Polymerization Of N-tosylhydrazones And Polymerization Of Olefins Catalyzed By Half-sandwich Rare-earth Complexes

With the advancement of science and technology,the field of functionalized polymer materials is undergoing innovation and development to serve the society.Compared with traditional polymers,functionalized polymer materials have exhibited tremendous application prospect in chemical reactivity,catalysis,conductive materials and optical properties.Development of synthesis methods of functionalized polymers with diverse structures has received considerable attention to broaden the application field.Therefore,in this thesis,ferrocene-containing cross-conjugated polymers and sulfur-containing polymers were synthesized by polymerization of N-tosylhydrazones,and the mechanism of polymerization and the properties of polymers were studied.At the same time,a series of functionalized polyolefins were synthesized using half-sandwich rare-earth complexes,which provided a new possibility for expanding the application field of polyolefins.The main contents are as follows:In the first part,ferrocene-containing cross-conjugated polymers in the main chain were synthesized by ferrocenyl ketone-derived N-tosylhydrazones（0.5 mmol）,arylbromides,Pd₂（dba）₃（2 mol%）,Li O^tBu（2.2 mmol）,XPhos（Pd/XPhos=1/1.5）,and 1,4-dioxane（5 m L）under N₂ at 110°C for 4 h.A diversity of ferrocene-containing cross-conjugated polymers with moderate number-average molecular weight and narrow molecular weight distribution could be obtained.This method had broad substrates scope.P7 was an efficient low migration BRC demonstrated by TGA curves and migration study.Additionally,cross coupling polymerization reaction also provides a feasible way to synthesize ferrocene-containing novel polymers in the main chain.In the second part,sulfur-containing polymers were synthesized by cross coupling polymerization of N-tosylhydrazones and thiols using K₂CO₃（6 equiv.）and 1,4-dioxane（5 m L）without transition-metal catalyst at 110°C for 24 h.The crystallinity,surface morphology and structure of the polymers were investigated by WAXD,SEM and MALDI-TOF-MS.It was noteworthy that polymerization occurred effectively starting from ketones with no need to separate N-tosylhydrazones,which had a series of advantages,such as operational simplicity,green economy,and broad substrates scope.As N-tosylhydrazones are readily available,synthetic versatile and stable to air and moisture,a novel,alternative route to form sulfur-containing polymers using N-tosylhydrazones as monomers was demonstrated.In the third part,polymerizations of 1-decene have been achieved by using catalyst systems a-b/[Ph₃C][B（C₆F₅）₄]varied in steric hindrance and central metal.Scandium complex 1a displayed high conversion（87.6%）,1,2-insertion selectivity（92.4%）,and number-average molecular weight ranging from 17.70×10~4 to 0.23×10~4.Complex 1b provided oligomers of 1-decene and 2,1-insertion selectivity（87.0%）suggesting specific selectivity of half-sandwich rare-earth complexes.GC-MS analysis showed that oligomers obtained by 1b were a mixture of dimer to hexamer,with hexamer content accounting for more than 40%.These experimental results demonstrated that high conversion,high regioselectivity,high viscosity index,and low pour point（<-45°C）poly（α-olefin）could be obtained using half-sandwich rare-earth catalyst systems.In the fourth part,functionalized polyolefins were prepared catalyzed by the scandium catalyst 1a/[Ph₃C][B（C₆F₅）₄].The copolymerization of oxygen-containingα-olefin with isoprene has afforded the corresponding functionalized P（A-IP）copolymers with excellent cis-1,4-IP selectivity（97%）.The obtained P（A-IP）copolymers were multi-block copolymers.The insertion ratio of A could be facilely tuned in the broad range.The copolymerization of oxygen-containingα-olefin and styrene was investigated,yielding the functionalized P（A-St）copolymers with a random sequence and random styrene unit.The insertion ratio of A could reach up to 63%.The copolymerization of myrcene with isoprene has been achieved.Half-sandwich rare-earth catalyst systems showed high cis-1,4-selectivity for the polymerization of conjugated diene.The incorporation strategy of heteroatom and unsaturated group into olefins provided a new possibility for the synthesis of functionalized polyolefin materials.