Tetrathiafulvalene–7,7,8,8‐Tetracyanoquinodimethane and Tetrathiafulvalene–2,3,5,6‐Tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane Organic Charge‐Transfer Complexes: Reusable Catalysts for Electron‐Transfer Reactions

Abstract

The application of organic charge‐transfer complexes such as TTF‐TCNQ (TTF=tetrathiafulvalene, TCNQ=7,7,8,8‐tetracyanoquinodimethane) is well known in the area of organic electronics. However, the applicability of this material and its derivatives has not been explored for catalytic reactions. Herein, we report on the catalytic properties of both TTF‐TCNQ and the significantly less‐known fluorinated analogue TTF‐TCNQF4 (TCNQF4=2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane). The model reaction of ferricyanide ion reduction by thiosulfate ions was chosen, for which it was found that both materials were indeed catalytically active. Significantly, the fluorinated TCNQF4 analogue showed considerably higher catalytic activity than TTF‐TCNQ. In addition, TTF‐TCNQF4 was found to be highly stable under the catalytic conditions and could be recovered and reused without any loss in performance for at least 10 catalytic cycles. This work opens up new avenues for investigating these types of materials for catalytic reactions.

Galvanic Replacement of Semiconducting CuTCNQF 4 with Ag + Ions to Enhance Electron Transfer Reaction

“…This suggests that the GR process did not lead to the formation of TCNQF 4 0 . Similarly, the infrared spectra (FTIR) also showed characteristic signatures corresponding to TCNQF 4 − species ( Figure S4 , Supporting Information) ascertaining that there is no change in the chemical nature of CuTCNQF 4 during the GR process ,…”

“…Signatures obtained from TCNQF 4 shows peaks at 2226 cm −1 (C N), 1665 cm −1 (C C ring) and 1460 cm −1 (C–CN stretching), which are characteristic of the neutral state ,. The shift in the C N (from 2226 to 2200 cm −1 ) and C C ring vibrations (from 1665 to 1640 cm −1 ) suggests that the TCNQF 4 is present in the reduced state following the formation of CuTCNQF 4 ,. The presence of the reduced TCNQF 4 − species was confirmed in all samples, while no signatures corresponding to TCNQF 4 0 were observed.…”

“…Illustrated in Figure b is the background corrected Raman spectra (background corrected using an smoothing free algorithm) obtained from all the GR samples as Raman spectroscopy has the ability to differentiate between neutral (TCNQF 4 0 ) and reduced (TCNQF 4 − ) species . Signatures obtained from TCNQF 4 shows peaks at 2226 cm −1 (C N), 1665 cm −1 (C C ring) and 1460 cm −1 (C–CN stretching), which are characteristic of the neutral state ,. The shift in the C N (from 2226 to 2200 cm −1 ) and C C ring vibrations (from 1665 to 1640 cm −1 ) suggests that the TCNQF 4 is present in the reduced state following the formation of CuTCNQF 4 ,.…”

“…2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (TCNQF 4 ) due to its superior optical, electrical, and magnetic properties in comparison to TCNQ‐based charge transfer complexes ,. Although the fluorinated analogues were primarily explored for field emission and switching devices, recent work by our group and others have shown the potential of MTCNQF 4 (where M=Cu or Ag) to be used as catalysts for electron transfer reactions between ferricyanide and thiosulfate, as well as for the conversion of Cr 6+ to Cr 3+ reduction in the presence of methanol as electron donor ,. To date, much of the work on TCNQ and TCNQF 4 ‐based materials has focused on exploring the applicability of the pristine MTCNQ complex.…”

Charge Transfer Complex betweenO-Phenylenediamine and 2, 3-Dichloro-5, 6-Dicyano-1, 4-Benzoquinone: Synthesis, Spectrophotometric, Characterization, Computational Analysis, and its Biological Applications

“…They have great significance in the field of DNA binding, drug receptors, and antimicrobial and antibacterial mechanisms. 7 , 8 CTCs 9 − 14 have been used in various categories of science like optics, solar physics, photonic science, chemosensors for sensing hazardous materials, materials chemistry, and catalysis.…”