Ruthenium Complexes Bearing N-H Acidic Pyrazole Ligands

Chelate ligands containing at least one pyrazole group were treated with RuCl2(PPh3)(3) RuHCl(CO)(PPh3)(3) and RuH2(CO)(PPh3)(3) to form ruthenium complexes bearing protic N-H groups m close proximity to the catalytically active ruthe mum centre In the case of the hydridoruthenium complex RuHCl(CO)(PPh3)(3) the resulting complexes also contain a basic hydrido ligand The combination of acidic and basic hydrogen species in one molecule and the arising two-site reactivity was thoroughly investigated spectroscopically and by DFT calculations Catalytic tests on the hydrogenation and transfer hydrogenation of acetophenone showed a general activity of these systems