The crucial role of the diphosphine heteroatom X in the stereochemistry and stabilization of the substitution-inert [M(N)(PXP)]2+ metal fragments (M = Tc, Re; PXP = diphosphine ligand)

The nature of the heteroatom X incorporated in the five-membered PXP-diphosphine bridging chain was found to play a primary unit role both in the overall stability and in the stereochemical arrangement of nitrido-containing (M(N)(PXP))2+ metal fragments (M ) Tc, Re). Thus, by mixing PXP ligands with labile (Re(N)Cl4)- and Tc(N)Cl2- (PPh3)2 nitrido precursors in CH2Cl2/MeOH mixtures, a series of neutral M(N)Cl2(PXP) complexes ( M =Tc, 1-5; M= Re, 8, 9) was collected. .....