Redox-Active Polyphenylene Dendrimers on the Way toward Efficient Electrochemical Sensors

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