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Prediction of the Photofading of Selected Derivatives of 5-(4-X-Phenylazo)-3-Cyano-1-(H or Ethyl)-6-Hydroxy-4-Methyl-2-Pyridone: Theoretical Studies, Comparison of AM1 and PM3 Methods

DOI: 10.4236/cc.2024.122002, PP. 25-56

Keywords: Photochemical Degradation, AM1 and PM3 Methods, Boundary Orbitals Electron Densities, Electrophilic and Nucleophilic Reaction, HOMO and LUMO Orbitals

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Abstract:

We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic ( O 2 ？？ ) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability ( S r E( N ) ) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O 2 ？？ on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.

 References

[1]  Racané, L., Mihalić, Z., Cerić, H., Popović, J. and Tralić-Kulenović, V. (2013) Synthesis, Structure and Tautomerism of Two Benzothiazolyl Azo Derivatives of 2-Naphthol: A Crystallographic, NMR and Computational Study. Dyes and Pigments, 96, 672-678.
https://doi.org/10.1016/j.dyepig.2012.10.009
[2]  Zollinger, H. (2003) Colour Chemistry: Synthesis, Properties and Application of Organic Dyes and Pigments. Wiley-VCH.
[3]  Porobić, S.J., Božić, B.Đ., Dramićanin, M.D., Vitnik, V., Vitnik, Ž., Marinović-Cincović, M., et al. (2020) Absorption and Fluorescence Spectral Properties of Azo Dyes Based on 3-Amido-6-Hydroxy-4-Methyl-2-Pyridone: Solvent and Substituent Effects. Dyes and Pigments, 175, Article ID: 108139.
https://doi.org/10.1016/j.dyepig.2019.108139
[4]  Vitnik, V.D., Vitnik, Ž.J., Božić, B.Đ., Valentić, N.V., Dilber, S.P., Mijin, D.Ž., et al. (2017) Experimental and Theoretical Insight into the Electronic Properties of 4-Aryl-5-Arylazo-3-Cyano-6-Hydroxy-2-Pyridone Dyes. Coloration Technology, 133, 223-233.
https://doi.org/10.1111/cote.12271
[5]  Abeta, S. (1992) Compatibility of Acid Dyes on Nylon. Dyes and Pigments, 18, 57-68.
https://doi.org/10.1016/0143-7208(92)80006-9
[6]  Chudgar, R.J. and Oakes, J. (2014) Dyes, Azo (Kirk-Othmer Encyclopedia of Chemical Technology). Enigma, Inc.
[7]  Mijin, D.Z., Baghbanzadeh, M., Reidlinger, C. and Oliver Kappe, C. (2010) The Microwave-Assisted Synthesis of 5-Arylazo-4,6-Disubstituted-3-Cyano-2-Pyridone Dyes. Dyes and Pigments, 85, 73-78.
https://doi.org/10.1016/j.dyepig.2009.10.006
[8]  Mirković, J.M., Božić, B.Đ., Mutavdžić, D.R., Ušćumlić, G.S. and Mijin, D.Ž. (2014) Solvent and Structural Effects on the Spectral Shifts of 5-(Substituted Phenylazo)-3-Cyano-6-Hydroxy-1-(2-Hydroxyethyl)-4-Methyl-2-Pyridones. Chemical Physics Letters, 615, 62-68.
https://doi.org/10.1016/j.cplett.2014.09.063
[9]  Al-Etaibi, A.M. and El-Apasery, M.A. (2020) A Comprehensive Review on the Synthesis and Versatile Applications of Biologically Active Pyridone-Based Disperse Dyes. International Journal of Environmental Research and Public Health, 17, Article 4714.
https://doi.org/10.3390/ijerph17134714
[10]  Lubai, C. (1986) Colour and Constitution of Azo Dyes Derived from 2-Thioalkyl-4,6-Diaminopyrimidines and 3-Cyano-1,4-Dimethyl-6-Hydroxy-2-Pyridone as Coupling Component. Dyes and Pigments, 7, 373-388.
https://doi.org/10.1016/0143-7208(86)80005-5
[11]  Schwander, H.R. (1982) Heterocyclic Azo Coupling Components. Dyes and Pigments, 3, 133-160.
