Time-Resolved Femtosecond Stimulated Raman Spectra and DFT Anharmonic Vibrational Analysis of an Electronically Excited Rhenium Photosensitizer

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F20%3A00522634" target="_blank" >RIV/61388955:_____/20:00522634 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/86652036:_____/20:00522634 RIV/68378271:_____/20:00522634 RIV/60461373:22310/20:43920809

Výsledek na webu

<a href="http://hdl.handle.net/11104/0307098" target="_blank" >http://hdl.handle.net/11104/0307098</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpca.9b10840" target="_blank" >10.1021/acs.jpca.9b10840</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Time-Resolved Femtosecond Stimulated Raman Spectra and DFT Anharmonic Vibrational Analysis of an Electronically Excited Rhenium Photosensitizer

Popis výsledku v původním jazyce

Time-resolved femtosecond stimulated Raman spectra (FSRS) of a prototypical organometallic photosensitizer/photocatalyst ReCl(CO)3(2,2′-bipyridine) were measured in a broad spectral range ∼40–2000 (4000) cm–1 at time delays from 40 fs to 4 ns after 400 nm excitation of the lowest allowed electronic transition. Theoretical ground- and excited-state Raman spectra were obtained by anharmonic vibrational analysis using second-order vibrational perturbation theory on vibrations calculated by harmonic approximation at density functional theory-optimized structures. A good match with anharmonically calculated vibrational frequencies allowed for assigning experimental Raman features to particular vibrations. Observed frequency shifts upon excitation (ν(ReCl) and ν(CC inter-ring) vibrations upward, ν(CC, CN) and ν(Re–C) downward) are consistent with the bonding/antibonding characters of the highest occupied molecular orbital and the lowest unoccupied molecular orbital involved in excitation and support the delocalized formulation of the lowest triplet state as ReCl(CO)3 → bpy charge transfer. FSRS spectra show a mode-specific temporal evolution, providing insights into the intersystem crossing (ISC) mechanism and subsequent relaxation. Most of the Raman features are present at ∼40 fs and exhibit small shifts and intensity changes with time. The 1450–1600 cm–1 group of bands due to CC, CN, and CC(inter-ring) stretching vibrations undergoes extensive restructuring between 40 and ∼150 fs, followed by frequency upshifts and a biexponential (0.38, 21 ps) area growth, indicating progressing charge separation in the course of the formation and relaxation of the lowest triplet state. Early (40–150 fs) restructuring was also observed in the low-frequency range for ν(Re–Cl) and δ(Re–C–O) vibrations that are presumably activated by ISC. FSRS experimental innovations employed to measure low- and high-energy Raman features simultaneously are described and discussed in detail.

Název v anglickém jazyce

Time-Resolved Femtosecond Stimulated Raman Spectra and DFT Anharmonic Vibrational Analysis of an Electronically Excited Rhenium Photosensitizer

Popis výsledku anglicky

Time-resolved femtosecond stimulated Raman spectra (FSRS) of a prototypical organometallic photosensitizer/photocatalyst ReCl(CO)3(2,2′-bipyridine) were measured in a broad spectral range ∼40–2000 (4000) cm–1 at time delays from 40 fs to 4 ns after 400 nm excitation of the lowest allowed electronic transition. Theoretical ground- and excited-state Raman spectra were obtained by anharmonic vibrational analysis using second-order vibrational perturbation theory on vibrations calculated by harmonic approximation at density functional theory-optimized structures. A good match with anharmonically calculated vibrational frequencies allowed for assigning experimental Raman features to particular vibrations. Observed frequency shifts upon excitation (ν(ReCl) and ν(CC inter-ring) vibrations upward, ν(CC, CN) and ν(Re–C) downward) are consistent with the bonding/antibonding characters of the highest occupied molecular orbital and the lowest unoccupied molecular orbital involved in excitation and support the delocalized formulation of the lowest triplet state as ReCl(CO)3 → bpy charge transfer. FSRS spectra show a mode-specific temporal evolution, providing insights into the intersystem crossing (ISC) mechanism and subsequent relaxation. Most of the Raman features are present at ∼40 fs and exhibit small shifts and intensity changes with time. The 1450–1600 cm–1 group of bands due to CC, CN, and CC(inter-ring) stretching vibrations undergoes extensive restructuring between 40 and ∼150 fs, followed by frequency upshifts and a biexponential (0.38, 21 ps) area growth, indicating progressing charge separation in the course of the formation and relaxation of the lowest triplet state. Early (40–150 fs) restructuring was also observed in the low-frequency range for ν(Re–Cl) and δ(Re–C–O) vibrations that are presumably activated by ISC. FSRS experimental innovations employed to measure low- and high-energy Raman features simultaneously are described and discussed in detail.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Physical Chemistry A

ISSN

1089-5639

e-ISSN

—

Svazek periodika

124

Číslo periodika v rámci svazku

7

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

13

Strana od-do

1253-1265

Kód UT WoS článku

000515216300005

EID výsledku v databázi Scopus

2-s2.0-85080845957