Solvent-Dependent Excited-State Hydrogen Transfer and Intersystem Crossing in 2-(2′-Hydroxyphenyl)-Benzothiazole

2014 ◽  
Vol 119 (6) ◽  
pp. 2596-2603 ◽  
Author(s):  
Shawkat M. Aly ◽  
Anwar Usman ◽  
Maytham AlZayer ◽  
Ghada A. Hamdi ◽  
Erkki Alarousu ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Transfer ◽  
Intersystem Crossing

Excited state hydrogen transfer dynamics in phenol–(NH3)2 studied by picosecond UV-near IR-UV time-resolved spectroscopy

2020 ◽  
Vol 22 (10) ◽  
pp. 5740-5748
Author(s):  
Shun-ichi Ishiuchi ◽  
Junko Kamizori ◽  
Norihiro Tsuji ◽  
Makoto Sakai ◽  
Mitsuhiko Miyazaki ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Transfer ◽  
Transfer Reaction ◽  
Bound State ◽  
Intersystem Crossing ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Hydrogen Transfer Reaction ◽  
Near Ir

Intersystem crossing from 1πσ* to 3πσ* states traps excited state hydrogen transfer reaction in a bound state formed by 3ππ* and 3πσ* states.

scholarly journals Probing Competing Relaxation Pathways in Malonaldehyde with Transient X-Ray Absorption Spectroscopy

2020 ◽  
Author(s):  
Nanna Holmgaard List ◽  
Adrian L. Dempwolff ◽  
Andreas Dreuw ◽  
Patrick Norman ◽  
Todd J. Martínez
Keyword(s):  
Excited State ◽  
Absorption Spectroscopy ◽  
Hydrogen Transfer ◽  
Intersystem Crossing ◽  
Light Sources ◽  
X Ray ◽  
Valence States ◽  
Specific Mapping ◽  
Intramolecular Hydrogen ◽  
X Ray Absorption

<p>Excited-state intramolecular hydrogen transfer (ESIHT) is a fundamental reaction relevant to chemistry and biology. Malonaldehyde is the simplest example of ESIHT, yet only little is known experimentally about its excited-state dynamics. Several competing relaxation pathways have been proposed, including internal conversion mediated by ESIHT and C=C torsional motion as well as intersystem crossing. We perform an in silico transient X-ray absorption spectroscopy (TRXAS) experiment at the oxygen K-edge to investigate its potential to monitor the proposed ultrafast decay pathways in malonaldehyde upon photoexcitation to its bright S2(pp*) state. We employ both restricted active space perturbation theory and algebraic diagrammatic construction for the polarization propagator along interpolated reaction coordinates as well as representative trajectories from ab initio multiple spawning simulations to compute the TRXAS signals from the lowest valence states. Our study suggests that oxygen K-edge TRXAS can distinctly fingerprint the passage through the H-transfer intersection and the concomitant population transfer to the S1(np*) state. Potential intersystem crossing to T1(pp*) is detectable from reappearance of the double pre-edge signature and reversed intensities. Moreover, the torsional deactivation pathway induces transient charge redistribution from the enol side towards the central C-atom and manifests itself as substantial shifts of the pre-edge features. Given the continuous advances in X-ray light sources, our study proposes an experimental route to disentangle ultrafast excited-state decay channels in this prototypical ESIHT system and provides a pathway-specific mapping of the TRXAS signal to facilitate the interpretation of future experiments.</p>

scholarly journals Probing Competing Relaxation Pathways in Malonaldehyde with Transient X-Ray Absorption Spectroscopy

2020 ◽  
Author(s):  
Nanna Holmgaard List ◽  
Adrian L. Dempwolff ◽  
Andreas Dreuw ◽  
Patrick Norman ◽  
Todd J. Martínez
Keyword(s):  
Excited State ◽  
Absorption Spectroscopy ◽  
Hydrogen Transfer ◽  
Intersystem Crossing ◽  
Light Sources ◽  
X Ray ◽  
Valence States ◽  
Specific Mapping ◽  
Intramolecular Hydrogen ◽  
X Ray Absorption

