A mixed valence zinc dithiolene system with spectator metal and reactor ligands
Dithiolene, Dithione, Donor-acceptor system, Ligand to ligand charge transfer, Zinc
Neutral complexes of zinc with N,N′-diisopropylpiperazine-2,3-dithione (iPr2Dt0) and N,N′-dimethylpiperazine-2,3-dithione (Me2Dt0) with chloride or maleonitriledithiolate (mnt2-) as coligands have been synthesized and characterized. The molecular structures of these zinc complexes have been determined using single crystal X-ray diffractometry. Complexes recrystallize in monoclinic P type systems with zinc adopting a distorted tetrahedral geometry. Two zinc complexes with mixed-valence dithiolene ligands exhibit ligand-to-ligand charge transfer bands. Optimized geometries, molecular vibrations and electronic structures of charge-transfer complexes were calculated using density functional theory (B3LYP/6-311G+(d,p) level). Redox orbitals are shown to be almost exclusively ligand in nature, with a HOMO based heavily on the electron-rich maleonitriledithiolate ligand, and a LUMO comprised mostly of the electron-deficient dithione ligand. Charge transfer is thus believed to proceed from dithiolate HOMO to dithione LUMO, showing ligand-to-ligand redox interplay across a d10 metal.
Ratvasky, S., Mogesa, B., Van Stipdonk, M., & Basu, P. (2016). A mixed valence zinc dithiolene system with spectator metal and reactor ligands. Polyhedron, 114, 370-377. https://doi.org/10.1016/j.poly.2016.01.023