Conformationally dynamic titanium and zirconium cationic complexes of bis(naphthoxy)pyridine ligands: structure, "oscillation" and olefin polymerization catalysis

Liana Annunziata (1) , Thierry Roisnel (1) , Abbas Razavi (2) , Jean-François Carpentier (1) , Evgueni Kirillov (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 Total Petrochemicals Research Feluy

Discrete ionic complexes {ONO}M(CHPh)((η-Ph)CHB(CF)) (M = Ti, 2-Ti; Zr, 2-Zr) have been prepared from the parent neutral dibenzyl precursors and B(CF). Also, a neutral dichloro complex {ONO}ZrCl(MeNH) (3) was synthesized by the reaction of a proligand {ONO}H (1-H2) with (MeN)ZrCl(DME). The compounds were characterized by NMR spectroscopy and X-ray crystallography (for 2-Zr and 3). In the solid state, both 2-Zr and 3 feature meso-like binding of the ligand. VT NMR studies of 2-Ti and 2-Zr revealed that the former species dissociates in solution to form an outer-sphere ion pair (OSIP) that features a complicated dynamic behavior, while the latter compound retains an inner-sphere ion pair (ISIP) structure that interconverts between C-symmetric (meso-like) and C-symmetric (rac-like) conformations. The mechanism of this interconversion was assessed by DFT calculations and the corresponding barrier for the straightforward interconversion was calculated ().

Domaines: Catalyse; Polymères

Liana Annunziata, Thierry Roisnel, Abbas Razavi, Jean-François Carpentier, Evgueni Kirillov. Conformationally dynamic titanium and zirconium cationic complexes of bis(naphthoxy)pyridine ligands: structure, "oscillation" and olefin polymerization catalysis. Dalton Transactions, 2017, 46 (10), pp.3150-3159. ⟨10.1039/c6dt04680k⟩. ⟨hal-01501258⟩