Synthesis, crystal structure and biological activity of thiophene-2-carboxaldehyde thiosemicarbazone and its tin complexes

Thiophene-2-carboxaldehyde thiosemicarbazone, C4H3S-CH=N-NH-C(S)NH2 (tctscH ) obtained by the condensation reaction of thiophene-2-carboxaldehyde with thiosemicarbazide forms SnPh2Cl(tctsc), 1 and SnCl2(tctsc)(2), 2 with SnPh2 Cl2 and SnPhCl3 in 1:1 and 1:2 tin:ligand molar ratios, respectively. The c rystal structure determination shows that in both 1 and 2, tctscH is deprot onated and functions as an anionic bidentate ligand, co-ordinating to the t in atom through its azomethine-Ar and thiol-S atoms. The geometry about the tin atom for complex 1 is distorted trigonal bipyramidal whereas for compl ex 2 is distorted octahedral. Note that dephenylation occurs during the for mation of complex 2. Fungitoxicity and cytotoxicity of the two tin complexe s and tctscH have been evaluated and the biological activity is more remark able in complex 1 in comparison to the other. (C) 1999 Elsevier Science S.A . All rights reserved.