117201-67-9Relevant academic research and scientific papers
Redox and acid-base chemistry of [Au2Re2(H)6(PPh3) 6]PF6 and related cluster compounds
Boyle, Paul D.,Boyd, David C.,Mueting, Ann M.,Pignolet, Louis H.
, p. 4424 - 4429 (2008/10/08)
The redox behavior of [Au2Re2(H)6(PPh3) 6]PF6 (1(PF6)) has been investigated by both cyclic voltammetry and chemical redox reactions. The role of the nitrate ion in the synthesis of 1 from Re2(H)8(PPh3)4 and Au(PPh3)NO3 has also been investigated, and NO3- has been found to cause the oxidation of the intermediate [Au2Re2(H)8(PPh3)6] 2+ (4). This has been confirmed by the reaction of 4(BF4)2, prepared by an alternate route, with (PPN)NO3 to yield 1(BF4). Complex 1 exhibits two quasi-reversible waves in the cyclic voltammogram, an oxidation of E1/2 = 67 mV (versus Ag/AgCl) giving rise to [Au2Re2(H)6(PPh3)6] 2+ (2) and a reduction at E1/2 = -713 mV to yield Au2Re2(H)6(PPh3)6 (3). Spectroelectrochemical experiments on the oxidation show the clean conversion of 1 to 2. Complex 2 may be prepared by reaction of 1 with ferrocenium, and 3 may be prepared by reaction of 1 with either sodium naphthalenide or potassium tert-butoxide. Complex 2 may be reduced back to 1 by reaction with H2, and 3 may be oxidized back to 1 by reaction with (PPN)NO3 (PPN = (μ-nitrido)bis(triphenylphosphorus)(1+)) in the presence of HBF4·Et2O. Compound 3 also reacts with HBF4·Et2O to yield 4. Re2(H)8(PPh3)4 has been found to react with [(Ph3PAu)3O]BF4 to give [Au2Re2(H)7(PPh3) 6]BF4 (5(BF4)) in good yield. This compound has been found to undergo a quasi-reversible oxidation by cyclic voltammetry, E1/2 = 148 mV. Spectroelectrochemical studies of the oxidation show the clean conversion to the oxidized species, [Au2Re2(H)7(PPh3)6] 2+. This species may be prepared by the reaction of 5 with ferrocenium and may be rereduced by the reaction with H2.
