Bis(stilbenyl)squaraines — Novel pigments with extended conjugation
作者:Herbert Meier、Uta Dullweber
DOI:10.1016/0040-4039(95)02414-x
日期:1996.2
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.
Extension of the Squaraine Chromophore in Symmetrical Bis(stilbenyl)squaraines
作者:Herbert Meier、Uta Dullweber
DOI:10.1021/jo970284e
日期:1997.7.1
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.