Silver(I) ions in nonpolar solvents were used to polymerize expanded l-lysine and l-ornithine derivatives. Introducing a bulky hydrophobic acyl group into the terminal amino group of the side chain increased the solubility of the amino acid in chloroform. Polymerization proceeded via the formation of head-to-head and tail-to-tail linkages, which resulted in chiral helical structures. Circular dichroism measurements and density functional theory calculations were used to estimate the overall secondary structures, which were significantly different from each other despite the small difference, namely, with or without the fourth CH2 moiety.
- Taka-aki Okamura
- Kyoko Tsubouchi
- Kiyotaka Onitsuka
