Abstract

The synthesis of the new zirconium complex [Zr(eta(5)-C5H5){NC-amidine}Cl-2] (1) has been achieved by reaction of the amidine (E)-N-(4-cyanophenyI)-N'-(2,6-diisopropylphenyl)acetimidamide with [Zr(eta(5)-C5H3)Cl-3] and the new complex has been characterized by spectroscopic methods. The reaction of one equivalent of B(C6F5)(3) with compound 1 produces the adduct [Zr(eta(5)-C5H5){(C6F3)B-NC-amidine}]Cl-2 (2). Complexes 1 and 2 have been tested as homogeneous catalysts in olefin polymerization using MAO as cocatalyst. The grafting of 1 and the previously reported complex [Zr(eta(5)-C5H5)(NC-NacNac)Cl-2] (3) on to several inorganic solid supports, namely dehydroxylated silica (SiO2(TEMP)) (S-1), dehydroxylated silica modified with O(SiMe3)(2) (S-2) or MAO (S-3), and MgCl2 (S-4) has been carried out by addition of a freshly prepared solution of 1 or 3 to the corresponding inorganic solid. FT-IR studies of the new materials showed that the links between complexes 1 or 3 and S-1 and S-2 occur through the zirconium center, whereas with S-3 and S-4 the links involve the CN functional group of the ligand. These new materials have been studied as catalysts in olefin polymerization reactions in the presence of MAO. A UV-vis study was carried out in order to identify the minimum amount of MAO necessary to produce the active species. A preliminary study into the activity in olefin polymerizations was also carried out. (C) 2014 Elsevier B.V. All rights reserved.