190371-55-2Relevant academic research and scientific papers
Extended conjugation in stilbenylsquaraines
Meier, Herbert,Petermann, Ralf,Dullweber, Uta
, p. 744 - 754 (2011/10/12)
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.
Extension of the Squaraine Chromophore in Symmetrical Bis(stilbenyl)squaraines
Meier, Herbert,Dullweber, Uta
, p. 4821 - 4826 (2007/10/03)
The bis(stilbenyl)squaraines 6d-j,d' j' represent a novel class of NIR pigments. Their synthesis was performed by the regioselective 2-fold condensation of highly nucleophilic 3,5-dihydroxystilbenes 4d-j,d'j' with squaric acid (5). Depending on the substitution with alkoxy groups, the absorption maxima range in solution from 680 to 735 nm. Reflexion measurements in the solid state reveal an exciton splitting with maxima at about 670 and 1000 nm.
Bis(stilbenyl)squaraines - Novel pigments with extended conjugation
Meier, Herbert,Dullweber, Uta
, p. 1191 - 1194 (2007/10/03)
We report on the synthesis of a novel type of squaraines (11a-f, 17c) in which the conjugation of the chromophore is extended by stilbene units. These pigments exhibit absorption bands which have their maxima at the end on the Vis region and reach partly into the NIR.