https://doi.org/10.1016/0143-7208(82)80018-1
[12]  Mijin, D.Ž., Ušćumlić, G.S., Perišić-Janjić, N.U. and Valentić, N.V. (2006) Substituent and Solvent Effects on the UV/vis Absorption Spectra of 5-(3-and 4-Substituted Arylazo)-4, 6-Dimethyl-3-Cyano-2-Pyridones. Chemical Physics Letters, 418, 223-229.
https://doi.org/10.1016/j.cplett.2005.10.130
[13]  Karcı, F. and Karcı, F. (2008) Synthesis and Absorption Spectra of Some Novel Heterocyclic Disazo Dyes Derived from Pyridone and Pyrazolone Derivatives. Dyes and Pigments, 76, 147-157.
https://doi.org/10.1016/j.dyepig.2006.07.029
[14]  Mijin, D., Uscumlic, G., Perisic-Janjic, N., Trkulja, I., Radetic, M. and Jovancic, P. (2006) Synthesis, Properties and Color Assessment of Some New 5-(3-and 4-Substituted Phenylazo)-4, 6-Dimethyl-3-Cyano-2-Pyridones. Journal of the Serbian Chemical Society, 71, 435-444.
https://doi.org/10.2298/jsc0605435m
[15]  Ušćumlić, G.S., Mijin, D.Z., Valentić, N.V., Vajs, V.V. and Sušić, B.M. (2004) Substituent and Solvent Effects on the UV/vis Absorption Spectra of 5-(4-Substituted Arylazo)-6-Hydroxy-4-Methyl-3-Cyano-2-Pyridones. Chemical Physics Letters, 397, 148-153.
https://doi.org/10.1016/j.cplett.2004.07.057
[16]  Griffiths, J. (1976) Colour and Constitution of Organic Molecules. Academic Press.
[17]  Towns, A.D. (1999) Developments in Azo Disperse Dyes Derived from Heterocyclic Diazo Components. Dyes and Pigments, 42, 3-28.
https://doi.org/10.1016/s0143-7208(99)00005-4
[18]  Hallas, G. (1999) Synthesis and Spectral Properties of Azo Dyes Derived from 2-Aminothiophenes and 2-Aminothiazoles. Dyes and Pigments, 42, 249-265.
https://doi.org/10.1016/s0143-7208(99)00031-5
[19]  Gordon, P.F. and Gregory, P. (1987) Organic Chemistry in Colour. Springer-Verlag.
[20]  Peng, Q. (1992) Hydrazone-Azo Tautomerism of Pyridone Azo Dyes Part III—Effect of Dye Structure and Solvents on the Dissociation of Pyridone Azo Dyes. Dyes and Pigments, 18, 271-286.
https://doi.org/10.1016/0143-7208(92)80017-h
[21]  Neevel, J.G., van Beek, H.C.A., den Ouden, H.H.I. and van de Graaf, B. (1990) Photo–oxidation of Azo Dyes in the Presence of Biacetyl and Oxygen. Journal of the Society of Dyers and Colourists, 106, 176-181.
https://doi.org/10.1111/j.1478-4408.1990.tb01255.x
[22]  Heijkoop, G. and van Beek, H.C.A. (1977) ESR Investigation of the Radical Intermediates Formed in the Photoreduction of Azo Dyes. Recueil des Travaux Chimiques des Pays-Bas, 96, 83-85.
https://doi.org/10.1002/recl.19770960309
[23]  Okada, Y., Hihara, T. and Morita, Z. (2009) Photofading of Phenylazo-Aniline,-Pyridone and-Quinolone Disperse Dyes on a Nylon 6 Substrate. Coloration Technology, 125, 86-98.
https://doi.org/10.1111/j.1478-4408.2009.00179.x
[24]  Peng, Q. (1991) Hydrazone-azo Tautomerism of Pyridone Azo Dyes Part II: Relationship between Structure and Ph Values. Dyes and Pigments, 15, 263-274.
https://doi.org/10.1016/0143-7208(91)80011-w
[25]  Wang, I.J. and Wang, P.Y. (1990) Photofading of Azo Pyridone Dyes in Solution: Part I: Photo-Fading Kinetics and Thermodynamics of 2-(p-and o-Substituted Aryla-zo)-2-Hydroxy-4-Methyl-5-Cyano-6-Pyridone Dyes in Amide Solvents. Textile Research Journal, 60, 297-300.
https://doi.org/10.1177/004051759006000508
[26]  van Beek, H.C.A., Heerjes, P.M. and Rutges, A.A.M. (1973) The Photofading of Mixtures of Azo Dyes and Mixtures of an Azo Dye and Oxygen in Aquous Solutions Containing D, L-Mandelic Acid. Journal of the Society of Dyers and Colourists, 89, 389-396.
https://doi.org/10.1111/j.1478-4408.1973.tb03108.x
[27]  Klessinger, M. and Michl, J. (1995) Excited States and Photochemistry of Organic Molecules. VCH.
