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首页> 外文期刊>European Polymer Journal >Synthesis of novel helical poly(N-propargylamides) containing azobenzene pendant groups and effects of substitution groups on azobenzene on the stability of helix
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Synthesis of novel helical poly(N-propargylamides) containing azobenzene pendant groups and effects of substitution groups on azobenzene on the stability of helix

机译：含偶氮苯侧基的新型螺旋聚（N-炔丙基酰胺）的合成及偶氮苯上取代基对螺旋稳定性的影响

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A series of novel N-propargylamides bearing substituted azobenzene pendant groups (R-C6H4-N=N-C6H4-CONHCH(CH3)CONHCH2C CH, R = CH3CH2N(CH2)(2)OOC(CH2)(3)CH3 (V-1), R = CH3CH2N(CH2)(2)OOCCH2NHCOCH3 (V-2), R = H (V-3)) were synthesized and polymerized with [Rh(nbd)Cl](2) as a catalyst to obtain the corresponding polymers (Poly(V1-3)). The azobenzene chromophores in the side chains of Poly(V-1,V-2) contained bulky electron-donating substituents, while the azobenzene in Poly(V-3) did not bear this kind of substituent The introduction of substituted azobenzene chromophores into the side chains of poly(N-propargylamides) was found to increase the hydrogen bond strength, steric repulsion and electrostatic interactions between the neighboring side chains. These factors worked together to improve the helical stability of poly(N-propargylamides). The solubility of these poly(N-propargylamides) was increased by introducing substituents into the azobenzene chromophores. CD and UV-vis spectra showed that all the poly(N-propargylamides) took the helical structures with predominantly one-handed screw sense, which were tight helices. Furthermore, the unsubstituted azobenzene groups in the side chains of Poly(V-3) also arranged to form the helical conformation. The helical structures of Poly(V1-3) remained stable at various temperatures (5-60 degrees C). Poly(V-1,V-2) exhibited good helicity in polar solvent, which indicated that the bulky substituents, electrostatic and steric repulsion between the adjacent side chains lessened the effect of polar solvent on the hydrogen bonding. The main chains of Poly(V-1,V-3) still kept helical sense after the isomerization of trans-azobenzene to the cis form upon UV irradiation. The helical array of azobenzene side chains in Poly(V-3) experienced reversible arrangement-disarrangement upon photoirradiation. (C) 2015 Elsevier Ltd. All rights reserved.
机译：一系列带有取代的偶氮苯侧​​基的新型N-炔丙基酰胺（R-C6H4-N = N-C6H4-CONHCH（CH3）CONHCH2C CH，R = CH3CH2N（CH2）（2）OOC（CH2）（3）CH3（V- 1），合成R = CH3CH2N（CH2）（2）OOCCH2NHCOCH3（V-2），R = H（V-3））并以[Rh（nbd）Cl]（2）为催化剂聚合，得到相应的聚合物（Poly（V1-3））。聚（V-1，V-2）侧链中的偶氮苯生色团含有庞大的供电子取代基，而聚（V-3）中的偶氮苯不带有这种取代基。发现聚（N-炔丙基酰胺）的侧链增加了相邻侧链之间的氢键强度，位阻和静电相互作用。这些因素共同作用，以提高聚（N-炔丙基酰胺）的螺旋稳定性。通过将取代基引入偶氮苯生色团来提高这些聚（N-炔丙基酰胺）的溶解度。 CD和UV-可见光谱表明，所有聚（N-炔丙基酰胺）均具有螺旋结构，其螺旋结构主要为单手螺旋。此外，聚（V-3）的侧链中的未取代的偶氮苯基团也排列成形成螺旋构象。 Poly（V1-3）的螺旋结构在各种温度（5-60摄氏度）下均保持稳定。聚（V-1，V-2）在极性溶剂中具有良好的螺旋性，这表明相邻侧链之间的大取代基，静电排斥和空间排斥减少了极性溶剂对氢键的影响。在紫外线照射下，反式偶氮苯异构化为顺式后，聚（V-1，V-3）的主链仍保持螺旋感。聚（V-3）中偶氮苯侧链的螺旋排列在光辐照下经历可逆的排列-失序。 （C）2015 Elsevier Ltd.保留所有权利。

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