Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 136 (2015) 1149–1156
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Spectroscopic, structural and theoretical investigation of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate Anna Komasa ⇑, Andrzej Katrusiak, Michał Kaz´mierczak, Zofia Dega-Szafran, Mirosław Szafran Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61614 Poznan, Poland
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
A short, asymmetric hydrogen bond
The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate has been studied by X-ray diffraction, DFT, FTIR, Raman and NMR. Two 4-trimethylammoniumbenzoate moieties are joined by asymmetric OHO hydrogen bond of 2.45(2) Å. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two hydrogen bonds of 2.70(3) and 3.51(1) Å. The FTIR spectrum shows a broad absorption in the 1500–400 cm 1 region corresponding to the mas(OHO) and c(OHO) vibrations.
1,4 1,2
Absorbance
joins a pair of 4-trimethylammoniumbenzoates. The water molecule interacts via two O–H O and O–H I hydrogen bonds. The FTIR spectrum is dominated by a broad absorption in the 1500–400 cm 1 region. Experimental and calculated IR and Raman vibrations of the complex are compared. The magnetic isotropic shielding constants confirm the experimental chemical shifts.
1,0 0,8 0,6 0,4 0,2 3500
3000
2500
2000
1500
1000
500
-1
Wavenumbers (cm )
a r t i c l e
i n f o
Article history: Received 29 April 2014 Received in revised form 5 September 2014 Accepted 18 September 2014 Available online 13 October 2014 Keywords: Bis(4-trimethylammoniumbenzoate) hydroiodide hydrate X-ray diffraction FTIR Raman and NMR spectra B3LYP calculations Hydrogen bonds
a b s t r a c t The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 has been studied by X-ray diffraction, B3LYP/6–311G(d,p) calculations, FTIR, Raman and NMR spectroscopic techniques. The crystal is polar in monoclinic space group Cc. Two 4-trimethylammoniumbenzoate moieties are joined by a short and asymmetric hydrogen bond of 2.45(2) Å. Water molecules are gradually released from the structure, causing shifts in the position of iodine anions, which induces their disorder. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two O(3)–H(1) O(1) and O(3)– H(2) I(1) hydrogen bonds of lengths 2.70(3) and 3.51(1) Å. Hydrogen bonds in theoretically predicted structures of 2 and 3 (in vacuum), and 4, 5 (in DMSO) optimized by the B3LYP/6-311G(d,p) approach are slightly longer than in crystal 1. The FTIR spectrum of 1 shows a broad and intense absorption in the 1500–400 cm 1 region, typical of short hydrogen bonds assigned to the mas(OHO) + c(OHO) vibrations. The correlations between the experimental 13C and 1H chemical shifts (dexp) of the investigated compound in DMSO and the GIAO/B3LYP/6-311G(d,p) magnetic isotropic shielding constants (rcalc) calculated by using the screening solvation model (COSMO) are linear, dexp = a + b rcalc, and they well reproduce the experimental chemical shifts. Ó 2014 Elsevier B.V. All rights reserved.
⇑ Corresponding author. Tel.: +48 618291004; fax: +48 618291555. E-mail address: [email protected] (A. Komasa). http://dx.doi.org/10.1016/j.saa.2014.09.138 1386-1425/Ó 2014 Elsevier B.V. All rights reserved.
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Fig. 1. The average structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate/anhydrate and its atom labeling scheme. The iodide anion resides at two positions depending on the water contents. If H2O is present, the iodide anion residues at site I(1), while in the dehydrated structure – at the I(2) site. The H-bond OH I in the hydrate is indicated by the dotted line.
Table 1 Crystal data and structure refinement for the bis(4-trimethylammoniumbenzoate) hydroiodide hydrate. Formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions
Volume Z Calculated density Absorption coefficient F(0 0 0) Crystal size h range for data collection (°) Limiting indices h, k, l Reflections collected/unique hMax(°)/Completeness (%) Absorption correction Max. and min. transmission Refinement method Data/restraints/parameters Goodness-of-fit on F2 Final R1/wR2 indices [I > 2rI] R1/wR2 indices (all data)
[C20H27N2O4]+I 0.5H2O 495.34 296(2) K 0.71073 Å Cc Monoclinic a = 13.240(19) Å b = 9.02(2) Å c = 19.228(16) Å 2171(6) Å3 4 1.516 g/cm3 1.504 mm 1 1001 0.17 0.08 0.12 mm 2.24–26.28 11/16, 11/10, 23/21 8591/2889 [R(int) = 0.1085] 26.27/99.1 Integration 0.89 and 0.81 Full-matrix least-squares on F2 2889/7/263 1.464 0.0868/0.2141 0.0939/0.2218
Introduction Zwitterions are compounds with oppositely charged centers and are often referred to as betaines, dipolar ions, salt-bridged-containing molecules and inner salts. This diverse nomenclature reflects the extraordinary importance of these species in biological transformations, organic synthesis, preparation of novel materials and as chromatographic supports [1–3]. An interesting group of compounds of this type are ortho-, meta- and para-trimethylammoniumbenzoates (benz-betaines), Me3N+–C6H4–COO , their esters and complexes with hydrohalides [4–6]. In the pyrolysis electron impact (EI) mass spectrometry experiment on trimethylammoniumalkanocarboxylates (Me3N+–(CH2)n–COO ) and their hydrochlorides, Wood et al. [7] have observed the methyl transfer to more volatile methyl esters (Me2N–(CH2)n–COOMe). Quaternization of dimethylaminobenzoic acids by an excess of methyl iodide in methyl alcohol depends on temperature and time of refluxing [6]. In trimethylammoniumbenzoic acids hydroiodides, heating triggers the methyl transfer and induces the formation of methyl dimethylammoniumbenzoates hydroiodides (Me2N–C6H4–COOMeHI). Recently, the structures of methyl 4-(trimethylammonium)benzoate iodide [8], 4-(trimethylammonium)benzoic acid chloride [9] and 4-(trimethylammonium)benzoate hydrate [10] have been described. In this paper, the crystal structure and spectroscopic properties of bis(4-trimethylammoniumbenzoate) hydroiodide
Table 2 Energies (Hartree, a.u.), dipole moments (l, Debye), OH O hydrogen bond distances (Å) and N I(1) contacts in the crystals (1), vacuum (2, 3) and DMSO (4, 5) for bis(4trimethylammonium-benzoate) hydroiodide hydrate and anhydrate. Compounds
Energy
l
1 X-ray (Fig. 1)
B3LYP/6–311G(d,p) 2 hydrate
8185.069601
10.921
3 anhydrate 4 DMSO anhydrate 5 DMSO hydrate
8108.602676 8108.683543 8185.149265
14.824 32.155 17.796
D–H A
d(D–H)
d(H A)
d(D A)
2000 cm 1 and 0.839 for m < 2000 cm 1. Average (signed) differences between experimental and computed data. Root-mean-square errors.
