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RESEARCH PRODUCT

ChemInform Abstract: Conjugated Compounds Based on Vinylthiazole Units.

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Conjugated oligomers attract increasing attention because of their interesting properties in materials science [1]. Moreover, they are model compounds for conjugated polymers. Molecules polarized by electronic effects, in particular push-pull systems having terminal donor-acceptor substitution represent a special class of such oligomers [2]. Their major applications are in the field of nonlinear optics (NLO), twophoton absorption (TPA), two-photon induced fluorescence (TPIF), and photorefractive materials (PR). Fig. 1 illustrates known 2,5-thienylenevinylenes with zwitterionic resonance structures 1 (D = NR2; A = NO2, CHO, SO2R; n = 1, 2) [3, 4]. The corresponding compounds 2 with thiazole instead of thiophene rings are unknown. On the whole, very few 1,2-di(thiazolyl)ethenes were reported. Among the three symmetric (2,2′; 4,4′; 5,5′) and the three unsymmetric (2,4′; 2,5′; 4,5′) linkings of two thiazole rings by a vinylene bridge, only one parent system, namely 1,2-di(2thiazolyl)ethene has been described [5]. Whereas some derivatives of 1,2-di(4-thiazolyl)ethene [6 – 8], 1,2-di(5-thiazolyl)ethene [9 – 13] and 1-(2-thiazolyl)-2-(4′-thiazolyl)ethene [14] are known, 2,5′and 4,5′-linkings are – to our best knowledge – unknown. We report here on 1-(2-thiazolyl)-2-(5′-thiazolyl)ethenes (2). The electron donor D is represented by a dihexylamino group, the electron acceptor A can be a thiazole ring (2a) or an thiazol bearing a carbonyl group (2b).