Squaraine chromophores

The dihydroxyaniline-squaraine chromophore was used by Akkaya and Isgor in the fluorescent chemosensor 30 for the measurement of pH [90]. This chemosensor, having the molar absorptivity about 200,000 M em 1 and quantum yield 0.2,... 

Physical and chemical stimuli such as temperature, solvent polarity and addition of various cations induce conformational changes in the nonconjugated polysquaraines, leading to either preferential folding to, or unfolding from, chromo-phore H-dimers. The binding event is translated into a shift in the monomer to H-dimer equilibrium of the squaraine chromophores and can be conveniently visualized by UV-Vis and fluorescence spectroscopy and, therefore, can successfully be exploited for cation sensing. 

The aggregate properties of surfactant squaraines 29-31 (Structure 10), which were designed to orient the bricklike squaraine chromophore in three different directions, when organized in monolayers and Langmuir-Blodgett films (LB films), have been reported [38]. 

The observed aggregational behavior has been rationalized in terms of an optimization between hydrophobic interactions (between hydrocarbon chains) and charge-transfer interactions (between the squaraine chromophores). In the... 

Soa, S. Koa, FI. M. Kima, C. Paeka, S. Choa, N. Songb, K. Leec, J. K. Koa, J. Novel unsymmetrical push-pull squaraine chromophores for solution processed small molecule bulk heterojunction solar cells. Sol. Energ. Mat Sol. C., 2012,98,224-232. 

Scheme 10 a- and /3-Epimers of two ALS gelators based on the trans-stilbene (27) and squaraine chromophores (28)... 

AT-Benzyl and A -alkyl substituents not only increase the solubility of these compounds in organic solvents, they also disturb the intermolecular CT interaction between the squaraine chromophores in the micro-... 

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