Galvanic replacement of anions in metal-organic semiconductors: a spontaneous redox reaction between TCNQ1− and TCNQF40 (TCNQ = 7, 7, 8, 8-tetracyanoquinodimethane). (December 2022)

• Record Type: Journal Article
• Authors: Hussain, Z.; Ojha, R.; La, D.D.; Nafady, A.; Bhosale, S.V.; Martin, L.L.; Bond, A.M.; Ramanathan, R.; Bansal, V.
• Is Part Of: Materials today chemistry. Volume 26(2022)
• Publication Date: 2022-12
• Subjects: Galvanic replacement -- Anions -- Redox reaction -- TCNQ -- TCNQF4 -- Metal-organic charge transfers complexes; GRR galvanic replacement reaction -- TCNQ 7, 7, 8, 8-tetracyanoquinodimethane -- TCNQF4 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanoquinodimethane -- MTCNQ metal-7, 7, 8, 8-tetracyanoquinodimethane -- MeCN acetonitrile -- CV cyclic voltammogram; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2022.100998
• Languages: English
• ISSNs: 2468-5194

Abstract

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 electrochemical techniques reveals that the exposure of metal-organic semiconductor of CuTCNQ (TCNQ = 7, 7, 8, 8-tetracyanoquinodimethane) to neutral TCNQF4 0 (TCNQF4 = 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 TCNQF4 0 to TCNQF4 1 − anion. In this case, the exposure of phase I CuTCNQ grown on a Cu foil (Cu(foil) │CuTCNQ(solid) ) to TCNQF4 0 in acetonitrile results in a hybrid material containing Cu(foil) │CuTCNQx (TCNQF4 )y(solid), where x + y = 1. The favorable difference in the redox potentials of the TCNQF4 1−/0 and TCNQ 1−/0 processes in acetonitrile provides a strong driving force to facilitate the GRR between TCNQ − and TCNQF4 . The resulting hybrids show superior redox catalytic behavior in the reduction of [Fe(CN)6 ] 3- to [Fe(CN)6 ] 4- by S2 O3 2− in comparison to CuTCNQ and CuTCNQF4 where the TCNQF4 content in the hybrid plays an important role in enhancing the catalytic rate. Mechanistic details related to the role of the Cu(foil) |CuTCNQ(F4 ) interface, and differences in the solubility of CuTCNQ and CuTCNQF4 in acetonitrile are presented. Graphical abstract: Image 1 Highlights: A redox mediated galvanic replacement reaction where an anion in the original template is replaced by another anion is shown. A spontaneous galvanic replacement of TCNQ 1 – anion in CuTCNQ with TCNQF4 0 dissolved in acetonitrile is shown. The galvanic replacement reaction is used to create hybrids materials containing Cu(foil) │CuTCNQx (TCNQF4 )y(solid) . The hybrids show superior redox catalytic behavior in comparison to the parent CuTCNQ and CuTCNQF4 .