Characterization of Ruthenium(II) Molecular Hydrogen Complex with ( R , R )-4,5-Bis(diphenylphosphinomethyl)-2,2-dimethyl-1,3-dioxolane (diop)

The Ru(II) molecular hydrogen complex [RuH(η2-H2)(diop)2]+ was prepared in situ from [RuH(diop)2]+ and H2 gas. The low temperature (213–243 K) 1H and 31P NMR data of this η2-H2 complex indicated the coexistence of two isomers (trans and cis) at equilibrium in solution. At 303 K the coalescence of Ru-H and Ru-(η2-H2) resonances due to their rapid exchanges was observed.