The solution structure of the zwitterionic complex [Zr(p-CH(2)C(6)H(4)CMe(3))(3)[B(C6F5)(3)(p-CH(2)C(6)H(4)CMe(3))]] and of the ion pair [Zr[m, m'-CH2C6H3(CMe(3))(2)](3)](+)[B(C6F5)(3)[m, m'-CH2C6H3(CMe(3))(2)](-) has been investigated by H-1- and C-13 NMR and compared with that of the zwitterion [Zr(CH(2)Ph)(3)[eta(6)-PhCH(2))B(C6F5)(3)]]. Comparative propene polymerization runs in the presence of the above zirconium complexes have been also performed. The influence of the hydrocarbyl ligands bonded to Zr in the three compounds was negligible, if any. It is concluded that possibly the active species promoting isotactic polymerization could be chiral polynuclear organometallic compounds arising from decomposition of the starting ionic species.
Homoleptic organometallic zirconium compounds as precursors of propene polymerization catalysts
LONGO, Pasquale;PROTO, Antonio;GRASSI, Alfonso;ZAMBELLI, Adolfo
1996-01-01
Abstract
The solution structure of the zwitterionic complex [Zr(p-CH(2)C(6)H(4)CMe(3))(3)[B(C6F5)(3)(p-CH(2)C(6)H(4)CMe(3))]] and of the ion pair [Zr[m, m'-CH2C6H3(CMe(3))(2)](3)](+)[B(C6F5)(3)[m, m'-CH2C6H3(CMe(3))(2)](-) has been investigated by H-1- and C-13 NMR and compared with that of the zwitterion [Zr(CH(2)Ph)(3)[eta(6)-PhCH(2))B(C6F5)(3)]]. Comparative propene polymerization runs in the presence of the above zirconium complexes have been also performed. The influence of the hydrocarbyl ligands bonded to Zr in the three compounds was negligible, if any. It is concluded that possibly the active species promoting isotactic polymerization could be chiral polynuclear organometallic compounds arising from decomposition of the starting ionic species.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