[28]  Görner, H. (2002) Photoreduction of Trans-4-R-4’-Nitrostilbenes with R: Ome, H and NO2 by Di-and Trialkylamines in Polar Media. Physical Chemistry Chemical Physics, 4, 482-489.
https://doi.org/10.1039/b108192f
[29]  Görner, H. and Döpp, D. (2003) Transients in the Photoreduction of Dinitroarenes by Triethylamine and N, n-Dialkylanilines in Benzene. Journal of Photochemistry and Photobiology A: Chemistry, 159, 219-225.
https://doi.org/10.1016/s1010-6030(03)00187-4
[30]  Özen, A.S., Aviyente, V. and Klein, R.A. (2003) Modeling the Oxidative Degradation of Azo Dyes: A Density Functional Theory Study. The Journal of Physical Chemistry A, 107, 4898-4907.
https://doi.org/10.1021/jp026287z
[31]  Özen, A.S., Aviyente, V., De Proft, F. and Geerlings, P. (2004) Modeling the Substituent Effect on the Oxidative Degradation of Azo Dyes. The Journal of Physical Chemistry A, 108, 5990-6000.
https://doi.org/10.1021/jp037138z
[32]  Nam, S., Renganathan, V. and Tratnyek, P.G. (2001) Substituent Effects on Azo Dye Oxidation by the FeIII-EDTA-H2O2 System. Chemosphere, 45, 59-65.
https://doi.org/10.1016/s0045-6535(00)00599-3
[33]  Griffiths, J. and Hawkins, C. (1977) Oxidation by Singlet Oxygen of Arylazonaphthols Exhibiting Azo-Hydrazone Tautomerism. Journal of the Chemical Society, Perkin Transactions 2, 1977, 747-752.
https://doi.org/10.1039/p29770000747
[34]  Fenical, W., Kearns, D.R. and Radlick, P. (1969) Mechanism of the Reaction of 1δg Excited Oxygen with Olefins. II. Elimination of the Concerted “Ene” Mechanism as the Route to Allylic Hydroperoxides. Journal of the American Chemical Society, 91, 7771-7772.
https://doi.org/10.1021/ja50001a057
[35]  Spadaro, J.T., Isabelle, L. and Renganathan, V. (1994) Hydroxyl Radical Mediated Degradation of Azo Dyes: Evidence for Benzene Generation. Environmental Science & Technology, 28, 1389-1393.
https://doi.org/10.1021/es00056a031
[36]  Das, S., Kamat, P.V., Padmaja, S., Au, V. and Madison, S.A. (1999) Free Radical Induced Oxidation of the Azo Dye Acid Yellow 9. Journal of the Chemical Society, Perkin Transactions 2, 1999, 1219-1224.
https://doi.org/10.1039/a809720h
[37]  Nasr, C., Vinodgopal, K., Fisher, L., Hotchandani, S., Chattopadhyay, A.K. and Kamat, P.V. (1996) Environmental Photochemistry on Semiconductor Surfaces. Visible Light Induced Degradation of a Textile Diazo Dye, Naphthol Blue Black, on TiO2 Nanoparticles. The Journal of Physical Chemistry, 100, 8436-8442.
https://doi.org/10.1021/jp953556v
[38]  Tanaka, K., Padermpole, K. and Hisanaga, T. (2000) Photocatalytic Degradation of Commercial Azo Dyes. Water Research, 34, 327-333.
https://doi.org/10.1016/s0043-1354(99)00093-7
[39]  Hihara, T., Okada, Y. and Morita, Z. (2003) Reactivity of Phenylazonaphthol Sulfonates, Their Estimation by Semiempirical Molecular Orbital PM5 Method, and the Relation between Their Reactivity and Azo-Hydrazone Tautomerism. Dyes and Pigments, 59, 201-222.
