Carboxylate complexation by a family of easy-to-make ortho-phenylenediamine based bis-ureas: studies in solution and the solid state

Simple bis-urea compounds based on ortho-phenylenediamine function as excellent receptors for carboxylate anions in DMSO-d(6)-0.5% water solution. By varying the functional groups in these compounds, the binding affinity of carboxylate anions can be modulated. Solid-state studies illustrate the cleft-like arrangement of the DDDD hydrogen bond array in the carboxylate complexes of these compounds.