Synergy Effects of Electric and Magnetic Fields on Locally Excited-State Fluorescence of Photoinduced Electron Transfer Systems in a Polymer Film

2009 ◽  
Vol 113 (40) ◽  
pp. 10603-10609 ◽  
Author(s):  
Kamlesh Awasthi ◽  
Toshifumi Iimori ◽  
Nobuhiro Ohta
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Magnetic Fields ◽  
Polymer Film ◽  
Photoinduced Electron Transfer ◽  
Locally Excited ◽  
Synergy Effects ◽  
Electric And Magnetic Fields ◽  
Locally Excited State

scholarly journals Role of active site conformational changes in photocycle activation of the AppA BLUF photoreceptor

2017 ◽  
Vol 114 (7) ◽  
pp. 1480-1485 ◽  
Author(s):  
Puja Goyal ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Electron Transfer ◽  
Free Energy ◽  
Excited State ◽  
Charge Transfer ◽  
Conformational Changes ◽  
Ground State ◽  
Active Site ◽  
Locally Excited ◽  
Proton Relay ◽  
Locally Excited State

Blue light using flavin adenine dinucleotide (BLUF) proteins are essential for the light regulation of a variety of physiologically important processes and serve as a prototype for photoinduced proton-coupled electron transfer (PCET). Free-energy simulations elucidate the active site conformations in the AppA (activation of photopigment and puc expression) BLUF domain before and following photoexcitation. The free-energy profile for interconversion between conformations with either Trp104 or Met106 closer to the flavin, denoted Trpin/Metout and Trpout/Metin, reveals that both conformations are sampled on the ground state, with the former thermodynamically favorable by ∼3 kcal/mol. These results are consistent with the experimental observation of both conformations. To analyze the proton relay from Tyr21 to the flavin via Gln63, the free-energy profiles for Gln63 rotation were calculated on the ground state, the locally excited state of the flavin, and the charge-transfer state associated with electron transfer from Tyr21 to the flavin. For the Trpin/Metout conformation, the hydrogen-bonding pattern conducive to the proton relay is not thermodynamically favorable on the ground state but becomes more favorable, corresponding to approximately half of the configurations sampled, on the locally excited state. The calculated energy gaps between the locally excited and charge-transfer states suggest that electron transfer from Tyr21 to the flavin is more facile for configurations conducive to proton transfer. When the active site conformation is not conducive to PCET from Tyr21, Trp104 can directly compete with Tyr21 for electron transfer to the flavin through a nonproductive pathway, impeding the signaling efficiency.

Photoinduced Electron Transfer from a Higher Excited State of a Porphyrin in a Zinc Porphyrin−Ruthenium(II)tris-Bipyridine Dyad

1999 ◽  
Vol 103 (5) ◽  
pp. 557-559 ◽  
Author(s):  
Denis LeGourriérec ◽  
Mikael Andersson ◽  
Jan Davidsson ◽  
Emad Mukhtar ◽  
Licheng Sun ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Photoinduced Electron Transfer ◽  
Zinc Porphyrin

Photoinduced electron transfer from the cerous ion excited state to cupric ion

1980 ◽  
Vol 19 (11) ◽  
pp. 3461-3465 ◽  
Author(s):  
R. P. Asbury ◽  
G. S. Hammond ◽  
P. H. P. Lee ◽  
A. T. Poulos
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Photoinduced Electron Transfer ◽  
Cupric Ion

A new fluorescence molecular switch incorporating TTF and tetraphenylporphyrin units

2007 ◽  
Vol 11 (10) ◽  
pp. 729-735 ◽  
Author(s):  
Yibo Liu ◽  
Chengyun Wang ◽  
Meijiang Li ◽  
Sufang Lv ◽  
Guoqiao Lai ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Excited State ◽  
Ground State ◽  
Photoinduced Electron Transfer ◽  
Intramolecular Charge Transfer ◽  
Molecular Switch ◽  
Target Compound ◽  
Chemical Methods ◽  
H Nmr

A donor-σ-acceptor compound incorporating tetrathiafulvalene and tetraphenylporphyrin units was synthesized. The structures of the target compound and its intermediates have been characterized by 1 H NMR, ESI MS, UV-vis, IR and mp. The results of UV-vis and cyclic voltammetry of the compound indicated negligible intramolecular charge transfer interaction in its ground state. The fluorescence and fluorescence lifetime of the compound were reduced, compared to tetraphenylporphyrin, which evidently indicated that photoinduced electron transfer occurred from the tetrathiafulvalene (TTF) unit to the tetraphenylporphyrin unit in the excited state. The fluorescence intensity of the compound could be reversibly modulated by sequential oxidation and reduction of the TTF unit using electrochemical and chemical methods. Therefore, a new fluorescence molecular switch based on TTF and porphyrin units was established.

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