The present work stems from our interest in the synthesis, characterization, and antibacterial evaluation of organosilicon(IV) complexes of a class of amino-acid-based Schiff base which have been prepared by the interaction of ethoxytrimethylsilane with the Schiff bases (N OH) in 1？:？1 molar ratio. These complexes have been characterized by elemental analysis, molar conductance, and spectroscopic studies including electronic IR and NMR (1H, 13C, and 29Si) spectroscopy. The analytical and spectral data suggest trigonal bipyramidal geometry around the silicon atom in the resulting complexes. The ligands and their organosilicon complexes have also been evaluated for in vitro antimicrobial activity against bacteria (Bacillus cereus, Nocardia spp., E. aerogenes, Escherichia coli, Klebsiella spp., and Staphylococcus spp.). The complexes were found to be more potent as compared to the ligands. 1. Introduction In the last decade, coordination and organometallic compounds of biologically active ligands [1–3] have received much attention. However, it is notable that the biological activity of Schiff bases was significantly enhanced on chelation. It has been reported that chelation is the cause and cure of many diseases including cancer. Schiff base complexes [4–7] have found antibacterial, antifungal, anticancer, tuberculostatic, and herbicidal activities [8–12]. The current research dealing with metal complexes of heteronuclear Schiff bases has expanded enormously and includes diversified subjects comprising their various aspects in biocoordination and bioinorganic chemistry. It is known that the presence of metal ions bonded to biologically active compounds may enhance their activity [13–16]. Heteronuclear Schiff base complexes have found applications as magnetic materials, catalysts and in the field of bioengineering [17, 18]. Organosilicon compounds of nitrogen and sulphur containing ligands are well known for their anticarcinogenic, antibacterial, tuberculostatic, antifungal, insecticidal, and acaricidal activities [19–22]. The interest in organosilicon(IV) compounds [23–25] is due to their versatile applicability in the pharmaceutical industries. Generally, organosilicon compounds seem to owe their antitumour properties to the immune-defensive system of the organism. The medical applications and effectiveness of the silatranes in the treatment of wounds and tumours are thought to be related to the role of silicon in the growth of epithelial and connective tissues and hair, where their function is to impart strength, elasticity, and impermeability to water
References
[1]
M. Iqbal, S. Ali, N. Muhammad, M. Parvez, P. Langer, and A. Villinger, “Synthesis, characterization, crystal structures and electrochemical studies of organotin(IV) carboxylates,” Journal of Organometallic Chemistry, vol. 723, pp. 214–223, 2013.
[2]
D. Karmakar, M. Fleck, R. Saha, M. Layek, S. Kumar, and D. Bandyopadhyay, “Synthesis and crystal structure of a group of phenoxo-bridged heterodinuclear [NiIIHgII] Schiff base complexes,” Polyhedron, vol. 49, pp. 93–99, 2013.
[3]
A. R. Parent, S. Vedachalam, C. P. Landee, and M. M. Turnbull, “Syntheses, crystal structures and magnetic properties of heteronuclear bimetallic compounds of [Cu(pdc)2][M(H2O)5] · 2H2O [M=Ni(II), Co(II), Mn(II); pdc = 2,6-pyridinedicarboxylato],” Journal of Coordination Chemistry, vol. 61, no. 1, pp. 93–108, 2008.
[4]
A. A. Khandar, V. T. Yilmaz, F. Costantino, S. Gumus, S. A. Hosseini-Yazdi, and G. Mahmoudi, “Syntheses, studies and crystal structures of coordination polymers and dinuclear complexes of mercury(II) halides and thiocyanate with a symmetrical Schiff base ligand,” Inorganica Chimica Acta, vol. 394, pp. 36–44, 2013.
[5]
A. Azadmeher, M. M. Amini, N. Hadipour, H. R. Khavasi, H.-K. Fun, and C.-J. Chen, “Synthesis and structural characterization of diorganotin(IV) complexes with 2,6-pyridinedicarboxylic acid,” Applied Organometallic Chemistry, vol. 22, no. 1, pp. 19–24, 2008.
[6]
C. J. Dhanaraj and M. S. Nair, “Synthesis, characterization, and antimicrobial studies of some Schiff-base metal(II) complexes,” Journal of Coordination Chemistry, vol. 62, no. 24, pp. 4018–4028, 2009.
[7]
L. Puccetti, G. Fasolis, D. Vullo, Z. H. Chohan, A. Scozzafava, and C. T. Supuran, “Carbonic anhydrase inhibitors. Inhibition of cytosolic/tumor-associated carbonic anhydrase isozymes I, II, IX, and XII with Schiff's bases incorporating chromone and aromatic sulfonamide moieties, and their zinc complexes,” Bioorganic and Medicinal Chemistry Letters, vol. 15, no. 12, pp. 3096–3101, 2005.
[8]
M. N. Patel, C. R. Patel, and H. N. Joshi, “Synthesis, characterization and biological studies of mononuclear copper(II) complexes with ciprofloxacin and N, O donor ligands,” Inorganic Chemistry Communications, vol. 27, pp. 51–55, 2013.
