Chlorosilyl-Substituted Monocyclopentadienyl Niobium Chloro, Imido Chloro, and Benzyl Complexes. X-ray Molecular Structure of [{(NbCl2)2(
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- 作者：M. Isabel Alcalde ; Pilar Gó ; mez-Sal ; Avelino Martí ; n ; and Pascual Royo
- 刊名：Organometallics
- 出版年：1998
- 出版时间：March 16, 1998
- 年：1998
- 卷：17
- 期：6
- 页码：1144 - 1150
- 全文大小：212K
- 年卷期：v.17,no.6(March 16, 1998)
- ISSN：1520-6041
文摘
We report the synthesis of1-(chloromethylphenylsilyl)cyclopentadiene. The reaction ofatoluene/CH2Cl2 suspension ofNbCl5 with1-(SiClMeX)-1-(SiMe3)C5H4 (X= Me, Ph) leads tothe monocyclopentadienyl derivatives[M{
5-C5H4(SiClMeX)}Cl4](X = Me, Ph) in 90 and78% yields, respectively. Reaction of 1 equiv of water with[M{5-C5H4(SiClMe2)}Cl4]intoluene takes place with elimination of HCl, resulting in formation ofthe dinuclear niobiumoxo derivative[{(NbCl2)2(
-O)(-Cl)2}{(5-C5H4)2(Me2SiOSiMe2)}].Reaction of the complexes[M{5-C5H4(SiClMeX)}Cl4]with LiNHtBu and NEt3 in toluene leads tothe half-sandwichimido complexes[Nb{5-C5H4(SiClMeX)}Cl2(NtBu)](X = Me, Ph), which react at roomtemperature with 1 equiv ofMg(CH2Ph)2(THF)2 togive the imido dibenzyl complexes [Nb{5-C5H4(SiClMeX)}(CH2Ph)2(NtBu)](X = Me, Ph). The reaction of the chloro imidocomplexes[Nb{5-C5H4(SiClMeX)}Cl2(NtBu)]with excessMg(CH2Ph)2(THF)2 onheating for2-3 days to 80-90 and 50-60 
C, respectively, takes place,affording the totally alkylatedcomplexes[Nb{5-C5H4[Si(CH2Ph)MeX]}(CH2Ph)2(NtBu)](X = Me, Ph). The chloro benzylderivative[Nb{5-C5H4(SiClMe2)}(CH2Ph)Cl(NtBu)],which could not be prepared by additionof the stoichiometric amount of the alkylating agent, was isolated inquantitative yield byheating a mixture of the dichloro and dibenzyl complexes in toluene at120 C for 4 h. The18-electron imido 2-iminoacyl derivatives[Nb{(5-C5H4(SiMeXY)}R(NtBu){2-C(CH2Ph)=N(2,6-Me2C6H3)}] (R =CH2Ph, X = Cl, Y = Me, Ph; R =CH2Ph, X = CH2Ph, Y = Me, Ph;R= Cl, X = Cl, Y = Me) are formed when the isocyanideCN(2,6-Me2C6H3) is added to ahexanesolution of the benzylimido complexes. The molecular structure ofthe oxo complex[{(NbCl2)2(-O)(-Cl)2}{(5-C5H4)2(Me2SiOSiMe2)}]has been determined by X-ray diffraction methods.
5-C5H4(SiClMeX)}Cl4](X = Me, Ph) in 90 and78% yields, respectively. Reaction of 1 equiv of water with[M{5-C5H4(SiClMe2)}Cl4]intoluene takes place with elimination of HCl, resulting in formation ofthe dinuclear niobiumoxo derivative[{(NbCl2)2(-O)(-Cl)2}{(5-C5H4)2(Me2SiOSiMe2)}].Reaction of the complexes[M{5-C5H4(SiClMeX)}Cl4]with LiNHtBu and NEt3 in toluene leads tothe half-sandwichimido complexes[Nb{5-C5H4(SiClMeX)}Cl2(NtBu)](X = Me, Ph), which react at roomtemperature with 1 equiv ofMg(CH2Ph)2(THF)2 togive the imido dibenzyl complexes [Nb{5-C5H4(SiClMeX)}(CH2Ph)2(NtBu)](X = Me, Ph). The reaction of the chloro imidocomplexes[Nb{5-C5H4(SiClMeX)}Cl2(NtBu)]with excessMg(CH2Ph)2(THF)2 onheating for2-3 days to 80-90 and 50-60 C, respectively, takes place,affording the totally alkylatedcomplexes[Nb{5-C5H4[Si(CH2Ph)MeX]}(CH2Ph)2(NtBu)](X = Me, Ph). The chloro benzylderivative[Nb{5-C5H4(SiClMe2)}(CH2Ph)Cl(NtBu)],which could not be prepared by additionof the stoichiometric amount of the alkylating agent, was isolated inquantitative yield byheating a mixture of the dichloro and dibenzyl complexes in toluene at120 C for 4 h. The18-electron imido 2-iminoacyl derivatives[Nb{(5-C5H4(SiMeXY)}R(NtBu){2-C(CH2Ph)=N(2,6-Me2C6H3)}] (R =CH2Ph, X = Cl, Y = Me, Ph; R =CH2Ph, X = CH2Ph, Y = Me, Ph;R= Cl, X = Cl, Y = Me) are formed when the isocyanideCN(2,6-Me2C6H3) is added to ahexanesolution of the benzylimido complexes. The molecular structure ofthe oxo complex[{(NbCl2)2(-O)(-Cl)2}{(5-C5H4)2(Me2SiOSiMe2)}]has been determined by X-ray diffraction methods.