292
T. Mutai
into a significant change in luminescence. ESIPT luminescence of HPIP can also
be controlled by common synthetic modifications, and the effects of substituents on
luminescence can be reasonably explained by the calculated electronic configurations
and energy levels of S 0 -IPT and S 1 -IPT states [36].
Theoretical studies of HPIP derivatives have presented valuable information on
the electronic state of molecular crystals that may affect PDL. Femtosecond timeresolved measurement is also promising technique that will offer much clear and
convincing experimental data for discussing the excited dynamics in crystals.
Thus, the remarkable polymorph dependence of the luminescence color demonstrates that ESIPT is a promising mechanism for packing-directed control of luminescence and will improve the understanding of the structure–property relationships
observed in PDL. It should be possible to design a library of compounds based on
the combination of conventional synthetic strategies and supramolecular chemistry
(i.e., polymorph dependence).
Currently, the number of compounds that show PDL is still limited. Therefore, the
development of a series of luminescent core-based PDL-active compounds should
contribute to the understanding of crystal structure–luminescence relationships and
may lead to the design of polymorphic materials displaying specific and desirable
luminescence properties. These findings should also offer a novel design concept
toward tunable organic luminescent solids and thus provide a roadmap for new
functional materials.
Acknowledgements We thank Dr. Yasuhiro Shigemitsu at the Industrial Technology Center of
Nagasaki (Japan) for the high level of quantum chemical calculations, and Prof. Tsuyoshi Asahi
and Dr. Yukihide Ishibashi for the femtosecond pump-probe spectroscopic measurement. We also
thank Emeritus Prof. Dr. Koji Araki at the Institute of Industrial Science, University of Tokyo.
References
1. Sasabe, H., Kido, J.: Multifunctional materials in high-performance OLEDs: challenges for
solid-state lighting. Chem. Mater. 23, 621–630 (2011)
2. Kamtekar, K.T., Monkman, A.P., Bryce, M.R.: Recent advances in white organic light-emitting
materials and devices (WOLEDS). Adv. Mater. 22, 572–582 (2010)
3. Yanai, N., Kitayama, K., Hijikata, Y., Sato, H., Matsuda, R., Kubota, Y., Takata, M., Mizuno, M.,
Uemura, T., Kitagawa, S.: Gas detection by structural variations of fluorescent guest molecules
in a flexible porous coordination polymer. Nat. Mater. 10, 787–793 (2011)
4. Samuel, I.D.W., Turnbull, G.A.: Organic semiconductor lasers. Chem. Rev. 107, 1272–1295
(2007)
5. Qian, G., Wang, Z.Y.: Near-infrared organic compounds and emerging applications. Chem.
-Asian J. 5, 1006–1029 (2010)
6. Mishra, A., Bäuerle, P.: Small molecule organic semiconductors on the move: promises for
future solar energy technology. Angew. Chem. Int. Ed. 51, 2020–2067 (2012)
7. Zhao, Y.S., Fu, H., Peng, A., Ma, Y., Liao, Q., Yao, J.: Construction and optoelectronic
properties of organic one-dimensional nanostructures. Acc. Chem. Res. 43, 409–418 (2010)
8. Birks, J.B.: Photophysics of Aromatic Molecules. Wiley-Interscience, London (1970)
T. Mutai
into a significant change in luminescence. ESIPT luminescence of HPIP can also
be controlled by common synthetic modifications, and the effects of substituents on
luminescence can be reasonably explained by the calculated electronic configurations
and energy levels of S 0 -IPT and S 1 -IPT states [36].
Theoretical studies of HPIP derivatives have presented valuable information on
the electronic state of molecular crystals that may affect PDL. Femtosecond timeresolved measurement is also promising technique that will offer much clear and
convincing experimental data for discussing the excited dynamics in crystals.
Thus, the remarkable polymorph dependence of the luminescence color demonstrates that ESIPT is a promising mechanism for packing-directed control of luminescence and will improve the understanding of the structure–property relationships
observed in PDL. It should be possible to design a library of compounds based on
the combination of conventional synthetic strategies and supramolecular chemistry
(i.e., polymorph dependence).
Currently, the number of compounds that show PDL is still limited. Therefore, the
development of a series of luminescent core-based PDL-active compounds should
contribute to the understanding of crystal structure–luminescence relationships and
may lead to the design of polymorphic materials displaying specific and desirable
luminescence properties. These findings should also offer a novel design concept
toward tunable organic luminescent solids and thus provide a roadmap for new
functional materials.
Acknowledgements We thank Dr. Yasuhiro Shigemitsu at the Industrial Technology Center of
Nagasaki (Japan) for the high level of quantum chemical calculations, and Prof. Tsuyoshi Asahi
and Dr. Yukihide Ishibashi for the femtosecond pump-probe spectroscopic measurement. We also
thank Emeritus Prof. Dr. Koji Araki at the Institute of Industrial Science, University of Tokyo.
References
1. Sasabe, H., Kido, J.: Multifunctional materials in high-performance OLEDs: challenges for
solid-state lighting. Chem. Mater. 23, 621–630 (2011)
2. Kamtekar, K.T., Monkman, A.P., Bryce, M.R.: Recent advances in white organic light-emitting
materials and devices (WOLEDS). Adv. Mater. 22, 572–582 (2010)
3. Yanai, N., Kitayama, K., Hijikata, Y., Sato, H., Matsuda, R., Kubota, Y., Takata, M., Mizuno, M.,
Uemura, T., Kitagawa, S.: Gas detection by structural variations of fluorescent guest molecules
in a flexible porous coordination polymer. Nat. Mater. 10, 787–793 (2011)
4. Samuel, I.D.W., Turnbull, G.A.: Organic semiconductor lasers. Chem. Rev. 107, 1272–1295
(2007)
5. Qian, G., Wang, Z.Y.: Near-infrared organic compounds and emerging applications. Chem.
-Asian J. 5, 1006–1029 (2010)
6. Mishra, A., Bäuerle, P.: Small molecule organic semiconductors on the move: promises for
future solar energy technology. Angew. Chem. Int. Ed. 51, 2020–2067 (2012)
7. Zhao, Y.S., Fu, H., Peng, A., Ma, Y., Liao, Q., Yao, J.: Construction and optoelectronic
properties of organic one-dimensional nanostructures. Acc. Chem. Res. 43, 409–418 (2010)
8. Birks, J.B.: Photophysics of Aromatic Molecules. Wiley-Interscience, London (1970)