EPR and UV-vis spectroelectrochemical studies of diketopyrrolopyrroles disubstituted with alkylated thiophenes
Monika Góra , Sandra Pluczyk , Paweł Zassowski , Wojciech Krzywiec , Małgorzata Zagórska , Józef Mieczkowski , Mieczysław Łapkowski , Adam Proń
AbstractEPR and UV-vis spectroelectrochemical behavior of a series of ambipolar donor-acceptor-donor (DAD) compounds, consisting of a diketopyrrolopyrrole (DPP) central unit symmetrically disubstituted with mono-, bi- and terthiophene, is reported. All derivatives studied undergo a reversible reduction to radical anions at E ca. -1.55V to ca. -1.65V vs Fc/Fc+. Electrochemically generated radical anions are sufficiently stable to be detected at RT. Two-step oxidation of these compounds involves the formation of radical cations in the first step followed by their transformation into spinless dications in the second one. The formed radical cations are detectable at RT, however, contrary to the case of radical anions they yield unresolved EPR spectra. The potential of their formation depends on the length of D segment decreasing from ca. 0.50V vs Fc/Fc+ for monothiophene disubstituted DPP to ca. 0.25V in the case of the terthiophene derivative. Combining differential pulse voltammetry with EPR and UV-vis spectroelectrochemistry allows for unequivocal identification of all new, electrochemically induced UV-vis bands to particular forms of the studied molecules (radical anions, radical cations or dications). Both electrochemical reduction and electrochemical oxidation processes involve profound and distinctly different spectral changes in the visible range of the spectrum. Since they are reversible, the studied compounds can be considered as promising multicolor electrochromophores. © 2015 Elsevier Ltd.
|Journal series||Synthetic Metals, ISSN 0379-6779|
|Publication size in sheets||0.5|
|Keywords in English||Diketopyrrolopyrrole derivatives; Donor-acceptor semiconductors; EPR spectroelectrochemistry; Radical anions; Radical cations; UV-vis spectroelectrochemistry; ESR spectroscopy|
|Score|| = 30.0, 28-11-2017, ArticleFromJournal|
= 30.0, 28-11-2017, ArticleFromJournal
|Publication indicators||: 2016 = 2.435 (2) - 2016=2.165 (5)|
|Citation count*||4 (2018-02-19)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.