Pharmachemie BV

Three polynuclear organotin(IV) derivatives of composition [n-Bu₃Sn(HL)]_n1, [Ph₃Sn(HL)]_n2and [n-Bu₂Sn(HL)₂]₂3were synthesized by reacting 2-((E)-(4-hydroxy-3-((E)-((4-(methoxycarbonyl)phenyl)imino)methyl)phenyl)diazenyl)benzoic acid (H′HL) with (n-Bu₃Sn)₂O, Ph₃SnOH andn-Bu₂SnO, respectively. The structures1–3were fully characterized by elemental analysis, IR and NMR (¹H,¹³C, and¹¹⁹Sn),¹¹⁹Sn Mössbauer spectroscopy, and additionally, the molecular and crystal structures of1–3and its pro-ligand (H′HL) were established by single-crystal X-ray diffraction analysis. The tributyltin(IV) complex1is a one-dimensional coordination polymer, in which the azo ligand bridges adjacent Sn(IV) centres solelyviathe two carboxylate O-atoms. The hydroxy H atom forms an intramolecular O–H···N hydrogen bond with the imine N-atom, as observed in the crystal structure ofH′ΗL. The triphenyltin(IV) complex2is also a one-dimensional coordination polymer, but in this case the azo ligand bridges adjacent Sn(IV) centresviaits carboxylate group and the deprotonated phenol O-atom. Unlike in1, the phenol H-atom has migrated to the imine N-atom, to give a zwitterionic form of the azo ligand. The tin centers in1and2are pentacoordinated and reveal a distortedtrans-R₃SnO₂trigonal-bipyramidal environment. The dibutyltin(IV) complex3crystallizes as discrete centrosymmetric dinuclear entities where the unique Sn(IV) center is heptacoordinated in a distorted pentagonal bipyramid coordination geometry.In vitrocytotoxicity studies of compound1was performed and compared with2across a panel of human tumor cell lines,viz., A498, EVSA-T, H226, IGROV, M19 MEL, MCF-7 and WIDR and the results were compared with the data of six clinically used anticancer drugs. Compounds1and2are potent cytotoxic agents and warrant further investigation as potential anticancer agents.