The controlled synthesis of monodisperse,
redox-active metallopolymers
and their redox properties and functions, including robust electrode
derivatization and sensing, remains a challenge. Here a series of
polynorbornene homopolymers and block copolymers containing side-chain
amidoferrocenyl groups and tetraethylene glycol linkers were prepared
via living ring-opening metathesis polymerization initiated by Grubbs’
third-generation catalyst (1). Their molecular weights
were determined using MALDI-TOF mass spectra, size exclusion chromatography
(SEC), end-group analysis, and the empirical Bard–Anson electrochemical
equation. All polymerizations followed a living and controlled manner,
and the number of amidoferrocenyl units varied from 5 to 332. These
homopolymers and block copolymers were successfully used to prepare
modified Pt electrodes that showed excellent stability. The modified
Pt electrodes show excellent qualitative sensing of ATP2– anions, in particular those prepared with the block copolymers.
The quantitative recognition and titration of [n-Bu4N]2[ATP] was carried out using the CH2Cl2 solution of the homopolymers, showing that
two amidoferrocenyl groups of the homopolymers interacted with each
ATP2– molecule. This stoichiometry led us to propose
the H-bonding modes in the supramolecular polymeric network.