https://doi.org/10.1016/s0143-7208(03)00109-8
[40]  Tripathi, S., Vasudev, I. and Ray, A. (2008) Photofading of Azo Dyes: A Theoretical Study. Coloration Technology, 124, 151-158.
https://doi.org/10.1111/j.1478-4408.2008.00135.x
[41]  Morley, J.O., Guy, O.J. and Charlton, M.H. (2004) Molecular Modeling Studies on the Photochemical Stability of Azo Dyes. The Journal of Physical Chemistry A, 108, 10542-10550.
https://doi.org/10.1021/jp047001o
[42]  Aksel Eren, H., Avinc, O. and Erismis, B. (2012) Comparison of Different Ultrasound Support Methods during Colour and Chemical Oxygen Demand Removal of Disperse and Reactive Dyebath Solutions by Ozonation. Coloration Technology, 128, 446-453.
https://doi.org/10.1111/j.1478-4408.2012.00398.x
[43]  Arslan-Alaton, I., Basar, G. and Olmez-Hanci, T. (2012) Ozonation of the Reactive Dye Intermediate 2-Naphthylamine 3, 6, 8-Trisulphonic Acid (K-Acid): Kinetic Assessment, Ozonation Products and Ecotoxicity. Coloration Technology, 128, 387-394.
https://doi.org/10.1111/j.1478-4408.2012.00392.x
[44]  Hihara, T. (2003) Azo-Hydrazone Tautomerism of Phenylazonaphthol Sulfonates and Their Analysis Using the Semiempirical Molecular Orbital PM5 Method. Dyes and Pigments, 59, 25-41.
https://doi.org/10.1016/s0143-7208(03)00093-7
[45]  Tauro, S. and Coutinho, E. (2000) Azo, Hydrazone and Other Tautomers of the Azo Dye 7-Amino-4-Hydroxy-3-[(4-Methoxy-2-Sulfophenyl)Azo]-2-Naphthalenesulfonic Acid: A PM3 Study. Journal of Molecular Structure: THEOCHEM, 532, 23-29.
https://doi.org/10.1016/s0166-1280(00)00500-5
[46]  Monahan, A.R., Germano, N.J. and Blossey, D.F. (1971) Aggregation of Arylazonaphthols. II. Steric Effects on Dimer Structure in Water. The Journal of Physical Chemistry, 75, 1227-1233.
https://doi.org/10.1021/j100679a009
[47]  Hihara, T., Okada, Y. and Morita, Z. (2002) Photo-Oxidation and-Reduction of Vat Dyes on Water-Swollen Cellulose and Their Lightfastness on Dry Cellulose. Dyes and Pigments, 53, 153-177.
https://doi.org/10.1016/s0143-7208(02)00017-7
[48]  Kumar, K., Saravana Devi, S., Krishnamurthi, K., Gampawar, S., Mishra, N., Pandya, G.H., et al. (2006) Decolorisation, Biodegradation and Detoxification of Benzidine Based Azo Dye. Bioresource Technology, 97, 407-413.
https://doi.org/10.1016/j.biortech.2005.03.031
[49]  Baird, M.S., Hamlin, J.D., O'Sullivan, A. and Whiting, A. (2008) An Insight into the Mechanism of the Cellulose Dyeing Process: Molecular Modelling and Simulations of Cellulose and Its Interactions with Water, Urea, Aromatic Azo-Dyes and Aryl Ammonium Compounds. Dyes and Pigments, 76, 406-416.
https://doi.org/10.1016/j.dyepig.2006.09.011
[50]  Flower, K.R., Hamlin, J.D. and Whiting, A. (2002) An Insight into the Mechanism of the Cellulose Dyeing Process, Part 1: Modelling Azo-Systems in Azo-Linked Aromatics and Dyes. Molecular Simulation, 28, 1031-1047.
https://doi.org/10.1080/0892702021000011061
[51]  Himeno, K., Okada, Y. and Morita, Z. (2000) Photofading of Monoazo Disperse Dyes on Polyester and Polyamide Substrates. Dyes and Pigments, 45, 109-123.
https://doi.org/10.1016/s0143-7208(00)00009-7
[52]  Batchelor, S.N., Carr, D., Coleman, C.E., Fairclough, L. and Jarvis, A. (2003) The Photofading Mechanism of Commercial Reactive Dyes on Cotton. Dyes and Pigments, 59, 269-275.
