Low-Valent Tungsten Aryloxide Compounds with Pyridine Ancillary Ligation: Intramolecular Reduction of Heterocyclic and Aromatic Rings Including Formation of an η5-Cyclohexadienyl Group
| Autor: | Phillip E. Fanwick, Margaret R. Lentz, Ian P. Rothwell |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
chemistry.chemical_classification
Stereochemistry Organic Chemistry chemistry.chemical_element Aromaticity Tungsten Medicinal chemistry Sodium amalgam Inorganic Chemistry chemistry.chemical_compound Hydrocarbon chemistry Molybdenum Intramolecular force Pyridine Proton NMR Physical and Theoretical Chemistry |
| Zdroj: | Organometallics. 22:2259-2266 |
| ISSN: | 1520-6041 0276-7333 |
| Popis: | The sodium amalgam reduction (2 Na per W) of hydrocarbon solutions of [W(OC6HPh4-2,3,5,6)2Cl4] in the presence of pyridine or 4-tert-butylpyridine leads to the W(IV) compounds [W(OC6HPh4-2,3,5,6)2Cl2(py)2] (1) and [W(OC6HPh4-2,3,5,6)2Cl2(4-tert-butylpyridine)2] (2) in good yields. The ambient-temperature 1H NMR spectra of both 1 and 2 were found to be sharp and to exhibit extensive contact shifts due to the paramagnetic tungsten center. The addition of 2,2‘-bipyridine to an emerald green solution of [W(OC6HPh3-η6-C6H5)(OC6HPh4-2,3,5,6)(PEt3)] produced [W(OC6HPh4-2,3,5,6)2(bipy)2] (3), containing two bipy rings and two terminal aryloxide ligands coordinated mutually cis. The W−N(bipy) distances of 2.092(2), 2.093(2), 2.096(2), and 2.115(2) A in 3 are among the shortest so far reported for bipy ligands bound to either molybdenum or tungsten. The solid state and solution data for 3 indicate that reduction of both bipy ligands has occurred, but whether this involves four-electron reduction to yield d0-W(VI) i... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|