Regioselective synthesis of 1,2- vs 1,3-squaraines
Elisabetta Ronchi1, Riccardo Ruffo, Silvia Rizzato
1Department of Materials Science and INSTM, University of Milano-Bicocca, Via Cozzi 53, I-20125, Milano, Italy.
Abstract:
Squaraines have been known for many decades as very stable and versatile vis-NIR absorbing dyes. They have found applications for example as sensitizers in organic photovoltaics and photodetectors. The most common squaraine structure is the 1,3-regioisomer. Their 1,2-regioisomers are seldom mentioned and unanimously regarded as side products. A facile direct synthesis of 1,2-squaraines, highlighting the role played by reaction conditions and electronic factors, is described. The first electrochemical characterization of these dyes is also shown.
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