ProDOT-Assisted Isomerically Pure Indophenines

Abstract

Reactions between 3,4-propylenedioxythiophenes (ProDOTs) and N-alkyl isatins under ambient conditions result in isomerically pure indophenine materials as confirmed by TLC and 1 H NMR analysis. The resulting low band gap materials exhibit favorable inter-and intramolecular interactions, high thermal stabilities, low energy electronic transitions, and amphoteric redox behavior.

Low-Band gap Conjugated Polymers with Strong Absorption in the Second Near-Infrared Region Based on Diketopyrrolopyrrole-Containing Quinoidal Units

“…The synthetic route to the isatin-terminated TDPP quinoidal compounds and their polymers is shown in Scheme . Isatin-terminated quinoidal compounds are generally synthesized by the indophenine reaction. ,,− However, this approach is only applicable to the simple electron-rich thiophene substrates, such as thiophene, 3,4-dimethoxythiophene, 3,4-propylenedioxythiophen, and 3,4-ethylenedioxythiophene. Recently, we and Wang’s group independently developed a new protocol, involving regioselective nucleophilic addition, dehydroxylation, and oxidation reactions, to access a wide array of isatin-terminated quinoidal compounds. , Lithium diisopropylamide (LDA) was used to lithiate compound 1 because the sterically hindered LDA can successfully deprotonate thiophene α-protons without attacking the carbonyl groups.…”

Significant alternation of molecular structures and properties in quinoidal conjugated polymers by chalcogen atom substitution

“…Isomers mQEDOT-Br (Z,E) and mQEDOT-Br (E,E) are less stable than mQEDOT-Br (Z,Z) by 3.72 and 10.4 kcal mol À1 , which is consistent with the previously reported calculations for an isomerfree quinoidal molecule. 28 Similarly, mQEDTT-Br (Z,Z) and mQEDTT-Br (E,E) are less stable than mQEDTT-Br (Z,E) by 1.65 and 2.39 kcal mol À1 , respectively, which are smaller differences compared to those for mQEDOT-Br. These results imply that the EDTT quinoid molecules could isomerize in ambient conditions owing to their small activation energies.…”

“…Both monomers exhibited This journal is © The Royal Society of Chemistry 2022 redox amphoteric behavior, which is observed in the majority of thienoquinoidal molecules. 2,28,[40][41][42] The FMO energy levels of the two monomers are listed in Table 1. The HOMO energy levels (E HOMO s) of mQEDOT-Br and mQEDTT-Br were estimated as À5.29 and À5.33 eV, respectively, and the LUMO energy levels (E LUMO s) were À3.47 and À3.73 eV, respectively.…”

“…Wang et al reported that quinoidal thieno[3,2- b ]thiophene (QTT) has less number of stereoisomers compared to quinoidal bithiophene (QBT) as the rotation between thiophene rings has been restricted in the former. 19 Bulky thieno[3,4- b ]thiophene (T b T), 7 3,4-dimethoxythiophene (DMOT) 27 and 3,4-propylenedioxythiophene (ProDOT) 28 on the quinoidal core also suppressed the production of geometric configurations that were energetically unfavorable and allowed only a single configuration in the absence of any isomer. Recently, our group has developed the isomer-free quinoidal building block bis-QEDOT.…”

3-Methoxythiophene-Based Indophenine Reaction Generating an Isomeric Dynamic Equilibrium System

“… 9 A much more ideal strategy to obtain indophenine derivatives without isomerism still is the indophenine reaction directly using thiophene derivatives containing steric substituents. In particular, all the indophenine reactions based on 3,4-propenedioxythiophene, 17 3,4-ethylenedioxythiophene, 18 or even 3,4-dimethoxythiophene 19 have been recently demonstrated to produce indophenine derivatives with a specific (Z,E,Z) configuration along the quinoidal π-conjugation system ( Figure 1 ).…”