at 1064 nm excitation line of Nd:YAG laser, with the resolution of 1 cm 1. The spectrum was accumulated by acquisition of 250 scans at 31 °C. NMR spectra were recorded on a Bruker Advance DRX spectrometer operating at 599.85 and 150.85 MHz for 1H and 13C, respectively. The 2D 1H–13C HSQC (Heteronuclear Single Quantum Coherence) and HMBC (Heteronuclear Multiple Bond Coherence) spectra were measured in DMSO-d6 solutions relative to TMS. The DFT calculations were performed using the Gaussian 09 program package [16]. The calculations employed the B3LYP exchange–correlation functional, which combines the hybrid functional of Becke [17] with the gradient-correlation functional of Lee et al. [18] and the split-valence polarized 6-311G(d,p) basis set [19]. The basis set for iodine is not available in the standard set of basis functions offered by the Gaussian 09 program. Therefore it has been taken from the EMSL, Basis Set Library [21,22]. Glukhovtsev et al. [20] tested their basis on a set of iodine-containing species assessing theoretical results by comparison with experimental data. The X-ray geometry of 1 was used as a starting point of calculations. The magnetic isotropic shielding constants were calculated using the standard GIAO/B3LYP/6-311G(d,p) (gauge-independent atomic orbital) approach with the Gaussian 09 program package using the conductor-like screening solvation model (COSMO) [23–26]. Results and discussion Crystal structure The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 with the atom numbering is shown in Fig. 1 and the molecular packing in the crystal is illustrated in Fig. S2. The
observed structure, with disordered sites of iodine anions and water molecules can be rationalized as a composite crystal, consisting of both hydrated and anhydrous compounds. In the average structure the distances between the disordered iodides are unrealistic, but they can be explained by assuming the presence of two compounds contributing to the diffraction data of the crystal. In the anhydrous compound the iodide anion is located at site I(2), and it is not involved in strong hydrogen bonds. In the hydrate, the iodide anion is located at site I(1) and it forms hydrogen bonds mediated by the crystalline water to carboxyl group C(7)–O(1) H (Fig. 1). The bond lengths, bond and dihedral angles are listed in Tables 2 and S2. Two molecules of betaines are bridged by a proton to form a homoconjugated cationic system with a short, asymmetric O(11)–H O(1) hydrogen bond with the O O distance of 2.45(2) Å. The H-bonded proton is closer to the benz-betaine molecule which has shorter contacts with I anion. Because the hydrogen bonded molecules are not symmetrically equivalent, the bis(4trimethylammoniumbenzoate) cation in the crystal lattice shown in Fig. S2 is similar to that of the pseudo-Type A acid salts of carboxylic acids [27]. The hydrogen bonds in Type A acid salts of aromatic monocarboxylic acids [27] and 2:1 complexes of betaines with mineral acids are slightly shorter [28–30]. The investigated cations are arranged approximately parallel in the crystal lattice, as shown in Fig. S2. The two carboxy-fragments participating in the hydrogen bond are planar, with the dihedral angle between the O(2)–C(7)–O(1) and O(12)–C(17)–O(11) planes equal to 18.98°. The dihedral angle between the planes through the rings is 0.45° and those between the ring and the COO moieties are 13.82° and 5.38°, respectively (Table S2). The benz-betaine moieties of the monocationic dimer are almost planar in the crystal. In the investigated 4-trimethylammoniumbenzoate molecules [8–10] dihedral angles C(2)–C(1)–C(7)–O(1) and C(2)–C(1)–C(7)–O(2)
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4000
2
Second-derivative (d ), cm
-1
optimized molecules both the O(11)–H O(1) and O(3)–H O(1) hydrogen bonds are slightly longer than in the crystal (Table 2). As indicated by the data in Table 2, the stability of the optimized complexes is controlled by the electrostatic attraction between the positively charged nitrogen atoms N(1) and N(11) and the I anion. In the optimized complexes benz-betaine molecules are non-planar (Table S2, the angle between ring-ring planes: (1) 0.45°, (2) 70.95°, (3) 51.51°, (4) 81.48°, (5) 62.23°).
3000
2000
1000
0
FTIR and Raman spectra 0
1000
2000
3000
4000
Calculated frequencies by B3LYP/6-311G(d,p), cm-1 Fig. 4. A correlation between the experimental (the second-derivative d2) 1 and calculated 2 wavenumbers (cm 1) for bis(4-trimethylammoniumbenzoate) hydroiodide hydrate; the straight line represents equation: mexp = 327 + 1.062 mcalc, r = 0.9926.
depend on hydrogen bonds and electrostatic interaction between N+ and anions (X ). Optimized structures The structures of anhydrate and hydrate bis(4-trimethylammoniumbenzoate) hydroiodide optimized by the B3LYP/ 6-311G(d,p) approach in vacuum 2 and 3, and in DMSO solution 4 and 5 are shown in Fig. 2. The geometries of 4 and 5 are used to predict the 13C and 1H chemical shifts in DMSO-d6 solution. The bent (2, 3 and 5) and linear (4) structures can be distinguished. The calculated geometrical parameters are listed in Table S2. In the
Fig. 3b shows the FTIR spectra of 2:1 and 1:1 complexes of 4trimethylammoniumbenzoate with HI. The spectrum of 2:1 complex displays a broad and strong absorption in the 1500– 400 cm 1 region with the center of gravity around 944 cm 1, whereas in the Raman spectrum this feature is absent (Fig. 3a). Similar differences between IR and Raman spectra appear for 1carboxyethylpyridinium-4-carboxylate inner salt [31], bis(4-(Nmethylpiperidinium)butyrate) hydrobromide [32], 1:1 complex of meso-tartaric acid with 1,4-dimethylpiperazine di-betaine [33] and bis(1-methylisonicotinate) hydrogen perchlorate [34]. In the FTIR spectrum of 1:1 complex the broad absorption is also absent. A similar broad absorption appears in the IR spectra of 2:1 complexes of homarine [35], trigonelline [36], 1-methylisonicotinate inner salt [37] and Type A acid salts of carboxylic acids [38a,39]. The broad absorption is typical of compounds with short H-bonds and is assigned to the mas(OHO) and c(OHO) vibrations of the strong hydrogen bonds [39,40]. In the FTIR spectrum, the broad absorption overlaps with the narrow skeletal absorption, but the latter can be distinguished in the second-derivative, d2 (Fig. 3c), or forth-derivative, d4, spectra.
Table 4 Experimental, dexp (DMSO-d6 solution), predicted (dpred = a + b rcalc) carbon-13 and proton chemical shifts, and calculated GIAO/B3LYP/6-311G(d,p) isotropic magnetic shielding constants (rcalc) for 4-(trimethylammoniumbenzoate) hydroiodide hydrate. Atom
C(1) C(2) C(3) C(4) C(5) C(6) C(7)OOH C(8)–C(10) av ac bd re Av. dif. f R.m.s.g Proton H(2) H(6) H(3) H(5) C(8)H3–C(10)H3 av ac bd re Av. dif.f R.m.s.g a b c d e f g
dexp
133.20 130.74 120.96 149.91 120.96 130.74 166.04 56.37
8.12 8.12 8.10 8.10 3.65
dpred 5
dpred 4
rcalc 5
0.5(A + B)
0.5(A + B)
Aa
Bb
0.5(A + B)
Aa
rcalc 4 Bb
0.5(A + B)
138.191 131.317 120.629 147.777 116.819 130.770 166.148 57.269
137.712 130.976 118.792 148.471 119.991 130.962 165.378 56.631
40.3105 46.1045 57.4876 28.0295 61.6181 45.3872 7.6214 125.1265 ± 2.1990
37.1209 45.9745 57.3658 28.9736 61.3561 47.8567 10.2339 124.7450 ± 2.5201
38.7157 46.0395 57.4267 28.5016 61.4871 46.6220 8.9277 124.9358 174.5275 0.9386 0.9967
43.3242 47.0475 60.5470 26.7600 55.0396 46.2980 10.7137 124.5501 ± 2.6658
35.9203 46.3521 58.4542 29.8781 61.4302 47.1311 10.3972 125.0696 ± 2.6994
39.6223 46.6998 59.5006 28.3191 58.2349 46.7146 10.5555 124.8099 175.4247 0.9518 0.9980
0 2.615
0 2.024
8.322 8.634 7.689 7.630 3.816
8.430 8.223 7.520 8.161 3.754
23.3508 23.4265 24.3008 24.1916 28.5340 ± 0.3739
23.8283 23.0639 24.2708 24.5114 28.5947 ± 0.4146
23.5896 23.2452 24.2858 24.3515 28.5511 29.7448 0.9082 0.9770
23.6247 23.3508 24.2707 22.8598 28.4650 ± 0.5529
22.9033 23.6444 24.3169 24.2763 28.6433 ± 0.2527
23.2640 23.4976 24.2938 23.5681 28.5542 28.9902 0.8838 0.9855
0 0.425
0 0.339
Ring with C(1)–C(10) atoms. Ring with C(11)–C(20) atoms. Intercept for the equation dexp = a + b rcalc. Slop for the equation dexp = a + b rcalc. Correlation coefficient for the equation dexp = a + b rcalc. Average (signed) differences between experimental and predicted chemical shifts. Root-mean-square errors.
