Synthesis, Characterization and In Vitro Antibacterial Studies of Organotin(IV) Complexes with 2-Hydroxyacetophenone-2-methylphenylthiosemicarbazone (H(2)dampt).

Five new organotin(IV) complexes of 2-hydroxyacetophenone-2-methylphenylthiosemicarbazone [H(2)dampt, (1)] with formula [RSnCl(n-1)(dampt)] (where R = Me, n = 2 (2); R = Bu, n = 2 (3); R = Ph, n = 2 (4); R = Me(2), n = 1 (5); R = Ph(2), n = 1 (6)) have been synthesized by direct reaction of H(2)dampt (1) with organotin(IV) chloride(s) in absolute methanol. The ligand (1) and its organotin(IV) complexes (2-6) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, (1)H, (13)C, and (119)Sn NMR spectral studies. H(2)dampt (1) is newly synthesized and has been structurally characterized by X-ray crystallography. Spectroscopic data suggested that H(2)dampt (1) is coordinated to the tin(IV) atom through the thiolate-S, azomethine-N, and phenoxide-O atoms; the coordination number of tin is five. The in vitro antibacterial activity has been evaluated against Staphylococcus aureus, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The screening results have shown that the organotin(IV) complexes (2-6) have better antibacterial activities and have potential as drugs. Furthermore, it has been shown that diphenyltin(IV) derivative (6) exhibits significantly better activity than the other organotin(IV) derivatives (2-5).

{4-Hy-droxy-N'-[(2E,3Z)-4-oxido-4-phenyl-but-3-en-2-yl-idene]benzo-hydra-zidato}diphenyl-tin(IV) methanol monosolvate.

Two independent diphenyl-tin mol-ecules and two independent methanol mol-ecules comprise the asymmetric unit of the title compound, [Sn(C(6)H(5))(2)(C(17)H(14)N(2)O(3))]·CH(3)OH. The Sn atom in each is five-coordinated by a tridentate ligand and the ipso-C atoms of the Sn-bound benzene substituents. The resulting C(2)N(2)O donor set defines a coordination geometry that is inter-mediate between trigonal-bipyramidal (TP) and square-pyramidal (SP), with one mol-ecule slightly tending towards TP and the other slightly towards SP. The mol-ecules differ in terms of the relative orientations of the terminal benzene rings [dihedral angles = 45.71 (18) and 53.98 (17)°] and of the Sn-bound benzene substituents [dihedral angles = 59.5 (2) and 45.77 (18)°, respectively]. The most prominent feature of the crystal packing is the formation of four-mol-ecule aggregates via O-H⋯O and O-H⋯N hydrogen bonds, in which the hy-droxy group is connected to a methanol mol-ecule which, in turn, is linked to a non-coordinating N atom. Weak C-H⋯π inter-actions also occur.

{4-Hy-droxy-N'-[(2E,3Z)-4-oxido-4-phenyl-but-3-en-2-yl-idene]benzo-hydrazidato}dimethyl-tin(IV).

The Sn(IV) atom in the title compound, [Sn(CH(3))(2)(C(17)H(14)N(2)O(3))], is five-coordinated within a C(2)N(2)O donor set provided by the N,N,O-tridentate ligand and two methyl groups. The resultant coordination geometry is inter-mediate between trigonal-bipyramidal and square-pyramidal. In the crystal, supra-molecular zigzag chains propagating along the c- axis direction are mediated by O-H⋯O hydrogen bonds, and weak C-H⋯π inter-actions consolidate the packing.

Di-n-but-yl{4-hydr-oxy-N'-[(2-oxido-1-naphthyl-κO)methyl-ene]benzo-hydrazidato-κO,N'}tin(IV).

The deprotonated Schiff base ligand in the title compound, [Sn(C(4)H(9))(2)(C(18)H(12)N(2)O(3))], O,N,O'-chelates to the Sn atom, which is five-coordinated in a cis-C(2)NO(2)Sn trigonal-bipyramidal environment. The apical sites are occupied by the O atoms [O-Sn-O = 155.2 (2)°]. The hydr-oxy group is a hydrogen-bond donor to the two-coordinate N atom of an adjacent mol-ecule, the hydrogen-bonding inter-action giving rise to a helical chain running along the c axis. The carbon atoms of the butyl chains are equally disordered over two positions.

{4-Hy-droxy-N'-[(2-oxido-1-naphthyl-κO)methyl-idene]benzohydrazidato-κN',O}dimethyl-tin(IV).

Two independent but very similar mol-ecules comprise the asymmetric unit of the title compound, [Sn(CH(3))(2)(C(18)H(12)N(2)O(3))]. Each Sn atom is coordinated by two methyl groups and two O atoms and an N atom from the dinegative tridentate ligand. The resultant C(2)NO(2) donor set defines a coordination geometry inter-mediate between square-pyramidal and trigonal-pyramidal, with a small tendency towards the former. Zigzag chains running along the a axis mediated by O-H⋯N hydrogen bonding characterize the crystal packing. These are connected into layers in the ab plane by a combination of C-H⋯N and π-π [centroid-centroid distances = 3.658 (2) and 3.6740 (18) Å] inter-actions. The layers are connected along the c axis via C-H⋯O inter-actions.