Halogen Effects On Phenylethynyl Palladium(?) Complexes For Living Polymerization Of Isocyanides

This paper is divided into three modules,the detailed content is as follows:1.Halogen effects on phenylethynyl palladium???complexes for living polymerization of isocyanides.In this part,two new phenylethynyl palladium???initiators bearing bromide?1b?and iodide?1c?were synthesized and applied for living polymerization of aryl and alkyl isocyanides.The coordinated halogen anions can significantly influence the kinetics of polymerization,with the observed order of reaction rates being 1c?I?>1b?Br?>1a?Cl?.Impressively,1c not only accelerates the reaction rate in both the initiation stage and propagation stage,but also can polymerize less active monomers that cannot be reacted by 1a.DFT calculations were then employed to understand the detailed mechanism and the halogen effects in this insertion polymerization process.2.The construction of optical active metallo-supramolecular polymers from enantiopure bis-pybox ligands.In this part,two types of optical active metallo-supramolecular polymers were successfully constructed from the complexation of two enantiopure bis-pyridine-dioxazole?bis-pybox?ligands and 3d transition metal ions such as Zn²⁺and Fe²⁺in organic solution.The self-assembly process was investigated via UV-vis and fluorescent titration.The chiral characteristic of polymers was detected by circular dichroism.It was revealed that the phenyl-substituted polymers showed higher stability than the benzyl-substituted ones.Temperature-dependent circular dichroism spectra demonstrated the dynamic structure of this type polymer under the variation of temperature.This work highlights the opportunity in designing and constructing of the optical active metallo-supramolecular polymers from the organic privilege ligands in the field of asymmetric catalysis.3.The effect of inductive properties on the spin states of[Fe?X-pybox-S?₂]²⁺complexes.In this part,four types of complexes were successfully constructed from the complexation of four pyridine-2,6-bis?thiazoline?s ligands with different substituents and3d transition metal ions Fe²⁺.Single crystals of four complexes were obtained by vapor diffusion method,and four complex single crystal structures were obtained by single crystal X-ray diffraction.Induction effects from the 4-position of the pyridine ring on its spin-crossover?SCO?behavior was investigated by magnetic testing.