Molecular recognition studies with a simple dipyrrinone

We present our investigations of 2-ethyl-3-methyl-(10H)-dipyrrin-1-one, its self-association, and anion binding properties. This receptor is easily accessible in a facile single step synthesis with a straightforward workup. An examination of the concentration dependence of the dipyrrinone NH chemical shifts in CDCl3 and (CDCl2)2 over the temperature range from −20 °C to 100 °C determined the self-association constant to be 3850 M−1. Molecular recognition studies have shown that it has a preference for guests with an OH moiety, such as hydrogen sulfate (HSO4−) and carboxylic acids (RCO2H).