Group 4 Metal Complexes of Fluorous (Di)Alkoxide-(Di)Imino Ligands: Synthesis, Structure, Olefin Polymerization Catalysis, and Decomposition Pathways

Abstract

The coordination chemistry of fluorous (di)alkoxide-(di)imino ligands onto Ti(IV), Zr(IV), and Hf(IV) centers has been studied. The diimino-diol [(CF3)2C(OH)CH2C(Me)═NCH2−]2 ({ONEtNO}H2) reacts selectively with Ti(OiPr)2Cl2 and Zr(CH2Ph)4 to give the corresponding complexes {ONEtNO}TiCl2 (1) and {ONEtNO}Zr(CH2Ph)2 (2), with concomitant alcohol and alkane elimination, respectively. Reactions of the imino-alcohols (CF3)2C(OH)CH2C(R1)═NR2 ({ONR1,R2}H; R1 = Me, Ph; R2 = Ph, CH2Ph) with Ti(OiPr)4 and M(CH2Ph)4 (M = Zr, Hf) gave the corresponding complexes Ti(OiPr)2{ONR1,R2}2 (3a,b) and M(CH2Ph)2{ONR1,R2}2 (M = Zr, 7a,b,c; M = Hf, 8a,b). Dibenzyl complexes 7 and 8 decompose above −30 °C by abstraction of a hydrogen from the methylene ligand backbone by a benzyl group to give M(CH2Ph){ONR1,R2}{ON−R1,R2} complexes (M = Zr, 9a−c; M = Hf, 10a), in which a ligand unit ({ON−R1,R2}) has been transformed to an α,β-unsaturated amido-alkoxy dianionic moiety. A slightly different process was observed for the pentafluoroph...