The reaction of a series of di-Me zirconocenes [Me2Si(Cp)2ZrMe2, 1; Cpt-bu2ZrMe2, 2; Cpn-bu2ZrMe2, 3; Ind2ZrMe2, 4; CpMe42ZrMe2, 5; Cp*2ZrMe2, 6] with [HNMe2Ph][B(C6F5)4] was investigated by NMR spectroscopy. It was found that protonolysis of a Zr-Me group occurred generating a coordinative vacancy at the metal center and methane. Cations coming from 1-4 di-Me precursors bound NMe2Ph, liberated from the protonation process, and formed zirconaaziridinium ion pairs {[Me2Si(Cp)2Zr(η2-CH2NMePh)][B(C6F5)4], 7; [Cpt-bu2Zr(η2-CH2NMePh)][B(C6F5)4], 8; [Cpn-bu2Zr(η2-CH2NMePh)][B(C6F5)4], 9; [Ind2Zr(η2-CH2NMePh)][B(C6F5)4], 10}, reasonably as a consequence of CH activation of one Me group of coordinated NMe2Ph and methane elimination. The intramol./interionic structures and dynamics of 7-10 ion pairs were investigated by 1H, 13C and 19F 1D-and 2D-NMR techniques. The reactions of 7 and 10 ion pairs with 2-methyl-1-heptene afforded stable diastereoisomeric ion pairs bearing a five-member azametallacycle.
An NMR study on the reaction of substituted dimethyl zirconocenes with dimethylanilinium borate
ROCCHIGIANI, LUCA;BELLACHIOMA, Gianfranco;ZUCCACCIA, Cristiano;MACCHIONI, Alceo
2012
Abstract
The reaction of a series of di-Me zirconocenes [Me2Si(Cp)2ZrMe2, 1; Cpt-bu2ZrMe2, 2; Cpn-bu2ZrMe2, 3; Ind2ZrMe2, 4; CpMe42ZrMe2, 5; Cp*2ZrMe2, 6] with [HNMe2Ph][B(C6F5)4] was investigated by NMR spectroscopy. It was found that protonolysis of a Zr-Me group occurred generating a coordinative vacancy at the metal center and methane. Cations coming from 1-4 di-Me precursors bound NMe2Ph, liberated from the protonation process, and formed zirconaaziridinium ion pairs {[Me2Si(Cp)2Zr(η2-CH2NMePh)][B(C6F5)4], 7; [Cpt-bu2Zr(η2-CH2NMePh)][B(C6F5)4], 8; [Cpn-bu2Zr(η2-CH2NMePh)][B(C6F5)4], 9; [Ind2Zr(η2-CH2NMePh)][B(C6F5)4], 10}, reasonably as a consequence of CH activation of one Me group of coordinated NMe2Ph and methane elimination. The intramol./interionic structures and dynamics of 7-10 ion pairs were investigated by 1H, 13C and 19F 1D-and 2D-NMR techniques. The reactions of 7 and 10 ion pairs with 2-methyl-1-heptene afforded stable diastereoisomeric ion pairs bearing a five-member azametallacycle.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
