SYNTHESIS, CHARACTERIZATION, AND CHEMISTRY OF 16-ELECTRON DIHYDROGEN COMPLEXES OF RUTHENIUM

The reaction of RuH2(H-2)2(PCy3)2 (1) with halocarbons (methyl iodide or dichloromethane) in pentane yields the new 16-electron hydrido dihydrogen derivatives RuHX(H-2)(PCy3)2 (X = I, 2a; X = Cl, 2b) characterized by spectroscopic methods and by X-ray crystallography in the case of 2a. In the presence of excess dihydrogen, 2a,b transform into bis(dihydrogen) species RuHX(H-2)2(PCy3)2 (X = Cl, 3b; X = I, 3a), in which all hydrides exchange rapidly in the whole range of accessible temperatures. Complexes 3a,b were only observed in solution. 1 reacts with thiols (RSH) to yield 16-electron thiolato species RuH(SR)(H-2)(PCy3)2 (R = Cy, 2c; R = Ph, 2d; R = (t)Bu, 2e). Whereas 2c shows a slow exchange with H-2, 2e reacts to give 1 and HS(t)Bu. Finally compounds 1 and 2a-f react with carbon monoxide to yield the cis dicarbonyl derivatives RuHX(CO)2(PCy3)2 (X = H, 4a; X = I, 4b; X = Cl, 4c; X = SCy, 4d; X = SPh, 4e; X = S(t)Bu, 4f).