Studies of a bola-type bis(dithiafulvene) molecular system: synthesis, crystal structure, and electrochemical properties

Abstract

A bis(dithiafulvene) compound that contains a 1,3-diphenoxypropane central unit was designed and investigated in this work. This compound is termed “bola-bis(DTF)” in view of the flexible, rope-like linker group that connects the two dithiafulvenyl (DTF) end groups in its molecular structure. Comparative studies were carried out on this bola-bis(DTF) and its mono-DTF analogue by means of single crystal X-ray diffraction, UV-Vis absorption, and cyclic voltammetric analyses. It was found that the bola-bis(DTF) shows significantly lowered redox potentials as a result of its flexible structure. Moreover, the bola-bis(DTF) could be electrochemically polymerized into redox-active polymers. A stable and redox-active double-layer polymer thin film was generated on a glassy carbon electrode through sequential electrodeposition of a structurally rigid bis(DTF) precursor and then the bola-bis(DTF). The resulting hybrid polymer thin film was found to show significant voltammetric responses to various phenolic compounds in the sub-μM concentration range, suggesting potential application in rapid and sensitive electrochemical sensing for phenolic compounds. Molecular dynamic simulations and molecular mechanics calculations revealed that intermolecular O⋯S interactions account for the high affinity of the polymer of bola-bis(DTF) for phenolic compounds.