Probing Microenvironment in Ionic Liquids by Time-Resolved EPR of Photoexcited Triplets Full article
| Journal |
The Journal of Physical Chemistry B
ISSN: 1520-6106 , E-ISSN: 1520-5207 |
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| Output data | Year: 2015, Volume: 119, Number: 42, