Reversible Interconversion of CC and CN Multiple Bond Systems on Clusters

Abstract

Cluster moieties can be so conditioned by metal exchange that they support one and the same reaction in the region of the organic ligands both in the forward and reverse direction. A spontaneous alkylidyne‐vinylidene transformation has been observed for the first time within the sequences of the type shown below. equation image

Synthesis and Reactivity of Triruthenium Carbonyl Cluster Complexes Containing a Bridging 1-Azavinylidene Ligand Derived from Benzophenone Imine

“…Some other ruthenium clusters containing bridging 1-azavinylidene ligands have been reported. They correspond to the general formula [Ru 3 (μ-H)(μ-NCHR)(CO) 10 ] and are isostructural with complex 1 , but they all contain a hydrogen atom on the azavinylidene carbon atom and have been made via hydrogenation reactions of coordinated nitrile ligands. − The structures of all these triruthenium clusters derived from N -unsubstituted Schiff bases are quite different from those found for clusters derived from N -substituted Schiff bases, in which both the N and C imine atoms are coordinated to the metals, as in compounds of types I and K (Chart )…”

“…In the case of transition metal carbonyl cluster compounds, the only previous examples known to contain N -unsubstituted imine-type ligands are aldehyde imine derivatives. − Thus, compounds of type G (Chart ) have been prepared in low yields by treating aromatic nitriles with [M 3 (CO) 12 ] (M = Ru, Os) in the presence of carboxylic acids or molecular hydrogen. − In a related reaction, insertion of trifluoroacetonitrile into an Os−H bond of [Os 3 (μ-H) 2 (CO) 10 ] gives the isomeric compounds H and I (Chart ). − The isomeric face-bridged derivatives J and K , derived from the reduction of acetonitrile on iron clusters, have also been reported 2 …”

“…[13][14][15][16][17][18][19][20][21] Thus, compounds of type G (Chart 2) have been prepared in low yields by treating aromatic nitriles with [M 3 (CO) 12 ] (M ) Ru, Os) in the presence of carboxylic acids or molecular hydrogen. [13][14][15][16][17] In a related reaction, insertion of trifluoroacetonitrile into an Os-H bond of [Os 3 (µ-H) 2 (CO) 10 ] gives the isomeric compounds H and I (Chart 2). [18][19][20] The isomeric face-bridged derivatives J and K, derived from the reduction of acetonitrile on iron clusters, have also been reported.…”

Tail-to-tail carbon–carbon bond coupling of acetylides on chalcogen-bridged Fe/W mixed-metal clusters

“…1 The preparation of heterometallic compounds, by several groups, using mononuclear acetylide precursors and the generation of acetylide bridged complexes has enriched our knowledge on the reactivity and bonding capability of acetylide ligands. [2][3][4][5] The coupling of terminal and functionalised metal acetylides has been extensively studied recently and through this route a number of polycarbon ligand-containing metal clusters have been realised. [3][4][5] In several cases it has been observed that either an oxidative or a Cadiot-Chodkiewicz coupling is operative.…”

Spectroscopic identification of the nickel acylate complex

“…One of the compounds obtained this way is the RuCoMo cluster la which has already shown its usefulness in a reversible alkylidyne-vinylidene rearrangement. 4 We have now found that la and the related clusters lb and 2b3 undergo an olefin insertion which yields organometallic compounds that can be called model intermediates of cluster-generated optical induction.…”