Multinuclear (Sn/Pd) complexes with disodium 2,2′-(dithiocarboxyazanediyl)diacetate hydrate; Synthesis, characterization and biological activities

Abstract

Bimetallic chlorodi-/triorganotin(IV) derivatives of general formulas R 2 (H 2 O)SnLCSSSn(Cl)R 2 (R=Me: 1; Ph: 2) and R 3 Sn(Na)LCSSSnR 3 ·H 2 O (R=Bu: 3; Ph: 4) were prepared by reaction of iminodiacetic acid disodium salt hydrate (Na 2 LH) with CS 2 and R 2 SnCl 2 /R 3 SnCl in methanol. The reaction between Na 2 LH, CS 2 , and PdCl 2 produced [Na 2 LCSS] 2 Pd·2H 2 O (5) which was treated with R 3 SnCl to synthesize the heterobimetallic derivatives [R 3 Sn(Na)LCSS] 2 Pd·2H 2 O (R=Me: 6; Ph: 7). The complexes were characterized by microanalysis, spectroscopic, and thermogravimetric analyses. Elemental analysis data, mass fragmentation, and thermal degradation patterns supported the molecular composition of the complexes. FT-IR data indicated monodentate binding of carboxylate while a chelating coordination mode of the dithiocarboxylate was verified in the solid state. A five-coordinate tin(IV) was demonstrated in the solid state. In solution, a tetrahedral/trigonal bipyramidal configuration around Sn(IV) and a square planar geometry of Pd(II) was indicated by multinuclear NMR ( 1 H and 13 C) and UV-visible studies. The Pd(II) derivatives showed interaction with salmon sperm-DNA and caused an inhibition of alkaline phosphatase (ALPs). The antibacterial/antifungal potential of the coordination products varied with the nature of incorporated metal and a substitution pattern at tin(IV); the palladium metallation decreased the antimicrobial activities. The triorganotin(IV) products exhibited more powerful action against bacteria/fungi as compared to their diorganotin(IV) counterparts. The complexes displayed sufficiently lower hemolytic effects in vitro as compared to triton X-100 and slightly higher than PBS.