ReviewSynthesis and applications of unsymmetrical carbocyanine dyes
Section snippets
Introduction to carbocyanine dyes
In 1856, C.H.G. Williams synthesized the first carbocyanine dye by heating quinoline with N-amyl lepidinium iodide in ammonia. The compound produced displayed a “magnificent blue color,” thus the Latin word cyanos, meaning blue, provided the general carbocyanine dye name [1]. This vast class of dyes shows absorption that covers a wider range of the electronic spectrum, from the ultraviolet to the infrared, than any other class of dyes; however, due to their extreme sensitivity to light, the
Synthesis of monomethine carbocyanine dyes
Monomethine carbocyanine dyes typically absorb in the visible region. Most literature on unsymmetrical dyes consists of monomethine dyes as they are the easiest to prepare. The majority of monomethine dyes are unsymmetrical as the synthesis is based on the condensation of one methyl-substituted quaternary ammonium salt with a second salt containing a different substitution and no methine linker is used. This allows for only one product to form. Unsymmetrical monomethine carbocyanines are the
Synthesis of tri-, penta-, and heptamethine carbocyanine dyes
The synthesis of tri-, penta-, and heptamethine unsymmetrical carbocyanine dyes is performed through two main synthetic routes that are very similar. The aldehyde method involves the addition of a short chain with an aldehyde to a quaternary ammonium salt for reaction with a second salt to form unsymmetrical dye. The hemicyanine method involves the synthesis of hemicyanine or “half dye” and its purification from any dye that forms. Hemicyanine dyes are sometimes hydrolyzed into aldehydes for
Microwave assisted solid-phase synthesis
As microwave synthesis becomes more popular due to the ability to avoid time-consuming reaction steps and increase purity [41], [42], [43], [44]. Lopalco et al. designed a solid-phase synthesis approach to the hemicyanine method for tri-, penta-, and heptamethine carbocyanines using microwave-assisted synthesis. As shown in Scheme 12, this solid-phase method first reduces reaction time by synthesizing quaternary ammonium salts at 150 °C in acetonitrile. Next, the alkylated indolenines are
Conclusion
Carbocyanine dyes have found a wide range of applications due to their diverse functionality. They are generally non-toxic [46], stable and exhibit exceptional biocompatibility making their cellular use tremendously appealing. One of the main reasons for carbocyanine dyes extensive applications is that they are highly modifiable. The synthesis of unsymmetrical carbocyanines allows for further modification of these compounds whether it will be for solubility, conjugation, or in vivo
References (46)
- et al.
Dyes Pigm
(1999) - et al.
J Photochem Photobiol A
(2007) - et al.
Dyes Pigm
(1998) - et al.
Dyes Pigm
(2009) - et al.
Dyes Pigm
(2011) - et al.
Spectrochim Acta A Mol Biomol Spectrosc
(2010) - et al.
Tetrahedron
(2012) - et al.
Synth Met
(2010) - et al.
Tetrahedron Lett
(2007) - et al.
Talanta
(2012)
J Photochem Photobiol A
Berichte der deutschen chemischen Gesellschaft
Near-infrared dyes for high technology applications
Angew Chem Int Ed
Appl Optics
Anal Chem
Breast Cancer Res Treat
Molecules
J Org Chem
J Org Chem
Bioconjug Chem
The cyanine dyes and related compounds
Cited by (37)
Effect of benzene-based dyes on optothermal properties of active layers for ternary organic solar cells
2023, Applied Surface SciencePrevalent Bioimaging Scaffolds: Synthesis, Photophysical Properties and Applications
2021, European Journal of Organic ChemistryPreparation of new nanocomposite poly(GDMA)/mesoporous silica and its adsorption behavior towards cationic dye
2020, Reactive and Functional PolymersVarious roles of dye molecules in organic ternary blend solar cells
2020, Dyes and PigmentsCitation Excerpt :Apart from near-IR sensitization, visible sensitization for organic solar cells by dye molecules were also reported by many groups [54,86,87]. Wang et al. added a wide-bandgap dye molecule, tris [4-(5-dicyanomethylidenemethyl-2-thienyl)phenyl]amine (TDCV-TPA), into a binary blend of a low-bandgap polymer, poly [2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (PTQ1), and a fullerene derivative (PCBM) in order to improve exciton generation in the visible region [54]. Due to the large absorption coefficient of TDCV-TPA (2.5 × 105 cm−1), with addition only 3.2 wt% of dye molecule, the optical absorption of PTQ1/PCBM/TDCV-TPA ternary blend at 550 nm was enhanced obviously compared with PTQ1/PCBM binary blend.
N-Bromosuccinimide-mediated dimerization of unsymmetrical indodicarbocyanine dyes
2019, Tetrahedron Letters