Diorganotin(IV) complexes of pyridoxal thiosemicarbazone:: Synthesis, spectroscopic properties and biological activity

The complexes [SnR2(L)] (R = Me, Et, Bu, Ph; H2L = pyridoxal thiosemicarbazone) have been prepared and characterized. In the light of the spectral properties of the complexes in the solid state (IR, mass, Mossbauer) the bideprotonated thiosemicarbazonato anion is O(phenolic)-, N(3)-, S-bonded to the tin atom which probably has trigonal bipyramidal coordination with N(3) atom and R groups occupying equatorial positions. NMR(H-1, C-13 and Sn-119) data in CDCl3 or DMSO-d(6) suggest that this coordinative picture remains in these solutions. The ethyl, butyl and phenyl derivatives suppress proliferation of Friend erithroleukaemia cells (FLC), Of the pyridoxal thiosemicarbazone complexes so far evaluated, [SnBu2(L)] and [SnPh2(L)] showed the lowest thresholds for inhibition of FLC proliferation. The effects of these compounds on DMSO-induced differentiation of FLC, DNA synthesis and reverse transcriptase were also assayed. (C) 1998 Elsevier Science Inc. All rights reserved.