Doublet Chirality Transfer and Reversible Helical Transition in Poly(3,5-disubstituted phenylacetylene)s with Pyrene as a Probe Unit  

作　　者：Sheng Wang Xuanyu Feng Jie Zhang Xinhua Wan 

机构地区：[1]Beijing National Laboratory for Molecular Sciences,Key Laboratory of Polymer Chemistry and Physics of Ministry of Education,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China

出　　处：《Chinese Journal of Chemistry》2020年第6期570-576,共7页中国化学（英文版）

基　　金：The financial support of the National Natural Scienee Foundation of China(Nos.51833001,21674002)is greatly appreciated.

摘　　要：A novel doublet chirality transfer(DCT)model was dem on strated in cis poly(3,5-disubstituted phenylacetylene)s,i.e.,S-l,R-l,and S-l-NMe.The chiral message from the stereocentwr of alkylamide substituent at 3-position induced the polyene backbone to take cis-transoid helical conformation with a predominant screw sense.And in turn the helical backbone acted as a scaffold to orient the pyrene probes,which was linked to phenyl rings through 5-position,to array in an asymmetric manner.A combinatory analyses of 1H NMR,Raman,FTIR,UV-vis absorption,CD,and computer simulation suggested that the main-chain stereostructure,solve nt nature,and intramolecular hydrogen bonds played important and complex roles on DCT.High c/s-structure content and intramolecular hydrogen bonds were beneficial for the realization of DCT.Reversible helix-helix transition was observed in S-l by changing the nature of solvents.In DMF,S-l adopted a relatively contracted helix,where the main chain exhibited strong optical activity,but that of pyrene was weak.In contrast,a relatively stretched helix formed in CHCI3/in which the optical activity of pyrene was much larger,whereas that of the polye ne backbone was the weakest.This helix-helix transition was attributed to the intramolecular hydrogen bon ds,which was confirmed by solution-state FTIR spectra and computer calculations.

关 键 词：BACKBONE substituted BONDS 

分 类 号：O62[理学—有机化学]