Self-assembly of rectangular shape-persistent diazaborole-linked macrocycles

Diazaboroles have become of recent interest in the area of organic materials. In this work we have synthesized arylene ethynylene macrocycles using diazaborole formation as the key chain-linking step. Specifically, bis(benzene-1,2-diamine) monomers were successfully condensed with 1,4-phenylenediboronic acid, which resulted in novel diazaborole-linked macrocycles through the formation of four diazaborole linkages. The new macrocycles were characterized by NMR spectroscopy, MALDI mass spectrometry, and computational calculations. These macrocycles may serve as model compounds for future diazaborole-based covalent organic frameworks.