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Photonic switching of photoinduced electron transfer in a dihydropyrene-porphyrin-fullerene molecular triad

P. A. Liddell ; G. Kodis ; Joakim Andréasson (Institutionen för kemi och biovetenskap, Fysikalisk kemi) ; L. de la Garza ; S. Bandyopadhyay ; R. H. Mitchell ; T. A. Moore ; A. L. Moore ; D. Gust
Journal of the American Chemical Society Vol. 126 (2004), 15, p. 4803-4811.
[Artikel, refereegranskad vetenskaplig]

Photonic control of photoinduced electron transfer has been demonstrated in a dimethyldihydropyrene (DHP) porphyrin (P) fullerene (C-60) molecular triad. In the DHP-P-C-60 form of the triad, excitation of the porphyrin moiety is followed by photoinduced electron transfer to give a DHP-P.+-C-60(.-) charge-separated state, which evolves by a charge shift reaction to DHP.+-P-C-60(.-). This final state has a lifetime of 2 mus and is formed in an overall yield of 94%. Visible (greater than or equal to300 nm) irradiation of the triad leads to photoisomerization of the DHP moiety to the cyclophanediene (CPD). Excitation of the porphyrin moiety of CPD-P-C-60 produces a short-lived (<10 ns) CPD-P&BULL;+-C-60(.-) state, but charge shift to the CPD moiety does not occur, due to the relatively high oxidation potential of the CPD group. Long-lived charge separation is not observed. Irradiation of CPD-P-C-60 with UV (254 nm) light converts the triad back to the DHP form. Thermal interconversion of the DHP and CPD forms is very slow, photochemical cycling is facile, and in the absence of oxygen, many cycles may be performed without substantial degradation. Thus, light is used to switch long-lived photoinduced charge separation on or off. The principles demonstrated by the triad may be useful for the design of molecule-based optoelectronic systems.



Denna post skapades 2008-10-21. Senast ändrad 2011-11-03.
CPL Pubid: 75956

 

Institutioner (Chalmers)

Institutionen för kemi och biovetenskap, Fysikalisk kemi (2004-2004)

Ämnesområden

Kemi

Chalmers infrastruktur