Acetylene incorporation into the spiked framework of the phosphinidene and arsinidene clusters [Ru4(CO)13(µ-H)2(µ4-ECF3)] (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-ECF₃)] (E = P 1 or As 2) with RCCR (R = Ph or H) under mild conditions yielded square planar clusters [Ru₄(CO)₉(µ-CO)₂(µ₄-ECF₃)(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 CF₃CCCF₃ afforded a similar cluster [Ru₄(CO)₁₂(µ₄-PCF₃)(CF₃C₂CF₃)] 6 in which the acetylene interacts with the Ru₄ square face only by 4σ bonds. Reactions of 1 and 2 with MeCCMe resulted in metal skeletal rearrangement and P–C bond formation to form the butterfly cluster [Ru₄(CO)₁₀(µ-CO)₂{CF₃PC(Me)C(Me)}] 7 and alkyne dimerization at the spiked Ru atom to form spiked clusters [Ru₄(CO)₉(µ-CO)₂(µ₄-ECF₃)(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-PCF₃){PhC(H)C(H)CCPh}] 10 where the bridging hydrogen migrates to the diyne to form a 1,4-diphenylbut-3-en-1-yne fragment attached to the Ru₄ face.