Activation of isocyanate ligands in Ru25+ complexes

The reaction of [Ru2(O2CMe)(DPhF)3(H2O)]BF4 · 0.5CH2Cl2 (DphFN,N′-diphenylformidinate) with sodium cyanate leads to the substitution of the H2O ligand giving Ru2(NCO)(O2CMe)(DPhF)3 (1). In contrast, in the similar reaction of Ru2Cl2(DPhF)3 with NaOCN one of the cyanate groups undergoes the addition of a MeOH molecule leading to the carbamate complex Ru2(NCO)(NH(O)COMe)(DPhF)3 (2). The spectroscopic properties of 1 and 2 are studied. Both complexes are paramagnetic showing the presence of three unpaired electrons with an important zero-field splitting and a small intermolecular antiferromagnetic interaction. The crystal structures of 1 · 3CHCl3 and 2 · C7H8 · 0.5MeOH are also reported. Compound 2 represents the first example of a ruthenium paddlewheel compound with a carbamate ligand.