Abstract
Photochromic reactions of 2H-benzopyrans have been extensively studied to design new materials for commercial applications such as optical memories. Photochromism of 2H-benzopyrans proceeds from a C–O bond cleavage of the colorless closed form to give the colored open forms, which can thermally revert back to the original closed form. From time-resolved absorption spectroscopy, the ring opening of 2H-benzopyrans, 2,4-diphenyl-and 2,2,4-triphenyl-2H-benzopyran, is found to occur via the excited singlet state within 2 ps to produce vibrationally excited open forms in the ground electronic state. In the subnanosecond to submillisecond time domain, several decay components are observed. These components are assigned to respective stereoisomers with respect to two double bonds and one single bond of the open enone forms. As revealed from pump-laser power dependencies of the yields of the open forms, the photocleavage of the benzopyran molecules gives at first only the open forms revertible to the closed form by a single-bond rotation, and the photoexcitation of the first generated open forms gives rise to other open forms that need a double-bond rotation for reversion to the original closed form. Such a two-step two-photon photochromism can be expected to have a wide range of application.
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References
- 1.Dürr H., & Bouas-Laurent H. (eds.) (1990) Photochromism: Molecules and Systems. Elsevier, Amsterdam. [Google Scholar]
- 2.Crano J. C., & Guglielmetti R. J. (eds.) (1999) Organic Photochromic and Thermochromic Compounds, Vols. 1 and 2. Plenum Press, New York. [Google Scholar]
- 3.Ward M. D. (1997) Current developments in molecular switches. Chem. Ind., 640–645. [Google Scholar]
- 4.Willner I. (1997) Photoswitchable biomaterials: en route to optobioelectronic systems. Acc. Chem. Res., 30, 347–356. [Google Scholar]
- 5.Tamai N., & Miyasaka H. (2000) Ultrafast dynamics of photochromic systems. Chem. Rev., 100, 1875–1890. [DOI] [PubMed] [Google Scholar]
- 6.Fischer E., & Hirshberg Y. (1952) Formation of coloured forms of spirans by low-temperature irradiation. J. Chem. Soc., 4522–4524. [Google Scholar]
- 7.Ernsting N. P., & Arthen-Engeland T. (1991) Photochemical ring-opening reaction of indolinospiropyrans studied by subpicosecond transient absorption. J. Phys. Chem., 95, 5502–5509. [Google Scholar]
- 8.Aramaki S., & Atkinson G. H. (1992) Spironaphthopyran photochromism: picosecond time-resolved spectroscopy. J. Am. Chem. Soc., 114, 438–444. [Google Scholar]
- 9.Bohne C., Fan M. G., Li Z. J., Liang Y. C., Lusztyk J., & Scaiano J. C. (1992) Laser photolysis studies of photochromic processes in spirooxazines: solvent effects on photomerocyanine behavior. J. Photochem. Photobiol. A, 66, 79–90. [Google Scholar]
- 10.Tamai N., & Masuhara H. (1992) Femtosecond transient absorption spectroscopy of a spirooxazine photochromic reaction. Chem. Phys. Lett., 191, 189–194. [Google Scholar]
- 11.Zhang J. Z., Schwartz B. J., King J. C., & Harris C. B. (1992) Ultrafast studies of photochromic spiropyrans in solution. J. Am. Chem. Soc., 114, 10921–10927. [Google Scholar]
- 12.Salemi-Delvaux C., Luccioni-Houze B., Baillet G., Giusti G., & Guglielmetti R. (1995) Effect of photodegradation on the thermal bleaching rate constant of photochromic compounds in spiro[indoline-pyran] and spiro[indoline-oxazine] series. J. Photochem. Photobiol. A, 91, 223–232. [Google Scholar]
- 13.Day P. N., Wang Z., & Pachter R. (1995) Ab initio study of the ring-opening reactions of pyran, nitrochromene, and spiropyran. J. Phys. Chem., 99, 9730–9738. [Google Scholar]
- 14.Pimienta V., Lavabre D., Levy G., Samat A., Guglielmetti R., & Micheau J. C. (1996) Kinetic analysis of photochromic systems under continuous irradiation. Application to spiropyrans. J. Phys. Chem., 100, 4485–4490. [Google Scholar]
- 15.Wilkinson F., Worrall D. R., Hobley J., Jansen L., Williams S. L., Langley A. J., & Matousek P. (1996) Picosecond time-resolved spectroscopy of the photocolouration reaction of photochromic naphthoxazine-spiro-indolines. J. Chem. Soc., Faraday Trans., 92, 1331–1336. [Google Scholar]
- 16.Tyer N. W. Jr., & Becker R. S. (1970) Photochromic spiropyrans. I. Absorption spectra and evaluation of the π-electron orthogonality of the constituent halves. J. Am. Chem. Soc., 92, 1289–1294. [Google Scholar]
- 17.Appriou P., Guglielmetti R., & Garnier F. (1978) Étude du processus photochimique impliqué dans la réaction d'ouverture du cycle benzopyrannique des spiropyrannes photochromiques. J. Photochem., 8, 145–165. [Google Scholar]
