Synthesis and spectroscopic characterization of group 4 post-metallocenes bearing (σ-aryl)-2-phenolate-6-pyridyl and -isoquinolinyl auxiliariesIn memory of Professor Ken Wade, a teacher and colossus amongst us.Electronic supplementary information (ESI) available: Experimental details and characterization data for 2-phenol-6-pyridylbenzene ligands, additional multinuclear NMR spectra, and table of ethylene polymerization results. See DOI: 10.1039/c5dt02497h

A new series of group 4 bis(benzyl) complexes supported by (σ-aryl)-2-phenolate-6-pyridyl [O,C,N] ligands have been prepared, and all derivatives have been characterized by multinuclear NMR spectroscopy. In the 1 H NMR spectrum of the Ti derivative where [N] = ( ortho -F)-substituted isoquinolinyl, one of the two CH 2 resonances is observed as a doublet of doublets (collapsing to a normal d upon 19 F-decoupling), whereas the [ 1 H, 19 F]-HMQC correlation spectrum reveals a strong crosspeak for this dd resonance only, thus indicating the presence of intramolecular C-H F-C interactions. [ 1 H, 19 F]-HMBC experiments have been performed which reveal a significant scalar component for this coupling and confirm that the interactions are genuine. The contrasting NMR spectral patterns for the ( ortho -F)-pyridyl Hf analogue, which exhibits two sets of non-identical doublet of doublets for the methylene resonances, have been rationalized. The activities of the isoquinolinyl-based Ti-[O,C,N] catalysts for ethylene polymerization are superior to those of pyridyl-based congeners. The title complexes have been characterized for X = F by multinuclear NMR (including [ 1 H, 19 F]-HMBC) experiments, confirming that the observed 19 F- 1 H (and - 13 C) coupling occurs with chemical connectivity across C-H F-C interactions, and their catalytic efficiencies for ethylene polymerization have been investigated.