Properties of Pt(II) complexes containing both a pyridyl N–N chelate ligand having a long alkyl chain and a sulfur-rich dithiolate ligand and their molecular interactions in the solid state

Abstract

Reactions of PtCl 2( N-alkyl-pyridine-2-carbaldimine) [alkyl = C 10H 21 and C 16H 33; C 10-pya and C 16-pya] with Na 2C 3S 5 [C 3S 5 2− = 4,5-disulfanyl-1,3-dithiole-2-thionate(2-)] or Na 2C 8H 4S 8 [C 8H 4S 8 2− = 2-{(4,5-ethylenedithio)-1,3-dithiole-2-ylidene}-1,3-dithiole-4,5-dithiolate(2-)] in methanol or ethanol afforded Pt(C 3S 5)(C 10-pya), Pt(C 3S 5)(C 16-pya) and Pt(C 8H 4S 8)(C 10-pya). Their electronic absorption spectra exhibited mixed metal/ligand-to-ligand charge transfer bands in the region of 570–780 nm in solution which are sensitive to a solvent. The C 3S 5 complexes show almost reversible redox waves around +0.62 V (versus SCE) and the C 8H 4S 8 complex at +0.17 and +0.51 V (versus SCE). They were reacted with excess amounts of iodine to afford [Pt(C 3S 5)(C 10-pya and C 16-pya)] (I 3) 0.7, [Pt(C 3S 5)(C 10-pya)] (I 3) 1.1 and [Pt(C 8H 4S 8)(C 10-pya)] (I 3) 1.5, which exhibited electrical conductivities of 1 × (10 −7 − 10 −3) S cm −1 measured for compacted pellets at room temperature. Molecular interactions of the complexes and their oxidized species in the solid state are discussed.