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The minima in the d2 spectrum have the same wavenumbers as the maxima in the absorbance spectrum. Since the relative intensities in the d2 spectrum vary inversely to the square of the half-width ratio of the absorbance bands in the FTIR spectrum, the broad bands assigned to the O H O modes are not observed in the d2 spectra [41,42]. As shown in Fig. 3d, the calculated frequencies agree well with the negative d2 bands. From this similarity we conclude that the calculated data describe only the narrow skeletal frequencies without the broad absorption. Table 3 lists the experimental and calculated frequencies, and intensities for normal modes in molecules of 1 and 2. The assignments pertinent to hydrogen bond OHO vibration are exposed in bold. The most intensive predicted band at mscaleq 2497 cm 1 is assigned to the asymmetric stretching vibration of the hydrogen bond. A comparison of the calculated and experimental frequencies shows typical differences. The calculated bands are shifted to higher wavenumbers relative to the experimental data. Two facts may be responsible for the differences between the experimental and computed spectra of the molecule investigated. The first is that the experimental spectrum was recorded for the complex in the solid state, while the computed spectrum refers to the isolated molecule 2 in the vacuum. The second one is the fact that the experimental results are anharmonic vibrations, while the calculated values are harmonic vibrations. Similar discrepancies between the calculated and experimental frequencies have been noted for 1-methylpyridinium-4-carboxylate monohydrate [43]. The overestimation of the computed wavenumbers is quite systematic and can be corrected by applying appropriate scaling factors or scaling equation [38b,44–51]. A linear relation between the experimental d2 and calculated frequencies with a good correlation coefficient r = 0.9926 is shown in Fig. 4. This scaling procedure, as recommended by Alcolea Palafox [50] was used for adjusting the predicted frequencies, listed in Table 3 as mscaleq. Additionally two scaling factors were applied to the harmonic vibrational frequencies (0.946 for m > 2000 cm 1 and 0.839 for m < 2000 cm 1) yielding scaled wavenumbers (mscalf) listed in Table 3. These two scaling factors were found by minimizing the root-mean-square deviation between experimental and theoretical data within two separate frequency ranges mentioned above. The assignment of vibrational bands of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate was made using the Gauss-View molecular visualization program [52]. The scaling harmonic vibration by equation reproduces the experimental solid FTIR frequencies with r.m.s. error of 104 cm 1, while by scaling factors the r.m.s. is 146 cm 1.
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obtained chemical shifts are comparable to those in (4-trimethylammonium)benzoic acid chloride [9]. The relations between the experimental 13C and 1H chemical shifts (dexp) for 1 and the GIAO (Gauge-Independent Atomic Orbitals) magnetic isotropic shielding constants (rcalc), in DMSO calculated for 4 and 5 are linear and described by the following equation: dexp = a + b rcalc [53–56]. The slope and intercept of the least-squares correlation line (Table 4, Fig. 5) are used to scale the GIAO magnetic isotropic shielding constants, rcalc, and to predict the chemical shifts, dpred = a + b rcalc. The magnetic isotropic shielding constants confirm the correct assignments of the chemical shifts to the appropriate atoms. The agreement between the experimental and predicted chemical shifts is satisfactory for the corresponding solutions. Conclusions The crystal and molecular structures of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1, were determined by X-ray diffraction and by the B3LYP/6-311G(d,p) calculations. In the crystal a pair of 4-trimethylammoniumbenzoates is joined by a proton to form a homoconjugated cation, featuring a short and asymmetric hydrogen bond with the O O distance equal to 2.45(2) Å. The hydrogen bond in 1 is similar to that in pseudo-Type A acid salts of carboxylic acids and it can be described by a potential energy function with a double minimum with low barrier. Water molecule in 1 interacts with bis(4-trimethylammoniumbenzoate) homoconjugated cation and iodide anion via two O(3)–H(1) O(1) and O(3)–H(2) I(1) hydrogen bonds of the lengths 2.70(3) and 3.51(1) Å. The experimental 13C and 1H chemical shifts (dexp) of the investigated compounds in DMSO-d6 correlate linearly with GIAO/ B3LYP/6-311G(d,p) magnetic isotropic shielding constants calculated according to the screening solvation model (COSMO), dexp = a + b rcalc, and confirm the correct assignment of the resonance signal. The FTIR spectrum of 1 shows a broad and intense absorption in the 1500–400 cm 1 region, typical of short hydrogen bonds and corresponds to the mas(OHO) and c(OHO) vibrations. The calculated IR frequencies agree well with the negative d2 bands, which suggest that the calculated data describe only the narrow skeletal frequencies without the broad absorption. The FTIR spectrum of the solid compound is consisted with the X-ray structure. Acknowledgments
NMR spectra
The calculations were performed at the Poznan´ Supercomputing and Networking Centre and supported in part by PL-Grid Infrastructure.
The assignments of carbon-13 and proton chemical shifts for the complex are based on two-dimensional HSQC (Fig. S3) and HMBC (Fig. S4) experiments [53] and are listed in Table 4. The
Appendix A. Supplementary data
Chemical shifts (ppm)
180
(a)
160
(b)
8
140
Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.saa.2014.09.138. References
7
120
6
100
5
80
4
60 40
9
0
20
40
60
80 100 120 140
3
22
24
26
28
Magnetic isotropic shielding constants Fig. 5. Plot of the experimental 13C (a) and 1H (b) chemical shifts of 1 in DMSO-d6 versus the magnetic isotropic shielding tensors from GIAO/B3LYP/6-311G(d,p) for 5, dexp = a + b rcalc.
[1] X. Domingo, Betaines, in: E.G. Lomax (Ed.), Amphoteric Surfactans, second ed., Marcel Dekker Inc., New York, 1996, pp. 76–190. [2] A. Schmidt, Adv. Heterocycl. Chem. 85 (2003) 67–171. [3] E. Alcalde, Adv. Heterocycl. Chem. 60 (1994) 197–259. [4] E.F. Strittmatter, R.L. Wong, E.R. Williams, J. Am. Chem. Soc. 122 (2000) 1247– 1248. [5] J. Picha, R. Cibulka, F. Liska, P. Parik, O. Pytela, Collect. Czech. Chem. Commun. 69 (2004) 2239–2252. [6] (a) W. Tadras, A.B. Sakla, J. Chem. Soc. (1954) 1116–1119; (b) R. Willstätter, W. Kahn, Ber. 37 (1904) 401–417. [7] G.W. Wood, R.J. Collacott, Org. Mass Spectrom. 18 (1983) 42–45. and references cited therein. [8] M. Szafran, A. Katrusiak, Z. Dega-Szafran, A. Komasa, I. Kowalczyk, J. Mol. Struct. 1006 (2011) 330–336.