- 18.Becker R. S., & Michl J. (1966) Photochromism of synthetic and naturally occurring 2H-chromenes and 2H-pyrans. J. Am. Chem. Soc., 88, 5931–5933. [Google Scholar]
- 19.Kolc J., & Becker R. S. (1967) Proof of structure of the colored photoproducts of chromenes and spiropyrans. J. Phys. Chem., 71, 4045–4048. [Google Scholar]
- 20.Becker R. S., Dolan E., & Balke D. E. (1969) Vibronic effects in photochemistry–competition between internal conversion and photochemistry. J. Chem. Phys., 50, 239–245. [Google Scholar]
- 21.Kolc J., & Becker R. S. (1970) The spectroscopy and photochemistry of naturally occurring and synthetic chromenes. Photochem. Photobiol., 12, 383–393. [DOI] [PubMed] [Google Scholar]
- 22.Edwards L., Kolc J., & Becker R. S. (1971) Theoretical calculations of the transitions of phtocolored forms of chromenes. Photochem. Photobiol., 13, 423–429. [Google Scholar]
- 23.Padwa A., Au A., Lee G. A., & Owens W. (1975) Photochemical ring-opening reactions of substituted chromenes and isochromenes. J. Org. Chem., 40, 1142–1149. [DOI] [PubMed] [Google Scholar]
- 24.Zerbetto F., Monti S., & Orlandi G. (1984) Thermal and photochemical interconversion of spiropyrans and merocyanines. A semi-empirical all-valence-electron study. J. Chem. Soc., Faraday Trans. 2, 80, 1513–1527. [Google Scholar]
- 25.Lenoble C., & Becker R. S. (1986) Photophysics, photochemistry and kinetics of photochromic 2H-pyrans and chromenes. J. Photochem., 33, 187–197. [Google Scholar]
- 26.Van Gemert B., Bergomi M., & Knowles D. (1994) Photochromism of diaryl-naphthopyrans. Mol. Cryst. Liq. Cryst., 246, 67–73. [Google Scholar]
- 27.Pozzo J.-L., Samat A., Guglielmetti R., Lokshin V., & Minkin V. (1996) Furo-fused 2H-chromenes: synthesis and photochromic properties. Can. J. Chem., 74, 1649–1659. [Google Scholar]
- 28.Crano J. C., Flood T., Knowles D., Kumar A., & Van Gemert B. (1996) Photochromic compounds: chemistry and application in ophthalmic lenses. Pure Appl. Chem., 68, 1395–1398. [Google Scholar]
- 29.Luccioni-Houzé B., Campredon M., Guglielmetti R., & Giusti G. (1997) Kinetic analysis of fluoro-2H-chromenes at the photostationary states. Mol. Cryst. Liq. Cryst., 297, 161–165. [Google Scholar]
- 30.Pozzo J.-L., Samat A., Guglielmetti R., Dubest R., & Aubard J. (1997) Synthesis and photochromic behavior of naphthopyrans, pyranoquinolines, pyranoquinazolines and pyranoquinoxalines. Helv. Chim. Acta, 80, 725–738. [Google Scholar]
- 31.Celani P., Bernardi F., Olivucci M., & Robb M. A. (1997) Conical intersection mechanism for photochemical ring opening in benzospiropyran compounds. J. Am. Chem. Soc., 119, 10815–10820. [Google Scholar]
- 32.Delbaere S., Luccioni-Houze B., Bochu C., Teral Y., Campredon M., & Vermeersch G. (1998) Kinetic and structural studies of the photochromic process of 3H-naphthopyrans by UV and NMR spectroscopy. J. Chem. Soc., Perkin Trans. 2, 1153–1157. [Google Scholar]
- 33.Ottavi G., Favaro G., & Malatesta V. (1998) Spectrokinetic study of 2,2-diphenyl-5,6-benzo(2H)chromene: a thermoreversible and photoreversible photochromic system. J. Photochem. Photobiol. A, 115, 123–128. [Google Scholar]
- 34.Pozzo J.-L., Lokshin V., Samat A., Guglielmetti R., Dubest R., & Aubard J. (1998) Effect of heteroaromatic annulation with five-membered rings on the photochromism of 2H-[1]-benzopyrans. J. Photochem. Photobiol. A, 114, 185–191. [Google Scholar]
- 35.Van Gemert B. (1999) Benzo and naphthopyrans (Chromenes). In: Crano J. C., & Guglielmetti R. J. (eds.) Organic Photochromic and Thermochromic Compounds, Vol. 1, Chap. 3, pp. 111–140. Plenum Press, New York. [Google Scholar]
- 36.Kodama Y., Nakabayashi T., Segawa K., Hattori E., Sakuragi M., Nishi N., & Sakuragi H. (2000) Time-resolved absorption studies on the photochromic process of 2H-benzopyrans in the picosecond to submillisecond time domain. J. Phys. Chem. A, 104, 11478–11485. [Google Scholar]
- 37.Sakuragi M., Kawanishi Y., Sonoda Y., Nagasawa J., Suzuki Y., & Nakanishi F. (1997) Photoaddition of alcohols and amines to diphenylchromene. Presented at Symposium on Photochemistry, Japan. Abstract p. 208.
- 38.Nakabayashi T., Okamoto H., & Tasumi M. (1997) Probe-Wavelength Dependence of Picosecond Time-Resolved Anti-Stokes Raman Spectrum of Canthaxanthin: Determination of Energy States of Vibrationally Excited Molecules Generated via Internal Conversion from the Lowest Excited Singlet State. J. Phys. Chem. A, 101, 3494–3500. [Google Scholar]
- 39.Haba E., Segawa K., & Sakuragi H. (2000) Photochromic behavior of isochromenes (1H-benzopyrans) as studied by transient absorption spectroscopy. Mol. Cryst. Liq. Cryst., 345, 221–226. [Google Scholar]