Photoinduced electron transfer and exciplex formation in bichromophoric molecules

1991 ◽  
Vol 95 (1) ◽  
pp. 711-713 ◽  
Author(s):  
Hansen Shou ◽  
Joseph C. Alfano ◽  
Niels A. van Dantzig ◽  
Donald H. Levy ◽  
Nien‐chu C. Yang
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Exciplex Formation ◽  
Bichromophoric Molecules

Transient states in photoinduced electron transfer reactions of porphyrin- and phthalocyanine-fullerene dyads

2009 ◽  
Vol 13 (10) ◽  
pp. 1090-1097 ◽  
Author(s):  
Helge Lemmetyinen ◽  
Nikolai Tkachenko ◽  
Alexander Efimov ◽  
Marja Niemi
Keyword(s):  
Electron Transfer ◽  
Charge Separation ◽  
Photoinduced Electron Transfer ◽  
Transient State ◽  
Primary Electron ◽  
Transfer Reactions ◽  
Acceptor Pair ◽  
Electron Transfer Reactions ◽  
Exciplex Formation ◽  
Donor And Acceptor

This paper combines the most important results on studies performed by the authors during the last decade on photoinduced electron transfer reactions of pheophytin-, phthalocyanine-, and porphyrin-fullerene dyads, in which donor and acceptor moieties are covalently linked to each other. Practically all studied molecules form an intramolecular exciplex as a transient state before the formation of the charge separation state or tight ion pair. When the center-to-center distance of the donor and acceptor pair is short (7–10 Å) both the exciplex formation and primary electron transfer are extremely fast with rate constants of 7–23 × 1012 s -1 and 40–1400 × 109 s -1, respectively. Rates become slower when the distance and orientational fluctuation increases. No systematic correlation between free energies and the rates of the formation and recombination of the exciplex and the charge separation state, respectively, were observed. The mechanism is discussed in frames of the Marcus electron transfer and the radiationless quantum transition theories.

Ultrafast Photodynamics of Exciplex Formation and Photoinduced Electron Transfer in Porphyrin−Fullerene Dyads Linked at Close Proximity

2003 ◽  
Vol 107 (42) ◽  
pp. 8834-8844 ◽  
Author(s):  
Nikolai V. Tkachenko ◽  
Helge Lemmetyinen ◽  
Junko Sonoda ◽  
Kei Ohkubo ◽  
Tomoo Sato ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Exciplex Formation ◽  
Close Proximity

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

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