<p>Excited-state intramolecular hydrogen transfer (ESIHT) is a fundamental reaction relevant to chemistry and biology. Malonaldehyde is the simplest example of ESIHT, yet only little is known experimentally about its excited-state dynamics. Several competing relaxation pathways have been proposed, including internal conversion mediated by ESIHT and C=C torsional motion as well as intersystem crossing. We perform an in silico transient X-ray absorption spectroscopy (TRXAS) experiment at the oxygen K-edge to investigate its potential to monitor the proposed ultrafast decay pathways in malonaldehyde upon photoexcitation to its bright S2(pp*) state. We employ both restricted active space perturbation theory and algebraic diagrammatic construction for the polarization propagator along interpolated reaction coordinates as well as representative trajectories from ab initio multiple spawning simulations to compute the TRXAS signals from the lowest valence states. Our study suggests that oxygen K-edge TRXAS can distinctly fingerprint the passage through the H-transfer intersection and the concomitant population transfer to the S1(np*) state. Potential intersystem crossing to T1(pp*) is detectable from reappearance of the double pre-edge signature and reversed intensities. Moreover, the torsional deactivation pathway induces transient charge redistribution from the enol side towards the central C-atom and manifests itself as substantial shifts of the pre-edge features. Given the continuous advances in X-ray light sources, our study proposes an experimental route to disentangle ultrafast excited-state decay channels in this prototypical ESIHT system and provides a pathway-specific mapping of the TRXAS signal to facilitate the interpretation of future experiments.</p>

Spin-Forbidden Excitation Enables Infrared Photoredox Catalysis

2020 ◽  
Author(s):  
Tomislav Rovis ◽  
Benjamin D. Ravetz ◽  
Nicholas E. S. Tay ◽  
Candice Joe ◽  
Melda Sezen-Edmonds ◽  
...  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Intersystem Crossing ◽  
Photoredox Catalysis ◽  
Infrared Irradiation ◽  
Triplet Excitation ◽  
New Family ◽  
Ir Light

We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation.

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.

scholarly journals UV-induced hydrogen transfer in DNA base pairs promoted by dark nπ* states

2020 ◽  
Vol 56 (2) ◽  
pp. 201-204 ◽  
Author(s):  
Kinga E. Szkaradek ◽  
Petr Stadlbauer ◽  
Jiří Šponer ◽  
Robert W. Góra ◽  
Rafał Szabla
Keyword(s):  
Excited State ◽  
Hydrogen Transfer ◽  
Base Pairs ◽  
Dna Base ◽  
Dna Base Pairs

Formation of an excited-state complex enables ultrafast photorelaxation of dark nπ* states in GC and HC base pairs.

INTERSYSTEM CROSSING OF THE ELECTRONICALLY EXCITED DIDEUTEROETHYLENE MOLECULES FORMED IN BENZENE PHOTOSENSITIZATION

1966 ◽  
Vol 44 (18) ◽  
pp. 2173-2180 ◽  
Author(s):  
Terumi Terao ◽  
Shun-Ichi Hirokami ◽  
Shin Sato ◽  
R. J. Cvetanović
Keyword(s):  
Excited State ◽  
Experimental Evidence ◽  
Rate Constants ◽  
Intersystem Crossing ◽  
Molecular Decomposition ◽  
Electronically Excited

Experimental evidence is presented for a rapidly occurring intersystem crossing of the electronically excited dideuteroethylene molecules initially formed in the benzene-photosensitized reaction at 2 537 Å and 25 °C to another excited state which is responsible for the internal H-atom scrambling. The mechanism is entirely analogous to that previously postulated for the photoexcited states sensitized by Hg(3P1) atoms but the rate constants for intersystem crossing and molecular decomposition are drastically decreased as a result of the smaller amount of energy available for the excitation.

Intracluster hydrogen transfer followed by dissociation in the phenol–(NH3)3 excited state: PhOH(S1)–(NH3)3→PhO•+(NH4)(NH3)2

1999 ◽  
Vol 111 (24) ◽  
pp. 10747-10749 ◽  
Author(s):  
G. A. Pino ◽  
C. Dedonder-Lardeux ◽  
G. Grégoire ◽  
C. Jouvet ◽  
S. Martrenchard ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Transfer

scholarly journals Excited state dynamics of protonated keto uracil: intersystem crossing pathways in competition

2021 ◽  
Vol 75 (1) ◽  
Author(s):  
Jordan Dezalay ◽  
Michel Broquier ◽  
Satchin Soorkia ◽  
Gilles Grégoire
Keyword(s):  
Excited State ◽  
Intersystem Crossing ◽  
Excited State Dynamics

Excited state absorption spectra and intersystem crossing kinetics in the naphthaldehydes

1984 ◽  
Vol 80 (7) ◽  
pp. 3179-3184 ◽  
Author(s):  
David W. Boldridge ◽  
Brian L. Justus ◽  
Gary W. Scott
Keyword(s):  
Excited State ◽  
Absorption Spectra ◽  
Excited State Absorption ◽  
Intersystem Crossing
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