Solid‐state conformation of copolymers of β‐benzyl‐ L ‐aspartate with L ‐alanine, L ‐leucine, L ‐valine, γ‐benzyl‐ L ‐glutamate, or ϵ‐carbobenzoxy‐ L ‐lysine

The solid‐state conformation of copolymers of β‐benzyl‐ L ‐aspartate [ L ‐Asp(OBzl)] with L ‐leucine ( L ‐Leu), L ‐alanine ( L ‐Ala), L ‐valine ( L ‐Val), γ‐benzyl‐ L ‐glutamate [ L ‐Glu(OBzl)], or ϵ‐carbobenzoxy‐ L ‐lysine (Cbz‐ L ‐Lys) has been studied by ir spectroscopy and circular dichroism (CD). The ir spectra in the region of the amide I and II bands and in the region of 700–250 cm −1 have been determined. The results from the ir studies are in good agreement with data obtained by CD experiments. Incorporation of the amino acid residues mentioned above into poly[ L ‐Asp(OBzl)] induces a change from the left‐handed into the right‐handed α‐helix. This conformational change for the poly[ L ‐Asp(OBzl)] copolymers was observed in the following composition ranges: L ‐Leu, 0–15 mol %; L ‐Ala, 0–32 mol %; L ‐Val, 0–8 mol %; L ‐Glu(OBzl), 3–10 mol %; and Cbz‐ L ‐Lys, 0–9 mol %.