Re(V) and Re(III) Complexes with Sal2phen and Triphenylphosphine: Rearrangement Oxidation and Reduction

摘要

Reactions of Re^V, tetradentate Schiff base complexes with tertiary phosphines have previously yielded both rearranged Re^V and reduced Re^III complexes. To further understand this chemistry, the rigid diiminediphenol (N2O2) Schiff base ligand sal2phen (N,N’-o-phenylenebis(salicylaldimine)) was reacted with (n-Bu4N)[ReOCl4] to yield trans-[ReOCl(sal2phen)] (>1). On reaction with triphenylphosphine (PPh3), a rearranged Re^V product cis-[ReO(PPh3)(sal2phen*)]PF6 (>2), in which one of the imines was reduced to an amine during the reaction, and the reduced Re^III products trans-[ReCl(PPh3)(sal2phen)] (>4) and trans- [Re(PPh3)2(sal2phen)]⁺ (>5) were isolated. Reaction of sal2phen with [ReCl₃(PPh₃)₂(CH₃CN)] resulted in the isolation of [ReCl₂(PPh₃)₂(salphen)] (>3). The compounds were characterized using standard spectroscopic methods, elemental analyses and single crystal X-ray crystallography.