1156
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[9] M. Szafran, A. Katrusiak, Z. Dega-Szafran, I. Kowalczyk, J. Mol. Struct. 996 (2011) 75–81. [10] M. Szafran, A. Katrusiak, Z. Dega-Szafran, I. Kowalczyk, J. Mol. Struct. 1005 (2011) 144–151. [11] KUMA KM4-CCD Software, Version 161, Kuma Diffraction, Wroclaw, Poland, 1999. [12] CrystAlis 162, Kuma Diffraction, Wroclaw, Poland, 1999. [13] G.M. Sheldrick, Acta Crystallogr. A 64 (2008) 112–122. [14] C.K. Johnsen, ORTEPH, Report ORNL-5138, Oak Ridge National Laboratory, Thennessee, USA, 1976. [15] Stereochemical Workstation Operation Manual, Release 3.4, Siemens Analytical X-ray Instruments Inc., Madison, 1989. [16] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro, M. Bearpark, J.J. Heyd, E. Brothers, K.N. Kudin, V.N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J.M. Millam, M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski, R.L. Martin, K. Morokuma, V.G. Zakrzewski, G.A. Voth, P. Salvador, J.J. Dannenberg, S. Dapprich, A.D. Daniels, Ö. Farkas, J.B. Foresman, J.V. Ortiz, J. Cioslowski, D.J. Fox, Gaussian 09, Revision D.01, Gaussian Inc., Wallingford CT, 2009. [17] A.D. Becke, J. Chem. Phys. 107 (1997) 8554–8560. and ref. cited therein. [18] C. Lee, W. Yang, R.G. Parr, Phys. Rev. B 37 (1988) 785–789. [19] W.J. Hehre, L. Random, P.V.R. Schleyer, J.A. Pople, Ab Initio Molecular Orbital Theory, Wiley, New York, 1989. [20] M.N. Glukhovtsev, A. Pross, M.P. McGrath, L. Radom, J. Chem. Phys. 103 (1995) 1878–1885. [21] D. Feller, J. Comput. Chem. 17 (1996) 1571–1586. [22] K.L. Schuchardt, B.T. Didier, T. Elsethagen, L. Sun, V. Gurumoorthi, J. Chase, J. Li, T.L. Windus, J. Chem. Inf. Model 47 (2007) 1045–1052. [23] V. Barone, M. Cossi, J. Phys. Chem. A 102 (1998) 1995–2001. [24] G. Brancato, N. Rega, V. Barone, Chem. Phys. 125 (2006). 164515–164515. [25] P. Pulay, X. Zhou, F. Fogarasi, in: R. Fausto (Ed.), Recent Experimental and Computational Advances in Molecular Spectroscopy, Kluver, Academic, Netherlands, 1993, pp. 88–111. [26] A. Klam, COSMO-RS from Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design, Elsevier, Amsterdam, 2005. [27] J.C. Speakman, Struct. Bond (Berlin) 12 (1972) 141–199. [28] X.-M. Chen, T.C.W. Mak, J. Mol. Struct. 221 (1990) 265–269. [29] X.-M. Chen, T.C.W. Mak, Acta Crystallogr. C50 (1994) 1807–1809.
[30] Z. Dega-Szafran, A. Katrusiak, M. Szafran, J. Mol. Struct. 555 (2000) 203–212. [31] P. Barczyn´ski, A. Katrusiak, Z. Dega-Szafran, M. Szafran, J. Mol. Struct. 937 (2009) 85–94. [32] E. Bartoszak-Adamska, Z. Dega-Szafran, M. Jaskólski, M. Szafran, J. Phys. Org. Chem. 22 (2009) 356–361. [33] Z. Dega-Szafran, A. Katrusiak, M. Szafran, J. Mol. Struct. 920 (2009) 202–207. [34] Z. Dega-Szafran, A. Katrusiak, M. Szafran, J. Mol. Struct. 880 (2008) 77–85. [35] M. Szafran, A. Katrusiak, Z. Dega-Szafran, J. Mol. Struct. 839 (2007) 99–106. [36] M. Szafran, A. Katrusiak, J. Koput, Z. Dega-Szafran, J. Mol. Struct. 784 (2006) 98–108. [37] M. Szafran, A. Katrusiak, Z. Dega-Szafran, J. Mol. Struct. 794 (2006) 46–53. [38] (a) D. Hadzˇi, S. Bratos, in: P. Schuster, G. Zundel, C. Sandorfy (Eds.), The Hydrogen Bond Recent Developments and Experiments, vol. 2, North-Holland, Amsterdam, 1976, pp. 565–611; (b) A.P. Scott, L. Radom, J. Phys. Chem. 100 (1996) 16502–16513. [39] A. Novak, Struct. Bond. 18 (1974) 177–216. [40] J. Baran, M. Drozd, T. Głowiak, M. Sledz, H. Ratajczak, J. Mol. Struct. 372 (1995) 131–144. [41] W.F. Maddams, M.J. Southon, Spectrochim. Acta 38A (1982) 459–466. [42] G. Talski, Derivative Spectrophotometry, Wiley-VCH, Weinheim, 1994. [43] M. Szafran, E. Bartoszak-Adamska, J. Koput, Z. Dega-Szafran, J. Mol. Struct. 844 (2007) 140–156. [44] K. Wolinski, J.F. Hilton, P. Pulay, J. Am. Chem. Soc. 112 (1990) 8251–8260. and ref. cited therein. [45] M. Alcolea Palafox, Recent Res. Dev. Phys. Chem. Transworld Research Network, Trivandrum, India 2 (1998) 213–232. [46] M. Alcolea Palafox, Int. J. Quant. Chem. 77 (2000) 661–684. [47] M. Alcolea Palafox, V.K. Rastogi, Spectrochim. Acta A 58 (2002) 411–440. [48] K. Szczepaniak, M.M. Szczesniak, W.B. Person, J. Phys. Chem. A 104 (2000) 3852–3863. [49] K. Szczepaniak, W.B. Person, D. Hadzˇi, J. Phys. Chem. A 109 (2005) 6710–6724. [50] M. Alcolea Palafox, M. Gill, N.J. Nunez, V.K. Rastogi, L. Mittal, R. Sharma, Int. J. Quantum Chem. 103 (2005) 394–421. [51] Y.I. Binev, M.K. Georgieva, L.I. Daskalowa, Spectrochim Acta A 60 (2004) 2601– 2610. [52] R. Dennington, T. Keith, J. Millan, Gauss View, Version 3.0, Semichem. Inc., Shawnee Mission, KS, 2007. [53] H. Simpson, Organic Structure Determination Using 2-D NMR Spectroscopy, Academic Press, Elsevier, Amsterdam, 2008. [54] R. Ditchfield, Mol. Phys. 27 (1974) 789–807. [55] D.A. Forsyth, A.B. Sebag, J. Am. Chem. Soc. 119 (1997) 9483–9494. [56] B. Os´miałowski, E. Kolehmainen, R. Gawinecki, Magn. Res. Chem. 29 (2001) 334–340.
