CC-coupling reactions at low-valent molybdenum centers. Selective formation of η2-iminoacyl, η3-1-azaallyl and η2-1,4-diazabutadien-2-yl complexes of molybdenum from ethyl isocyanide complexes
| Autor: | Alexander Constantin Filippou, Christian Völkl, Walter Grünleitner |
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| Rok vydání: | 1991 |
| Předmět: |
Ligand
Stereochemistry Isocyanide Organic Chemistry chemistry.chemical_element Crystal structure Alkylation Metallacycle Biochemistry Medicinal chemistry Coupling reaction Inorganic Chemistry chemistry.chemical_compound chemistry Molybdenum Materials Chemistry Physical and Theoretical Chemistry Isomerization |
| Zdroj: | Journal of Organometallic Chemistry. 413:181-203 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/0022-328x(91)80049-p |
| Popis: | A stepwise, high-yield synthesis of low-valent molybdenum η2-iminoacyl, η3-azaallyl and η2-1,4-diazabutadien-2-yl complexes is reported starting from readily accessible ethyl isocyanide complexes. Thus reduction of cis/trans-Cp*Mo(CO)2(EtNC)I (Cp* = η5-C5Me5) (1a/1b) with sodium gives the Mo0-metallate Na[Cp*Mo(CO)2(EtNC)] (2) in quantitative yield. Reaction of 2 with RI yields (via alkylation of the metal center and insertion of the ethyl isocyanide ligand into the metalalkyl bond exclusively the MoII-iminoacyl complexes Cp*(CO)2Mo[η2-C(NEt)R] (3: R = Me; 4: R = Et). Complexes 3 and 4 undergo isomerization in refluxing toluene by H-migration into the 1-azaallyl compounds Cp*(CO)2Mo(η3-CH2⋯CH⋯NEt) (5) and Cp*(CO)2Mo[η3-CH(Me⋯CH⋯NEt] (6), respectively. Treatment of 3 with RNC (R = Me, Et) results in the quantitative formation of the isocyanide insertion products Cp*(CO)2Mo[C(NR)C(NEt)Me] (7: R = Me; 8: R = Et). The solid state structure of 8 was established by a single-crystal X-ray crystallographic study. A striking feature of the structure is the planarity of the four-membered metallaheterocycle resulting from (C,N)-coordination of the 1,4-diaza-3-methylbutadien-2-yl ligand to molybdenum. |
| Databáze: | OpenAIRE |
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