Ligand exchange photochemistry and thermal acetylene exchange.

Article abstract of DOI:10.1016/S0022-328X(96)06770-8

Photolysis of Fe₂(CO)₄( μ-η⁵,η⁵-C₅H₄CH₂C₅H₄) in the presence of phosphines or phosphites results in the formation of simple carbonyl substitution products Fe₂(CO)( μ-CO)₂L(μ-η⁵,η⁵-C₅H₄CH₂C₅H₄) or Fe₂(μ-CO)₂L₂(μ-η⁵,η⁵-C₅H₄CH₂C₅H₄). Acetylenes react photochemically with the diiron compound to give vinylketone-bridged derivatives of the form Fe₂(CO)( μ-CO)[ μ-η¹:η³-RC=C(R)CO](μ,-η⁵,η⁵-C₅H₄CH₂C₅H₄), where R = CH₃O₂C and C₆H₅. Reaction of Ru₂(CO)₄(μ-η⁵,η⁵-C₅H₄CH₂C₅H₄) with triphenylphosphine under photochemical conditions resulted in loss of two carbon monoxide ligands and P-C insertion by ruthenium to yield Ru₂(CO)(σ-C₆H₅)(μ-CO)[μ-P(C₆H₅)₂](μ-η⁵,η⁵-C₅H₄CH₂C₅H₄). Photolysis of Ru₂(CO)₄(μ-η⁵,η⁵-C₅H₄CH₂C₅H₄) with diphenylacetylene gave the previously reported Ru₂(CO)₂(μ-CO)[μ-η¹:η¹-(C₆H₅)₂C₂](μ-η⁵,η⁵-C₅H₄CH₂C₅H₄) and an air oxidation product, Ru₂(CO)(μ-CO)[μ-η¹:η³-C₆H₅C=C(C₆H₅)O](μ-η₅,η⁵-C₅H₄CH₂C₅H₄). The diphenylacetylene derivative underwent acetylene exchange, but did not undergo exchange with triphenylphosphine. All compounds have been characterized by spectroscopic methods, elemental analysis and/or mass spectroscopy. The molecular structures of two ruthenium compounds were determined by X-ray crystallography. Ru₂(CO)(σ-C₆H₅)(μ,-CO)[μ-P(C₆H₅)₂](μ-η⁵,η-C₅H₄CH₂C₅H₄): monoclinic, P2₁/c, a = 13.902(3) A, b = 13.283(3) A, c = 14.426(4) A, β = 101.62(2)°, V = 2609(1) A³, z = 4, R(F) = 3.98%. Ru₂(CO)μ-CO)[μ-η¹:η³-C₆H₅C=C(C₆H₅)O](μ-η⁵,η⁵-C₅H₄CH₂C₅H₄): orthorhombic, Pccn, a = 15.000(4)A, b = 15.662(4)A, c = 19.053(4)A, V = 4476(2) A³, z = 8, R(F) = 3.05%.