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Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa
Spectroscopic, structural and theoretical investigation of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate Anna Komasa ⇑, Andrzej Katrusiak, Michał Kaz´mierczak, Zofia Dega-Szafran, Mirosław Szafran Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61614 Poznan, Poland
h i g h l i g h t s
g r a p h i c a l a b s t r a c t
A short, asymmetric hydrogen bond
The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate has been studied by X-ray diffraction, DFT, FTIR, Raman and NMR. Two 4-trimethylammoniumbenzoate moieties are joined by asymmetric OHO hydrogen bond of 2.45(2) Å. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two hydrogen bonds of 2.70(3) and 3.51(1) Å. The FTIR spectrum shows a broad absorption in the 1500–400 cm 1 region corresponding to the mas(OHO) and c(OHO) vibrations.
1,4 1,2
Absorbance
joins a pair of 4-trimethylammoniumbenzoates. The water molecule interacts via two O–H O and O–H I hydrogen bonds. The FTIR spectrum is dominated by a broad absorption in the 1500–400 cm 1 region. Experimental and calculated IR and Raman vibrations of the complex are compared. The magnetic isotropic shielding constants confirm the experimental chemical shifts.
1,0 0,8 0,6 0,4 0,2 3500
3000
2500
2000
1500
1000
500
-1
Wavenumbers (cm )
a r t i c l e
i n f o
Article history: Received 29 April 2014 Received in revised form 5 September 2014 Accepted 18 September 2014 Available online 13 October 2014 Keywords: Bis(4-trimethylammoniumbenzoate) hydroiodide hydrate X-ray diffraction FTIR Raman and NMR spectra B3LYP calculations Hydrogen bonds
a b s t r a c t The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 has been studied by X-ray diffraction, B3LYP/6–311G(d,p) calculations, FTIR, Raman and NMR spectroscopic techniques. The crystal is polar in monoclinic space group Cc. Two 4-trimethylammoniumbenzoate moieties are joined by a short and asymmetric hydrogen bond of 2.45(2) Å. Water molecules are gradually released from the structure, causing shifts in the position of iodine anions, which induces their disorder. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two O(3)–H(1) O(1) and O(3)– H(2) I(1) hydrogen bonds of lengths 2.70(3) and 3.51(1) Å. Hydrogen bonds in theoretically predicted structures of 2 and 3 (in vacuum), and 4, 5 (in DMSO) optimized by the B3LYP/6-311G(d,p) approach are slightly longer than in crystal 1. The FTIR spectrum of 1 shows a broad and intense absorption in the 1500–400 cm 1 region, typical of short hydrogen bonds assigned to the mas(OHO) + c(OHO) vibrations. The correlations between the experimental 13C and 1H chemical shifts (dexp) of the investigated compound in DMSO and the GIAO/B3LYP/6-311G(d,p) magnetic isotropic shielding constants (rcalc) calculated by using the screening solvation model (COSMO) are linear, dexp = a + b rcalc, and they well reproduce the experimental chemical shifts. Ó 2014 Elsevier B.V. All rights reserved.
⇑ Corresponding author. Tel.: +48 618291004; fax: +48 618291555. E-mail address: [email protected] (A. Komasa). http://dx.doi.org/10.1016/j.saa.2014.09.138 1386-1425/Ó 2014 Elsevier B.V. All rights reserved.
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Fig. 1. The average structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate/anhydrate and its atom labeling scheme. The iodide anion resides at two positions depending on the water contents. If H2O is present, the iodide anion residues at site I(1), while in the dehydrated structure – at the I(2) site. The H-bond OH I in the hydrate is indicated by the dotted line.
Table 1 Crystal data and structure refinement for the bis(4-trimethylammoniumbenzoate) hydroiodide hydrate. Formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions
Volume Z Calculated density Absorption coefficient F(0 0 0) Crystal size h range for data collection (°) Limiting indices h, k, l Reflections collected/unique hMax(°)/Completeness (%) Absorption correction Max. and min. transmission Refinement method Data/restraints/parameters Goodness-of-fit on F2 Final R1/wR2 indices [I > 2rI] R1/wR2 indices (all data)
[C20H27N2O4]+I 0.5H2O 495.34 296(2) K 0.71073 Å Cc Monoclinic a = 13.240(19) Å b = 9.02(2) Å c = 19.228(16) Å 2171(6) Å3 4 1.516 g/cm3 1.504 mm 1 1001 0.17 0.08 0.12 mm 2.24–26.28 11/16, 11/10, 23/21 8591/2889 [R(int) = 0.1085] 26.27/99.1 Integration 0.89 and 0.81 Full-matrix least-squares on F2 2889/7/263 1.464 0.0868/0.2141 0.0939/0.2218
Introduction Zwitterions are compounds with oppositely charged centers and are often referred to as betaines, dipolar ions, salt-bridged-containing molecules and inner salts. This diverse nomenclature reflects the extraordinary importance of these species in biological transformations, organic synthesis, preparation of novel materials and as chromatographic supports [1–3]. An interesting group of compounds of this type are ortho-, meta- and para-trimethylammoniumbenzoates (benz-betaines), Me3N+–C6H4–COO , their esters and complexes with hydrohalides [4–6]. In the pyrolysis electron impact (EI) mass spectrometry experiment on trimethylammoniumalkanocarboxylates (Me3N+–(CH2)n–COO ) and their hydrochlorides, Wood et al. [7] have observed the methyl transfer to more volatile methyl esters (Me2N–(CH2)n–COOMe). Quaternization of dimethylaminobenzoic acids by an excess of methyl iodide in methyl alcohol depends on temperature and time of refluxing [6]. In trimethylammoniumbenzoic acids hydroiodides, heating triggers the methyl transfer and induces the formation of methyl dimethylammoniumbenzoates hydroiodides (Me2N–C6H4–COOMeHI). Recently, the structures of methyl 4-(trimethylammonium)benzoate iodide [8], 4-(trimethylammonium)benzoic acid chloride [9] and 4-(trimethylammonium)benzoate hydrate [10] have been described. In this paper, the crystal structure and spectroscopic properties of bis(4-trimethylammoniumbenzoate) hydroiodide
Table 2 Energies (Hartree, a.u.), dipole moments (l, Debye), OH O hydrogen bond distances (Å) and N I(1) contacts in the crystals (1), vacuum (2, 3) and DMSO (4, 5) for bis(4trimethylammonium-benzoate) hydroiodide hydrate and anhydrate. Compounds
Energy
l
1 X-ray (Fig. 1)
B3LYP/6–311G(d,p) 2 hydrate
8185.069601
10.921
3 anhydrate 4 DMSO anhydrate 5 DMSO hydrate
8108.602676 8108.683543 8185.149265
14.824 32.155 17.796
D–H A
d(D–H)
d(H A)
d(D A)
2000 cm 1 and 0.839 for m < 2000 cm 1. Average (signed) differences between experimental and computed data. Root-mean-square errors.
