Imidazole as a parent π-conjugated backbone in charge-transfer chromophores

Abstract

SummaryResearch activities in the field of imidazole-derived push–pull systems featuring intramolecular charge transfer (ICT) are reviewed. Design, synthetic pathways, linear and nonlinear optical properties, electrochemistry, structure–property relationships, and the prospective application of such D-π-A organic materials are described. This review focuses on Y-shaped imidazoles, bi- and diimidazoles, benzimidazoles, bis(benzimidazoles), imidazole-4,5-dicarbonitriles, and imidazole-derived chromophores chemically bound to a polymer chain.

T‐Shaped (Donor–π–)2Acceptor–π–Donor Push–Pull Systems Based on Indan‐1,3‐dione

“…[8] However, push-pull molecules with extraordinary arrangements such as V, Y, H, and X shapes have also been reported recently. [9][10][11][12] Since their first syntheses in 1888-89, [13] indan-1,3-dione and its derivatives have been used as dyestuffs (indenigo) [14] and as reagents for fingerprint development in forensic science (ninhydrin). [15] Later, indan-1,3-dione evolved into a powerful and readily accessible electron acceptor.…”

Synthesis and properties of push-pull imidazole derivatives with application as photoredox catalysts

“…With respect to DCP 1 (λmax 448 nm), these maxima are hypsochromically shifted by more than 100 nm as a result of lower electron-withdrawing ability of the DCI acceptor unit as well as presence of one vs. two electron-donating (5-methoxy)thienyl moieties. 22,31 The molar absorption coefficients of imidazole derivatives 2 and 3 are slightly lower as well. However, the absorption maxima of 2 (λmax 296 nm) can easily be red-shifted by attaching methoxy group as in 3 (λmax 323 nm).…”

“…29 In this work, we focus on synthesis of Yshaped push-pull analogues 2 and 3 based on five-membered acceptor unit -imidazole-4,5-dicarbonitrile (dicyanoimidazole, DCI) and further evaluation of their optoelectronic properties and photoredox catalytic activities. The DCI unit proved to be readily available heterocyclic acceptor for push-pull molecules, [30][31][32][33][34][35][36] however, none of them has been investigated as potential photoredox catalyst. In principal, the structural tuning of the original DCP derivative 1 can be achieved by replacing the acceptor unit (DCPDCI) and also by variation of the peripheral R-substituent (H or OMe).…”

“…Bromo precursor 4 is well-known to undergo Suzuki-Miyaura cross-coupling, whereas Sonogashira reaction is complicated by a subsequent polymerization. [30][31][32][33][34][35][36] Hence, we introduced the (5-methoxy)thienyl donors via the reaction with commercially available thiophen-2-ylboronic acid 5 and 5-methoxythiophen-2-ylboronic acid pinacol ester 6. The latter was prepared from 2-methoxythiophene and its lithiation and reaction with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (iPrOBpin) with 89% yield.…”

Synthesis of some 1- and 2-carboxyalkyl substituted benzimidazoles and their derivatives

“…Benzimidazole derivatives are distinguished for antimicrobial [1][2][3][4], antifungal [5][6][7], antiviral [8], anthelmintic [9,10], antihypertensive [11], antihistaminic [12], analgesic [13], and anti-HIV [14] actions. Also, some of benzimidazoles are used in coordination chemistry [15,16], in optoelectronics [17], etc. The aim of this study was to synthesize new potentially bioactive benzimidazole derivatives or its intermediates containing carboxyalkyl, hydrazone, pyrrole, and dimethylpyrazole fragments.…”