Migration of a phenyl group from co-ordinated CH2(PPh2)2 to an acetylide on an Ru3 cluster: crystal structure of [Ru3(μ-H)(μ3-PPhCH2PPh2)(μ3-PhC2But)(CO)6] †

Abstract

Thermolysis (refluxing toluene, 60 h) of [Ru 3 (µ-H)(µ 3 -C 2 Bu t )(µ-dppm)(CO) 7 ] resulted in phenyl transfer from co-ordinated dppm to the µ 3 -acetylide to give [Ru 3 (µ-H)(µ 3 -PPhCH 2 PPh 2 )(µ 3 -PhC 2 Bu t )(CO) 6 ] in 41% yield, fully characterised by X-ray determinations of thf and CH 2 Cl 2 monosolvates. The alkyne is co-ordinated to the Ru 3 cluster such that the C(1)-C(2) vector forms an angle of 23Њ with the Ru(1)-Ru(2) vector. This distortion brings two C atoms of the alkyne Ph group close to Ru(2). Density functional and extended Hückel calculations carried out on the new compound indicated that the unusual co-ordination of the alkyne ligand can be attributed to the stereoelectronic asymmetry of the metallic fragment.

Reactivity of a Triruthenium Acetylide Complex toward Alkynes and the Silica-Mediated Dehydration of Cluster-Bound Alkynols: X-ray Crystal Structures of the Novel Butadienyl Species [Ru3(CO)8{μ3-η8-C(But)CC(Ph)C(H)Ph}] and the Unusual Complex [Ru3(CO)5(μ-CO){μ3-η5-CC(But)- OC(Ph)2CCH}{μ3-η6-CHC(CPh2OH)COC(CPh2)CH}]

“…This interaction results in localization of the π-bonding in the phenyl ring, with the C(19)−C(20) and C(21)−C(22) bonds [of length 1.358(5) and 1.362(6) Å] being significantly shorter than the remaining four C−C bonds (all greater than 1.390 Å). Similar results were obtained for [Ru 3 (μ-H)(μ 3 -PPhCH 2 PPh 2 )(μ 3 -PhC 2 Bu t )(CO) 6 ] by Bruce et al…”

Mixed-Metal Cluster Chemistry. 19. Crystallographic, Spectroscopic, Electrochemical, Spectroelectrochemical, and Theoretical Studies of Systematically Varied Tetrahedral Group 6−Iridium Clusters

“…Studies of cluster electrochemistry, − carried out frequently in concert with electronic structure calculations, − have afforded information about the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs). Calculations using density functional theory have been promulgated to enhance understanding of spectroscopic properties, charge distributions, and reactivities. ,− Cluster electrochemistry, in combination with IR and UV−visible spectroelectrochemistry and frequently EPR, has afforded insight into the electronic and molecular structure of clusters in varying oxidation states. ,− …”