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Solvent Effects in Halogen and Hydrogen Bonding Mediated Electrochemical Anion Sensing in Aqueous Solution and at Interfaces
Author(s) -
Patrick Sophie C.,
Hein Robert,
Docker Andrew,
Beer Paul D.,
Davis Jason J.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202101102
Subject(s) - chemistry , aqueous solution , ferrocene , halide , solvent , halogen bond , halogen , electrochemistry , hydrogen bond , inorganic chemistry , selectivity , monolayer , photochemistry , molecule , organic chemistry , catalysis , electrode , alkyl , biochemistry
Sensing anionic species in competitive aqueous media is a well‐recognised challenge to long‐term applications across a multitude of fields. Herein, we report a comprehensive investigation of the electrochemical anion sensing performance of novel halogen bonding (XB) and hydrogen bonding (HB) bis‐ferrocene‐(iodo)triazole receptors in solution and at self‐assembled monolayers (SAMs), in a range of increasingly competitive aqueous organic solvent media (ACN/H 2 O). In solution, the XB sensor notably outperforms the HB sensor, with substantial anion recognition induced cathodic voltammetric responses of the ferrocene/ferrocenium redox couple persisting even in highly competitive aqueous solvent media of 20 % water content. The response to halides, in particular, shows a markedly lower sensitivity to increasing water content associated with a unique halide selectivity at unprecedented levels of solvent polarity. The HB sensor, in contrast, generally displayed a preference towards oxoanions. A significant surface‐enhancement effect was observed for both XB/HB receptive films in all solvent systems, whereby the HB sensor generally displayed larger responses towards oxoanions than its halogen bonding analogue.