Table of Contents
ISRN Organic Chemistry
Volume 2011, Article ID 708162, 5 pages
http://dx.doi.org/10.5402/2011/708162
Research Article

Synthesis, Characterization, and Crystal Structure of a Diorganotin(IV) Complex with 2-Oxo-2-Phenylacetic Acid 4-Hydroxybenzohydrazone

Department of Chemistry, Liaocheng University, Liaocheng 252059, China

Received 20 January 2011; Accepted 13 March 2011

Academic Editors: S. J. Garden, K. Matsubara, and L. Novak

Copyright © 2011 Jing Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The complex dibutyltin 2-oxo-2-phenylacetic acid 4-hydroxybenzohydrazone has been synthesized and characterized by elemental analysis, IR, 1H and 13C NMR, and X-ray single-crystal diffraction studies. The crystal structure belongs to triclinic, space group P-1 with 𝑎 = 9 . 3 2 2 0 ( 1 0 )  Å, 𝑏 = 9 . 8 7 7 9 ( 1 1 )  Å, 𝑐 = 1 5 . 9 4 0 1 ( 1 7 )  Å, 𝛽 = 9 7 . 0 9 3 0 ( 1 0 ) , 𝑍 = 2 , 𝑉 = 1 4 2 7 . 6 ( 3 )  Å3, 𝐷 𝑐 = 1 . 4 1 3  mg/cm3, 𝜇 = 0 . 9 3 6  mm−1, 𝐹 ( 0 0 0 ) = 6 2 8 , 𝑅 = 0 . 1 1 5 8 , and 𝑤 𝑅 = 0 . 2 5 2 2 . X-ray analysis indicates that O(2), N(2), O(4), and O(4)#1 from the ligand and O(5) from ethanol molecule are in the equatorial positions; the axial positions are occupied by two n-butyl groups. It shows a distorted pentagonal bipyramid configuration with seven-coordination for central tin atom. Fascinatingly, the supramolecular infrastructures are observed, which exist as two-dimensional sheets assembled from the organometallic subunits through intermolecular and intramolecular O–HX or C–HX (X = O or N) hydrogen bonds.

1. Introduction

Organotin complexes have attracted more and more attention in recent years, partly owing to their determinately or potentially pharmic value, which have been reported many times before [1], and also for the versatile molecular structure and supramolecular architecture exhibited by these complexes [24]. Among these, Schiff base organotin complexes have received much attention, as such ligands and their metal complexes are reported to exhibit bactericidal and antitumor activities [5, 6]. The coordination chemistry of tin is extensive with various geometries and coordination numbers known for both inorganic and organometallic complexes [7]. Especially, organotin complexes react with the ligands with nitrogen atoms, yielding products characterized by Sn–N bonds [8]. Studies of Schiff base organotin complexes containing carboxylate ligands with additional donor atoms (e.g., N, O or S), which are available for coordinating to tin atom, have revealed that new structural types may lead to different activities [9]. In our previous work, we have reported several novel molecular structures of organotin complexes with Schiff bases containing carboxylate [1014]. As an extension of studies of organotin complexes with Schiff base, we synthesized a new diorganotin complex of 2-oxo-2-phenylacetic acid 4-hydroxybenzohydrazone by the reaction of di-n-butyltin dichloride and ligand in 1 : 1 stoichiometry. The synthesis, structure, and spectra characterizations of the complex are reported herein. X-ray diffraction shows that the central tin atom is seven-coordinate by the two n-butyl carbon atoms, the imino nitrogen atom, and four oxygen atoms from ethanol and the ligand. The supramolecular infrastructures are observed, which exist as two-dimensional sheets assembled from the organometallic subunits through intermolecular and intramolecular O–HX or C–HX (X = O or N) hydrogen bonds.

2. Experimental

2.1. Materials and Physical Measurements

Di-n-butyltin chloride, 4-hydroxybenzohydrazide, and 2-oxo-2-phenylacetic acid were commercially available and used without further purification. All the solvents used in the reaction were of AR grade and dried using standard literature procedures. The melting points were obtained with Kofler micromelting point apparatus and were uncorrected. IR spectra were recorded with a Nicolet-460 spectrophotometer using KBr discs and sodium chloride optics. 1H and 13C NMR spectra were recorded with a Varian Mercury Plus 400 spectrometer. The chemical shifts are reported in ppm with respect to the references and are stated relative to the inner reference tetramethylsilane for 1H, 13C NMR spectroscopy. Elemental analyses were performed with a PE-2400 II elemental analyzer.

