Abstract
The ultrafast photochemistry of the [Cr(NCS)6]3- complex upon excitation to the 4T2 ligand-field (LF) state was studied in dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) in a wide temporal range (100 fs to 9 ms) by a combination of femtosecond and nanosecond transient absorption spectroscopy techniques and supported by quantum-chemical DFT/TD-DFT calculations. The initially excited 4T2 state undergoes intersystem crossing to the vibrationally hot 2E state with time constants of 1.1 ± 0.2 and 1.8 ± 0.1 ps in DMSO and DMF, respectively. Vibrational relaxation occurs in the same time scale and takes 1-5 ps. A major part of the [Cr(NCS)6]3- complex in the 2E state undergoes intersystem crossing to the ground state with time constants of 65 ± 5 and 85 ± 5 ns in DMSO and DMF, respectively. A minor part of electronically excited [Cr(NCS)6]3- undergoes irreversible photochemical decomposition. In DMSO, the photolysis of the [Cr(NCS)6]3- complex results in single or double isothiocyanate ion release followed by the coordination of the solvent molecules with a time constant of 1 ± 0.2 ms.
Original language | English |
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Pages (from-to) | 3724-3733 |
Number of pages | 10 |
Journal | Journal of Physical Chemistry B |
Volume | 124 |
Issue number | 18 |
DOIs | |
Publication status | Published - 2020 |
Publication type | A1 Journal article-refereed |
Funding
The measurements were performed in the Research Park of Saint-Petersburg State University (“Magnetic Resonance Research Centre”, “SPbU Computing Centre”, “Cryogenic Department”, “Interdisciplinary Resource Centre for Nanotechnology”, “Centre for X-ray Diffraction Studies”, and “Centre for Optical and Laser Materials Research”) and in Faculty of Engineering and Natural Sciences of Tampere University. The reported study was funded by RFBR, project number 20-33-70025.
Publication forum classification
- Publication forum level 1
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry