Unusual solvent polarity dependent excitation relaxation dynamics of a bis[p-ethynyldithiobenzoato]Pd-linked bis[(porphinato)zinc] complex

2018 ◽  
Vol 3 (1) ◽  
pp. 275-284 ◽  
Author(s):  
Jaehong Park ◽  
Tae-Hong Park ◽  
Louise E. Sinks ◽  
Pravas Deria ◽  
Jiyong Park ◽  
...  
Keyword(s):  
Excited State ◽  
Zinc Complex ◽  
Decay Channel ◽  
Solvent Polarity ◽  
Relaxation Dynamics ◽  
Excited State Dynamics ◽  
Porphyrin Dimer

A porphyrin dimer linked by a Pd(ii)-based linker displays unusual excited-state dynamics where solvent polarity steers singlet and triplet decay-channel population.

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.

Excited-state dynamics of guanosine in aqueous solution revealed by time-resolved photoelectron spectroscopy: experiment and theory

2015 ◽  
Vol 17 (47) ◽  
pp. 31978-31987 ◽  
Author(s):  
Franziska Buchner ◽  
Berit Heggen ◽  
Hans-Hermann Ritze ◽  
Walter Thiel ◽  
Andrea Lübcke
Keyword(s):  
Aqueous Solution ◽  
Excited State ◽  
Photoelectron Spectroscopy ◽  
Relaxation Dynamics ◽  
Time Resolved ◽  
Excited State Dynamics ◽  
Spectroscopy Experiment

Time-resolved photoelectron spectroscopy is performed on aqueous guanosine solution to study its excited-state relaxation dynamics.

Geometry and Solvent-Polarity Dependences of the Relaxation Dynamics of the Singlet Excited State of Center-to-Edge Phosphorus(V) Porphyrin Heterodimers

2006 ◽  
Vol 110 (10) ◽  
pp. 5120-5126 ◽  
Author(s):  
Kenji Nagao ◽  
Yasuko Takeuchi ◽  
Hiroshi Segawa
Keyword(s):  
Excited State ◽  
Solvent Polarity ◽  
Singlet Excited State ◽  
Relaxation Dynamics

scholarly journals Excited State Dynamics of 7-Deazaguanosine and Guanosine 5’ Monophosphate

2021 ◽  
Author(s):  
Sarah E. Krul ◽  
Sean J. Hoehn ◽  
Karl Feierabend ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Ground State ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Water Mixture ◽  
Relaxation Dynamics ◽  
Similar Time ◽  
Excited State Dynamics ◽  
Computational Calculations

<p>Minor structural modifications to the DNA and RNA nucleobases have a significant effect on their excited state dynamics and electronic relaxation pathways.<b> </b>In this study, the excited state dynamics of 7-deazaguanosine and guanosine 5’-monophosphate are investigated in aqueous and in a mixture of methanol and water using femtosecond broadband transient absorption spectroscopy following excitation at 267 nm. The transient spectra are collected using photon densities that ensure no parasitic multiphoton-induced signal from solvated electrons. The data can be fit satisfactorily using a two- or three-component kinetic model. By analyzing the results from steady-state, time-resolved, computational calculations, and the methanol-water mixture, the following general relaxation mechanism is proposed for both molecules, L<sub>b</sub> ® L<sub>a</sub> ® <sup>1</sup>ps*(ICT) ® S<sub>0</sub>, where the <sup>1</sup>ps*(ICT) stands for an intramolecular charge transfer excited singlet state with significant ps* character. In general, longer lifetimes for internal conversion are obtained for 7-deazaguanosine compared to guanosine 5’-monophosphate. Internal conversion of the <sup>1</sup>ps*(ICT) state to the ground state occurs on a similar time scale of a few picoseconds in both molecules. Collectively, the results demonstrate that substitution of a single nitrogen for a methine (C-H) group at position seven of the guanine moiety stabilizes the <sup>1</sup>pp* L<sub>b</sub> and L<sub>a</sub> states and alter the topology of their potential energy surfaces in such a way that the relaxation dynamics in 7-deazaguanosine are slowed down compared to those in guanosine 5’-monophosphate but not for the internal conversion of <sup>1</sup>ps*(ICT) state to the ground state.</p>

scholarly journals Excited State Dynamics of 7-Deazaguanosine and Guanosine 5’ Monophosphate

2021 ◽  
Author(s):  
Sarah E. Krul ◽  
Sean J. Hoehn ◽  
Karl Feierabend ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Ground State ◽  
Internal Conversion ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Water Mixture ◽  
Relaxation Dynamics ◽  
Similar Time ◽  
Excited State Dynamics ◽  
Computational Calculations