2.2. Synthesis of Schiff Base Ligand 1 (2Z)-[(4-Hydroxybenzoyl) Hydrazono] (Phenyl) Acetic Acid

The Schiff base ligand 1 was prepared from the benzoylformic acid and 4-hydroxybenzoic hydrazide in ethanol solution. A mount of yellow power was obtained. Yield: 85%. M.p.: 199–201°C. Anal. Calc. for C15H12N2O4: C, 63.38; H, 4.25, N, 9.85%. Found: C, 63.30; H, 4.22; N, 9.79%.

2.3. Preparation of the Complex 1

The reaction was carried out under nitrogen atmosphere with the use of standard Schlenk technique. The ligand 1 (0.28 g, 1.0 mmol) and sodium ethoxide (0.07 g, 1.0 mmol) were added to a solution of absolute ethanol (30 mL) and heated under reflux with stiring for 0.5 h. After the addition of di-n-butyltin chloride (0.30 g, 1.0 mmol) to the reactor, the reaction mixture was refluxed for 10 h more. The reaction solution thus obtained was filtered and evaporated under vacuum to form a yellow solid and then recrystallized from dichloromethane/hexane to give yellow single crystal of complex. Yield: 70%. M.p.: 168–170°C. Anal. Calc. for C27H40N2O6Sn: C 53.40; H 6.64; N 4.61%. Found: C 53.35; H 6.29; N 4.58%. IR (KBr, cm−1): 1608, 1369 (m, CO2), 1635 (s, C=N), 1608 (m, C=NN=C), 570 (m, SnO), 537 (w, SnC). 1H NMR (400 MHz, CDCl3, 298 K, ppm): 0.96 (t, 6H, CH3), 1.37–1.42 (m, 8H, CH2CH2), 1.68–1.82 (m, 4H, SnCH2-), 1.42 (t, 3H, –CH2CH3), 3.67 (m, 2H, OCH2), 8.53 (s, 1H, OH), 3.57 (m, 2H, OCH2), 1.11 (t, 3H, –CH3), 2.10 (s, 1H, OH), 7.267.59 (m, 5H, C6H5), 6.86–7.49 (m, 4H, C6H4O), 5.40 (s, 1H, PhOH). 13C NMR (100 MHz, CDCl3, 298 K, ppm): 173.68, 169.53, 160.78, 142.85, 133.24, 131.12, 130.67, 129.25, 128.94, 122.56, 116.02, 57.94, 57.93, 27.06, 21.93, 21.42, 17.45, 17.42, 13.81.

2.4. Structure Determination

A yellow single crystal with the dimensions of 0.50 mm × 0.46 mm × 0.41 mm was mounted on a Bruker SMART CCD 1000 diffractometer equipped with a graphite-monochromatic Mo-Kα ( 𝜆 = 0 . 7 1 0 7 3  Å) radiation by using a ωscan mode [2.21 < θ < 25.02] at 298(2) K. A total of 7006 reflections were collected with 4855 unique ones (Rint = 0.0887), of which 330 were observed with I > 2σ(I) and used in the succeeding refinements. Intensity data were corrected for Lp factors and empirical absorption. The structure was solved by direct methods and expanded by difference Fourier techniques with SHELXS-97 program [15, 16]. All of the nonhydrogen atoms were located with successive difference Fourier syntheses. The structure was refined by full-matrix least-squares techniques on 𝐹 2 using anisotropic thermal parameters for all nonhydrogen atoms. The hydrogen atoms were added according to theoretical models. The final full-matrix least-squares refinement converged at 𝑅 = 0 . 1 1 5 8 and 𝜔 𝑅 = 0 . 2 5 2 2    ( 𝜔 = 1 / [ 𝜎 2 ( 𝐹 2 𝑜 ) + ( 0 . 1 5 8 6 𝑃 ) 2 ] , where 𝑃 = ( 𝐹 2 𝑜 + 2 𝐹 2 𝑐 ) / 3 ) , 𝑆 = 1 . 0 3 , ( Δ 𝜌 ) m a x = 1 . 4 5 , ( Δ 𝜌 ) m i n = 1 . 9 2 e/Å3, and ( Δ / 𝜎 ) m a x = 0 . 0 0 7 . The molecular structure and two-dimensional sheets of the title complex are shown in Figures 1 and 2, respectively. The crystal data and structure refinement are listed in Table 1. The selected bond lengths and bond angles are listed in Table 2. The hydrogen bond lengths and bond angles are listed in Table 3.

tab1
Table 1: Crystal data and structure refinement for complex 1.
tab2
Table 2: Selected bond lengths (Å) and bond angles (°).
tab3
Table 3: Hydrogen bond lengths (Å) and bond angles (°).
708162.fig.001
Figure 1: Molecular structure of the complex.
708162.fig.002
Figure 2: Two-dimensional sheets, formed by O–HX, C–HN (X = O,N) hydrogen bonds.

