Formation of Ruthenium Thiolates via Complexes of Molecular Hydrogen

Abstract

RuH[sub 2](DMPE)[sub 2][DMPE = 1,2-bis(dimethylphosphino)ethane] was synthesized by reduction of trans-RuCl[sub 2](DMPE)[sub 2] with sodium/2-propanol. Protonation of RuH[sub 2](DMPE)[sub 2] with weak organic acids such as methanol, ethanol, and thiols affords the molecular hydrogen complex trans-[RuH([eta][sup 2]-H[sub 2])(DMPE)[sub 2]][sup +], which has an [eta][sup 2]-bound H[sub 2] ligand and a [sigma]-bound hydride ligand. T[sub 1] measurements and the observation of a large [sup 1]J[sub HD] coupling in the [eta][sup 2]-HD isotopomer ligand support the [open quotes]nonclassical[close quotes] structure. In the [sup 1]H NMR spectrum of the trans-[RuH([eta][sup 2]-HD)(DMPE)[sub 2]][sup +] isotopomer, the proton-proton coupling (across the metal center) between [sigma]-H and [sup 1]H in the [eta][sup 2]-HD was measured at 4.5 Hz. Between 220 and 300 K, the molecular hydrogen complex undergoes intermolecular exchange with the protonating reagent and all the ruthenium-bound hydrogens in the molecular hydrogen complex undergo intramolecular exchange. The weakly bound [eta][sup 2[minus]]H[sub 2] ligand is readily displaced by alkane- and arenethiols to give trans-monothiolate hydrides. With thiophenol, a second substitution occurs to give a dithiolate complex. Crystals of trans-Ru(SPH)[sub 2](DMPE)[sub 2] are; monoclinic, space group P2[sub 1]/a, with a - 15.035(3) [angstrom], b = 9.881(3) [angstrom], c = 19.604(4) [angstrom], [beta] = 97.51(2)[degrees], Z = 4,more » and R = 0.029 [3348 reflections used with I>2.5[sigma](I)]. The structural analysis shows that Ru is coordinated by two bidentate phosphine and two monodentate benzenethiolate ligands in a trans arrangement.« less