PREPARATION, STRUCTURE, AND FORMATION MECHANISM OF CIS-RUH(OAR)(PME3)4 (AR = C6H5, C6H4-PARA-ME) AND CIS-RUH(OC6H4-P-CN)(PME3)4(HOC6H4-PARA-CN)

Reactions of RuH2(PMe3)4 with phenol, p-methylphenol, and p-cyanophenol give the hydrido-aryloxido complexes cis-RuH(OPh)(PMe3)4 (1), cis-RuH(OC6H4-p-Me)(PMe3)4 (2), and cis-RuH(OC6H4-p-CN)(PMe3)4(HOC6H4-p-CN) (3-HOC6H4-p-CN), respectively. NMR spectra (H-1, C-13, and P-31) of these complexes are consistent with the cis structures. The H-1 NMR spectrum of complex 3-HOC6H4-p-CN at -40-degrees-C in CD2Cl2 shows a signal due to the OH hydrogen of the associated p-cyanophenol at 16.3 ppm, indicating the presence of O-H...O hydrogen bonding between the p-cyanophenoxide and the p-cyanophenol. The molecular structure of 2 has been determined by X-ray crystallography. Crystal data: monoclinic, space group P2(1)/a, a = 29.332 (5) angstrom, b = 13.741 (8) angstrom, c = 13.568 (3) angstrom, beta = 102.37 (2)-degrees, V = 5341.9 angstrom-3, = 8, R = 0.061, R(w) = 0.070 for 6011 reflections with \F0\ > 3-sigm?? a(F0). H-1 and P-31 NMR spectra of the reaction mixture of RuH2(PMe3)4 with phenol at low temperature indicate formation of an ionic complex formulated as [RuH3(PMe3)4]OPh (4), which is gradually converted into 1 at room temperature. Reaction mixtures of RuH2(PMe3)4 with other Bronsted acids such as HBF4 and 1,1,1,3,3,3-hexafluoro-2-propanol show similar H-1 and P-31{H-1} NMR signals at low temperature, indicating the formation of complexes such as [RuH3(PMe3)4]BF4 and [RuH3(PMe3)4]OCH(CF3)2. The H-1 NMR signal of hydrogen bonded to ruthenium in [RuH3(PMe3)4]OCH(CF3)2 shows a value of 70 ms for T1 at -40-degrees-C and 500 MHz.