[Ti(MgCl)2· xTHF]q: a reagent for the McMurry reaction and a novel inorganic Grignard complex
| Autor: | Andre Gaidies, Borislav Bogdanovicć, Jacques Rozière, Shijian Liao, Lorraine E. Aleandri, Deborah J. Jones, Alain Michalowicz, Andrea Schott |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Chemistry
Magnesium Organic Chemistry Inorganic chemistry chemistry.chemical_element Ether Biochemistry Inorganic Chemistry Bond length chemistry.chemical_compound Crystallography Reagent Materials Chemistry Single bond Physical and Theoretical Chemistry McMurry reaction Ether cleavage Tetrahydrofuran |
| Zdroj: | Journal of Organometallic Chemistry. 459:87-93 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/0022-328x(93)86059-q |
| Popis: | The stepwise formation of two distinct bimetallic titanium/magnesium complexes during the reduction of TiCl3 (or TiCl4) by magnesium in tetrahydrofuran (THF) has been identified. [TiMgCl2·xTHF] (1) is produced in a first stage, but reacts further with excess Mg to give [Ti(MgCl)2·xTHF] (2). The reaction is reversible in the presence of excess TiCl3. X-ray absorption spectroscopy has been used to identify the local environment in 2. The most striking feature is the existence of the shortest TiMg interatomic distance yet observed. The TiMg bond length, 2.72(1) A, is close to the sum of the Pauling single bond metallic radii (2.69 A) and the complex is termed an inorganic Grignard reagent by analogy with other complexes containing direct transition metalmagnesium bonds. Overall, a dimeric model is compatible with the EXAFS-derived structural parameters and solubility characteristics. The titanium atoms are linked through two bridging MgCl2Mg units and their coordination shells are completed by THF ligands. The structure of 2, and the existence of intermediate 1, can be used to rationalize the known catalytic activity of the TiCl3/Mg/THF system with respect to ether cleavage. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|