Photoswitchable Intramolecular H-Stacking of Perylenebisimide J. Am. Chem. Soc., 2010, 132, 4191-4196 Photoswitchable Intramolecular H-Stacking of Perylenebisimide Jiaobing Wang, Arterm Kulago, Wesley R. Browne*, Ben L. Feringa* Center of Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

Self-assembly and Aggregation (Nature) <Tobacoo Mosaic Virus> A. Klug, Angew. Chem. Int. Ed., 1983, 22, 565 (Nobel Lecture). (Artificial System) S. Yagai et al., J. Am. Chem. Soc., 2009, 131, 5408.

Photoswitching of Aggregation UV-light S. Yagai et al., J. Am. Chem. Soc., 2005, 127, 11134. (open-ring isomer) (closed-ring isomer) T. Fukaminato and M. Irie, Adv. Mater., 2006, 18, 3225.

Molecular Design “non-stacked” “H-stacked” Switching Unit Fluorescence Unit Fluorescence Unit

Aggregation of Perylenebisimide (PBI) 4 ・large absorption coefficient ・high-fluorescence quantum yield ・extremely high-stability K. Müllen et al., Angew. Chem. Int. Ed., 2006, 45, 1401. F. Wurthner et al., Chem. Eur. J., 2001, 7, 2245.

Molecular Design “non-stacked” “H-stacked” Switching Unit Fluorescence Unit Fluorescence Unit

Synthesis

Photoisomerization of 3 312 nm (cis) 365 nm (trans) 365 nm 312 nm 365 nm 312 nm in THF, 20 ºC F (trans → cis) : 0.159, F (cis → trans) : 0.078

Photoisomerization of 2 312 nm (cis) 365 nm (Absorption) (Fluorescence) in THF, 20 ºC Concentration : 8 x 10-6 M F (trans → cis) : 0.141, F (cis → trans) : 0.085

Photoisomerization of 1 312 nm (cis) 365 nm (Absorption) (Fluorescence) in THF, 20 ºC Concentration : 4 x 10-6 M F (trans → cis) : 0.091, F (cis → trans) : 0.045

S. Yagai et al., Angew. Chem. Int. Ed., 2008, 48, 3367. Aggregation of PBI H-Aggregate. H-Aggregate. J-Aggregate. J-Aggregate. S. Yagai et al., Angew. Chem. Int. Ed., 2008, 48, 3367.

Photoisomerization of 1 312 nm (cis) 365 nm (Absorption) (Fluorescence) in THF, 20 ºC Concentration : 4 x 10-6 M F (trans → cis) : 0.091, F (cis → trans) : 0.045

Concentration Dependence F. Wurthner et al., Chem. Eur. J., 2001, 7, 2245.

1H NMR Study of 2 a b c in CD2Cl2, at 20 ºC

1H NMR Study of 1 (312 nm, 10 min.) Conversion : 81 % (312 nm, 2 min.) PBI-Hc (312 nm, 10 min.) PBI-Hb Conversion : 81 % (312 nm, 2 min.) (before) in CD2Cl2, at 20 ºC

Photoisomerization of 1 312 nm (cis) 365 nm (Fluorescence response) <Conversion> trans → cis (312 nm) : 81 % (NMR) cis → trans (365 nm) : 83 % (trans → cis) : 0.091, F (cis → trans) : 0.045

Conclusions Light-driven dynamic control of intramolecular H-stacking of PBI units using a molecular switch is demonstrated. The approach presented here allows for uniform and significant spectral changes spanning at least 4orders of magnitude of concentration. This approach could be extended to control several processes such as molecular recognition, electron and energy transfer.