Synthesis, Evaluation, and study of Mechanistic
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This document discusses photoactive dyes and their application in photodynamic therapy (PDT). It outlines the aims of using the photoactive dye Neutral Red in a light-promoted reaction to synthesize target compounds. While initial reactions showed low yields of the target compounds, introducing a light source helped overcome activation barriers and allowed the reactions to go to completion with good yields. Future work involves further studying the photochemistry and mechanistic pathways of the reactions to better control and optimize the process.
Synthesis, Evaluation, and study of Mechanistic
- 2. Interest in Dyes PDT: A modern application of photoactive dyes Project Aims Chemical Strategy Dark and Light Promoted Reactions Reaction Highlights Challenges Future Work References
- 3. Broad spectrum of applications owing to unique physio- chemical properties Synthesis of dyes is what revolutionised the synthetic organic chemistry Cover the full spectrum in particular yellow, red and oranges/complete rainbow of colours Intense bright colours with good fastness properties Extensively utilised in pharmaceutical, cosmetics, food, dyeing/textiles, printing and analytical chemistry Medically important as they are well-known for their antibiotic, antifungal and anti-HIV properties
- 4. Mauveine Neutral red Methylene blue
- 5. Photoactive – A substance/compound is considered photoactive if it is capable of absorbing light of appropriate wavelength, and as a result of this light absorption undergoes various photochemical and photophysical events mainly Fluorescence and Phosphorescence. Photodynamic Therapy (PDT)- A type of treatment that involves the use of a light-sensitive medication (photoactive dye) and a source of light to destroy abnormal cells.
- 6. Neutral Red • Triplet-photosensitizer • Photoredox catalyst • Low quantum yield Targeted compounds (1) (3) (4) (5)
- 7. Diazo component Diazonium salt Coupling component
- 8. 1. Reduced form of the salt is the major product 2. Other side products 3. Target compound is in low yield 4. Reduced form highly stable/high redox potential 5. High activation barrier
- 9. 1. Using a light source helps to overcome the activation barrier 2. Reaction goes to completion 3. Targeted compound isolated in good yield 4. Reaction is reproducible
- 10. Instability of “Aryl Diazonium Salt” under RT Determination of the reaction mechanism is required to establish right conditions
- 11. Simple and cheap, easy to handle reagents, readily available Mild reaction conditions No need to use organometallic reagents as Neutral Red autocatalyses the reaction Low environmental impact due to use of water as a solvent Easy to scale-up
- 12. Study of photo- and electrochemistry of diazonium salt of Neutral Red to understand the mechanistic pathways Acquire details of photoredox chemistry of participating reagents and intermediates to better understand the kinetics of the reaction
- 13. CHEMIK 2012, 66, 12, 1298-1307 MUHAMMAD A RAUF, A.A.S., MUHAMMAD KHATTAB. Solvent effects on the spectral properties of Neutral Red. Chemistry Central Journal, 2008, 2(19). BINDEWALD, E., R. LORENZ, O. HUBNER, D. BROX, D.-P. HERTEN, E. KAIFER and H.-J. HIMMEL. Tetraguanidino-functionalized phenazine and fluorene dyes: synthesis, optical properties and metal coordination. Dalton Transactions, 2015, 44(7), pp.3467-3485. SINGH, M.K., H. PAL and A.V. SAPRE. Studies on the Radiolytically Produced Transients of Neutral Red: Triplet and Reduced Radicals. Photochemistry and Photobiology, 2000, 71(1), pp.44-52. WAINWRIGHT, M. Dyes in the development of drugs and pharmaceuticals. Dyes and Pigments, 2008, 76(3), pp.582-589. MARKS, G.T., LEE, E. D., AIKENS, D. A. AND RICHTOL, H. H. TRANSIENT PHOTOCHEMISTRY OF NEUTRAL RED. Photochemistry and Photobiology, 1984, 39, pp.323–328. WAINWRIGHT, M. Photodynamic therapy – from dyestuffs to high–tech clinical practice. Review of Progress in Coloration and Related Topics, 2004, 34(1), pp.95-109. MURUBE, J. Rose Bengal: The Second Most Commonly Used Surfocular Vital Stain. The Ocular Surface, 2014, 12(1), pp.14-22. MINGLIANG HAN, X.Z., XIAOXIA ZHANG, CHAOQIANG LIAO, BAIQING ZHU, QIAOLING LI. Azo-coupled zinc phthalocyanines: Towards broad absorption and application in dye-sensitized solar cells. Polyhedron, 2015, 85, pp.864-873. BONNETT, R. Photosensitizers of the porphyrin and phthalocyanine series for photodynamic therapy. Chemical Society Reviews, 1995, 24(1), pp.19-33. ANA P. CASTANO, T.N.D., MICHAEL R, HAMBLIN. Mechanisms in photodynamic therapy: part one-photosensitizers, photochemistry and cellular localization. Photodiagnosis and Photodynamic Therapy, 2004, 1(4), pp.279-293. LASTOVOI, A.P., A.A. IGNATOVA, A.V. FEOFANOV, E.A. MACHINSKAYA and V.I. IVANOVA-RADKEVICH. Properties of the Novel Photosensitizer β,β,β′,β′-Tetramethyltribenzotetraazachlorin. Pharmaceutical Chemistry Journal, 2014, 48(2), pp.77-81.
- 14. Dr. Natalia Sergeeva Dr. Terry Key Ana Maria Garrote Canas Ellana Beard Department of Colour Science Faculty of Mathematics and Physical Sciences at University of Leeds
- 15. Thank you