185676-28-2Relevant academic research and scientific papers
Heterolytic H2 Activation by Dihydrogen Complexes. Effects of the Ligand X in [M(X)H2{Ph2P(CH2)3PPh 2}2]n+ (M = Ru, Os; X = CO, Cl, H)
Rocchini, Eliana,Mezzetti, Antonio,Rüegger, Heinz,Burckhardt, Urs,Gramlich, Volker,Del Zotto, Alessandro,Martinuzzi, Paolo,Rigo, Pierluigi
, p. 711 - 720 (2008/10/09)
Complexes of the general formula [MXH2(dppp)2]n+ (M = Ru, Os; X = H, Cl, CO; dppp = 1,3-bis-(diphenylphosphino)propane) have been prepared and characterized, and the effect of the donor/acceptor properties of X on their structure and acidity has been studied. The five-coordinate complexes [MCl(dppp)2]+ (M = Ru (1a), Os (1b)) react with H2 gas in CH2Cl2 to give the complexes [MCl(η2-H2)(dPPP)2]+ (M = Ru (2a), Os (2b)) containing elongated dihydrogen ligands. The molecular structure, of 2b has been determined by X-ray crystallography (monoclinic, space group P21/n with a = 13.314(7) A?, b = 18.63(2) A?, c = 23.20(2) A? β = 94.58(6)° and Z = 4). Chlorohydride [OsH(Cl)(dppp)2] (3b) reacts with H2 gas in the presence of Na[BPh4] forming [OsH3(dppp)2]+ (4b). Protonation of [OsH2(dPpp)2] (5b) with HBF4·Et2O also gives 4b. A combination of X-ray crystallography (monoclinic, space group P21/n with a = 13.392(3) A?, b = 25.306(7) A?, c = 21.247(7) A?, β = 91.15(2)° and Z = 4) and 1H and 31P NMR studies indicate that 4b is a classical trihydride. Hydridocarbonyls [MH(CO)(dppp)2]+ (M = Ru (6a), Os (6b)) are protonated by F3CSO3H in CD2Cl2 to yield [M(CO)(η2-H2)(dPpp)2]2+ (M = Ru (7a), Os (7b)), which were characterized in solution. 7a is stable only at low temperature. Compound 7b is a highly acidic dihydrogen complex with an estimated PKa of -6.
