一锅法制备具有AIE效应含对苯二乙腈单元聚合物

Preparation of polymer containing p-phenyldiacetonitrile units with aggregation induced emission effect by one-pot method

以对苯二乙腈和对羟基苯甲醛为原料通过Knoevenagel缩合反应合成α,α’-双-(对羟基亚苄基)-对苯二乙腈(M1),然后与环氧氯丙烷通过Williamson反应合成α,α’-双-[对-(2,3-环氧丙氧基)亚苄基]-对苯二乙腈(M2).以2-氰基-2-丙基苯并二硫为可逆加成断裂链转移试剂,引发2-(2',3',4',6'-四-O-乙酰基-α-D-吡喃甘露糖基氧基)甲基丙烯酸乙酯聚合制备了含双硫酯片段的聚合物P1,P1与M2通过“一锅法”合成含对苯二乙腈单元聚合物P2,脱除乙酰基保护得到水溶性荧光聚合物P3.利用核磁共振波谱、傅里叶变换红外光谱、凝胶渗透色谱、紫外-可见光谱和荧光光谱对化合物和聚合物的化学结构和光学性质等进行了表征与测试.结果表明:P3的紫外吸收峰和荧光发射峰分别在368 nm和440 nm,P3荧光强度随着DMSO-H2O体系DMSO体积分数的增加而逐渐增强,并且在体积分数大于80%时荧光强度显著增强,表现出聚集诱导发光特性.P3具有较好的热稳定性,相转变温度为118℃.

Compoundα,α’-bis-(p-hydroxybenzylidene)-p-benzenediacetonitrile(M1)was synthesized by Knoevenagel condensation reaction using p-benzenediacetonitrile and p-hydroxybenzaldehyde as raw materials.Compoundα,α’-bis-[p-(2,3-epoxypropoxy)-benzylidene]-p-benzenediacetonitrile(M2)was synthesized from M1 and epichlorohydrin by Williamson reaction.Polymer P1 was synthesized by using 2-(2',3',4',6'-tetra-O-acetyl-α-D-mannopyranosyloxy)ethyl methacrylate(M4)as monomer and 2-cyano-2-propyl benzodithioate as reversible addition-fragmentation transfer agent.Polymer P2 with defined structure was synthesized via one-pot reaction with P1 and M2(the reduction reaction of dithioester(P1)and click reaction between the thiol group and epoxy group(M2)were simultaneously conducted in one pot with high conversion).The water-soluble fluorescent polymer P3 was obtained in a high yield after the deacetylation protection reaction of P2.The chemical structures and optical properties of compounds and polymers were characterized and tested by nuclear magnetic resonance spectrum,Fourier transform infrared spectroscopy,gel permeation chromatography,ultraviolet-visible spectroscopy and fluorescence spectroscopy,These results showed that the ultraviolet-visible absorption peak and the fluorescence emission peak of P3 were 368 nm and 440 nm,Fluorescence intensity of P3 gradually increased with the increase of DMSO fraction in DMSO/H 2O system,when DMSO fraction was over 80%,which indicated the aggregation-induced emission characteristic of P3.Polymer P3 had good thermal stability,and the phase transition temperature was 118℃.