Influence of solvents on the insertion of methacrolein into zirconacyclopropenes
摘要:
The reaction of Cp(2)Zr(L)(eta(2)-Me(3)SiC(2)SiMe(3)) (L = THF, py) with equimolar amounts of H2C=CMe-CHO at room temperature depends strongly on the ligands L and the solvents that are used. With L = THF, in THF solution the insertion product Cp(2)Zr-O-CH(CMe=CH2)-C(SiMe(3))=C(SiMe(3)) 1 was isolated, whereas by conducting the reaction in n-hexane solution an alkyne substitution with 1,4-coordination of the methacrolein takes place and the binuclear complex [Cp(2)Zr-O-CH=CMe-CH2](2) 2 was obtained. In contrast, with L = py (a stronger ligand) only a 1:1 ratio of 1 and 2 was observed in both THF and in n-hexane, At 50 degrees C complex 1 was converted into 2 and the alkyne was eliminated quantitatively.Complexes 1 and 2 were characterized by IR and NMR spectroscopical measurements and 1 by an additional X-ray structure determination.
Influence of solvents on the insertion of methacrolein into zirconacyclopropenes
摘要:
The reaction of Cp(2)Zr(L)(eta(2)-Me(3)SiC(2)SiMe(3)) (L = THF, py) with equimolar amounts of H2C=CMe-CHO at room temperature depends strongly on the ligands L and the solvents that are used. With L = THF, in THF solution the insertion product Cp(2)Zr-O-CH(CMe=CH2)-C(SiMe(3))=C(SiMe(3)) 1 was isolated, whereas by conducting the reaction in n-hexane solution an alkyne substitution with 1,4-coordination of the methacrolein takes place and the binuclear complex [Cp(2)Zr-O-CH=CMe-CH2](2) 2 was obtained. In contrast, with L = py (a stronger ligand) only a 1:1 ratio of 1 and 2 was observed in both THF and in n-hexane, At 50 degrees C complex 1 was converted into 2 and the alkyne was eliminated quantitatively.Complexes 1 and 2 were characterized by IR and NMR spectroscopical measurements and 1 by an additional X-ray structure determination.