The synthesis of diquinone and dihydroquinone derivatives of calix[4]arene and electrochemical characterization on Au(111) surface

Abstract

Several new electroactive diquinone and dihydroquinone derivatives of calix[4]arene bearing anchor functional groups were designed, synthesized and characterized. A method for selective protection of the hydroquinone-OH groups with trimethylsilyl groups (TMS) either on lower-rim or on upper-rim was developed. Four selected molecules - with sulfide anchor groups and carboxylic anchor groups - were adsorbed onto Au(111) single crystal surface using ex-situ and insitu self-assembly methods. Adsorbed molecules were then electrochemically probed with cyclic voltammetry. All adsorbed molecules showed redox response which changed during cycling. After conditioning CVs stabilized and showed two distinct current peaks for all molecules. Synthesized and electrochemically probed molecules are of interest to: Li-ion batteries (as cathode materials and overcharge protection), beyond Li-ion batteries and redox-flow batteries.