Preparation and properties of [Pt^II(SS)(NN)]-type complexes and their iodine-doped analogues

Summary

Complexes of the general formula [Pt(SS) (NN)], where SS is dddt (5,6-dihydro-1,4-dithiin-2,3-dithiolate) or pddt (6,7-dihydro-5H-1,4-dithiepin-2,3-dithiolate) and NN is bipy (2,2′-bipyridine) or phen (1,10-phenanthroline), were prepared by the reaction of [PtCl₂(NN)] with dithiolate ligands. The¹H-n.m.r. spectra shows upfield shifts in the bipy or phen signals upon substitution of the chlorides in [PtCl₂(bipy)] or [PtCl₂(phen)] by dddt or pddt. The u.v.-vis. spectra exhibits intense intramolecular ligand-to-ligand charge transfer bands ca. 600 nm. Cyclic voltammograms show a reversible oxidation step, assigned to [Pt(SS) (NN)]⁰/[Pt(SS)(NN)]⁺. When the complexes were partially oxidized by I₂, two broad e.s.r. signals atg∥ = 1.91,g⊥ = 2.02 appeared. Raman spectra show the presence of I ⁻₃ and I^5/− in the iodine-doped complexes. The electrical conductivities of the neutral mixed ligand complexes (10⁻⁹-10⁻¹⁰S cm⁻¹) are raised to 10⁻⁷–10⁻⁸S cm⁻¹ by I₂ doping.