Syntheses, structures and redox properties of {Os(PPh3)2Cp}2{μ-(CC)x} (x = 2, 3, 4): Comparisons with the Ru analogues

Abstract The syntheses of {Os(PPh 3 ) 2 Cp} 2 {μ-(C C) x } ( x  = 2, 3, 4) from reactions between OsBr(PPh 3 ) 2 Cp* and Me 3 Si(C C) x SiMe 3 in the presence of KF/NaBPh 4 are described. The molecular structure of x  = 3 has been determined by a single-crystal XRD study. Comparison of the redox properties of {M(PPh 3 ) 2 Cp} 2 {μ-(C C) x } (M = Ru, Os) shows that the oxidation potentials of the osmium complexes are invariably lower (by between 0.16 and 0.64 V) than those of the Ru analogues.