1,4-bis(aryl)-[1,2,4,5]-tetrazines prepared by light-driven ring-expansion skeletal editing

Abstract

Nitrogen-containing heterocycles essential components in the medicine-agriculture-materials continuum and beyond. Recently, functional N-heterocycles can facilely prepared by light-driven skeletal editing by starting with easily accessible compounds. In this work, three four-substituted 1,2,4,5-tetrazine compounds PTn (n = 1, 2, 3), which were difficult to attain via previously reported synthetic strategies, were successfully synthesized through light-driven ring-expansion skeletal editing of 2,5-disubstituted tetrazoles. Spectroscopic analyses and Density Functional Theory (DFT/TD-DFT) calculations confirmed that the unique multiple emission of PTn in solution and powder forms exhibits anti-Kasha-like characteristics. Additionally, the compact, twisted π-systems based on tetrazine core demonstrated the attractive cubic nonlinear optical (NLO) capabilities.