at 1064 nm excitation line of Nd:YAG laser, with the resolution of 1 cm 1. The spectrum was accumulated by acquisition of 250 scans at 31 °C. NMR spectra were recorded on a Bruker Advance DRX spectrometer operating at 599.85 and 150.85 MHz for 1H and 13C, respectively. The 2D 1H–13C HSQC (Heteronuclear Single Quantum Coherence) and HMBC (Heteronuclear Multiple Bond Coherence) spectra were measured in DMSO-d6 solutions relative to TMS. The DFT calculations were performed using the Gaussian 09 program package [16]. The calculations employed the B3LYP exchange–correlation functional, which combines the hybrid functional of Becke [17] with the gradient-correlation functional of Lee et al. [18] and the split-valence polarized 6-311G(d,p) basis set [19]. The basis set for iodine is not available in the standard set of basis functions offered by the Gaussian 09 program. Therefore it has been taken from the EMSL, Basis Set Library [21,22]. Glukhovtsev et al. [20] tested their basis on a set of iodine-containing species assessing theoretical results by comparison with experimental data. The X-ray geometry of 1 was used as a starting point of calculations. The magnetic isotropic shielding constants were calculated using the standard GIAO/B3LYP/6-311G(d,p) (gauge-independent atomic orbital) approach with the Gaussian 09 program package using the conductor-like screening solvation model (COSMO) [23–26]. Results and discussion Crystal structure The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 with the atom numbering is shown in Fig. 1 and the molecular packing in the crystal is illustrated in Fig. S2. The
observed structure, with disordered sites of iodine anions and water molecules can be rationalized as a composite crystal, consisting of both hydrated and anhydrous compounds. In the average structure the distances between the disordered iodides are unrealistic, but they can be explained by assuming the presence of two compounds contributing to the diffraction data of the crystal. In the anhydrous compound the iodide anion is located at site I(2), and it is not involved in strong hydrogen bonds. In the hydrate, the iodide anion is located at site I(1) and it forms hydrogen bonds mediated by the crystalline water to carboxyl group C(7)–O(1) H (Fig. 1). The bond lengths, bond and dihedral angles are listed in Tables 2 and S2. Two molecules of betaines are bridged by a proton to form a homoconjugated cationic system with a short, asymmetric O(11)–H O(1) hydrogen bond with the O O distance of 2.45(2) Å. The H-bonded proton is closer to the benz-betaine molecule which has shorter contacts with I anion. Because the hydrogen bonded molecules are not symmetrically equivalent, the bis(4trimethylammoniumbenzoate) cation in the crystal lattice shown in Fig. S2 is similar to that of the pseudo-Type A acid salts of carboxylic acids [27]. The hydrogen bonds in Type A acid salts of aromatic monocarboxylic acids [27] and 2:1 complexes of betaines with mineral acids are slightly shorter [28–30]. The investigated cations are arranged approximately parallel in the crystal lattice, as shown in Fig. S2. The two carboxy-fragments participating in the hydrogen bond are planar, with the dihedral angle between the O(2)–C(7)–O(1) and O(12)–C(17)–O(11) planes equal to 18.98°. The dihedral angle between the planes through the rings is 0.45° and those between the ring and the COO moieties are 13.82° and 5.38°, respectively (Table S2). The benz-betaine moieties of the monocationic dimer are almost planar in the crystal. In the investigated 4-trimethylammoniumbenzoate molecules [8–10] dihedral angles C(2)–C(1)–C(7)–O(1) and C(2)–C(1)–C(7)–O(2)
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4000
2
Second-derivative (d ), cm
-1
optimized molecules both the O(11)–H O(1) and O(3)–H O(1) hydrogen bonds are slightly longer than in the crystal (Table 2). As indicated by the data in Table 2, the stability of the optimized complexes is controlled by the electrostatic attraction between the positively charged nitrogen atoms N(1) and N(11) and the I anion. In the optimized complexes benz-betaine molecules are non-planar (Table S2, the angle between ring-ring planes: (1) 0.45°, (2) 70.95°, (3) 51.51°, (4) 81.48°, (5) 62.23°).
3000
2000
1000
0
FTIR and Raman spectra 0
1000
2000
3000
4000
Calculated frequencies by B3LYP/6-311G(d,p), cm-1 Fig. 4. A correlation between the experimental (the second-derivative d2) 1 and calculated 2 wavenumbers (cm 1) for bis(4-trimethylammoniumbenzoate) hydroiodide hydrate; the straight line represents equation: mexp = 327 + 1.062 mcalc, r = 0.9926.
depend on hydrogen bonds and electrostatic interaction between N+ and anions (X ). Optimized structures The structures of anhydrate and hydrate bis(4-trimethylammoniumbenzoate) hydroiodide optimized by the B3LYP/ 6-311G(d,p) approach in vacuum 2 and 3, and in DMSO solution 4 and 5 are shown in Fig. 2. The geometries of 4 and 5 are used to predict the 13C and 1H chemical shifts in DMSO-d6 solution. The bent (2, 3 and 5) and linear (4) structures can be distinguished. The calculated geometrical parameters are listed in Table S2. In the
Fig. 3b shows the FTIR spectra of 2:1 and 1:1 complexes of 4trimethylammoniumbenzoate with HI. The spectrum of 2:1 complex displays a broad and strong absorption in the 1500– 400 cm 1 region with the center of gravity around 944 cm 1, whereas in the Raman spectrum this feature is absent (Fig. 3a). Similar differences between IR and Raman spectra appear for 1carboxyethylpyridinium-4-carboxylate inner salt [31], bis(4-(Nmethylpiperidinium)butyrate) hydrobromide [32], 1:1 complex of meso-tartaric acid with 1,4-dimethylpiperazine di-betaine [33] and bis(1-methylisonicotinate) hydrogen perchlorate [34]. In the FTIR spectrum of 1:1 complex the broad absorption is also absent. A similar broad absorption appears in the IR spectra of 2:1 complexes of homarine [35], trigonelline [36], 1-methylisonicotinate inner salt [37] and Type A acid salts of carboxylic acids [38a,39]. The broad absorption is typical of compounds with short H-bonds and is assigned to the mas(OHO) and c(OHO) vibrations of the strong hydrogen bonds [39,40]. In the FTIR spectrum, the broad absorption overlaps with the narrow skeletal absorption, but the latter can be distinguished in the second-derivative, d2 (Fig. 3c), or forth-derivative, d4, spectra.
Table 4 Experimental, dexp (DMSO-d6 solution), predicted (dpred = a + b rcalc) carbon-13 and proton chemical shifts, and calculated GIAO/B3LYP/6-311G(d,p) isotropic magnetic shielding constants (rcalc) for 4-(trimethylammoniumbenzoate) hydroiodide hydrate. Atom
C(1) C(2) C(3) C(4) C(5) C(6) C(7)OOH C(8)–C(10) av ac bd re Av. dif. f R.m.s.g Proton H(2) H(6) H(3) H(5) C(8)H3–C(10)H3 av ac bd re Av. dif.f R.m.s.g a b c d e f g
dexp
133.20 130.74 120.96 149.91 120.96 130.74 166.04 56.37
8.12 8.12 8.10 8.10 3.65
dpred 5
dpred 4
rcalc 5
0.5(A + B)
0.5(A + B)
Aa
Bb
0.5(A + B)
Aa
rcalc 4 Bb
0.5(A + B)
138.191 131.317 120.629 147.777 116.819 130.770 166.148 57.269
137.712 130.976 118.792 148.471 119.991 130.962 165.378 56.631
40.3105 46.1045 57.4876 28.0295 61.6181 45.3872 7.6214 125.1265 ± 2.1990
37.1209 45.9745 57.3658 28.9736 61.3561 47.8567 10.2339 124.7450 ± 2.5201
38.7157 46.0395 57.4267 28.5016 61.4871 46.6220 8.9277 124.9358 174.5275 0.9386 0.9967
43.3242 47.0475 60.5470 26.7600 55.0396 46.2980 10.7137 124.5501 ± 2.6658
35.9203 46.3521 58.4542 29.8781 61.4302 47.1311 10.3972 125.0696 ± 2.6994
39.6223 46.6998 59.5006 28.3191 58.2349 46.7146 10.5555 124.8099 175.4247 0.9518 0.9980
0 2.615
0 2.024
8.322 8.634 7.689 7.630 3.816
8.430 8.223 7.520 8.161 3.754
23.3508 23.4265 24.3008 24.1916 28.5340 ± 0.3739
23.8283 23.0639 24.2708 24.5114 28.5947 ± 0.4146
23.5896 23.2452 24.2858 24.3515 28.5511 29.7448 0.9082 0.9770
23.6247 23.3508 24.2707 22.8598 28.4650 ± 0.5529
22.9033 23.6444 24.3169 24.2763 28.6433 ± 0.2527
23.2640 23.4976 24.2938 23.5681 28.5542 28.9902 0.8838 0.9855
0 0.425
0 0.339
Ring with C(1)–C(10) atoms. Ring with C(11)–C(20) atoms. Intercept for the equation dexp = a + b rcalc. Slop for the equation dexp = a + b rcalc. Correlation coefficient for the equation dexp = a + b rcalc. Average (signed) differences between experimental and predicted chemical shifts. Root-mean-square errors.
