Reaction of electron-deficient 6-methoxyquinolinate-substituted cluster [Os3(CO)9{μ3-η1,κ1-C9H5N(6-OMe)}(μ-H)] with PPh3: Thermally induced ligand isomerization, decarbonylation and orthometallation
| Autor: | Shariff E. Kabir, Edward Rosenberg, Shishir Ghosh, Shahin A. Begum, Kenneth I. Hardcastle, Arshad H. Chowdhury, Derek A. Tocher |
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| Rok vydání: | 2018 |
| Předmět: |
010405 organic chemistry
Chemistry Hydride Ligand Decarbonylation chemistry.chemical_element 010402 general chemistry 01 natural sciences Medicinal chemistry 0104 chemical sciences Adduct Inorganic Chemistry chemistry.chemical_compound Hapticity Materials Chemistry Osmium Physical and Theoretical Chemistry Triphenylphosphine Isomerization |
| Zdroj: | Inorganica Chimica Acta. 478:25-31 |
| ISSN: | 0020-1693 |
| DOI: | 10.1016/j.ica.2018.03.045 |
| Popis: | The reaction of the electron-deficient 6-methoxyquinolinate-substituted triosmium cluster [Os3(CO)9{μ3-η1,κ1-C9H5N(6-OMe)}(μ-H)] (1) with PPh3 proceeds readily at room temperature to afford the electron-precise adduct [Os3(CO)9(PPh3){μ-η1,κ1-C9H5N(6-OMe)}(μ-H)] (2), in which the PPh3 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 μ3-η1,κ1 to μ-η1,κ1 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 PPh3 ligand. Clusters 3 and 4 are isomers of 2 and the location of the metal-bound hydride and PPh3 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 PPh3 ligand, whilst 7 is formed from 6 through replacement of an equatorial carbonyl of the nitrogen-bound osmium by PPh3 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. |
| Databáze: | OpenAIRE |
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