Control of Helical Sense and Tightness of Amino Acid‐Based Poly(N‐propargylamide) by Temperature and Solvents

Summary: Poly(N‐(α‐tert‐butoxycarbonyl)‐L‐aspartic acid β‐cyclohexyl ester N′‐propargylamide) [poly(1)] was synthesized by the polymerization of the corresponding monomer 1 catalyzed by (nbd)Rh+[η6‐C6H5B−(C6H5)3] in CH2Cl2 at 30 °C for 2 h. Poly(1) was soluble in CH2Cl2, CHCl3, THF, and partly soluble in DMF. The specific rotation, CD, and UV‐vis spectroscopic data revealed that poly(1) exists in a helical structure in CH2Cl2, CHCl3, CHCl3/DMF, and CHCl3/MeOH. Poly(1) underwent thermo‐ and solvent‐driven switch of helical sense, accompanying the change of tightness. Schematic representation of the synthesis of the here discussed L‐aspartic acid‐based novel polyacetylene. image Schematic representation of the synthesis of the here discussed L‐aspartic acid‐based novel polyacetylene.