Regioseletive 1,3-dipolar polycycloadditions of 4,4'-isopropylidenediphenyl dipropiolate (1) and tetraphenylethene (TPE)-containing diazides (2) are carried out in polar solvents such as DMF/toluene at a moderate temperature of 100℃ for 6 h,producing poly(aroxycarbonyltriazole)s (PACTs) P3 with high molecular weights (Mw up to 23900) and regioregularities (F1,4 up to ～90%) in high yields (up to ～99%).These metal-free click polymerizations can propagate smoothly in an open atmosphere without protection from oxygen and moisture.The obtained polymers are soluble in common organic solvents and thermally stable at temperatures up to 375℃.Thanks to their contained TPE moieties,the PACTs show aggregation-induced emission and can serve as fluorescent chemosensors for superamplified detection of explosives.
LI HongKunMEI JuWANG JianZHANG ShuangZHAO QiuLiWEI QiangQIN AnJunSUN JingZhiTANG Ben Zhong
We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes （PAs, P3） through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA （P2） was derived by desilylation of the pristine PA with trimethylethynylsilane side chains （P1）. P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane （M） under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps （from P1 to P3 via precursor P2） and one-pot （from P1 to P3 without separation and purification of P2） were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.
TONG LiQIN AnJunZHANG XiaoAMAO YuSUN JingZhiTANG Ben Zhong
Compositing gold nanoparticles into conjugated molecules have been developed to be one of the most important approaches to increase stability, since degradation of conjugated materials is now one of the biggest bottle-necks to be conquered before industrialization application. Big-size colloidal gold nanoparticles with strong surface plasma resonance are designed to composite with conjugated molecules, in order to realize effective fluorescence enhancement and stabilization. The uniform composition film of hydrophilic colloidal gold nanoparticles (particle diameter of 30 nm) and hydrophobic carbazole functionalized fluorene trimers has been obtained by direct mixing of their aqueous and THF solutions, which is determined by AFM. By the comparison of composition based on fluorene trimers with similar structures, we have found that peripheral carbazole group and molecular size of fluorene trimers play an important role in the balance of incompatible solubility, which is regarded as increasing solubility of fluorene trimers in mixed solvent, connecting AuNP and peripheral carbazole groups, and restraining aggregate of gold nanoparticle. This allows facile hydrophilic gold nanoparticle to disperse uniformly in hydrophobic-conjugated host. Our investigations show that fluorescence intensity of composition film is enhanced by 4 folds, and heat treatment (200°C for 4h) for the composition film does not induce the degradation of conjugated backbone without the appearance of low-energy emission band, demonstrating the prominent potency of gold nanoparticles in enhanced fluorescence and stability of conjugated molecules and polymers.
The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field. This review assembles an update of the advances of using azide-alkyne click polymerization to prepare functional polytriazoles（PTAs） with linear and hyperbranched structures.The Cu（I）-mediated click polymerization furnishes 1,4-regioregular PTAs,whereas,the metal-free click polymerization of propiolates and azides produces PTAs with 1,4-regioisomer contents up to 90%.The PTAs display advanced functions,such as aggregation-induced emission,thermal stability,biocompatibility and optical nonlinearity.
