183555-76-2Relevant academic research and scientific papers
Characterization and reactivity of an unprecedented unsaturated zero-valent ruthenium species: Isolable, yet highly reactive
Ogasawara, Masamichi,Macgregor, Stuart A.,Streib, William E.,Folting, Kirsten,Eisenstein, Odile,Caulton, Kenneth G.
, p. 10189 - 10199 (1996)
Magnesium reduction of cis,cis,trans-RuCl2(CO)2L2 (L = P(t)Bu2Me) yields isolable Ru(CO)2L2, shown by solution spectroscopies and X-ray diffraction to have trans phosphines but cis carbonyls, in a nonplanar structure which resembles a trigonal bipyramid with one equatorial ligand missing. This unusual geometric structure is traced by ab initio (MP2) study to enhanced back-donation to CO by zero-valent Ru. This molecule reacts in time of mixing to add CO, MeNC, O2, CS2, C2H4, or PhC≡CPh. Rapid oxidative addition occurs with H2, HCl, Cl2, and PhC≡CH. Oxidative addition is slower with MeCl, Me3SiH, and MeOH, which leads to more complicated reaction schemes. Reaction with PPh2H gives not oxidative addition but addition and displacement, yielding Ru(CO)2(PPh2H)2(P(t)Bu2Me) and equimolar free P(t)Bu2Me. Magnesium reduction of cis,cis,trans-RuCl2(CO)2L'2 proceeds analogously for L' = P(i)Pr3, but for L' = PPh3, decomposition and ligand scavenging give Ru(CO)2(PPh3)3. Reduction of cis,trans-RuCl2(CO)(CNMe)L2 gives the product of oxidative addition of a (t)Bu C-H bond: RuH(CO)(CNMe)[η2-P(CMe2CH2)(t)BuMe]L, showing the influence of electron density at unsaturated Ru(0) on its persistence.
