ChemInform Abstract: Bathochromic or Hypsochromic Effects via the Extension of Conjugation: A Study Stilbenoid Squaraines.

ChemInform Abstract: Extended Conjugation in Stilbenylsquaraines.

Conjugated Compounds Based on Vinylthiazole Units

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 …

Erweiterte Konjugation in unsymmetrischen Stilbenylsquarainen

Extended Conjugation in Stilbenylsquaraines Unsymmetrical 1-aryl-3-stilbenylsquaraines 2a–e and 1,3-bis(stilbenyl)squaraines 3a–c were prepared by CC coupling reactions of the corresponding substituted arenes with derivatives of squaric acid (Schemes 2 and 3). Dialkylamino and alkoxy groups enhance the solubility of these dyes and enlarge the intramolecular charge transfer of these donor–acceptor–donor systems. The extended conjugation of the stilbene units – in comparison with arene building blocks – leads to significant bathochromic shifts in the Vis/NIR absorption spectra.

ChemInform Abstract: Conjugated Compounds Based on Vinylthiazole Units.

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 …

Near infrared dyes by combination of squaraine and ferrocene chromophores

Abstract Squaraines represent a class of compounds which attracts a lot of attention in materials science. A synthetic sequence for the preparation of the symmetrical squaraines 12a , b , which contain ferrocene units as electron donors, is described. The compounds exhibit, in dichloromethane or chloroform, two intense absorption bands. One of them is located at 641/650 nm—a normal region for squaraines; however, the other band is strongly shifted to long wavelengths and has its maximum at 921/961 nm. Alkyl sidechains enhance the solubility of 12a , b , which represent a new type of NIR dyes.