202872-85-3Relevant articles and documents
Chlorosilyl-substituted monocyclopentadienyl niobium chloro, imido chloro, and benzyl complexes. X-ray molecular structure of [{(NbCl2)2(μ-O)(μ-Cl)2}{(η 5-C5H4)2(Me2SiOSiMe 2)}]
Alcalde, M. Isabel,Gómez-Sal, Pilar,Martín, Avelino,Royo, Pascual
, p. 1144 - 1150 (2008/10/08)
We report the synthesis of 1-(chloromethylphenylsilyl)cyclopentadiene. The reaction of a toluene/CH2Cl2 suspension of NbCl5 with 1-(SiClMeX)-1-(SiMe3)C5H4 (X = Me, Ph) leads to the monocyclopentadienyl derivatives [M{η5-C5H4(SiClMeX)}Cl4] (X = Me, Ph) in 90 and 78% yields, respectively. Reaction of 1 equiv of water with [M{η5-C5H4(SiClMe2)}Cl 4] in toluene takes place with elimination of HCl, resulting in formation of the dinuclear niobium oxo derivative [{(NbCl2)2(μ-O)(μ-Cl)2}{(η 5-C5H4)2(Me2SiOSiMe 2)}]. Reaction of the complexes [M{η5-C5H4(SiClMeX)}Cl4] with LiNHtBu and NEt3 in toluene leads to the half-sandwich imido complexes [Nb{η5-C5H4(SiClMeX)}Cl2(N tBu)] (X = Me, Ph), which react at room temperature with 1 equiv of Mg(CH2Ph)2(THF)2 to give the imido dibenzyl complexes [Nb-{η5-C5H4(SiClMeX)}(CH 2Ph)2(NtBu)] (X = Me, Ph). The reaction of the chloro imido complexes [Nb{η5-C5H4(SiClMeX)}Cl2(N tBu)] with excess Mg(CH2Ph)2(THF)2 on heating for 2-3 days to 80-90 and 50-60°C, respectively, takes place, affording the totally alkylated complexes [Nb{η5-C5H4[Si(CH 2Ph)MeX]}(CH2Ph)2(NtBu)] (X = Me, Ph). The chloro benzyl derivative [Nb{η5-C5H4(SiClMe2)}(CH 2Ph)Cl(NtBu)], which could not be prepared by addition of the stoichiometric amount of the alkylating agent, was isolated in quantitative yield by heating a mixture of the dichloro and dibenzyl complexes in toluene at 120°C for 4 h. The 18-electron imido η2-iminoacyl derivatives [Nb{η5-C5H4(SiMeXY)}R(N tBu){η2-C(CH2Ph)=N-(2,6-Me 2C6H3)}] (R = CH2Ph, X = Cl, Y = Me, Ph; R = CH2Ph, X = CH2Ph, Y = Me, Ph; R = Cl, X = Cl, Y = Me) are formed when the isocyanide CN(2,6-Me2C6H3) is added to a hexane solution of the benzylimido complexes. The molecular structure of the oxo complex [{(NbCl2)2-(μ-O)(μ-Cl)2}{(η 5-C5H4)2(Me2SiOSiMe 2)}] has been determined by X-ray diffraction methods.
