The Synthesis And Application Of Chiral Polymers With Fluorene Groups

In the field of asymmetric synthesis,the synthesis and study of the chiral polymer is an important subject.There are two common methods for obtaining chiral polymers.One is that chiral monomers undergo polymerization under the conditions of the catalyst to prepare optically active chiral polymers;The other is the use of achiral monomers to initiate polymerization under chiral initiators or chiral additives to give chiral polymers.Based on this,in this paper,seven monomers of 9,9-dipentadiynylfluorene,9,9-dipropynylhydrazine and its derivatives,and anthraquinone derivatives with ch iral oxazoline were designed and synthesized.Polymerization studies were carri ed out to obtain optically active chiral polymers.The details are as follows:(1)Two new monomers containing dipentadiynyl groups were synthesized:9,9-tetrapropynylfluoren(TPYF),and(S)-2-(9H-tetrapropynyl-fluoren-2-yl)-4-tertbut yl-4,5-dihydrooxazoline((S)-2-FTDH).Under the cocatalysis of(S)-(+)-1-(2-pyrrol idinomethyl)pyrrolidine((L)-PDMPD)and CuCl,the polymerization conditions un der different solvent systems were studied and the chiral optical properties of t he product were also reserched.The results show that the achiral TPYF mono mer prepared under the induction of chiral catalyst has obvious optical activity;However,the product obtained from the polymerization of chiral(S)-2-FTDH monomer has the opposite optical orientation to the monomer.(2)Preparation of 9,9-dipropynyl hydrazines and derivatives of three non-chir al monomers:9,9-dipropynylfluoren(DPYF),2-acetyl-9,9-dipropynylfluoren(ADPF)and(R)/(S)-2-(9H-dipropyne-fluoren-2-yl)-4-phenyl-4,5-dihydrooxazoline(DPDH).Under the action of the catalyst,the polymerization reaction and the chiral ch aracter of the polymer obtained under different solvents,different temperatures and different molar ratios of monomers and catalysts were studied.The results show that this non-chiral monomers can also form polymers having a single-he lical conformation under the induction of a chiral catalyst.(3)Synthesis of two hydrazine derivative monomers with pendant oxazoline side groups:(S)-2-(9H-fluoren-2-yl)-4-tertbutyl-4,5-dihydrooxazoline((S)-1-FTBDH),and(S)-2-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazoline((S)-2-FIPDH).Usin g the Sc(OTf)3 as the catalyst,To study the ring-opening polymerization of ox azoline and the chiral nature of the product under different conditions.The resul ts show that the oxazoline side group has a great influence on the polymerizati on ability of the monomer,and the sterically hindered monomer(S)-1-FTBDH can not undergo ring-opening polymerization,while the slightly hindered mono mer(S)-2-FIPDH of the polymer product yield and molecular weight are not v ery high.