Unsaturated Ru(0) species with a constrained bis-phosphine ligand: [Ru(CO)(2)((Bu2PCH2CH2PBu2)-Bu-t-Bu-t)](2). Comparison to [Ru(CO)(2)((PBu2Me)-Bu-t)(2)]

The synthesis of Ru(C2H4)(CO)(2)(d(t)bpe) (d(t)bpe = tBu(2)PC(2)H(4)P(t)Bu( 2)), then green [Ru(CO)(2)(d(t)bpe)](n) is described. In solution, n = 1, w hile in the solid state, n = 2; the dimer has two carbonyl bridges. DFTPW91 , MP2, and CCSD(T) calculations show that the potential energy surface for bending one carbonyl out of the RuP2C(O) plane is essentially flat. Ru(CO)( 2)(d(t)bpe) reacts rapidly in benzene solution to oxidatively add the H-E b ond of H-2, HCl, HCCR (R = H, Ph), [HOEt2]BF4, and HSiEt3. The H-C bond of C6HF5 oxidatively adds at 80 degrees C. CO adds, as does the C=C bond of H2 C=CHX (X = H, F, Me). The following do not add: N-2 THF, acetone, H3COH, an d H2O.