Simultaneous enhancement of fluorescence and solubility by N-alkylation and functionalization of 2-(2-thienyl)imidazo[4,5-f][1,10]-phenanthroline with heterocyclic bridges

Abstract

A family of 2-(2-thienyl)imidazo[4,5-f][1,10]-phenanthroline (TIP) based compounds with large delocalized π system has been designed and synthesized by following the strategy of introducing alkyl chains and extending different S-, N-and O-containing aromatic heterocyclic tails.Simultaneous enhancement of fluorescence emissions and solubility in organic solvents for resultant aromatic heterocyclic compounds 1-13 has been achieved. Analyses on twelve X-ray single-crystal structures indicate that the thiophene ring of TIP unit in this series of compounds shows the same trans configuration with its imidazo[4,5-f][1,10]-phenanthroline core but different dihedral angles with adjacent aromatic heterocycles. Thermal gravimetric analyses for ten imidazole N-substituted TIP derivatives reveal that they still remain good thermal stability with the decomposition temperature higher than 300 °C originating from their common TIP core, even if introduction of the n-butyl radical in their molecular structures. Moreover, TPA and carbazole substituted compounds 2 and 9 were used as the ancillary ligands to prepare corresponding ruthenium(II) sensitizers BM3 and BM4, and their dye-sensitized solar cell performance has been evaluated.

Thiazolo[5,4-d]thiazoles with a spirobifluorene moiety as novel D–π–A type organic hosts: design, synthesis, structure–property relationship and applications in electroluminescent devices

“…Known and effective strategies rely on the incorporation of alkyl chains into the aromatic/heterocyclic core. 58 Since the TzTz unit adopts a lack of free positions, hexyl-substitution and bis- n -butyl-substitution in the structure of compounds 4b , 5b and 4c , respectively, is directed towards the neighbouring thiophene ring. The thiophene scaffold serves as an ideal π-bridge between the D and A units.…”