A Comparative Study of Redox-Active Dithiafulvenyl-Functionalized 1,3,6,8-Tetraphenylpyrene Derivatives

A series of 1,3,6,8-tetraphenylpyrene (TPPy) derivatives substituted with redox-active 1,4-dithiafulvenyl (DTF) groups was synthesized and characterized. The conformational properties of these DTF-TPPys and their TPPy precursors were assessed by X-ray single-crystal and nuclear magnetic resonance analyses. Their electronic and redox properties were examined by ultraviolet-visible absorption, fluorescence, and cyclic voltammetric analyses. The DTF substitution was found to strongly modify the absorption, emission, and electrochemical properties, while detailed effects can be linked to substitution patterns and alkyl side chains attached to the DTF groups. Furthermore, the DTF-TPPy derivatives showed sensitivity to acids; in particular, the vinylic proton of DTF group could undergo efficient proton/deuterium exchange with D2O in an acidic medium.