A re-examination of the reaction between 1,1′-bis(diphenylphosphino)ferrocene (dppf) diselenide and [Ru3(CO)12]. Electrochemical behaviour of the isomeric nido-clusters [Ru3(μ3-Se)2(dppf)(CO)7] and [Ru3(μ3-Se)2(μ-dppf)(CO)7] and crystal structure of [Ru3S

The reactions of 1,1′-bis(diphenylphosphino)ferrocene diselenide (dppfSe2) with [Ru3(CO)12] at 60 and 110 °C afford, respectively, the two isomeric nido-clusters [Ru3(μ3-Se)2(dppf)(CO)7] (2) and [Ru3(μ3-Se)2(CO)7(μ-dppf)] (3) which contain dppf as chelating and bridging ligand, respectively. The chelated derivative 2, attainable under kinetic control, can be converted to the more stable bridged cluster 3 by thermal treatment in toluene solution. Moreover the cluster [Ru3Se{μ-P(Ph)C5H4FeC5H4PPh2}(μ-OCPh)(CO)6] (4) was isolated as a minor product. Its cluster core consists of a metal triangle capped by a selenium atom and bridged on two sides, respectively, by a phosphido ligand and by a benzoyl group both deriving from multiple fragmentation of dppf diselenide and migratory insertion of a Ph ring into a CO ligand. Isomers 2 and 3 present different electrochemical behaviour, the bridged one giving a more complicated voltammetric pattern.