Acetylene incorporation into the spiked framework of the phosphinidene and arsinidene clusters [Ru4(CO)13(μ-H)2(μ4-ECF 3)] (E = P or As): Skeletal rearrangement and crystal structures of a series of tetranuclear ruthenium clusters bearing alkynes

Abstract

Reactions of [Ru4(CO)13(μ-H)2(μ4-ECF 3)] (E = P 1 or As 2) with RC≡CR (R = Ph or H) under mild conditions yielded square planar clusters [Ru4(CO)9(μ-CO)2(μ4-ECF 3)(RC2R)] (E = As, R = Ph 3; E = P, R = Ph 4 or E = P, R = H 5) in which the acetylene ligands are attached to the metal square planes via 2σ + 4π bonds. Under similar conditions, the reaction of 1 with CF3C≡CCF3 afforded a similar cluster [Ru4(CO)12(μ4-PCF3)(CF 3C2CF3)] 6 in which the acetylene interacts with the Ru4 square face only by 4σ bonds. Reactions of 1 and 2 with MeC≡CMe resulted in metal skeletal rearrangement and P-C bond formation to form the butterfly cluster [Ru4(CO)10(μ-CO)2{CF 3PC(Me)-C(Me)}] 7 and alkyne dimerization at the spiked Ru atom to form spiked clusters [Ru4(CO)9(μ-CO)2(μ4-ECF 3)-(C4Me4)] (E = P 8 or As 9) containing a metallocyclic RuC4Me4 ring. Reaction of 1 with diphenylbutadiyne under similar conditions afforded a square planar cluster [Ru4(CO)11(μ4-PCF 3){PhC(H)C(H)CCPh}] 10 where the bridging hydrogen migrates to the diyne to form a 1,4-diphenylbut-3-en-l-yne fragment attached to the Ru4 face.