Unravelling the Role of Water in Ultrafast Excited‐State Relaxation Dynamics within Nano‐Architectures of Chlorophyll a

ChemPhysChem ◽  
2020 ◽  
Vol 21 (17) ◽  
pp. 1908-1917
Author(s):  
Yogita Silori ◽  
Sakshi Chawla ◽  
Arijit K. De
Keyword(s):  
Excited State ◽  
Chlorophyll A ◽  
Relaxation Dynamics

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

scholarly journals Revealing the role of excited state proton transfer (ESPT) in excited state hydrogen transfer (ESHT): systematic study in phenol–(NH3)n clusters

2021 ◽  
Author(s):  
Christophe Jouvet ◽  
Mitsuhiko Miyazaki ◽  
Masaaki Fujii
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Systematic Study ◽  
General Model ◽  
Hydrogen Transfer ◽  
Excited State Proton Transfer

A general model of excited state hydrogen transfer (ESHT) which unifies ESHT and the excited state proton transfer (ESPT) is presented from experimental and theoretical works on phenol–(NH3)n. The hidden role of ESPT is revealed.

The role of conformational heterogeneity in the excited state dynamics of linked diketopyrrolopyrrole dimers

2021 ◽  
Author(s):  
Siobhan Bradley ◽  
Ming Chi ◽  
Jonathan White ◽  
Christopher R. Hall ◽  
Lars Goerigk ◽  
...  
Keyword(s):  
Excited State ◽  
Conformational Heterogeneity ◽  
Singlet Fission ◽  
Excited State Dynamics

Diketopyrrolopyrrole (DPP) derivatives have been proposed for both singlet fission and energy upconversion as they meet the energetic requirements and exhibit superior photostability compared to many other chromophores. In this...

Role of Solvent in Excited-State Proton Transfer in Hypericin

1994 ◽  
Vol 98 (34) ◽  
pp. 8352-8358 ◽  
Author(s):  
F. Gai ◽  
M. J. Fehr ◽  
J. W. Petrich
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Excited State Proton Transfer ◽  
Role Of Solvent

scholarly journals Ultrafast excited state dynamics and light-switching of [Ru(phen)2(dppz)]2+ in G-quadruplex DNA

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Chunfan Yang ◽  
Qian Zhou ◽  
Zeqing Jiao ◽  
Hongmei Zhao ◽  
Chun-Hua Huang ◽  
...  
Keyword(s):  
Excited State ◽  
State Formation ◽  
Rational Design ◽  
Bound Water ◽  
Binding Modes ◽  
Relaxation Dynamics ◽  
Dark State ◽  
Excited State Dynamics ◽  
G Quadruplex ◽  
Mechanistic Basis

AbstractThe triplet metal to ligand charge transfer (3MLCT) luminescence of ruthenium (II) polypyridyl complexes offers attractive imaging properties, specifically towards the development of sensitive and structure-specific DNA probes. However, rapidly-deactivating dark state formation may compete with 3MLCT luminescence depending on different DNA structures. In this work, by combining femtosecond and nanosecond pump-probe spectroscopy, the 3MLCT relaxation dynamics of [Ru(phen)2(dppz)]2+ (phen = 1,10-phenanthroline, dppz = dipyridophenazine) in two iconic G-quadruplexes has been scrutinized. The binding modes of stacking of dppz ligand on the terminal G-quartet fully and partially are clearly identified based on the biexponential decay dynamics of the 3MLCT luminescence at 620 nm. Interestingly, the inhibited dark state channel in ds-DNA is open in G-quadruplex, featuring an ultrafast picosecond depopulation process from 3MLCT to a dark state. The dark state formation rates are found to be sensitive to the content of water molecules in local G-quadruplex structures, indicating different patterns of bound water. The unique excited state dynamics of [Ru(phen)2(dppz)]2+ in G-quadruplex is deciphered, providing mechanistic basis for the rational design of photoactive ruthenium metal complexes in biological applications.

A meta-analysis and review examining a possible role for oxidative stress and singlet oxygen in diverse diseases

2017 ◽  
Vol 474 (16) ◽  
pp. 2713-2731 ◽  
Author(s):  
Athinoula L. Petrou ◽  
Athina Terzidaki
Keyword(s):  
Oxidative Stress ◽  
Excited State ◽  
Singlet Oxygen ◽  
Ground State ◽  
Meta Analysis ◽  
Common Mechanism ◽  
High Electron ◽  
A Value ◽  
First Excited State

From kinetic data (k, T) we calculated the thermodynamic parameters for various processes (nucleation, elongation, fibrillization, etc.) of proteinaceous diseases that are related to the β-amyloid protein (Alzheimer's), to tau protein (Alzheimer's, Pick's), to α-synuclein (Parkinson's), prion, amylin (type II diabetes), and to α-crystallin (cataract). Our calculations led to ΔG≠ values that vary in the range 92.8–127 kJ mol−1 at 310 K. A value of ∼10–30 kJ mol−1 is the activation energy for the diffusion of reactants, depending on the reaction and the medium. The energy needed for the excitation of O2 from the ground to the first excited state (1Δg, singlet oxygen) is equal to 92 kJ mol−1. So, the ΔG≠ is equal to the energy needed for the excitation of ground state oxygen to the singlet oxygen (1Δg first excited) state. The similarity of the ΔG≠ values is an indication that a common mechanism in the above disorders may be taking place. We attribute this common mechanism to the (same) role of the oxidative stress and specifically of singlet oxygen, (1Δg), to the above-mentioned processes: excitation of ground state oxygen to the singlet oxygen, 1Δg, state (92 kJ mol−1), and reaction of the empty π* orbital with high electron density regions of biomolecules (∼10–30 kJ mol−1 for their diffusion). The ΔG≠ for cases of heat-induced cell killing (cancer) lie also in the above range at 310 K. The present paper is a review and meta-analysis of literature data referring to neurodegenerative and other disorders.

Excited state relaxation dynamics and up-conversion phenomena in Gd 3 (Al,Ga) 5 O 12 single crystals co-doped with holmium and ytterbium

2016 ◽  
Vol 656 ◽  
pp. 573-580 ◽  
Author(s):  
W. Ryba-Romanowski ◽  
J. Komar ◽  
T. Niedźwiedzki ◽  
M. Głowacki ◽  
M. Berkowski
Keyword(s):  
Excited State ◽  
Single Crystals ◽  
Relaxation Dynamics ◽  
Co Doped
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