Supramolecular Polyglycine II-Type Structure of Glycylglycine Bolaamphiphile

Abstract

Bolaamphiphile with a glycylglycine unit at each end, N,N′-bis(carboxymethylcarbamoylmethyl)decane-1, 10-dicarboxamide, has been synthesized. The crystal structure was determined by single-crystal X-ray analysis. The space group is P2₁/a with unit cell parameters: a = 8.678(3), b = 4.873(4), c = 27.161(3) Å, β = 92.68(2)°, Z = 2, Dc = 1.33g/cm³, and R = 0.051 for 2095 data. The two halves of the molecule are related by a center of symmetry and have a folded ‒ CH₂ ‒ CH₂ ‒ CO ‒ conformation (TGS or TGS). The molecules are arranged in a layered structure along the c-axis, forming a linear polymolecular chain stabilized by acid-acid dimerization at each end. Each chain is arranged in a pseudo-hexagonal lattice stabilized by three-dimensional hydrogen-bond networks between amide groups. This supramolecular crystal structure provides the first example of polyglycine II-type structure made of noncovalent polymolecular chains.