Synthesis and characterization of novel p-terphenoquinone analogs involving a central dihydrothiophenediylidene structure

Abstract

The title quinones, 2,5-bis(4-oxo-2,5-cyclohexadien-1-ylidene)-2,5-dihydrothiophene and its tetraalkyl derivatives, were synthesized via 2-(4-alkoxyphenyl) thiophene and 2,5-bis(4-alkoxyphenyl) thiophene conveniently prepared by using palladium (0)-catalyzed cross coupling reaction of 4-alkoxyaryl halides and thienylzinc chloride. The ground-state structures and redox properties of these quinones were fully characterized based on spectroscopic data (IR, 1 H NMR, 13 C NMR, UV-vis, and MS), X-ray analysis, cyclic voltammetry, CNDO/2 calculation, and EPR spectroscopic investigation