Preparation, Properties, and Reactions of Five-Coordinate Re(VII) Dioxo and Diimido Complexes

Abstract

The reactions of aliphatic and aromatic 1,2-diamines, diols, and dithiols with CH3ReO3 (1), {CH3Re(NAr)2O}2 (2, Ar = 2,6-diisopropylphenyl), and {CH3Re(NAr)2S}2 (3) have been studied. Two of the reaction products, [CH3Re(O)2{1,2-(NH)2C6H4}]2{μ-1,2-(NH2)2C6H4} (4a‘) and CH3Re(NAr)2(SCH2CH2S) (5c), have been structurally characterized. The former is a binuclear species in which each rhenium is six-coordinate with a pseudo-octahedral structure. The bridging phenylenediamine ligand can be replaced by pyridine and its derivatives. Unlike the known catecholato complex CH3ReVII(O)2(1,2-O2C6H4)(Py), the ReV-benzoquinonediimine resonance form contributes noticeably to the overall structure of 4a‘. The five-coordinate diimido complex 5c does not interact with coordinating ligands such as pyridines. The initial reactions of 2 with catechol and ethylene glycol lead to CH3Re(NAr)2(1,2-O2C6H4) (5b‘) and CH3Re(NAr)2(OCH2CH2O) (5b), respectively. Further hydrolysis of 5b affords CH3Re(NAr)(O)(OCH2CH2O) (6b). Compound 3, ...