Abstract

The development of group 4 post-metallocene catalysts bearing tridentate [O,N,C(sp3)] auxiliary ligands has been reported, and excellent olefin polymerization activities have been achieved.1–3 In this work, a new family of homobimetallic Ti(Ⅳ) complexes containing different planar bridging components (dibenzofuran and xanthene) have been synthesized, and the employment of a combination of toluene and n-pentane as reaction solvents has been shown to produce cleaner reactions and higher product yields.  These derivatives have been fully characterized by 1H and 13C spectroscopy, together with [1H, 1H]-COSY, [13C, 1H]-HSQC and DEPT-135 NMR experiments. Studies have been undertaken to assess their olefin polymerization reactivity in conjunction with [Ph3C][B(C6F5)4]. DFT calculations have been performed to investigate the nature of the active species (including agostic interactions) and rationalize the observed catalytic behavior. The Ti2 catalysts display excellent olefin homo- and co-polymerization activities, and high degrees of comonomer incorporation. 

This work was supported by the Research Grants Council of the Hong Kong SAR, China (CityU 11308220). 

1. Liu, C.-C.; Chan, M. C. W.; Lo, P.-K.; Lau, K.-C.; Yiu, S.-M. Chem. Commun 2016, 52, 11056. DOI: 10.1039/c6cc05535d
2. Liu, C.-C.; Liu, Q.; Lo, P.-K.; Lau, K.-C.; Yiu, S.-M.; Chan, M. C. W. ChemCatChem 2019, 11, 628. DOI: 10.1002/cctc.201801008 
3. Liu, C.-C.; Liu, Q.; Yiu, S.-M.; Chan, M. C. W. Organometallics 2019, 38, 2963. DOI: 10.1021/acs.organomet.9b00307