Synthesis of Helical Poly(N-propargylamides) Carrying Azobenzene Moieties in Side Chains. Reversible Arrangement-Disarrangement of Helical Side Chain Arrays upon Photoirradiation Keeping Helical Main Chain Intact

Autor:	Masashi Shiotsuki, Fumio Sanda, Yoshihito Inai, Toshio Masuda, Toru Fujii
Rok vydání:	2007
Předmět:	Azo compound Polymers and Plastics Photoisomerization Hydrogen bond Organic Chemistry Cis trans isomerization Inorganic Chemistry chemistry.chemical_compound Azobenzene chemistry Polymerization Amide Polymer chemistry Materials Chemistry Side chain
Zdroj:	Macromolecules. 40:7079-7088
ISSN:	1520-5835 0024-9297
Popis:	Optically active novel N-propargylamides bearing azobenzene, (R)-HC⋮CCH2NHCOCH(CH3)O-1,4-C6H4−NN−C6H5 (1a), (R)-HC⋮CCH2NHCOCH(CH3)O-1,4-C6H4−NN-1‘,4‘-C6H4-n-hexyl (1b), (R)-HC⋮CCH2NHCOCH(CH2C6H5)O-1,4-C6H4−NN−C6H5 (2a), (R)-HC⋮CCH2NHCOCH(CH2C6H5)O-1,4-C6H4−NN-1‘,4‘-C6H4-n-hexyl (2b), and (R)-HC⋮CCH2NHCOCH(C6H5)O-1,4-C6H4−NN−C6H5 (3) were synthesized and polymerized with [(nbd)RhCl]2 as a catalyst to obtain the corresponding polymers with moderate molecular weights (Mn = 6900−44 000) in 46−99% yields. Polarimetric, CD, UV−vis, NOE−NMR, and IR spectroscopic studies demonstrated that the resulting polymers took a helical structure with predominantly one-handed screw sense stabilized by intramolecular hydrogen bonding between the amide groups in the side chains in various solvents. The CD spectra simulated by molecular orbital calculation well agreed with the experimental ones, and indicated the arrangement of azobenzene moieties in a mutual chiral geometry of one-handed screw sense. The trans-azobenzene in t...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::25a6362063c5873314f837c7be063e95 https://doi.org/10.1021/ma070917j Zobrazit plný text záznamu