[9]
M. Ul-Hassan, Z. H. Chohan, A. Scozzafava, and C. T. Supuran, “Carbonic anhydrase inhibitors: Schiff's bases of aromatic and heterocyclic sulfonamides and their metal complexes,” Journal of Enzyme Inhibition and Medicinal Chemistry, vol. 19, no. 3, pp. 263–267, 2004.
[10]
H.-Y. Zhang, J. Lei, Y.-Y. Chen, Q.-A. Wu, Y.-S. Zhang, and L.-H. Gao, “Synthesis of the N, -bis(ferrocenylmethylene)-1,2-phenylenediamine schiff base and six rare earth metal complexes,” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, vol. 31, no. 6, pp. 973–981, 2001.
[11]
J. Zuo, C. Bi, Y. Fan et al., “Cellular and computational studies of proteasome inhibition and apoptosis induction in human cancer cells by amino acid Schiff base-copper complexes,” Journal of Inorganic Biochemistry, vol. 118, pp. 83–93, 2013.
[12]
H. L. Singh, J. B. Singh, and K. P. Sharma, “Synthetic, structural, and antimicrobial studies of organotin(IV) complexes of semicarbazone, thiosemicarbazone derived from 4-hydroxy-3-methoxybenzaldehyde,” Research on Chemical Intermediates, vol. 38, no. 1, pp. 53–65, 2012.
[13]
M. Sharma, H. L. Singh, S. Varshney, P. Sharma, and A. K. Varshney, “Some new coordination compounds of organosilicon(IV) with schiff bases of sulpha drugs,” Phosphorus, Sulfur and Silicon and the Related Elements, vol. 178, no. 4, pp. 811–819, 2003.
[14]
K. Singh, D. Dharampal, and V. Parkash, “Synthesis, spectroscopic studies, and in vitro antifungal activity of organosilicon(IV) and organotin(IV) complexes of 4-amino-5-mercapto-3-methyl-S-triazole Schiff bases,” Phosphorus, Sulfur and Silicon and the Related Elements, vol. 183, no. 11, pp. 2784–2794, 2008.
[15]
A. Doddi, J. V. Kingston, V. Ramkumar, M. Suzuki, M. Hojo, and M. N. S. Rao, “Synthesis and characterization of dianionic hexacoordinate silicon(iv) complexes of substituted catechols, flavones, and fluorone: X-ray crystal structures of [(n-C3H7)2NH2]2[(Cl4C6O2)3Si] · 3 CH3CN and [(n-C3H7)2NH2]2[(Br4C6O2)3Si] · 2 (CH3)2SO,” Phosphorus, Sulfur and Silicon and the Related Elements, vol. 187, no. 3, pp. 343–356, 2012.
[16]
G. Eng, D. Whalen, P. Musingarimi, J. Tierney, and M. DeRosa, “Fungicidal and spectral studies of some triphenyltin compounds,” Applied Organometallic Chemistry, vol. 12, no. 1, pp. 25–30, 1998.
[17]
Z. Moradi-Shoeili, D. M. Boghaei, M. Amini, M. Bagherzadeh, and B. Notash, “New molybdenum(VI) complex with ONS-donor thiosemicarbazone ligand: preparation, structural characterization, and catalytic applications in olefin epoxidation,” Inorganic Chemistry Communications, vol. 27, pp. 26–30, 2013.
[18]
M. M. Tamizh, B. F. T. Cooper, C. L. B. Macdonald, and R. Karvembu, “Palladium(II) complexes with salicylideneimine based tridentate ligand and triphenylphosphine: synthesis, structure and catalytic activity in Suzuki-Miyaura cross coupling reactions,” Inorganica Chimica Acta, vol. 394, pp. 391–400, 2013.
[19]
J. Devii, N. Batra, and S. Kumar, “Synthesis and characterization of novel Organosilicon (IV) complexes with pyridine dicarboxylic acid and Mercapto pyridine carboxylic acid,” International Journal of Research in Chemistry and Environment, vol. 1, no. 2, pp. 50–56, 2011.
[20]
M. Nath, S. Goyal, and S. Goyal, “Synthesis, spectral and biological studies of organosilicon(IV) complexes of Schiff bases derived from amino acids,” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, vol. 30, no. 9, pp. 1791–1804, 2000.
[21]
R. Malhotra, M. S. Malik, J. P. Singh, and K. S. Dhindsa, “Synthesis, characterization, and microbiocidal activity of α-methyl-(2-thiophenomethylene) aryloxyacetic acid hydrazides and their metal complexes,” Journal of Inorganic Biochemistry, vol. 45, no. 4, pp. 269–275, 1992.
[22]
T. M. Aminabhavi, N. S. Biradar, S. B. Patil, D. E. Hoffman, and V. N. Biradar, “Synthesis and characterization of biologically active organosilicon and organotin complexes of phenylglycyl hydrazones,” Inorganica Chimica Acta, vol. 135, no. 2, pp. 139–143, 1987.
[23]
S. Sonika, M. Meenakshi, and R. Malhotra, “Novel bioactive thio- and semicarbazide ligands and their organosilicon (IV) complexes,” Phosphorus, Sulfur and Silicon and the Related Elements, vol. 185, no. 9, pp. 1875–1885, 2010.
