Synthesis Of Dinuclear Half-titanocene Complex Bearing Anthracene Skeleton Bifunctional Alkoxide Ligand And Its Catalytic Activity

Polyolefin materials are extensively utilized in various fields due to their cost-effectiveness,excellent processability,and comprehensive properties.The key to the unique performance of polyolefin materials lies in the design and synthesis of catalysts.Among all catalysts,metallocene catalysts are an indispensable component in the industrial production of polyolefin.With its advantages of high catalytic activity,good selectivity,and controllable polymer structure,a novel dinuclear half-titanocene complex bearing anthracene skeleton bifunctional alkoxide ligand Ti2 was synthesized,characterized,and analyzed with its anthracene-based phenoxy ligands and titanium complexes.Its catalytic properties were also studied,aiming to produce polyolefin materials with remarkable characteristics.The primary focus of this paper can be summarized as follows:A new dinuclear half-titanocene complex bearing anthracene skeleton bifunctional alkoxide ligand was designed,synthesized,and characterized.Based on X-ray single crystal diffraction,evidence supports the complex possessing a symmetrical C₂structure,with a distance of 7.433?between its two metal atoms.The catalytic performance of Ti2 in olefin polymerization was investigated,and the results demonstrated that Ti2 exhibited high temperature resistance and excellent copolymerization capabilities when used in conjunction with tetrapentafluorophenyl borate（[Ph₃C][B（C₆F₅）₄]）as a co-catalyst.The homopolymerization activity of ethylene reached 62400 kg（PE）·mol^-1（Ti）·h^-1 at a polymerization temperature of120°C and a pressure of 5 atm.Additionally,under conditions of a polymerization temperature of 120°C,an ethylene pressure of 3 MPa,and a 1-octene concentration of2.5 M,Ti2 catalyst exhibited an activity of up to 112800 kg（PE）·mol^-1（Ti）·h^-1 for ethylene-octene copolymerization.At a higher polymerization temperature of 160°C,the polymerization activity decreased,but still retained a considerable activity of82800 kg（PE）·mol^-1（Ti）·h^-1.Compared to its mononuclear analogue Cp’Ti（O-2,6-ⁱPr₂C₆H₃）Me₂（Ti1）,the copolymerization of ethylene and norbornene catalyzed by Ti2 shows greater efficiency.Ti2 exhibits clear advantages in terms of activity,monomer insertion rate,and polymer molecular weight.At a norbornene concentration of 4 M and an ethylene pressure of 1 atm,Ti2 achieves a norbornene monomer insertion rate of up to 48.7 mol%in the copolymer produced,with a polymer molecular weight as high as 1650 kg?mol^-1.Under the same conditions,Ti1 is not active.