“…For the polyisocyanopeptides previously discussed, the presence of a hydrogen‐bonding array between the amide groups is in all cases (i.e., L,L ‐PIAA, L , D ‐PIAA, and L ‐PIGA) accompanied by a strong positive Cotton effect around λ = 315 nm attributed to a right‐handed ( P ) helix, whereas for the polyisocyanides in which these arrays were absent (i.e., L ‐PIAG and L , D ‐PIAA after TFA treatment), CD spectra were obtained lacking this signal. For polyisocyanopeptides derived from alanyl–serine35 and alanyl–histidine36, 37 prepared in the past by our group, similar differences in CD spectra were observed, including differences between the two stereoisomers of poly(isocyanoalanyl serine methyl ester), L,L ‐PIAS36, 37 and L , D ‐PIAS, and between the two stereoisomers of poly(isocyanoalanyl histidine methyl ester), L,L ‐PIAH and D , L ‐PIAH (Fig. 8).…”