Abstract
Galvanic replacement reactions (GRRs) are spontaneous electroless reactions that proceed due to the favorable difference in the electrochemical potentials of the two chemical species participating in the reaction. To date, the reacting species in GRRs almost exclusively have been limited to a metal cation. In this work, for the first time, we provide a rare example of a redox mediated GRR where an anion in the original template is replaced by another anion. Extensive use of spectroscopies, microscopies and elec-trochemical techniques reveals that the exposure of metal-organic semiconductor of CuTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) to neutral TCNQF(4)(0) (TCNQF(4) = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) dissolved in acetonitrile results in the spontaneous oxidation of the TCNQ(1-)anion in CuTCNQ along with the concomitant reduction of the TCNQF(4)(0) to TCNQF(4)(1-)anion. In this case, the exposure of phase I CuTCNQ grown on a Cu foil (Cu((foil))ICuTCNQ((solid))) to TCNQF(4)(0) in acetonitrile results in a hybrid material containing Cu-(foil)ICuTCNQ(x)(TCNQF(4))(y(solid)), where x + y = 1. The favorable difference in the redox potentials of the TCNQF(4)(1-/0) and TCNQ(1-/0) processes in acetonitrile provides a strong driving force to facilitate the GRR between TCNQ- and TCNQF(4). The resulting hybrids show su-perior redox catalytic behavior in the reduction of [Fe(CN)(6)](3)-to [Fe(CN)(6)](4-)by S(2)O(3)(2-)in comparison to CuTCNQ and CuTCNQF(4) where the TCNQF(4) content in the hybrid plays an important role in enhancing the catalytic rate. Mechanistic details related to the role of the Cu(foil)|CuTCNQ(F-4) interface, and dif-ferences in the solubility of CuTCNQ and CuTCNQF(4) in acetonitrile are presented. (C) 2022 Elsevier Ltd. All rights reserved.