Redox-Active Polyphenylene\nDendrimers on the Way toward\nEfficient Electrochemical Sensors

The redox-active dendrimers consisting of a rigid, wholly\naromatic\npolyphenylene interior and elongated flexible ferrocenyl-terminated\nspacers were synthesized for ion sensing purposes. The resulting compounds\nwere characterized by NMR spectroscopy, matrix-assisted laser desorption/ionization\ntime-of-flight (MALDI-TOF) mass spectrometry, and gel permeation chromatography.\nThe electrochemical properties of the dendrimers and corresponding\nmodified electrodes were studied using cyclic voltammetry, which exhibited\na single chemically and electrochemically reversible wave for each\nsystem. An electrochemical response to the presence of transition\nmetal cations (Pd<sup>2+</sup>, Cu<sup>+</sup>) and oxo anions ([H<sub>2</sub>PO<sub>4</sub>]<sup>−</sup>, [HSO<sub>4</sub>]<sup>−</sup>) was observed. The fundamental origins of these phenomena\nwere studied using DFT computations. It was also shown that the synthesized\ndendrimers were able to stabilize palladium nanoparticles, which were\ntested in a model reaction of 4-nitrophenol reduction.