Title:Solid-Phase Synthesis of Asymmetric Cyanine Dyes
Volume: 25
Issue: 15
Author(s): Marco Giordano, Giacomo Renno, Pierluigi Quagliotto, Claudia Barolo, Giancarlo Cravotto, Andrea Fin*Guido Viscardi
Affiliation:
- 2Department of Drug Science and Technology, University of Torino, Via Pietro Giuria 9 - 10125, Torino,Italy
Keywords:
Cyanine dyes, asymmetric dyes, solid state synthesis, resins, solvent-free, user-friendly method.
Abstract: Cyanine Dyes (CD) are a functional class of organic molecules used in several applications
ranging from photography to bioimaging. Most well-known features of CDs reside
on high molar extinction coefficients up to 105 L mol-1cm-1 and on the absorption spectra,
ranging from 500 to 1000 nm, which can be fine-tuned both by extending the length of the
central methylene bridge or by modulating the terminal heterocycles. In the last decades, new
synthetic methodologies, namely microwave-assisted and the solid-phase procedure, have
been developed to overcome the limitation of the classical synthetic protocols. While the microwave
approach usually reduces the exposure time of the reagents and products to thermal
degradation, the solid-phase methodology allows easier synthetic protocols, which are translated
into higher yields and simpler products purification. In the present review, a comprehensive
analysis of the solid-phase methods for the synthesis of asymmetrical CDs is discussed,
with a critical evaluation of the difference among the currently available solid-state approaches.