199582-38-2Relevant academic research and scientific papers
Synthesis, Characterization, and Reactivity of Dicationic Dihydrogen Complexes of Osmium and Ruthenium
Luther, Thomas A.,Heinekey, D. Michael
, p. 127 - 132 (2008/10/08)
The dicationic complexes [Os(H2)(PR3)2+ (bpy)(CO)]2+ [PR3 = PPh3, PMePh2 (2a.b)], [Os(H2) (PPh3)2(phen)(CO)]2+ (2c), and [Ru(H2)(PPh3)2(bpy)(CO)]2+ (4) (bpy = 2,2′-bipyridine; phen = 1,10-phenanthroline) have been prepared by the protonation of the corresponding monocationic hydrides using an excess of trifluoromethanesulfonic acid. The presence of a bound dihydrogen ligand is indicated by short T1 minimum values consistent with H-H distances of 0.92-1.04 ?. For the partially deuterated derivatives, JHD values of 25.1-31.0 Hz were observed. The dicationic complexes are strong acids, indicating that the bound H2 is substantially activated toward heterolytic cleavage. The H2 ligand is tightly bound to the metal center and does not undergo exchange with D2 over the course of several weeks. The complex [Os(H2)(PPh3)2(bpy)(CO)]2+ (2a) has been shown to be very stable in solution at room temperature. In contrast, the ruthenium analogue, [Ru(H2)(PPh3)2(bpy)(CO)]2+ (4), decomposes in solution at room temperature but is relatively stable at temperatures less than 245 K.