3. Results and Discussion

3.1. Synthesis of Organotin(IV) Complex 1

See Scheme 1.

708162.sch.001
Scheme 1: Synthesis of organotin(IV) complex 1.
3.2. Spectral Characterization

The IR spectra show the metal-ligand bonds formation through –CO2, –O, and –N sites, and the associated Sn–O–Sn, Sn–O, and Sn–N absorption values also support this. The absence of the N–H and C=O stretching vibration bands is consistent with the deprotonation of the CO–NH groups and coordination to the organotin(IV) ions in the enol form. And the characteristic absorption at 1608 cm−1 indicates the presence of C=N–N=C group [17], thus indicating the ligand coordinate to the tin centre in an enolic form, which is in accordance with the X-ray structure analysis and their corresponding reaction mechanism. The 1H NMR spectrum of the complex shows that those signals of –OH and –CONH protons in the spectrum of the ligand are absent, thus indicating the removal of those protons and the formation of Sn–O bonds. The 13C NMR spectrum of the complex shows that the chemical shift of the carboxylate carbon shifts to a lower field region in almost all the organotin(IV) derivatives indicating participation of the carboxyl (COO) group in coordination to tin atom [18]. On the basis, we can conclude that the tin atom of complex in solution is seven-coodinated, and this can be confirmed by the X-ray crystal structures.

3.3. Description of the Crystal Structure

The crystal and unit cell structures are given in Figures 1 and 2, respectively. As illustrated in Figure 1, the environment of Sn(1) is in a distorted pentagon bipyramid with a nitrogen atom, four oxygen atoms, and two n-butyl groups (C(20)–Sn(1)–C(16) = 161.8(7)°, which is deviated from linear angle 180°). It is a centrosymmetric arrangement leading to a Sn2O2 core connected by the Sn–O bond, and the Sn(1)–O(4)#1 bond distance is 2.805(11) Å, is greater than the sum of the covalent radii of Sn and O (2.56 Å), but is considerably less than the sum of the Van der Waals radii Sn–O (3.68 Å), indicating the weak bonding interaction between Sn(1) and O(1)#1. The Sn(1)–N(2) distance is 2.258(12) Å, which is greater and longer than the sum of the covalent radii of Sn and N (2.15 Å) but is considerably less than the sum of the Van der Waals radii (3.75 Å) and should be considered as bonding interactions [19]. It is noteworthy that the solvent molecule-ethanol involved in the coordination. Fascinatingly, the supramolecular infrastructures were observed in the complex, which exist as two-dimensional sheets assembled from the organometallic subunits through intermolecular and intramolecular O–HX or C–HX (X = O or N) hydrogen bonds.

Acknowledgments

The authors acknowledge the National Natural Foundation of China (20771053), the National Basic Research Program (no. 2010CB234601), and the Natural Science Foundation of Shandong Province (Y2008B48 and ZR2010BQ021) for financial support. This work was supported by Shandong “Tai-Shan Scholar Research Fund”.

