Synthesis and reactivity of new silyl-substituted monocyclopentadienyl molybdenum and tungsten complexes
The functionalized silylated cyclopentadienyl molybdenum and tungsten complexes [MCpCl(CO)3H] (M=Mo, W; CpCl=η5-C5H4SiMe2Cl) are prepared easily from the reaction of [M(CO)3(NCMe)3] with C5H5SiMe2Cl in refluxing THF, via C–H activation and H transfer to the metal centre. Metathetical replacement of...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 1999 |
| País: | España |
| Institución: | Universidad de Alcalá (UAH) |
| Repositorio: | e_Buah Biblioteca Digital Universidad de Alcalá |
| Idioma: | inglés |
| OAI Identifier: | oai:ebuah.uah.es:10017/4247 |
| Acceso en línea: | http://hdl.handle.net/10017/4247 https://dx.doi.org/10.1016/S0022-328X(98)00962-0 |
| Access Level: | acceso abierto |
| Palabra clave: | Molybdenum Tungsten Cyclopentadienyl Chlorosilyl Ciencia Química inorgánica Science Chemistry, inorganic |
| Sumario: | The functionalized silylated cyclopentadienyl molybdenum and tungsten complexes [MCpCl(CO)3H] (M=Mo, W; CpCl=η5-C5H4SiMe2Cl) are prepared easily from the reaction of [M(CO)3(NCMe)3] with C5H5SiMe2Cl in refluxing THF, via C–H activation and H transfer to the metal centre. Metathetical replacement of hydride by chloride is readily achieved when their methylene chloride solutions are treated with a few milliliters of CCl4 to give the chloro complexes [MCpCl(CO)3Cl] (M=Mo, W). The chloro–molybdenum complexes react with 1/2 equivalent of deoxygenated water to give the corresponding dinuclear complexes [{Mo(CO)3X}2(μ-CpOCp)], (X=H, Cl; CpOCp=η5-C5H4-SiMe2-O-SiMe2-η5-C5H4), whereas their reaction with one equivalent of anhydrous LiOH in toluene leads to selective substitution of the silicon-bonded chlorine atom to give the hydroxo complexes [MoCpOH(CO)3X] (X=H, Cl; CpOH=η5-C5H4SiMe2OH). These hydroxosilyl complexes can be transformed into the dinuclear compounds [{Mo(CO)3X}2(μ-CpOCp)] by heating (50°C, 2 h) or by their reaction with one equivalent of the respective hydrido and chloro derivatives [MoCpCl(CO)3X]. Total decarbonylation of the hydrido compounds results from oxidation with a stoichiometric amount of PCl5 to give the paramagnetic molybdenum(V) and tungsten(V) complexes [MCpClCl4] (M=Mo, W). Reactions of these complexes with one equivalent of NH2R in the presence of NEt3 yield the imido derivatives [MCpCl(NR)Cl2] (M=Mo, R=2,6-Me2-Ph; M=W, R=tBu) and subsequent oxidation of the tungsten complex with 1/2 equivalent of PCl5 gives [WCpCl(NtBu)Cl3]. Reduction of [MoCpClCl4] with two equivalents of Na/Hg gives the dinuclear molybdenum(III) complex [MoCpCl]2(μ-Cl)4. All of the reported compounds were characterized by elemental analysis and 1H- and 13C NMR-spectroscopy. |
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