https://doi.org/10.1016/s0143-7208(03)00118-9
[53]  Hihara, T., Okada, Y. and Morita, Z. (2004) Relationship between Photochemical Properties and Colourfastness Due to Light-Related Effects on Monoazo Reactive Dyes Derived from H-Acid, γ-Acid, and Related Naphthalene Sulfonic Acids. Dyes and Pigments, 60, 23-48.
https://doi.org/10.1016/s0143-7208(03)00139-6
[54]  Chang, J. and Kuo, T. (2000) Kinetics of Bacterial Decolorization of Azo Dye with Escherichia coli NO3. Bioresource Technology, 75, 107-111.
https://doi.org/10.1016/s0960-8524(00)00049-3
[55]  Ince, N.H. (1999) “Critical” Effect of Hydrogen Peroxide in Photochemical Dye Degradation. Water Research, 33, 1080-1084.
https://doi.org/10.1016/s0043-1354(98)00295-4
[56]  Giles, C.H. and de Bernat, J. (1976) The Nature of Azo Dye Light Fading in Polyester and the Physical State of the Dye. Textile Research Journal, 46, 673-676.
https://doi.org/10.1177/004051757604600911
[57]  Evans, N.A. and Stapleton, I.W. (1978) Structural Factors Affecting the Lightfastness of Dyed Fibers. Antraquinoid Dyes. In: Venkataraman, K., Ed., The Chemistry of Synthetic Dyes, vol. VIII, Academic Press, 247.
[58]  Ray, A. (1995) CNDO/II Study on the Fading of Anthraquinone Dyes. Dyes and Pigments, 27, 327-331.
https://doi.org/10.1016/0143-7208(94)00069-e
[59]  Guo, L., Meng, F.S., Gong, X.D., Xiao, H.M., Chen, K.C. and Tian, H. (2001) Synthesis and Spectral Properties of Soluble Trimethylsilyl Substituted Metal-Phthalocyanines. Dyes and Pigments, 49, 83-91.
https://doi.org/10.1016/s0143-7208(01)00011-0
[60]  Wang, L., Wang, X. and Zhang, H. (2005) A Theoretical Study on Photobleaching Mechanisms of Hypocrellins. Dyes and Pigments, 67, 161-166.
https://doi.org/10.1016/j.dyepig.2004.11.007
[61]  Corbett, J.F. (1984) Chemistry of Hair Colorant Process-Science as an Aid to Formulation and Development. Journal of the Society of Cosmetic Chemists, 35, 297-310.
[62]  Evans, N.A. and Stapleton, I.W. (1978) Structural Factors Affecting the Lightfastness of Dyed Fibres. Nitrodiphenylamine Dyes. In: Venkataraman, K., Ed., The Chemistry of Synthetic Dyes, Vol. VIII, Academic Press, 256.
[63]  Okada, Y., Hihara, T. and Morita, Z. (2008) Analysis of the Photofading of Phenylazo-Aniline and Phenylazo-Pyridone Disperse Dyes on Poly(Ethylene Terephthalate) Substrate Using the Semiempirical Molecular Orbital PM5 Method. Dyes and Pigments, 79, 111-125.
https://doi.org/10.1016/j.dyepig.2008.01.013
[64]  Dewar, M.J.S., Zoebisch, E.G., Healy, E.F. and Stewart, J.J.P. (1985) Development and Use of Quantum Mechanical Molecular Models. 76. AM1: A New General Purpose Quantum Mechanical Molecular Model. Journal of the American Chemical Society, 107, 3902-3909.
https://doi.org/10.1021/ja00299a024
[65]  Dewar, M.J.S. and Dieter, K.M. (1986) Evaluation of AM1 Calculated Proton Affinities and Deprotonation Enthalpies. Journal of the American Chemical Society, 108, 8075-8086.
https://doi.org/10.1021/ja00285a033
[66]  Stewart, J.J.P. (1989) Optimization of Parameters for Semiempirical Methods I. Method. Journal of Computational Chemistry, 10, 209-220.
https://doi.org/10.1002/jcc.540100208
[67]  Morita, Z. and Hada, S. (1999) A Semiempirical Molecular Orbital Study on the Reaction of an Aminopyrazolinyl Azo Dye with Singlet Molecular Oxygen. Dyes and Pigments, 41, 1-10.
