groups (Fig. 3), with N O distances ranging from 2.844(3) to 2.625(3) A˚. The hydrogen bonds range from 2.07(3) to 1.66(3) A˚ in length (H O) with N–H O angles from 179(3)8 to 115(2)8 (Table 4). Two crystallographically independent (C7H10NO)+ groups exist also in this atomic arrangement. They are organized in opposition; this situation is favourable to a centro symmetric arrangement. In the first cation [C7H10N(1)O(5)]+, location of H(2N1) in the cyclobenzene favors an intramolecular hydrogen bond with the oxygen of methoxy group. The N(1)H3 group is the 1808 rotational isomer of the second cation [C7H10N(2)O(6)]+. The geometrical features measured in o-anisidinium are similar to
intramolecular bond distances and angles for o-anisidinium dihydrogenomonophosphate [10] and 3-ammonio-4-methoxybenzesulfonate [11]. Interatomic distances and angles in these two organic groups spread within the respective ranges: 1.361(4)–1.464(3) A˚ and 114.6(2)–126.1(3)8 (Table 3). The first organic group is bridged to two SO42 anions via three N–H O bonds, whereas the second group is linked to three SO42 anions. The determined bonding angles in the NH3+ groups spread in the range 106.7(3)–111.6(3)8. The reason why the expected tetrahedral symmetry of these groups is somewhat disturbed is probably owing to the intense participation of the protons in the hydrogen bond system. The bond angles in the phenyl group deviate from the idealized value of 1208 (Table 3). Domenicano and Murray-Rust [12] have, among others, shown that the angular deformations of phenyl groups can be described as the sum of the effects of the different substitutents. 3.2. Thermal analysis Two curves, corresponding to DTA and TGA analysis in open air, are reported in Fig. 4. From these curves we were able to deduce that the anhydrous compound is stable in the range 25–130 8C. Its decomposition begins at 130 8C with evolution of ammonia represented by a set of endothermic peaks. Above this temperature the product undergoes a decomposition of the C7H9NO groups over a wide temperature range (170–350 8C). The TGA curve shows an important weight loss corresponding to the progressive pyrolysis of organic molecule in this temperature range.
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565
563
Fig. 2. Projection along the a-axis of the atomic arrangement in (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
3.3. IR spectroscopic investigation
Table 4 Bond lengths (A˚) and angles (8) in the hydrogen-bonding schemea of (C7H10NO)2SO4 (C7H10NO)2SO4 i
N(1)—H(1N1) O(3 ) N(1)—H(2N1) O(5) N(1)—H(3N1) O(1ii) N(2)—H(1N2) O(2iii) N(2)—H(2N2) O(1) N(2)—H(3N2) O(4iv)
N—H
H O
N O
N—H O
0.97 0.99 0.92 0.96 0.96 0.93
1.66(3) 2.07(3) 1.81(4) 1.78(3) 1.92(3) 1.82(3)
2.625(3) 2.651(3) 2.736(3) 2.740(3) 2.844(3) 2.737(3)
178(3) 115(2) 179(3) 171(3) 159(3) 174(3)
(4) (4) (4) (3) (4) (3)
a Symmetry code: (i) x, y + 3/2, z + 1/2; (ii) x, y + 1/2, z + 1/2; (iii) x1, y, z; (iv) x, y + 1, z.
A free regular XO4 tetrahedron has four fundamental vibrations, the no degenerate symmetric stretching mode n1(A1), the doubly degenerate bending mode n2(E), the triply asymmetric stretching mode n3(F2) and 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 observed for these modes are, respectively: 981, 451, 1104 and 614 cm1, when X = S [13]. In the crystal, the SO42 ion occupies lower site symmetry C1, as a result the IR inactive n1 and n2 modes may become active and the degeneracy 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 411 and 446 cm1. Appearance of this IR inactive mode can be due to the symmetry lowering of the sulfate ion from Td to C1. The n3 mode
564
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565 Table 5 Spectral data and band assignment
Fig. 3. Representation of the SO42 environment in (C7H10NO)2SO4. Hydrogen bonds are represented by dashed lines.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
Fig. 4. TG–DTA thermograms of (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
appears as three bands at 1018, 1043 and 1118 cm1. The n4 mode is also observed as three bands at 554, 585 and 620 cm1. The no degenerate stretching mode n1 appears as one band at 970 cm1. The lower frequency value obtained for the n1 mode than those in a free SO42 ion also confirms the distortion of SO4 tetrahedral 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 observed distortion in the SO4 tetrahedral.