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The minima in the d2 spectrum have the same wavenumbers as the maxima in the absorbance spectrum. Since the relative intensities in the d2 spectrum vary inversely to the square of the half-width ratio of the absorbance bands in the FTIR spectrum, the broad bands assigned to the O H O modes are not observed in the d2 spectra [41,42]. As shown in Fig. 3d, the calculated frequencies agree well with the negative d2 bands. From this similarity we conclude that the calculated data describe only the narrow skeletal frequencies without the broad absorption. Table 3 lists the experimental and calculated frequencies, and intensities for normal modes in molecules of 1 and 2. The assignments pertinent to hydrogen bond OHO vibration are exposed in bold. The most intensive predicted band at mscaleq 2497 cm 1 is assigned to the asymmetric stretching vibration of the hydrogen bond. A comparison of the calculated and experimental frequencies shows typical differences. The calculated bands are shifted to higher wavenumbers relative to the experimental data. Two facts may be responsible for the differences between the experimental and computed spectra of the molecule investigated. The first is that the experimental spectrum was recorded for the complex in the solid state, while the computed spectrum refers to the isolated molecule 2 in the vacuum. The second one is the fact that the experimental results are anharmonic vibrations, while the calculated values are harmonic vibrations. Similar discrepancies between the calculated and experimental frequencies have been noted for 1-methylpyridinium-4-carboxylate monohydrate [43]. The overestimation of the computed wavenumbers is quite systematic and can be corrected by applying appropriate scaling factors or scaling equation [38b,44–51]. A linear relation between the experimental d2 and calculated frequencies with a good correlation coefficient r = 0.9926 is shown in Fig. 4. This scaling procedure, as recommended by Alcolea Palafox [50] was used for adjusting the predicted frequencies, listed in Table 3 as mscaleq. Additionally two scaling factors were applied to the harmonic vibrational frequencies (0.946 for m > 2000 cm 1 and 0.839 for m < 2000 cm 1) yielding scaled wavenumbers (mscalf) listed in Table 3. These two scaling factors were found by minimizing the root-mean-square deviation between experimental and theoretical data within two separate frequency ranges mentioned above. The assignment of vibrational bands of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate was made using the Gauss-View molecular visualization program [52]. The scaling harmonic vibration by equation reproduces the experimental solid FTIR frequencies with r.m.s. error of 104 cm 1, while by scaling factors the r.m.s. is 146 cm 1.
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obtained chemical shifts are comparable to those in (4-trimethylammonium)benzoic acid chloride [9]. The relations between the experimental 13C and 1H chemical shifts (dexp) for 1 and the GIAO (Gauge-Independent Atomic Orbitals) magnetic isotropic shielding constants (rcalc), in DMSO calculated for 4 and 5 are linear and described by the following equation: dexp = a + b rcalc [53–56]. The slope and intercept of the least-squares correlation line (Table 4, Fig. 5) are used to scale the GIAO magnetic isotropic shielding constants, rcalc, and to predict the chemical shifts, dpred = a + b rcalc. The magnetic isotropic shielding constants confirm the correct assignments of the chemical shifts to the appropriate atoms. The agreement between the experimental and predicted chemical shifts is satisfactory for the corresponding solutions. Conclusions The crystal and molecular structures of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1, were determined by X-ray diffraction and by the B3LYP/6-311G(d,p) calculations. In the crystal a pair of 4-trimethylammoniumbenzoates is joined by a proton to form a homoconjugated cation, featuring a short and asymmetric hydrogen bond with the O O distance equal to 2.45(2) Å. The hydrogen bond in 1 is similar to that in pseudo-Type A acid salts of carboxylic acids and it can be described by a potential energy function with a double minimum with low barrier. Water molecule in 1 interacts with bis(4-trimethylammoniumbenzoate) homoconjugated cation and iodide anion via two O(3)–H(1) O(1) and O(3)–H(2) I(1) hydrogen bonds of the lengths 2.70(3) and 3.51(1) Å. The experimental 13C and 1H chemical shifts (dexp) of the investigated compounds in DMSO-d6 correlate linearly with GIAO/ B3LYP/6-311G(d,p) magnetic isotropic shielding constants calculated according to the screening solvation model (COSMO), dexp = a + b rcalc, and confirm the correct assignment of the resonance signal. The FTIR spectrum of 1 shows a broad and intense absorption in the 1500–400 cm 1 region, typical of short hydrogen bonds and corresponds to the mas(OHO) and c(OHO) vibrations. The calculated IR frequencies agree well with the negative d2 bands, which suggest that the calculated data describe only the narrow skeletal frequencies without the broad absorption. The FTIR spectrum of the solid compound is consisted with the X-ray structure. Acknowledgments
NMR spectra
The calculations were performed at the Poznan´ Supercomputing and Networking Centre and supported in part by PL-Grid Infrastructure.
The assignments of carbon-13 and proton chemical shifts for the complex are based on two-dimensional HSQC (Fig. S3) and HMBC (Fig. S4) experiments [53] and are listed in Table 4. The
Appendix A. Supplementary data
Chemical shifts (ppm)
180
(a)
160
(b)
8
140
Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.saa.2014.09.138. References
7
120
6
100
5
80
4
60 40
9
0
20
40
60
80 100 120 140
3
22
24
26
28
Magnetic isotropic shielding constants Fig. 5. Plot of the experimental 13C (a) and 1H (b) chemical shifts of 1 in DMSO-d6 versus the magnetic isotropic shielding tensors from GIAO/B3LYP/6-311G(d,p) for 5, dexp = a + b rcalc.
[1] X. Domingo, Betaines, in: E.G. Lomax (Ed.), Amphoteric Surfactans, second ed., Marcel Dekker Inc., New York, 1996, pp. 76–190. [2] A. Schmidt, Adv. Heterocycl. Chem. 85 (2003) 67–171. [3] E. Alcalde, Adv. Heterocycl. Chem. 60 (1994) 197–259. [4] E.F. Strittmatter, R.L. Wong, E.R. Williams, J. Am. Chem. Soc. 122 (2000) 1247– 1248. [5] J. Picha, R. Cibulka, F. Liska, P. Parik, O. Pytela, Collect. Czech. Chem. Commun. 69 (2004) 2239–2252. [6] (a) W. Tadras, A.B. Sakla, J. Chem. Soc. (1954) 1116–1119; (b) R. Willstätter, W. Kahn, Ber. 37 (1904) 401–417. [7] G.W. Wood, R.J. Collacott, Org. Mass Spectrom. 18 (1983) 42–45. and references cited therein. [8] M. Szafran, A. Katrusiak, Z. Dega-Szafran, A. Komasa, I. Kowalczyk, J. Mol. Struct. 1006 (2011) 330–336.