[24]
M. Jain and R. V. Singh, “Synthesis, characterization, and biotoxicity of donor sulphonamide imine silicon(IV) complexes,” Bioinorganic Chemistry and Applications, vol. 2006, Article ID 13743, 10 pages, 2006.
[25]
M. Nath and S. Goyal, “Synthesis, characteristic spectral studies, and in vitro antimicrobial activity of organosilicon(IV) derivatives of N-benzoylamino acids,” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, vol. 34, no. 1, pp. 187–210, 2004.
[26]
M. G. Voronkov and V. P. Baryshok, Silatranes for Medicine and Agriculture, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia, 2005.
[27]
H. L. Singh and J. B. Singh, “Synthesis and characterization of new lead(II) complexes of Schiff bases derived from amino acids,” Research on Chemical Intermediates, vol. 39, pp. 1997–2009, 2013.
[28]
H. L. Singh and J. B. Singh, “Synthesis, spectroscopic and antimicrobial studies of lead(II) complexes of Schiff bases derived from amino acids and isatins,” Spectroscopy Letters, vol. 46, pp. 286–296, 2013.
[29]
H. L. Singh and J. B. Singh, “Synthesis, spectral, 3D molecular modeling and antibacterial studies of dibutyltin (IV) Schiff base complexes derived from substituted isatin and amino acids,” Natural Science, vol. 4, no. 3, pp. 170–178, 2012.
[30]
M. Jain, S. Gaur, V. P. Singh, and R. V. Singh, “Organosilicon(IV) and organotin(IV) complexes as biocides and nematicides: synthetic, spectroscopic and biological studies of N∩N donor sulfonamide imine and its chelates,” Applied Organometallic Chemistry, vol. 18, no. 2, pp. 73–82, 2004.
[31]
M. Nath and S. Goyal, “Triorganosilicon(IV) derivatives of aminoacids,” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, vol. 32, no. 7, p. 1205, 2002.
[32]
M. Jain, S. Gaur, S. C. Diwedi, S. C. Joshi, R. V. Singh, and A. Bansal, “Nematicidal, insecticidal, antifertility, antifungal and antibacterial activities of salicylanilide sulphathiazole and its manganese, silicon and tin complexes,” Phosphorus, Sulfur and Silicon and the Related Elements, vol. 179, no. 8, pp. 1517–1537, 2004.
[33]
X. Zhang, W. H. Li, H. Z. Jia, S. F. Weng, and J. G. Wu, Proceedings of the Twelfth International Conference on Fourier Transform Spectroscopy, Waseda University, Tokyo, Japan, 1999.
[34]
M. S. Singh and P. K. Singh, “Hexa-coordinate silicon complexes, syntheis and chacterization,” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, vol. 33, no. 2, p. 271, 2003.
[35]
M. D. Raju, “Nitrogen, oxygen bonded hetrocyclic organosilicon(IV) derivatives of a new Schiff base: synthesis and spectral aspects,” Journal of Current Chemical & Pharmaceutical Sciences, vol. 1, no. 1, pp. 9–14, 2011.
[36]
R. Malhotra, J. Mehta, and J. K. Puri, “Heterobimetallic complexes containing iron (II) and hexa-coordinated organosilicon,” Central European Journal of Chemistry, vol. 5, no. 3, pp. 858–867, 2007.
[37]
M. Sharma, B. Khungar, S. Varshney, H. L. Singh, U. D. Tripaathi, and A. K. Varshney, “Coordination behavior of biologically active schiff bases of amino acids towards silicon(IV) ion,” Phosphorus, Sulfur and Silicon and Related Elements, vol. 174, pp. 239–246, 2001.
[38]
J. H. Small, K. J. Shea, D. A. Loy, and G. M. Jamison, ACS Symposium Series 585, American Chemical Society, Washington, DC, USA, 1995.
[39]
K. Singh, P. Puri, and D. Dharampal, “Synthesis and spectroscopic studies of some new organometallic chelates derived from bidentate ligands,” Turkish Journal of Chemistry, vol. 34, no. 4, pp. 499–507, 2010.
[40]
G. Tweedy, “Possible mechanism for reduction of elemental sulfur by monilinia fructicola,” Phytopathology, vol. 55, pp. 910–914, 1964.
[41]
B. Geeta, K. Shravankumar, P. M. Reddy et al., “Binuclear cobalt(II), nickel(II), copper(II) and palladium(II) complexes of a new Schiff-base as ligand: synthesis, structural characterization, and antibacterial activity,” Spectrochimica Acta Part A, vol. 77, no. 4, pp. 911–915, 2010.
[42]
A. W. Varnes, R. B. Dodson, and E. L. Wehry, “Interactions of transition-metal ions with photoexcited states of flavins. Fluorescence quenching studies,” Journal of the American Chemical Society, vol. 94, no. 3, pp. 946–950, 1972.
[43]
E. Abele, “Activation of silicon bonds by fluoride ion in the organic synthesis in the new millennium: a review,” Main Group Metal Chemistry, vol. 28, no. 2, pp. 45–69, 2005.