The remaining observed bands in the spectrum can be assigned to CH3, CH, CO, NH3 and skeletal symmetric and asymmetric stretching and deformation modes [14]. The domain of high frequencies in the spectrum is characterized by N(C)–H stretching, combination bands and harmonics, while the lower one corresponds to the bending and to the external modes [15]. The IR spectrum of the compound is depicted in Fig. 5. The valence vibrations of the N–H and O–H groups interconnected by a system of hydrogen bonds of the crystal appear in the IR spectrum as broad bands in the 3200–1800 cm1 region [16]. As can be seen from Table 4, these consist of hydrogen bonds of N–H O type with a length of approximately 2.625(3) to 2.844(3) A˚. The presence of strong bands at 1294 and 1324 cm1 is assigned to the stretching vibration modes of C–O groups. A broad band extending from 3287 to 1741 cm1 is observed in the IR spectrum. This broad band must be due to the symmetric and asymmetric stretching modes of NH3, CH and CH3 groups. NH3 bending, rocking and torsion may occur in the ranges 1627–1530, 935–860 and 500 cm1. The shifting of stretching and bending vibrations of the NH3 group from the free state value confirms the formation of hydrogen bonds of varying strengths in the structure. The presence of the strong band at 749 cm1 corresponds to the stretching vibration modes of C C groups. The frequencies and assignments of the observed bands are given in Table 5. 4. Main conclusion
Fig. 5. IR spectrum of (C7H10NO)2SO4.(For interpretation of the references to color in the artwork, the reader is referred to the web version of the article.)
Single crystals of the bis(o-anisidinium)sulfate were grown for the first time, using a classical method of aqueous chemistry. The crystal structure is resolved, with final R(F2) = 0.0447and Rw(F2) =
A. Chtioui et al. / Materials Research Bulletin 44 (2009) 560–565
0.1149 for 3494 independent reflections. It is shown that (C7H10NO)2SO4 crystallizes in the monoclinic system with P21/c space group. The structure of this organic-cation sulfate is organized as a succession of ribbons. The structural cohesion is established by weak interactions originating from the organic cations. It is to be noted that no thermal feature is observed in the DTA/TGA analysis, the stability of the compound is not very high since it decomposes at 130 8C. IR spectroscopic investigation, confirmed the symmetry lowering of the sulfate ion from Td to C1. References [1] L. Chertanova, C. Pascard, Acta Cryst. B 52 (1996) 677. [2] Z. Otwinowski, W. Minor, Methods in Enzymology, vol.276, Academic Press, New York, 1997.
565
[3] G.M. Sheldrick, SHELXS97 and SHELXL97, in: Program for Crystal Structure Solution and Refinement, University of Go¨ttingen, Germany, 1997. [4] T. Guerfel, A. Jouini, J. Chem. Crystallogr. 30 (2000) 95. [5] S. Capasso, C.A. Mattia, L. Mazzarella, A. Zagari, Acta Crystallogr: Sect. C 39 (1983) 281. [6] S.M. Haile, P.M. Calkins, D. Boysen, J. Solid State Chem. 139 (1998) 373. [7] L. Benhamada, A. Jouini, Mater. Res. Bull. 41 (2006) 1917. [8] T. Guerfel, A. Jouini, J. Chem. Crystallogr. 31 (6) (2002) 333. [9] W.H. Baur, Acta Cryst. B30 (1974) 1195. [10] M.O. Abdellahi, T. Jouini, Acta Crystallogr. Sect. C: Cryst. Struct. Commun. 51 (1995) 922. [11] S. Gao, L.H. Huo, S.W. Ng, Acta Crystallogr. Sect. E: Struct. Rep. Online 61 (2005) 539. [12] A. Domenicano, P. Murray-Rust, Tetrahedron Lett. 24 (1979) 2283. [13] G. Hertzberg, Infrared and Raman Spectra of Polyatomic Molecules, Van Nostrand, New York, 1966. [14] K. Nakamoto, IR and Ra Spectra of Inorganic and Coordinating Compounds, Wiley Interscience, 1986. [15] A. Chtioui, T. Guerfel, L. Benhamada, A. Jouini, J. Solid State Sci. 3 (2001) 859. [16] I. Ne˘mec, I. Cı´sarˇova´, Z. Micˇka, J. Solid State Chem. 71 (1998) 140.