Conformational studies of poly‐β‐1‐naphthylmethyl‐L‐aspartate

Poly‐β‐1‐naphthylmethyl‐ L ‐aspartate and copolymers of β‐1‐naphthylmethyl‐ L ‐aspartate and γ‐benzyl‐ L ‐glutamate were prepared. From the results obtained by a study of infrared and circular dichroism spectra, poly‐β‐1‐naphthylmethyl‐ L ‐aspartate was found to be a left‐handed α‐helix both in the solid state and in solution. The fluorescence spectra of these polymers showed excimer emission of the naphthyl chromophores and gave some information about the arrangement of the side‐chain chromophores. By optical titration experiments, it was found that an increasing amount of β‐1‐naphthylmethyl‐ L ‐aspartate residues in the copolymers induces a progressive instability of the helical structure.