Shekhovtsov, Nikita A. and Kokina, Tatyana E. and Vinogradova, Katerina A. and Panarin, Andrey Y. and Rakhmanova, Marianna and Naumov, Dmitry Y. and Pervukhina, Natalya and Nikolaenkova, Elena B. and Krivopalov, Viktor P. and Czerwieniec, Rafal and Bushuev, Mark B. (2022) Near-infrared emitting copper(I) complexes with a pyrazolylpyrimidine ligand: exploring relaxation pathways. DALTON TRANSACTIONS, 51 (7). pp. 2898-2911. ISSN 1477-9226, 1477-9234
Full text not available from this repository. (Request a copy)Abstract
Mononuclear copper(I) complexes [CuL2]I (1), [CuL2](2)[Cu2I4]center dot 2MeCN (2) and [CuL2]PF6 (3) with a new chelating pyrazolylpyrimidine ligand, 2-(3,5-dimethyl-1H-pyrazol-1-yl)-4,6-diphenylpyrimidine (L), were synthesized. In the structures of complex cations [CuL2](+), Cu+ ions coordinate two L molecules (N,N-chelating coordination). Extended pi-systems of the L molecules in [CuL2](+) favor the formation of paired pi-pi stacking intramolecular interactions between the pyrimidine and phenyl rings leading to significant distortions of tetrahedral coordination cores, CuN4. The free ligand L demonstrates dual excitation wavelength dependent luminescence in the UV and violet regions, which is attributed to S-1 -> S-0 fluorescence and T-1 -> S-0 phosphorescence with intraligand charge transfer character. The complexes 1-3 demonstrate T-1 -> S-0 phosphorescence in the near-infrared region. Theoretical investigations point to its ligand-to-metal charge transfer (LMCT) origin. Large Stokes shifts of emission (ca. 200 nm) are the result of notable planarizations of CuN4 cores in the T-1 state as compared to the S-0 state. Spin-orbit coupling computations revealed that the most effective intersystem crossing channels for [CuL2](+) appear in high-lying excited states, while the S-1 -> T-1 transition is unfavourable according to El-Sayed's rule and the energy gap law. Electron-vibration coupling calculations showed that the C-C and C-N stretching vibrations of the pyrimidine and phenyl moieties, the asymmetric Cu-N stretching vibrations and the wagging motions of phenyl rings contribute the most to the non-radiative deactivation of L and [CuL2](+).
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ACTIVATED DELAYED FLUORESCENCE; EXCITED-STATE; PHOTOPHYSICAL PROPERTIES; CUPROUS COMPLEXES; TRIPHENYLPHOSPHINE COMPLEXES; MONOVALENT COPPER; CU(I) COMPLEXES; LUMINESCENCE; BLUE; ELECTROLUMINESCENCE |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Feb 2024 11:11 |
| Last Modified: | 16 Feb 2024 11:11 |
| URI: | https://pred.uni-regensburg.de/id/eprint/58156 |
Actions (login required)
 |
View Item |
