Systematic synthesis, comparative studies of the optical properties, and the ICT-based sensor properties of a series of 2,4,6-tri(5-aryl-2-thienyl)pyrimidines with the D–π–A system

Abstract

A series of 2,4,6-tri(5-aryl-2-thienyl)pyrimidines with a star-shaped D–π–A system, which have an electron deficient pyrimidine core (A) and three donor type aryl groups (D) linked by a thiophene spacer (π-spacer), were designed and systematically synthesized. Through the characterization of the molecules by UV–vis absorption and fluorescence spectroscopies, we revealed that the molecules possess distinct absorption and emission wavelengths controlled by the donor effect of the terminal aryl groups. Interestingly, 2,4,6-tris(5-p-N,N-dibutylaminophenyl-2-thienyl)pyrimidine was found to exhibit strong fluorosolvatochromic properties and a proton-sensibility based on its intramolecular charge transfer (ICT) and basic characteristics, which could allow its use as a polarity or proton sensor.