697310-75-1Relevant academic research and scientific papers
Isocyanide insertion reactivity of dinuclear niobium and tantalum imido complexes: X-ray crystal structure of [{Nb(η5 -C5H4SiMe3)(CH2Ph) 2}2(μ-1,4-NC6H4N)]
Prashar, Sanjiv,Fajardo, Mariano,Garcés, Andrés,Dorado, Iván,Anti?olo, Antonio,Otero, Antonio,López-Solera, Isabel,López-Mardomingo, Carmen
, p. 1304 - 1314 (2004)
The reactivity of dinuclear niobium and tantalum imido complexes with the isocyanide compound 2,6-Me2C6 H3NC has been studied. The trialkyl complexes [{NbR3(CH3CN)}2 (μ-1,3-NC6H4N)], [{NbR3 (CH3CN)}2(μ-1,4-NC6H4N)] and [{TaR3(CH3CN)}2 (μ-1,4-NC6H4N)] (R=CH2 SiMe3) gave [{Nb(η2-RC=NAr) 2R}2(μ-1,3-NC6H4N)] (1), [{Nb(η2-RC=NAr)2R}2 (μ-1,4-NC6H4N)] (2) and [{Ta(η2-RC=NAr)2R}2 (μ-1,4-NC6H4N)] (3) (R=CH2 SiMe3; Ar=2,6-Me2C6H3), from the isocyanide insertion in two of the metal alkyl carbon bonds. The reaction of the isocyanide reagent with the di-alkyl mono-cyclopentadienyl derivatives [{Nb(η5-C5H4 SiMe3)R2}2(μ-1,3-NC6 H4N)] R=Me, CH2Ph, CH2SiMe3), [{Nb(η5-C5H4SiMe3) R2}2(μ-1,4-NC6H4N)] (R=Me, CH2Ph (4), CH2SiMe3) and [{Ta(η5-C5Me5)(CH2 SiMe3)2}2(μ-1,4-NC6 H4N)] yielded [{Nb(η5-C5 H4SiMe3)(η2-RC=NAr)R}2 (μ-1,3-NC6H4N)] (R=Me (5), CH2Ph (6), CH2SiMe3 (7)), [{Nb(η5 -C5H4SiMe3)(η2-RC=NAr) R}2(μ-1,4-NC6H4N)] (R=Me (8), CH2Ph (9), CH2SiMe3 (10)) and [{Ta(η5-C5Me5)(η2 -Me3SiCH2C=NAr) CH2SiMe3} 2(μ-1,4-NC6H4N)] (11) (Ar=2,6-Me2C6H3), respectively, from a single insertion process. The reaction with the mono-alkyl complex [{Nb(η5-C5H4SiMe3) (Me)Cl}2(μ-1,4-NC6H4N)] gave [{Nb(η5-C5H4SiMe3) (η2-MeC=NAr)Cl}2(μ-1,4-NC6 H4N)] (12), produced from the isocyanide insertion in the metal-alkyl carbon bond. The alkyl-amido complex [{Nb(η5-C5H4SiMe3) (Me)NMe2}2(μ-1,4-NC6H4N)] gave, from the preferential isocyanide insertion in the metal-amide nitrogen bond, [{Nb(η5-C5H4 SiMe3)(η2-Me2NC=NAr)Me}2 (μ-1,4-NC6H4N)] (13). The molecular structure of one of the alkyl precursors, [{Nb(η5 -C5H4SiMe3)(CH2Ph) 2}2(μ-1,4-NC6H4N)] (4), has been determined.