<p>Minor structural modifications to the DNA and RNA nucleobases have a significant effect on their excited state dynamics and electronic relaxation pathways.<b> </b>In this study, the excited state dynamics of 7-deazaguanosine and guanosine 5’-monophosphate are investigated in aqueous and in a mixture of methanol and water using femtosecond broadband transient absorption spectroscopy following excitation at 267 nm. The transient spectra are collected using photon densities that ensure no parasitic multiphoton-induced signal from solvated electrons. The data can be fit satisfactorily using a two- or three-component kinetic model. By analyzing the results from steady-state, time-resolved, computational calculations, and the methanol-water mixture, the following general relaxation mechanism is proposed for both molecules, L<sub>b</sub> ® L<sub>a</sub> ® <sup>1</sup>ps*(ICT) ® S<sub>0</sub>, where the <sup>1</sup>ps*(ICT) stands for an intramolecular charge transfer excited singlet state with significant ps* character. In general, longer lifetimes for internal conversion are obtained for 7-deazaguanosine compared to guanosine 5’-monophosphate. Internal conversion of the <sup>1</sup>ps*(ICT) state to the ground state occurs on a similar time scale of a few picoseconds in both molecules. Collectively, the results demonstrate that substitution of a single nitrogen for a methine (C-H) group at position seven of the guanine moiety stabilizes the <sup>1</sup>pp* L<sub>b</sub> and L<sub>a</sub> states and alter the topology of their potential energy surfaces in such a way that the relaxation dynamics in 7-deazaguanosine are slowed down compared to those in guanosine 5’-monophosphate but not for the internal conversion of <sup>1</sup>ps*(ICT) state to the ground state.</p>

Optical Properties and Excited-State Dynamics of Atomically Precise Gold Nanoclusters

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Meng Zhou ◽  
Rongchao Jin
Keyword(s):  
Excited State ◽  
Gold Nanoclusters ◽  
Electron Excitation ◽  
Annual Review ◽  
Publication Date ◽  
Relaxation Dynamics ◽  
Excited State Dynamics ◽  
Quantum Confinement Effects ◽  
Electron Transitions ◽  
Shape Structure

Understanding the excited-state dynamics of nanomaterials is essential to their applications in photoenergy storage and conversion. This review summarizes recent progress in the excited-state dynamics of atomically precise gold (Au) nanoclusters (NCs). We first discuss the electronic structure and typical relaxation pathways of Au NCs from subpicoseconds to microseconds. Unlike plasmonic Au nanoparticles, in which collective electron excitation dominates, Au NCs show single-electron transitions and molecule-like exciton dynamics. The size-, shape-, structure-, and composition-dependent dynamics in Au NCs are further discussed in detail. For small-sized Au NCs, strong quantum confinement effects give rise to relaxation dynamics that is significantly dependent on atomic packing, shape, and heteroatom doping. For relatively larger-sized Au NCs, strong size dependence can be observed in exciton and electron dynamics. We also discuss the origin of coherent oscillations and their roles in excited-state relaxation. Finally, we provide our perspective on future directions in this area. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 72 is April 20, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Excited-state torsional relaxation dynamics of meso–meso directly linked corrole dimers: importance of linking position

2016 ◽  
Vol 18 (33) ◽  
pp. 23374-23382 ◽  
Author(s):  
Kyu Hyung Park ◽  
Shota Ooi ◽  
Taeyeon Kim ◽  
Takayuki Tanaka ◽  
Atsuhiro Osuka ◽  
...  
Keyword(s):  
Excited State ◽  
Relaxation Dynamics ◽  
Excited State Dynamics

The effect of linking position on the excited-state dynamics of meso-meso directly linked corrole dimers is explored.

scholarly journals Excited state dynamics of BODIPY-based acceptor–donor–acceptor systems: a combined experimental and computational study

2021 ◽  
Vol 23 (14) ◽  
pp. 8900-8907
Author(s):  
Zimu Wei ◽  
Sushil Sharma ◽  
Abbey M. Philip ◽  
Sanchita Sengupta ◽  
Ferdinand C. Grozema
Keyword(s):  
Excited State ◽  
Computational Study ◽  
Solvent Polarity ◽  
Excited State Dynamics ◽  
Sensing Applications ◽  
Boron Dipyrromethene ◽  
Donor Acceptor

Donor-bridge-acceptor systems based on boron dipyrromethene (BODIPY) are attractive candidates for bio-imagining and sensing applications because of their sensitivity to temperature, micro-viscosity and solvent polarity.

Photophysical properties and excited state dynamics of 4,7-dithien-2-yl-2,1,3-benzothiadiazole

2017 ◽  
Vol 19 (21) ◽  
pp. 13604-13613 ◽  
Author(s):  
Alessandro Iagatti ◽  
Barbara Patrizi ◽  
Andrea Basagni ◽  
Agnese Marcelli ◽  
Andrea Alessi ◽  
...  
Keyword(s):  
Excited State ◽  
Structural Properties ◽  
Computational Methods ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Excited State Dynamics

The relationships between the photophysics and structural properties of 4,7-dithien-2-yl-2,1,3-benzothiadiazole as a function of solvent polarity are investigated both experimentally and by computational methods.

scholarly journals Finite-temperature Wigner phase-space sampling and temperature effects on the excited-state dynamics of 2-nitronaphthalene

2019 ◽  
Vol 21 (26) ◽  
pp. 13906-13915 ◽  
Author(s):  
J. Patrick Zobel ◽  
Juan J. Nogueira ◽  
Leticia González
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
Phase Space ◽  
Excited States ◽  
Finite Temperature ◽  
Temperature Effects ◽  
Relaxation Dynamics ◽  
Vibrationally Excited ◽  
Excited State Dynamics

The concept of finite temperature Wigner phase-space sampling allowing the population of vibrationally excited states is introduced and employed to study temperature effects on the absorption spectrum of 2-nitronaphtalene (2NN) and its relaxation dynamics.

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