Synthesis and spectroscopic and thermogravimetric characterization of heterobimetallic complexes with Sn(IV) and Pd(II); DNA binding, alkaline phosphatase inhibition and biological activity studies

Abstract

<div><p>A palladium complex, [KLCSS]₂Pd (<b>1</b>), has been prepared by stirring sarcosine (HLH), KOH and CS₂ in methanol and subsequently treating with palladium(II) chloride. Six heterobimetallic derivatives of the type [R₂(Cl)SnLCS₂]₂Pd (R = Me: <b>2</b>; Bu: <b>3</b>; Ph: <b>4</b>)/[R₃SnLCS₂]₂Pd (R = Me: <b>5</b>; Bu: <b>6</b>; Ph: <b>7</b>) were also synthesized by stirring sarcosine (HLH) with KOH and CS₂ in methanol followed by an addition of R₂SnCl₂/R₃SnCl and then PdCl₂. FT-IR data demonstrated bidentate binding of dithiocarbamate and carboxylate with four- and five-coordinate environments around Pd(II) and Sn(IV) centers, respectively, in the solid state. UV–visible studies verified the square planar arrangement around Pd(II) in solution. The magnitude of ²<i>J</i>(¹¹⁹Sn-¹H) demonstrates a distorted trigonal bipyramidal geometry around tin(IV) in solution. Elemental analysis (C, H, N, and S), mass spectroscopic (EI-MS and ESI), and thermogravimetric analyses verified the chemical composition of products. Complexes <b>1–7</b> exhibited interaction with salmon sperm DNA (SS-DNA). The palladium complex <b>1</b> had shown higher potential to bind with SS-DNA and to inhibit the alkaline phosphatase when compared to the heteronuclear products (<b>2–7</b>). However, the antifungal/antibacterial activities of the bimetallic complexes (<b>2–7</b>) were significantly higher than the palladated derivative <b>1</b>. The <i>in vitro</i> hemolytic activity investigations on human red blood cells showed that bimetallic derivative <b>2</b> with chlorodimethyltin(IV) exhibited the lowest hemolytic effects (17.55%), while <b>5</b> having trimethyltin(IV) center exhibited the highest hemolytic activity (78.64%).</p></div