Theoretical investigations on the structure of poly(iminomethylenes) with aliphatic side chains: conformational studies and comparison with experimental spectroscopic data

Ab initio and molecular mechanics calculations were performed to investigate the octamers of poly(methyl)iminomethylene bearing aliphatic side chains. Diimines considered included N,N'-diisopropylethanediimine while substituents used were isopropyl and 1-cyclohexylethyl. The results, which were compared to empirical data on PIMs in solution, indicated a preference for the nonhelical syndio geometry over the 4(1) helical conformer characteristically known as the secondary structure of PIMs.