217655-20-4

Upstream product

• 5222-73-1 3,4-dimethoxy-3-cyclobutene-1,2-dione 
• 589-15-1 1-bromomethyl-4-bromobenzene 
• 38186-51-5 diethyl (4-bromobenzyl)phosphonate 

Downstream Products

• 217655-25-9 3-{4-[(E)-2-(4-Hexyloxy-phenyl)-vinyl]-phenyl}-4-hydroxy-cyclobut-3-ene-1,2-dione 

Relevant academic research and scientific papers

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.

Bis(stilbenyl)squaraines - Novel pigments with extended conjugation

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.