Coordination of a Bifunctional Ligand to a Rhodium(III) Dimethyl Complex: Lewis Acidity Enhancement by Chelation
详细信息 查看全文
- 作者：Marie-Hé ; lè ; ne Thibault ; José ; e Boudreau ; Sophie Mathiotte ; Fré ; dé ; ric Drouin ; Olivier Sigouin ; Annie Michaud ; Fré ; dé ; ric-Georges Fontaine
- 刊名：Organometallics
- 出版年：2007
- 出版时间：July 16, 2007
- 年：2007
- 卷：26
- 期：15
- 页码：3807 - 3815
- 全文大小：168K
- 年卷期：v.26,no.15(July 16, 2007)
- ISSN：1520-6041
文摘
The addition of the ambiphilic compound (Me2PCH2AlMe2)2 (1) to Cp*RhMe2(DMSO) (DMSO =dimethylsulfoxide) (2) gives Cp*RhMe2(PMe2CH2AlMe2·DMSO) (3·DMSO). The addition of Lewis acids(LA) such as La(dbm)3 (dbm = dibenzoylmethane) and AlMe3 to a solution of complex 3·DMSO givesa competition reaction that results in the formation of LA·DMSO and Cp*RhMe2(PMe2CH2AlMe2) (3).When heated to 40 
C, complex 3 ionizes to a putative zwitterionic species, Cp*Rh+Me(PMe2CH2AlMe3-)(3'), which is converted to [Cp*Rh(Me)(
2-
hars/eta.gif" BORDER=0 >2-Me2PCH2)]2 (4) irreversibly. Spin saturation transferexperiments demonstrated that the rate of the methyl abstraction by the alane moiety was 0.76 ± 0.09s-1, while the rate of abstraction of the methyl in Cp*RhMe2(PMe3) by AlMe3 was 0.10 ± 0.02 s-1. Thezwitterionic species 3' could be trapped in solution by addition of PMe3 to afford both Cp*Rh+Me(PMe3)(Me2PCH2AlMe3-) (5) and [Cp*Rh+Me(PMe3)(Me2PCH2AlMe2)]AlMe4- (6). When compound 1 was addedto complex 3', the formation of the zwitterionic complex Cp*Rh+Me(hars/eta.gif" BORDER=0 >2-Me2PCH2Al-Me2CH2PMe2) (7)was observed.
C, complex 3 ionizes to a putative zwitterionic species, Cp*Rh+Me(PMe2CH2AlMe3-)(3'), which is converted to [Cp*Rh(Me)(2-hars/eta.gif" BORDER=0 >2-Me2PCH2)]2 (4) irreversibly. Spin saturation transferexperiments demonstrated that the rate of the methyl abstraction by the alane moiety was 0.76 ± 0.09s-1, while the rate of abstraction of the methyl in Cp*RhMe2(PMe3) by AlMe3 was 0.10 ± 0.02 s-1. Thezwitterionic species 3' could be trapped in solution by addition of PMe3 to afford both Cp*Rh+Me(PMe3)(Me2PCH2AlMe3-) (5) and [Cp*Rh+Me(PMe3)(Me2PCH2AlMe2)]AlMe4- (6). When compound 1 was addedto complex 3', the formation of the zwitterionic complex Cp*Rh+Me(hars/eta.gif" BORDER=0 >2-Me2PCH2Al-Me2CH2PMe2) (7)was observed.