Highly Active Nickle Complexes For Vinyl Polymerization Of Norbornene

In this dissertation,a series of salicylketimines ligands in the coordination sphere have been synthesized rapidly without solvent under microwave irradiation,the synthesis steps were shorted and yields were enhanced,and a new ecofriendly synthesis method was realized.Some niche complexes of general forms were synthesised and characterized.These nickel(â…¡)complexes were investigated as catalysts for the vinylic polymerization of norbornene.The influence of electronic effects,Al/Ni molar radio, monomer concentration and reaction temperature on polymerization reaction have been discussed in detail.Conclusions were summarized as follows:1.A microwave-assisted preparation of a serious of schiff-base was performed via efficient condensation of salicylaldehyde and amine without solvent,the ligands were prepared in good yields(65-98%)and short time(20s-6min)by the simple synthesis method.The compounds of 1c to 10c and 26c to 32c were previously synthesized through traditional Schiff-base formation.Their stuctures were confirmed by ¹HNMR. With the best of our knowledge,the compounds of 11c to 25c were unknown and their stuctures were confirmed by IR,NMR date and elemental analysis.Some of their niche and coalt complexes containing functionalized pyridine were synthesised and characterized.The solid-state structures of the coalt complexe were confirmed by X-ray single-crystal analyses.2.The nickle(â…¡)complexes were investigated as catalysts for the vinylic polymerization of norbomene in the presence of methylaluminoxane as cocatalyst.The complexes were found not to be an active catalyst for the polymerization of norbomene in the absence of MAO.However,after activation with MAO,they could catalyze the polymerization of norbomene to afford addition-type polynorbomene(PNB)with high activity(10⁸gPNBmol^-1Nih^-1),high molecular weight(10⁶gmol^-1)and moderate molecular weight distributions Mw/Mn(2.74-6.6).The results indicates that electron effect on the nickle precursors play an important role in the activation of the catalysts.But steric stucture of the nickle complexes doesn't appreciably influence their catalytic activity. Catalytic activities,polymer yield,Mw and Mw/Mn of PNB have been controlled over a wide range by the variation of the reaction parameters such as electronic effects,Al/Ni molar radio,reaction temprature,monomer concentration.PNBs obtained here are amorphous and soluble in halogenated aromatic hydrocarbons.