A series of complexes of the phosphorus-based TTF ligando-P2 with the metal ions FeII, CoII, NiII, PdII, PtII, and AgI

Abstract

Reactions of 3,4-dimethyl-3′,4′-bis(diphenylphosphino)tetrathiafulvalene, o-P2, with [BF₄]⁻ salts of Fe(II), Co(II), Ni(II), Pd(II), and Pt(II) yield complexes of general formula [M(o-P2)₂][BF₄]₂. Similar reactions between o-P2 and AgSbF₆ or AgPF₆ produced the salts [Ag(o-P2)₂][X] where X = [SbF₆]⁻ or [PF₆]⁻. The resulting compounds were fully characterized by ¹H and ³¹P{¹H} NMR, infrared and electronic absorption spectroscopies, cyclic voltammetry, FAB-MS and single-crystal X-ray diffraction. The paramagnetic Co(II) compound exhibits an S = 3/2 state with large spin–orbit coupling contribution at higher temperatures and an effective S′ = 1/2 state below 20 K. Electrochemical studies of the compounds indicate that the two functionalized TTF ligands are not in electronic communication and that they essentially behave as isolated redox centers.