References

  1. C. Ma, Q. Zhang, R. Zhang, and L. Qiu, “Structural diversity of di and triorganotin complexes with 4-sulfanylbenzoic acid: supramolecular structures involving intermolecular SnO, O-HO or C-HX (X=O or S) interactions,” Journal of Organometallic Chemistry, vol. 690, no. 12, pp. 3033–3043, 2005. View at Publisher · View at Google Scholar · View at Scopus
  2. C. Ma, Q. Jiang, R. Zhang, and D. Wang, “Synthesis and crystal structure characterization of a novel eighteen-tin-nuclear macrocyclic complex,” Dalton Transactions, no. 15, pp. 2975–2978, 2003. View at Publisher · View at Google Scholar · View at Scopus
  3. C. L. Ma and J. F. Sun, “A novel self-assembling synthesis and crystal structure of 40-membered macrocyclic complex containing eight-tin,” Dalton Transactions, vol. 1, pp. 1785–1786, 2004. View at Publisher · View at Google Scholar
  4. C. Ma, Y. Man, R. Zhang, and D. Wang, “Self-assembly of diorganotin(IV) moieties and 2-pyrazinecarboxylic acid: syntheses, characterizations and crystal structures of monomeric, polymeric or trinuclear macrocyclic compounds,” Dalton Transactions, no. 12, pp. 1832–1840, 2004. View at Publisher · View at Google Scholar · View at Scopus
  5. M. N. Xanthopoulou, S. K. Hadjikakou, N. Hadjiliadis et al., “Biological studies of new organotin(IV) complexes of thioamide ligands,” European Journal of Medicinal Chemistry, vol. 43, no. 2, pp. 327–335, 2008. View at Publisher · View at Google Scholar · View at Scopus
  6. W. Rehman, M. K. Baloch, and A. Badshah, “Synthesis, spectral characterization and bio-analysis of some organotin(IV) complexes,” European Journal of Medicinal Chemistry, vol. 43, no. 11, pp. 2380–2385, 2008. View at Publisher · View at Google Scholar · View at Scopus
  7. B. L. Smith, Ed., Chemistry of Tin, Blackie, London, UK, 2nd edition, 1998. View at Scopus
  8. M. A. Girasolo, L. Pellerito, G. C. Stocco, and G. Valle, “Crystal and molecular structure of dimethyl(L-tryptophyl-L-alaninato)tin(IV)-methanol (1/1) and Mössbauer spectroscopy studies of lattice dynamics of diorganotin(IV)dipeptide complexes,” Journal of the Chemical Society—Dalton Transactions, no. 7, pp. 1195–1201, 1996. View at Google Scholar · View at Scopus
  9. L. Pellerito and L. Nagy, “Organotin(IV) complexes formed with biologically active ligands: equilibrium and structural studies, and some biological aspects,” Coordination Chemistry Reviews, vol. 224, no. 1-2, pp. 111–150, 2002. View at Publisher · View at Google Scholar · View at Scopus
  10. H. D. Yin, M. Hong, QI. B. Wang, S. C. Xue, and DA. Q. Wang, “Synthesis and structural characterization of diorganotin(IV) esters with pyruvic acid isonicotinyl hydrazone and pyruvic acid salicylhydrazone Schiff bases,” Journal of Organometallic Chemistry, vol. 690, no. 6, pp. 1669–1676, 2005. View at Publisher · View at Google Scholar · View at Scopus
  11. H. D. Yin and S. W. Chen, “Synthesis and characterization of di- and tri-organotin(IV) complexes with Schiff base ligand pyruvic acid 3-hydroxy-2-naphthoyl hydrazone,” Inorganica Chimica Acta, vol. 359, no. 10, pp. 3330–3338, 2006. View at Publisher · View at Google Scholar · View at Scopus
  12. H. D. Yin, JI. C. Cui, and Y. L. Qiao, “Synthesis, characterization and crystal structure of binuclear diorganotin(IV) complexes derived from hexadentate diacylhydrazone ligands,” Polyhedron, vol. 27, no. 9-10, pp. 2157–2166, 2008. View at Publisher · View at Google Scholar · View at Scopus
  13. M. Hong, H. D. Yin, S. W. Chen, and DA. Q. Wang, “Synthesis and structural characterization of organotin(IV) compounds derived from the self-assembly of hydrazone Schiff base series and various alkyltin salts,” Journal of Organometallic Chemistry, vol. 695, no. 5, pp. 653–662, 2010. View at Publisher · View at Google Scholar · View at Scopus
  14. H. Yin, J. Li, M. Hong, J. Cui, L. Dong, and Q. Zhang, “Synthesis, crystal structures and spectral characterization of diorganotin compounds with phenylglyoxylic acid isonicotinyl hydrazone,” Journal of Molecular Structure, vol. 985, no. 2-3, pp. 261–269, 2011. View at Publisher · View at Google Scholar
  15. G. M. Sheldrick, SHELXS97 and SHELXL97, University of Göttingen, Göttingen, Germany, 1997.
  16. Bruker, SAINT and SHELXTL, Bruker AXS, Madison, Wis, USA, 1998.
  17. H. D. Yin, M. Hong, G. Li, and DA. Q. Wang, “Synthesis, characterization and structural studies of diorganotin(IV) complexes with Schiff base ligand salicylaldehyde isonicotinylhydrazone,” Journal of Organometallic Chemistry, vol. 690, no. 16, pp. 3714–3719, 2005. View at Publisher · View at Google Scholar · View at Scopus
  18. M. Hussain, M. Hanif, S. Ali et al., “Synthesis, spectroscopic investigation, crystal structure, and biological screening, including antitumor activity, of organotin(IV) derivatives of piperonylic acid,” Turkish Journal of Chemistry, vol. 31, no. 3, pp. 349–361, 2007. View at Google Scholar · View at Scopus
  19. A. Bondi, “Van der waals volumes and radii,” Journal of Physical Chemistry, vol. 68, no. 3, pp. 441–451, 1964. View at Google Scholar · View at Scopus