Synthesis, characterization, cytotoxic activity and crystal structures of tri- and di-organotin(IV) complexes constructed from the b-{[(E)-1-(2- hydroxyaryl)alkylidene]amino}propionate and b-{[(2Z)-(3-hydroxy-1- methyl-2-butenylidene)]amino}propionate skeletons

Reactions of potassium b-{[(E)-1-(2-hydroxyaryl)alkylidene]amino}propionates (LHK-LHK) and potassium b-{[(2Z)-(3-hydroxy1-methyl-2butenylidene)]amino}propionate (LHK) with R3SnCl (R = Ph and Bu) and Bu2SnCl2 yielded complexes of composition Ph3SnL H (1), Ph3SnL H (2), Ph3SnL H (3), Bu3SnL H (4), and {[Bu2Sn(L H)]2O}2 (5) and {[ Bu2Sn(L H)]2O}2 (6), respectively. These complexes have been characterized by H, C, Sn NMR, ESI-MS, IR and Sn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of 1, 4, 5 and 6 were determined. In the solid state, compound 1 is a one-dimensional polymer built from SnPh3 moieties bridged by single carboxylate ligands, but two alternating modes of bridging are present along the polymeric chain. Compound 4 is also a one-dimensional polymer built from SnBu3 moieties bridged by the two carboxylate O-atoms of a single ligand, but only one mode of bridging is present. Di-n-butyltin compounds 5 and 6 are centrosymmetric tetranuclear bis(dicarboxylatotetrabutyldistannoxane) complexes containing a planar Sn4O2 core in which two l3-oxo O-atoms connect an Sn2O2 ring to two exocyclic Sn-atoms. The four carboxylate ligands display two different modes of coordination where both modes involve bridging of two Sn-atoms. The solution structures were predicted by Sn NMR spectroscopy. The in vitro cytotoxic activity of compound 5 against WIDR, M19 MEL, A498, IGROV, H226, MCF7 and EVSA-T human tumor cell lines is reported. 2005 Elsevier B.V. All rights reserved.