Substituent-Driven Anion-Binding Selectivity in Aliphatic Chain-Substituted 1,2-Phenylene Urea Macrocycles and Optimized Synthetic Methodology

Abstract

1,2-Phenylene tetraurea macrocycles recently attracted attention as self-assembled channel-making compounds with high selectivity to chlorides. Here, we report on the introduction of aliphatic chains in the periphery of the 1,2-phenylene tetraurea macrocycle, which led to deterioration in the ability of the macrocycle to form channels and to a reversal of anion binding preferences in favour of dihydrogen phosphate. In addition, we have developed a new method of synthesis of 1,2-phenylene tetraurea macrocycle, using a direct click of two diamino ureido derivatives by triphosgene in the presence of chloride template. This approach saves time and eliminates demanding isolation of the non-cyclic tetrameric intermediates.