1156
A. Komasa et al. / Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 136 (2015) 1149–1156
[9] M. Szafran, A. Katrusiak, Z. Dega-Szafran, I. Kowalczyk, J. Mol. Struct. 996 (2011) 75–81. [10] M. Szafran, A. Katrusiak, Z. Dega-Szafran, I. Kowalczyk, J. Mol. Struct. 1005 (2011) 144–151. [11] KUMA KM4-CCD Software, Version 161, Kuma Diffraction, Wroclaw, Poland, 1999. [12] CrystAlis 162, Kuma Diffraction, Wroclaw, Poland, 1999. [13] G.M. Sheldrick, Acta Crystallogr. A 64 (2008) 112–122. [14] C.K. Johnsen, ORTEPH, Report ORNL-5138, Oak Ridge National Laboratory, Thennessee, USA, 1976. [15] Stereochemical Workstation Operation Manual, Release 3.4, Siemens Analytical X-ray Instruments Inc., Madison, 1989. [16] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H.P. Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro, M. Bearpark, J.J. Heyd, E. Brothers, K.N. Kudin, V.N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J.C. Burant, S.S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J.M. Millam, M. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J. Austin, R. Cammi, C. Pomelli, J.W. Ochterski, R.L. Martin, K. Morokuma, V.G. Zakrzewski, G.A. Voth, P. Salvador, J.J. Dannenberg, S. Dapprich, A.D. Daniels, Ö. Farkas, J.B. Foresman, J.V. Ortiz, J. Cioslowski, D.J. Fox, Gaussian 09, Revision D.01, Gaussian Inc., Wallingford CT, 2009. [17] A.D. Becke, J. Chem. Phys. 107 (1997) 8554–8560. and ref. cited therein. [18] C. Lee, W. Yang, R.G. Parr, Phys. Rev. B 37 (1988) 785–789. [19] W.J. Hehre, L. Random, P.V.R. Schleyer, J.A. Pople, Ab Initio Molecular Orbital Theory, Wiley, New York, 1989. [20] M.N. Glukhovtsev, A. Pross, M.P. McGrath, L. Radom, J. Chem. Phys. 103 (1995) 1878–1885. [21] D. Feller, J. Comput. Chem. 17 (1996) 1571–1586. [22] K.L. Schuchardt, B.T. Didier, T. Elsethagen, L. Sun, V. Gurumoorthi, J. Chase, J. Li, T.L. Windus, J. Chem. Inf. Model 47 (2007) 1045–1052. [23] V. Barone, M. Cossi, J. Phys. Chem. A 102 (1998) 1995–2001. [24] G. Brancato, N. Rega, V. Barone, Chem. Phys. 125 (2006). 164515–164515. [25] P. Pulay, X. Zhou, F. Fogarasi, in: R. Fausto (Ed.), Recent Experimental and Computational Advances in Molecular Spectroscopy, Kluver, Academic, Netherlands, 1993, pp. 88–111. [26] A. Klam, COSMO-RS from Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design, Elsevier, Amsterdam, 2005. [27] J.C. Speakman, Struct. Bond (Berlin) 12 (1972) 141–199. [28] X.-M. Chen, T.C.W. Mak, J. Mol. Struct. 221 (1990) 265–269. [29] X.-M. Chen, T.C.W. Mak, Acta Crystallogr. C50 (1994) 1807–1809.
[30] Z. Dega-Szafran, A. Katrusiak, M. Szafran, J. Mol. Struct. 555 (2000) 203–212. [31] P. Barczyn´ski, A. Katrusiak, Z. Dega-Szafran, M. Szafran, J. Mol. Struct. 937 (2009) 85–94. [32] E. Bartoszak-Adamska, Z. Dega-Szafran, M. Jaskólski, M. Szafran, J. Phys. Org. Chem. 22 (2009) 356–361. [33] Z. Dega-Szafran, A. Katrusiak, M. Szafran, J. Mol. Struct. 920 (2009) 202–207. [34] Z. Dega-Szafran, A. Katrusiak, M. Szafran, J. Mol. Struct. 880 (2008) 77–85. [35] M. Szafran, A. Katrusiak, Z. Dega-Szafran, J. Mol. Struct. 839 (2007) 99–106. [36] M. Szafran, A. Katrusiak, J. Koput, Z. Dega-Szafran, J. Mol. Struct. 784 (2006) 98–108. [37] M. Szafran, A. Katrusiak, Z. Dega-Szafran, J. Mol. Struct. 794 (2006) 46–53. [38] (a) D. Hadzˇi, S. Bratos, in: P. Schuster, G. Zundel, C. Sandorfy (Eds.), The Hydrogen Bond Recent Developments and Experiments, vol. 2, North-Holland, Amsterdam, 1976, pp. 565–611; (b) A.P. Scott, L. Radom, J. Phys. Chem. 100 (1996) 16502–16513. [39] A. Novak, Struct. Bond. 18 (1974) 177–216. [40] J. Baran, M. Drozd, T. Głowiak, M. Sledz, H. Ratajczak, J. Mol. Struct. 372 (1995) 131–144. [41] W.F. Maddams, M.J. Southon, Spectrochim. Acta 38A (1982) 459–466. [42] G. Talski, Derivative Spectrophotometry, Wiley-VCH, Weinheim, 1994. [43] M. Szafran, E. Bartoszak-Adamska, J. Koput, Z. Dega-Szafran, J. Mol. Struct. 844 (2007) 140–156. [44] K. Wolinski, J.F. Hilton, P. Pulay, J. Am. Chem. Soc. 112 (1990) 8251–8260. and ref. cited therein. [45] M. Alcolea Palafox, Recent Res. Dev. Phys. Chem. Transworld Research Network, Trivandrum, India 2 (1998) 213–232. [46] M. Alcolea Palafox, Int. J. Quant. Chem. 77 (2000) 661–684. [47] M. Alcolea Palafox, V.K. Rastogi, Spectrochim. Acta A 58 (2002) 411–440. [48] K. Szczepaniak, M.M. Szczesniak, W.B. Person, J. Phys. Chem. A 104 (2000) 3852–3863. [49] K. Szczepaniak, W.B. Person, D. Hadzˇi, J. Phys. Chem. A 109 (2005) 6710–6724. [50] M. Alcolea Palafox, M. Gill, N.J. Nunez, V.K. Rastogi, L. Mittal, R. Sharma, Int. J. Quantum Chem. 103 (2005) 394–421. [51] Y.I. Binev, M.K. Georgieva, L.I. Daskalowa, Spectrochim Acta A 60 (2004) 2601– 2610. [52] R. Dennington, T. Keith, J. Millan, Gauss View, Version 3.0, Semichem. Inc., Shawnee Mission, KS, 2007. [53] H. Simpson, Organic Structure Determination Using 2-D NMR Spectroscopy, Academic Press, Elsevier, Amsterdam, 2008. [54] R. Ditchfield, Mol. Phys. 27 (1974) 789–807. [55] D.A. Forsyth, A.B. Sebag, J. Am. Chem. Soc. 119 (1997) 9483–9494. [56] B. Os´miałowski, E. Kolehmainen, R. Gawinecki, Magn. Res. Chem. 29 (2001) 334–340.