https://doi.org/10.1016/s0143-7208(98)00038-2
[68]  Dewar, M.J.S. and Thiel, W. (1975) Ground States of Molecules. XXX. MINDO/3 Study of Reactions of Singlet (1.δ.g) Oxygen with Carbon-Carbon Double Bonds. Journal of the American Chemical Society, 97, 3978-3986.
https://doi.org/10.1021/ja00847a018
[69]  Fukui, K., Kato, H. and Yonezawa, T. (1961) “Frontier Electron Density” in Saturated Hydrocarbons. Bulletin of the Chemical Society of Japan, 34, 442-445.
https://doi.org/10.1246/bcsj.34.442
[70]  Fukui, K., Nagata, C. and Yonezawa, T. (1958) Electronic Structure and Auxin Activity of Benzoic Acid Derivatives. Journal of the American Chemical Society, 80, 2267-2270.
https://doi.org/10.1021/ja01542a058
[71]  Wojciechowski, K. and Szuster, L. (2020) Prediction of Photofading of n-β-Hydroxyethylamino-o-Nitrophenyl Derivatives: A Theoretical Study. Coloration Technology, 137, 134-144.
https://doi.org/10.1111/cote.12517
[72]  Reichardt, C. (1988) Solvent and Solvent Effects in Organic Chemistry. 2nd Edition, VCH.
[73]  Katritzky, A.R. and Lagowski, J.M. (1963) Prototropic Tautomerism of Heteroaromatic Compounds. IV Edition, Academic Press.
[74]  Kelemen, J. (1981) Azo-hydrazone Tautomerism in Azo Dyes. I. A Comparative Study of 1-Phenylazo-2-Naphthol and 1-Phenylazo-2-Naphthylamine Derivatives by Electronic Spectroscopy. Dyes and Pigments, 2, 73-91.
https://doi.org/10.1016/0143-7208(81)80009-5
[75]  Mustroph, H. (1987) Über die Azo-Hydrazon-Tautomerie. Zeitschrift für Chemie, 27, 281-289.
https://doi.org/10.1002/zfch.19870270803
[76]  Zollinger, H. (1961) Azo and Diazo Chemistry, Aliphatic and Aromatic Compounds. Interscience.
[77]  Antonov, L.M. (1996) Theoretical Investigations of the Tautomerism of Some Phenyla-Zonaphthols. 31 UNESCO Course for Advanced Research in Chemistry and Chemical Engineering, Tokyo Institute of Technology.
[78]  Chevrier, M., Bensaude, O., Guillerez, J. and Dubois, J. (1980) Equilibre lactime-lactame des hydroxy-pyridines et des hydroxy-pyrimidines (uraciles) en milieu apolaire: Etude infra-rouge. Tetrahedron Letters, 21, 3359-3362.
https://doi.org/10.1016/s0040-4039(00)78688-6
[79]  Scanlan, M.J., Hillier, I.H. and Davies, R.H. (1982) Prediction of Tautomeric Equilibri of Hydroxypyridines by Ab Initio Molecular Orbital Methods. Journal of the Chemical Society, Chemical Communications, 1982, 685-686.
https://doi.org/10.1039/c39820000685
[80]  Mason, S.F. (1957) 1002. The Tautomerism of N-Heteroaromatic Hydroxy-Compounds. Part II. Ultraviolet Spectra. Journal of the Chemical Society (Resumed), 1957, 5010-5017.
https://doi.org/10.1039/jr9570005010
[81]  Mason, S.F. (1958) 131. the Tautomerism of N-Heteroaromatic Hydroxy-Compounds. Part III. Ionisation Constants. Journal of the Chemical Society (Resumed), 1958, 674-685.
https://doi.org/10.1039/jr9580000674
[82]  Antonov, L. and Nedeltcheva, D. (2000) Resolution of Overlapping UV-Vis Absorption Bands and Quantitative Analysis. Chemical Society Reviews, 29, 217-227.
https://doi.org/10.1039/a900007k
[83]  Giles, C.H. and McKay, R.B. (1973) The Lightfastness of Dyes: A Review. Textile Research Journal, 33, 528-577.
https://doi.org/10.1177/004051756303300707

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