| Redox and Acid - Base Chemistry of TCNQ, TCNQ•-, TCNQ2- and H2TCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) in Acetonitrile. | |
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MedLine Citation:
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PMID: 22229829 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The chemistry and electrochemistry of TCNQ (7,7,8,8-tetracyanoquinodimethane), TCNQ•-, TCNQ2- and H2TCNQ in acetonitrile (0.1 M Bu4NPF6) solution containing trifluoroacetic acid (TFA) has been studied by transient, and steady-state voltammetric methods with the interrelationship between the redox and the acid-base chemistry being supported by simulations of the cyclic voltammograms. In the absence of acid, TCNQ and its anions undergo two electrochemically and chemically reversible one-electron processes. However, in the presence of TFA, the voltammetry is considerably more complex. The TCNQ2- dianion is protonated to form HTCNQ-, which is oxidized to HTCNQ•, and H2TCNQ, which is electroinactive over the potential range of -1.0 to +1.0 V vs. Ag/Ag+. The monoreduced TCNQ•- radical anion is weakly protonated to give HTCNQ•, which disproportionates to TCNQ and H2TCNQ. In acetonitrile, H2TCNQ deprotonates slowly, whereas in N,N-dimethylformamide or tetrahydrofuran, rapid deprotonation occurs to yield HTCNQ- as the major species. H2TCNQ is fully deprotonated to the TCNQ2- dianion in the presence of an excess concentration of the weak base, CH3COOLi. Differences in the redox and acid-base chemistry relative to the fluorinated derivative TCNQF4 are discussed in term of structural and electronic factors. |
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Authors:
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Thanh Hai LE; Ayman Nafady; Xiaohu Qu; Alan M Bond; Lisandra L Martin |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-9 |
Journal Detail:
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Title: Analytical chemistry Volume: - ISSN: 1520-6882 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-10 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0370536 Medline TA: Anal Chem Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
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