Synthesis and chiroptical properties of optically active poly(N-propargylamide) bearing photoisornerizable azobenzene moieties

A chiral azobenzene-containing N-propargylamide monomer, that is, (R)-2-(4-phenylazophenoxy)-n-prop-2-ynyl-propionamide, was prepared and polymerized in the presence of a rhodium catalyst to yield an optically active polyacetylene. The H-1 NMR analysis of the polymer indicated a predominant cis structure of the backbone (cis concentration = 80%); and the chiroptical property studies showed an enhanced optical rotatory power and a strong Cotton effect, indicating the formation of a secondary helical conformation. A reversible optical modulation of chiroptical properties of the polymer due to the reversible photoisomerization of the azobenzene was observed. (c) 2006 Wiley Periodicals, Inc.