Crystal Engineering of Melamine-Imide Complexes; Tuning the Stoichiometry by Steric Hindrance of the Imide Carbonyl Groups

摘要

The proposed infinite, two-dimensional lattice, formed by complexation of melamine with cyanuiic acid through triple hydrogen bonds, has been a unique inspiration to supra-molecular chemists. Various model studies have been performed to mimic this triple hydrogen bond formation. Whitesides et al. reported the formation of a well-defined complex of six melamine and six cyanuric acid derivatives, linked together by 36 hydrogen bonds. Using substituted melamines and barbituric acid derivatives, they were also able to prepare molecular tapes, crinkled tapes, and rosettes. A variation of the linear tape was described by Lehn et al. Furthermore, helical and tube-like nanostructures are formed by complexation of dialkyl-substituted melamines with a diimide, whereas Rebek et al reported on a trisimide which could act as a molecular "tool chuck" for melamine. Until now, only two crystalline complexes containing melamine have been reported in literature.