Conformationally dynamic titanium and zirconium cationic complexes of bis(naphthoxy)pyridine ligands: structure, "oscillation" and olefin polymerization catalysis. Issue 10 (30th January 2017)

• Record Type: Journal Article
• Authors: Annunziata, Liana; Roisnel, Thierry; Razavi, Abbas; Carpentier, Jean-François; Kirillov, Evgueni
• Is Part Of: Dalton transactions. Volume 46:Issue 10(2017)
• Page Start: 3150
• Page End: 3159
• Publication Date: 2017-01-30
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt04680k
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The interconversion and reorganization processes occurring in cationic Ti and Zr complexes were studied by NMR techniques and DFT computations. Abstract : Discrete ionic complexes {ONO SiMe2 t Bu }M(CH2 Ph)((η 6 -Ph)CH2 B(C6 F5 )3 ) (M = Ti, 2-Ti ; Zr, 2-Zr ) have been prepared from the parent neutral dibenzyl precursors and B(C6 F5 )3 . Also, a neutral dichloro complex {ONO SiMe2 t Bu }ZrCl2 (Me2 NH) (3 ) was synthesized by the reaction of a proligand {ONO SiMe2 t Bu }H2 (1-H2 ) with (Me2 N)2 ZrCl2 (DME). The compounds were characterized by NMR spectroscopy and X-ray crystallography (for2-Zr and3 ). In the solid state, both2-Zr and3 feature meso -like binding of the ligand. VT NMR studies of2-Ti and2-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 s -symmetric ( meso -like) and C 1 -symmetric ( rac -like) conformations. The mechanism of this interconversion was assessed by DFT calculations and the corresponding barrier for the straightforward interconversion was calculated ( ).