DIORGANOTIN(IV) DIPEPTIDE COMPLEXES WITH POTENTIAL ANTITUMOR-ACTIVITY

A series of complexes of the dimethyltin(IV) moiety with dipeptides ha s been synthesized. The dipeptides are L-alanyl-L-histidine (H-2AlaHis ), L-methionyl-L-methionine (H-2MetMet), L-glycyl-L-histidine (H-2GlyH is) and L-histidyl-L-glycine (H-2HisGly). The complexes have been char acterized by IR and Sn-119 Mossbauer spectroscopy in the solid state a nd by H-1 NMR in CD3OD and D2O solutions. They consist of monomeric en tities, with the tin atom arranged in a pentacoordinated trigonal bipy ramidal structure. The dipeptides are coordinated via the amino group, deprotonated peptide nitrogen and carboxylate group. Neither imidazol e in histidine-containing dipeptides, nor the thioether group in MetMe t, is involved in bonding; they act as pendant arms on the outer surfa ce of the complexes.