Group 4 Imido Complexes Stabilized by a Tridentate Diamido-Donor Ligand
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- 作者：Alexander J. Blake ; Philip E. Collier ; Lutz H. Gade ; Philip Mountford ; Julian Lloyd ; Stephen M. Pugh ; Martin Schubart ; Michael E. G. Skinner ; and Dominique J. M. Trö ; sch
- 刊名：Inorganic Chemistry
- 出版年：2001
- 出版时间：February 26, 2001
- 年：2001
- 卷：40
- 期：5
- 页码：870 - 877
- 全文大小：146K
- 年卷期：v.40,no.5(February 26, 2001)
- ISSN：1520-510X
文摘
Reaction of the lithium amides [(2-C5H4N)C(CH3){CH2N(Li)SiMe3}2]2 (2a) and [(2-C5H4N)C(CH3){CH2N(Li)SiMe2tBu}2]2 (2b) with the imidotransition metal complexes [Ti(NtBu)Cl2(py)3], [Ti(N-2,6-C6H3iPr2)Cl2(py)3],and [Zr(N-2,6-C6H3iPr2)Cl2(thf)2] yielded the five-coordinate imido-titanium and -zirconium complexes [{
3N-(2-C5H4N)C(CH3)(CH2NSiMe2R)2}Ti(NR')(py)] (R = Me, R' = tBu: 3a, R= tBu, R' = tBu: 3b, R = Me,R' = 2,6-C6H3iPr2: 4a, R = Me, R' = 2,6-C6H3Me2: 4b) and [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Zr(N-2,6-C6H3iPr2)(py)] (5). The tridentate diamido-pyridine ligand adopts a facial coordination mode in the distortedtrigonal bipyramidal complexes with the imido ligand occupying an equatorial position, as was established byX-ray diffraction for 3a and 5. Sublimation of 3a and 4a yielded the pure four-coordinate imidotitanium complexes[{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NR')] (R' = tBu: 6, 2,6-C6H3iPr2: 7) which were structurallycharacterized by X-ray crystallography. Reaction of 3a with the Lewis acid B(C6F5)3 also led to abstraction ofthe axially bound pyridine ligand and the formation of the adduct [py-B(C6F5)3] and 6. Reaction of 6 with thf,PMe3, and pyridine led to the formation of pentacoordinate complexes [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NtBu)(thf)] (8), [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NtBu)(PMe3)] (9), and [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NtBu)(py)] (3a) in which the donor ligands occupy axial positions.
3N-(2-C5H4N)C(CH3)(CH2NSiMe2R)2}Ti(NR')(py)] (R = Me, R' = tBu: 3a, R= tBu, R' = tBu: 3b, R = Me,R' = 2,6-C6H3iPr2: 4a, R = Me, R' = 2,6-C6H3Me2: 4b) and [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Zr(N-2,6-C6H3iPr2)(py)] (5). The tridentate diamido-pyridine ligand adopts a facial coordination mode in the distortedtrigonal bipyramidal complexes with the imido ligand occupying an equatorial position, as was established byX-ray diffraction for 3a and 5. Sublimation of 3a and 4a yielded the pure four-coordinate imidotitanium complexes[{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NR')] (R' = tBu: 6, 2,6-C6H3iPr2: 7) which were structurallycharacterized by X-ray crystallography. Reaction of 3a with the Lewis acid B(C6F5)3 also led to abstraction ofthe axially bound pyridine ligand and the formation of the adduct [py-B(C6F5)3] and 6. Reaction of 6 with thf,PMe3, and pyridine led to the formation of pentacoordinate complexes [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NtBu)(thf)] (8), [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NtBu)(PMe3)] (9), and [{3N-(2-C5H4N)C(CH3)(CH2NSiMe3)2}Ti(NtBu)(py)] (3a) in which the donor ligands occupy axial positions.