Chelating diamide group IV metal olefin polymerization catalysts

The novel group IV metal chelating diamide complexes [(2,6-diisopropylanili do)B(NMe2)B(NMe2)(2,6-diisopropylanilido)] MX2, 7a (M = Ti, X = CI), 7b (M = Ti, X = Me), and 8 (M = Zr, X = CH2Ph), have been prepared and characteri zed by H-1 and C-13{H} NMR spectroscopy and single-crystal X-ray structure analysis (7a). These complexes are active polymerization catalysts upon com bining with the appropriate activator. The catalyst efficiencies, however, are considerably lower than those of Cp-based catalysts. The molecular weig hts of the polymers produced are activator dependent, and the polydispersit ies were found to be broader than those observed for Cp-based single-site c atalytic systems.