Disordered Crystal Structure of the 1:3 Solvated Molecular Ionic Complex of 1,10-Diaza-18-crown-6 with (+)-Tartaric Acid

Abstract

The disordered crystal structure of the 1:3 solvated molecular ionic complex of 1,10-diaza-18-crown-6 with (+)-tartaric acid [C₁₂H₂₈N₂O₄]²⁺·2C₄H₅O ^-₆ ·C₄H₆O₆·1.5CH₃OH·1.7H₂O (I) was investigated by XRD analysis. Crystals I are monoclinic: space group P2 ₁, a = 9.662(2), b = 13.618(5), c = 14.316(3) Å, β = 93.97(2)°, Z = 2. Structure I was solved by direct methods and refined by the full-matrix least-squares procedure anisotropically to R = 0.081 for all 3539 unique measured reflections (CAD-4 automatic diffractometer, λCuK _α). In structure I, the solvated methanol and water molecules are disordered on many sites. The DA18C6 dication is also disordered and has two different asymmetric conformations. The two tartrate anions lie on different sides of the cavity of the DA18C6 dication, whose two NH ⁺₂ groups each forms two H-bonds of N–H...O type with each of the tartrate anions. The (+)-tartaric acid molecule and the solvated molecules are not involved in the H-bonds with the DA18C6 dication. The molecular ionic complex I exists in crystal as a complex infinite three-dimensional supramolecular structure.