Abstract
1H NMR spectroscopy coupled with in situ laser irradiation has been used together with density functional theory (DFT) computation to examine the structures of the photoisomers of a series of sulfonated reactive azo dyes. Assignment of 1H NMR spectra acquired at the photostationary state has allowed, for the first time, NMR characterisation of unstable cis isomers of commercially relevant water-soluble azo dyes. Structural features of the two isomeric forms predicted by DFT calculations are clearly reflected in the experimental NMR data. The trans–cis photoisomerisation process could be unambiguously identified in each case, based on the large chemical shift change observed for resonances associated with aromatic protons adjacent to the azo linkage.
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References
K. G. Yager and C. J. Barrett, Novel photo-switching using azobenzene functional materials, J. Photochem. Photobiol., A, 2006, 182, 250–261.
K. J. Fritzsche, Photochromism of yellow azo dyes: a specific phenomenon of cotton dyed with reactive dyes, J. Soc. Dyers Col., 1992, 108, 225–228.
For general treatments see: H. Zollinger, Color Chemistry, Syntheses, Properties, and Applications of Organic Dyes and Pigments, VHCA and Wiley-VCH, Zürich and Weinheim, 2003.
P. Bamfield, Chromic Phenomena, Technological Applications of Colour Chemistry, RSC, Cambridge, 2001.
1Organic Photochromic and Thermochromic Compounds, ed. J. C. Crano and R. J. Guglielmetti, Plenum, New York and London, 1999, vol. 1 and 2.
M. Irie, Photochromism: Memories and Switches-Introduction, Chem. Rev., 2000, 100, 1683 and following articles in this edition.
M. B. Sponsler, in Optical Sensors and Switches, ed. V. Ramamurthy and K. S. Schanze, Marcel Dekker, New York and Basel, 2001, ch. 8.
R. H. El Halabieh, O. Mermut and C. J. Barrett, Using light to control physical properties of polymers and surfaces with azobenzene chromophores, Pure Appl. Chem., 2004, 76, 1445–1465.
G. Cheetham, M. G. Hutchings, T. D. W. Claridge and H. L. Anderson, Enzymatic synthesis and photoswitchable enzymatic cleavage of a peptide-linked rotaxane, Angew. Chem., 2006, 45, 1596–1599.
A. C. Olivieri, R. B. Wilson, I. C. Paul and D. Y. Curtin, Carbon-13 NMR and X-ray structure determination of 1-(arylazo)-2-naphthols. intramolecular proton transfer between nitrogen and oxygen atoms in the solid state, J. Am. Chem. Soc., 1989, 111, 5525–5532.
A. R. Kennedy, C. McNair, W. E. Smith and G. S. J. Teat, The first red Azo Lake Pigment whose structure is characterized by single crystal diffraction, Angew. Chem., Int. Ed., 2000, 39, 638.
W. H. Ojala, L. K. Lu, K. E. Albers and W. B. Gleason, Interactions between sulfonated azo dyes and biomolecules: Orange G/adenine and Orange G/cytosine salts, Acta Crystallogr., Sect. C, 1994, C50, 1615–1620.
J. F. Malone, S. J. Andrews, J. F. Bullock and R. Docherty, The solid state structure of CI Disperse Orange 44, Dyes Pigm., 1996, 30, 183–200.
A. R. Kennedy, M. P. Hughes, M. L. Monaghan, E. Staunton, S. J. Teat and W. E. Smith, Supramolecular motifs in s-block metal bound sulfonated monoazo dyes, J. Chem. Soc., Dalton Trans., 2001 2199–2205.
K. M. Park, I. Yoon, S. S. Lee, G. Choi and J. S. Lee, X-ray crystal structure of C.I. Disperse, Blue 79, Dyes Pigm., 2002, 54, 155–161.
A. Mostad and C. Romming, Refinement of the crystal structure of cis-azobenzene, Acta Chem. Scand., 1971, 25, 3561–3568.
L. C. Abbott, S. N. Batchelor, J. Oakes, B. C. Gilbert, A. C. Whitwood, J. R. Lindsay Smith and J. N. Moore, Experimental and computational studies of structure and bonding in parent and reduced forms of the azo dye Orange II, J. Phys. Chem. A, 2005, 109, 2894–2905.
L. C. Abbott, S. N. Batchelor, J. Oakes, J. R. Lindsay Smith and J. N. Moore, Semiempirical and ab initio studies of the azo dye Direct Blue I, J. Phys. Chem. A, 2004, 108, 10208–10218.
N. Biswas and S. Umpathy, Sructures, vibrational frequencies and normal modes of substituted azo dyes: infrared, Raman and density functional calculations, J. Phys. Chem. A, 2000, 104, 2734–2745.
J. O. Morley, O. J. Guy and M. H. Charlton, Molecular modelling studies on the photochemical stability of azo dyes, J. Phys. Chem. A, 2004, 108, 10542–10550.
P. C. Chen and Y. C. Chieh, Azobenzene and stilbene: a computational study, J. Mol. Struct. (THEOCHEM), 2003, 64, 191–200.
K. M. Tait, J. A. Parkinson, S. P. Bates, W. J. Ebenezer and A. C. Jones, The novel use of NMR spectroscopy with in situ laser irradiation to study azo photoisomerisation, J. Photochem. Photobiol., A, 2003, 154, 179–188.
K. M. Tait, J. A. Parkinson, A. C. Jones, W. J. Ebenezer and S. P. Bates, Comparison of experimental and calculated 1H NMR chemical shifts of geometric photoisomers of azo dyes, Chem. Phys. Lett., 2003, 374, 372–380.
The broadness of signal e compared with signal f was ascribed either to hindered rotation of the chlorotriazine unit about the ureido aromatic ring linkage, or the occurrence of a relatively slow interconversion between tautomeric forms of the molecule, as indicated by a sharpening of the relevant signal under raised temperature conditions (data not shown).
S. Bell, A. Bisset and T. J. Dines, Ab initio and density functional study of the resonance Raman spectra of Methyl Red, Ethyl Red and their protonated derivatives, J. Raman Spectrosc., 1998, 29, 447–462.
M. Skowronek, I. Roterman, L. Konieczny, B. Stopa, J. Rybarska, B. Piekarska, A. Gorecki and M. Krol, The conformational characteristics of Congo red, Evans blue and Trypan blue, Comput. Chem., 2000, 24, 429–450.
M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. G. Johnson, W. Chen, M. W. Wong, C. Gonzalez and J. A. Pople, GAUSSIAN 03 (Revision B.02), Gaussian, Inc., Wallingford, CT, 2004.
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This paper was published as part of the special issue in honour of David Phillips.
Electronic supplementary information (ESI) available: UV-Vis and 1H NMR spectra. See DOI: 10.1039/b703044d
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Tait, K.M., Parkinson, J.A., Gibson, D.I. et al. Structural characterisation of the photoisomers of reactive sulfonated azo dyes by NMR spectroscopy and DFT calculations. Photochem Photobiol Sci 6, 1010–1018 (2007). https://doi.org/10.1039/b703044d
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DOI: https://doi.org/10.1039/b703044d