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[Display omitted] Reactions of the electron defficient triosmium [Os 3 (CO) 9 (μ 3 -η1,κ1-C 9 H 6 N)(μ-H)] with Ph 3 EH (E = Si, Ge, Sn) have been investigated. The reactions of quinoline-capped triosmium cluster [Os 3 (CO) 9 (μ 3 -η1,κ1-C 9 H 6 N)(μ-H)] (1) with Ph 3 EH (E = Si, Ge, Sn) have been investigated. Cluster 1 reacts with Ph 3 EH in refluxing benzene to afford [Os 3 (CO) 9 (EPh 3)(μ-η1,κ1-C 9 H 6 N)(µ-H) 2 ] (2a , E = Si; 2b , E = Ge; 2c , E = Sn) and [Os 3 (CO) 8 (EPh 3)(μ 3 -η1,κ1-C 9 H 6 N)(µ-H) 2 ] (3a , E = Si; 3b , E = Ge; 3c , E = Sn). Control experiments confirm that 2 is a precursor of 3. Cluster 2 is formed via oxidative-addition of E–H bond to 1 whose decarbonylation leads to the formation of 3. The molecular structures of all the new clusters (except 3c) have been determined by X-ray crystallography. Both 2 and 3 exist as a pair of isomers in solution, and their fluxionality in solution has been probed by VT NMR experiments. [ABSTRACT FROM AUTHOR]

The reaction of the electron-deficient 6-methoxyquinolinate-substituted triosmium cluster [Os 3 (CO) 9 {μ 3 -η 1 ,κ 1 -C 9 H 5 N(6-OMe)}(μ-H)] ( 1 ) with PPh 3 proceeds readily at room temperature to afford the electron-precise adduct [Os 3 (CO) 9 (PPh 3 ){μ-η 1 ,κ 1 -C 9 H 5 N(6-OMe)}(μ-H)] ( 2 ), in which the PPh 3 ligand is bound to the osmium that serves as the coordination site for the hydride and the metallated-carbon atom of the benzoheterocycle. This reaction also leads to a change in the hapticity of the 6-methoxyquinolinate ligand from μ 3 -η 1 ,κ 1 to μ-η 1 ,κ 1 as confirmed by X-ray crystallography. Thermolysis of 2 in boiling toluene furnishes five new triosmium clusters ( 3 – 7 ) as a result of ligand isomerization, decarbonylation and orthometallation of the ancillary PPh 3 ligand. Clusters 3 and 4 are isomers of 2 and the location of the metal-bound hydride and PPh 3 with respect to 6-methoxyquinolinate moiety is the only difference between these isomers. Control experiments show that 5 is a decarbonylation product of 4 which converts into 6 as a result of further decarbonylation with concomitant orthometallation of one of the phenyl rings of the coordinated PPh 3 ligand, whilst 7 is formed from 6 through replacement of an equatorial carbonyl of the nitrogen-bound osmium by PPh 3 ligand. All the new clusters have been characterized by a combination of analytical and spectroscopic methods as well as by X-ray crystallography in the case of 2 , 3 , 6 and 7 . [ABSTRACT FROM AUTHOR]