Conformationally dynamic titanium and zirconium cationic complexes of bis(naphthoxy)pyridine ligands: structure, "oscillation" and olefin polymerization catalysis
Abstract
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 ().
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Conformationally Dynamic Titanium and Zirconium Cationic Complexes_revised.pdf (1.85 Mo)
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Conformationally dynamic titanium and zirconium cationic complexes_supplementary data.pdf (2.6 Mo)
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Origin : Files produced by the author(s)
Origin : Files produced by the author(s)
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