Synthesis and Photophysical Properties of Substituted 2,2′:6′,2′′-Terpyridine Derivatives and Analogous Compounds with a Central Thiophene Ring

Abstract New 2,2′:6′,2′′‐terpyridine derivatives were prepared by Suzuki–Miyaura coupling of the corresponding 4,4′′‐bis(nonaflate) with the appropriate boronic acid derivatives. The corresponding 4,4′′‐diazido terpyridine derivative allowed a copper(I)‐promoted click reaction with phenyl acetylene to provide the bis(triazolyl)‐substituted terpyridine in excellent yield. For comparison, analogs or terpyridines with a central thiophene ring were synthesized by applying the well proven cyclocondensation reaction of the bis(β‐ketoenamide) derived from 2,5‐thiophenedicarboxylic acid. The UV/Vis spectra as well as the fluorescence spectra of these new compounds were recorded and compared with related heterocycles.