D-A-D Compounds Combining Dithienopyrrole Donors and Acceptors of Increasing Electron-Withdrawing Capability: Synthesis, Spectroscopy, Electropolymerization, and Electrochromism

Abstract

Five D-π-A-π-D compounds consisting of the same donor unit (dithieno[3,2- b :2′,3′- d ]pyrrole, DTP ), the same π-linker (2,5-thienylene), and different acceptors of increasing electron-withdrawing ability (1,3,4-thiadiazole ( TD ), benzo[ c ][1,2,5]thiadiazole ( BTD ), 2,5-dihydropyrrolo[3,4- c ]pyrrole-1,4-dione ( DPP ), 1,2,4,5-tetrazine ( TZ ), and benzo[ lmn ][3,8]phenanthroline-1,3,6,8(2 H ,7 H )-tetraone ( NDI )) were synthesized. DTP-TD , DTP-BTD , and DTP-DPP turned out to be interesting luminophores emitting either yellow ( DTP-TD) or near-infrared ( DTP-BTD and DTP-DPP ) radiation in dichloromethane solutions. The emission bands were increasingly bathochromically shifted with increasing solvent polarity. Electrochemically determined electron affinities (|EA|s) were found to be strongly dependent on the nature of the acceptor changing from 2.86 to 3.84 eV for DTP-TD and DTP-NDI , respectively, while the ionization potential (IP) values varied only weakly. Experimental findings were strongly supported by theoretical calculations, which correctly predicted the observed solvent dependence of the emission spectra. Similarly, the calculated IP and EA values were in excellent agreement with the experiment. DTP-TD , DTP-BTD , DTP-TZ , and DTP-NDI could be electropolymerized to yield polymers of very narrow electrochemical band gap and characterized by redox states differing in color coordinates and lightness. Poly(DTP-NDI) and poly(DTP-TD) showed promising electrochromic behavior, not only providing a rich color palette in the visible but also exhibiting near-infrared (NIR) electrochromism.

Polymeric Benzothiadiazole, Benzooxadiazole, and Benzoselenadiazole Photocathodes for Photocatalytic Oxygen Reduction to Hydrogen Peroxide

“…The determined optical band gaps (Eg opt ) of studied polymers are lower than the electrochemical ones (Eg el ), which was a common occurrence in the similar low‐ and high‐molecular‐mass electroactive compounds. [ 28 ] The optical bandgaps values, together with electrochemical ones and IP and EA values calculated on the basis of these electrochemical data, are listed in Table 1.…”

Survey of Recent Advances in Molecular Fluorophores, Unconjugated Polymers, and Emerging Functional Materials Designed for Electrofluorochromic Use

“…The major constraint of electropolymerization is the quantity of material that can be prepared, which is limited to a thin layer deposited on the working electrode. Nonetheless, this method continues to be used to prepare conjugated polymers [ 159 , 160 , 161 , 162 ], especially EC polymers [ 163 ], in order to establish structure–property relationships [ 164 , 165 ]. The preparation of EFC polymers has, however, been limited.…”

Photophysical and redox properties of new donor–acceptor–donor (DAD) compounds containing benzothiadiazole (A) and dimethyldihydroacridine (D) units: a combined experimental and theoretical study

“…[10][11][12][13][14][15][16] Moreover, these films frequently show interesting electrochemical activity over a wide potential range since both D and A segments are often characterized by several reversible redox couples. 17 Thus, electrochemically prepared films are perspective electrochromic materials providing electrochromism not only in the visible range of the spectrum but also in near infrared, 10,[18][19][20][21] which is of great technological interest. 22 It seems, however, that the most spectacular achievement in the field of organic electronics exploiting organic semiconductors of the donor-acceptor type is their application as efficient luminophores in organic light emitting diodes (OLEDs).…”

“…10–16 Moreover, these films frequently show interesting electrochemical activity over a wide potential range since both D and A segments are often characterized by several reversible redox couples. 17 Thus, electrochemically prepared films are perspective electrochromic materials providing electrochromism not only in the visible range of the spectrum but also in near infrared, 10,18–21 which is of great technological interest. 22…”