Hydrazido(2−) complexes of niobocene
| Autor: | Alexander N. Chernega, Malcolm L. H. Green, J. Thomas James |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Journal of the Chemical Society, Dalton Transactions. :1719-1726 |
| ISSN: | 1364-5447 0300-9246 |
| DOI: | 10.1039/a608008a |
| Popis: | The new compounds [Nb(η-C 5 H 4 R)(η-C 5 H 4 R′)Cl(NNMe 2 )] (R = H or Me; R′ = H or Me), [Nb(η 5 -C 5 H 4 R) 2 (η 1 -C 5 H 4 R)(NNMe 2 )] (R 3 = H x or Me y , x + y = 3), [Nb{CMe 2 (η 5 -C 5 H 4 )(η 1 -C 5 H 4 )}(η 5 -C 5 H 5 )(NNMe 2 )] and [Nb(η-C 5 H 5 ) 2 (thf)(NNMe 2 )][BPh 4 ] (thf = tetrahydrofuran) have been prepared. The crystal structure of [Nb(η-C 5 H 4 Me) 2 Cl(NNMe 2 )] has been determined. A variable-temperature NMR study of [Nb(η 5 -C 5 H 5 ) 2 (η 1 -C 5 H 5 )(NNMe 2 )] reveals a fluxional interchange of the three cyclopentadienyl rings. This compound has been shown to react with the electrophiles SiMe 3 Cl, FeCl 2 ·1.5thf, [NMe 3 H]Cl and [Nb(η-C 5 H 5 )Cl 2 (NNMe 2 )] to form in each case [Nb(η-C 5 H 5 ) 2 Cl(NNMe 2 )]. A variable-temperature NMR study of [Nb{CMe 2 (η 5 -C 5 H 4 )(η 1 -C 5 H 4 )}(η 5 -C 5 H 5 )(NNMe 2 )] shows the presence of two interconvertible diastereomers. The bis- and tris-cyclopentadienyl compounds have been shown to undergo exchange of their cyclopentadienyl rings in solution with each other or Li(C 5 H 4 R). The compound [Nb(η-C 5 H 5 )(OBu t ) 2 (NNMe 2 )] has also been shown to undergo a cyclopentadienyl ligand-exchange reaction. |
| Databáze: | OpenAIRE |
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