DESIGN OF ORGANIC STRUCTURES IN THE SOLID-STATE - MOLECULAR TAPES BASED ON THE NETWORK OF HYDROGEN-BONDS PRESENT IN THE CYANURIC ACID MELAMINE COMPLEX

This paper describes the single-crystal X-ray structures of 1: 1 compl exes between seven N,N'-bis(4-X-phenyl)melamines (X = H, F, Cl, Br, I, CH3, and CF3) and 5,5-diethylbarbituric acid. These complexes crystal lize as infinite tapes having components joined by triads of hydrogen bonds; the tapes pack with their long axes parallel. The crystalline a rchitecture of these complexes-parallel tapes-serves as a structurally constrained framework with which to study physical-organic relationsh ips between the structures of the crystals and the molecules of which they are composed. The complex with X = Br exists in polymorphic forms . One of the polymorphs is isomorphous to the X = Cl complex; the othe r is related to the X = I complex.