1H and 13C nuclear magnetic relaxation in helical poly(γ-benzyl-L-glutamate). Internal rotation about the Cα—Cβ bond

Abstract

¹ H and ¹³C nuclear magnetic relaxation has been studied in a single fraction of helical poly(γ-benzyl-L-glutamate) in [²H₇]dimethylformamide at 60 °C, and the results analysed in terms of librations, anisotropic molecular rotational diffusion and internal rotation about the C_α—C_β side-chain bond. The data can be interpreted consistently only if the rotation of the C_α—C_β bond is restricted to transitions between two rotational isomers.