Synthesis, X-ray diffraction structure, and redox chemistry of Re2(CO)8(bmf)
Source: Journal of Chemical Crystallography, Volume 35, Number 9, September 2005 , pp. 709-716(8)
Abstract:The reaction between Re2(CO)8(-H)(-1,2-CH=CHBu) (1) and the diphosphine ligand 3,4-bis(diphenylphosphino)-5-methoxy-2(5H)-furanone (bmf) proceeds at room temperature to give the dirhenium compound Re2(CO)8(bmf) (2) as the sole observable product in good yield after 24 h. Re2(CO)8(bmf) has been isolated and characterized in solution by IR and NMR (31P and 1H) spectroscopies, and the molecular structure of Re2(CO)8(bmf) has been determined by X-ray crystallography. The solid-state structure of 2 reveals a bridging bmf ligand that spans the Re=Re vector and whose Re(CO)4 moieties exhibit a staggered rotational geometry about the equatorial phosphine and CO groups. The redox properties of Re2(CO)8(bmf) have been explored by cyclic voltammetry in CH2Cl2, where an irreversible oxidation was found at Epa = 1.04 V, along with a reversible, one-electron reduction at E1/2 = −1.23 V. These redox couples have been assigned to the oxidation of the Re=Re bond and electron occupation of the ∗ system associated with the furanone ring of Re2(CO)8(bmf), respectively. The electrochemical behavior is discussed relative to the nature of the HOMO and LUMO levels in the model compound Re2(CO)8(H4-bmf), whose HOMO and LUMO compositions have been established by extended Hückel MO calculations. The electrochemistry and MO data from Re2(CO)8(bmf) are contrasted with the structurally similar dirhenium compound Re2(CO)8(bma).
Document Type: Research Article
Affiliations: 1: Department of Chemistry, University of Houston, Houston, Texas, 77204, Email: email@example.com 2: Department of Chemistry, University of Houston, Houston, Texas, 77204, 3: Department of Chemistry, University of North Texas, Denton, Texas, 76203, Email: firstname.lastname@example.org
Publication date: September 2005