Electrochemical investigation of the electron-poor/precise ( n=5/6) complexes [Fe 2(CO) n(μ-PR 2)(μ-PR′ 2)] ( n=5, RR′Bu t;n=6, RR′Ph; RBu t, R′Ph; RBu t, R′Cy). EPR study of the radical anion [Fe 2(μ-PBu t2) 2(CO) 5]· .

• Published in: Inorganica Chimica Acta Vol. 217; no. 1; pp. 29 - 32
• Main Authors: van der Linden, J.G.M., Heck, J., Walther, B., Böttcher, H.-C.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 1994; Elsevier Science
• Subjects: Carbonyl and nitrosyl metals; Carbonyl complexes; Chemistry; Dinuclear complexes; Electrochemistry; Exact sciences and technology; Inorganic chemistry and origins of life; Iron complexes; Phosphido complexes; Preparations and properties; Electrochemistry; Carbonyl complexes; Iron complexes; Phosphido complexes; Dinuclear complexes; Cyclic voltammetry; Mu complex; Iron Carbonyl Complexes; Dinuclear complex; Organic ligand; Radical anion; Transition metal Carbonyl Complexes; Anionic complex; EPR spectrum; Electrochemical reaction
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/0020-1693(93)03748-Y

The redox behavior of the bis(phosphido)-bridged diiron carbonyl complexes [Fe 2(CO) n (μ-PR 2)(μ-PR′ 2)] ( n=5, RR′Bu t; n=6, RR′Ph; RBu t, R′Ph; RBu t, R′Cy) has been studied electrochemically at a platinum electrode in THF (0.1 M in Bu 4N[PF 6]). The electron-poor complex ( n=5, RR′Bu t) shows two well-defined reduction steps at −1.34 and −2.35 V assigned to the formation of the radical anion [Fe 2(CO) 5(μ- PBu t 2)] .− and the dianion [Fe 2(CO) 5(μ-PBu t 2) 2] 2−. The uninegative radical ion has been further investigated by EPR spectroscopy. The fluid as well as the rigid solution spectra indicate that the two phosphido bridges are linking the two iron centers in the same manner and that the unpaired electron is metal centered. The electron- precise complexes ( n=6) are reduced at approximately the same potentials (−1.74 to −1.91 V) in two closely spaced one-electron steps. Molecular configurational changes accompany these reductions and make both processes, reduction and re-oxidation, quite slow.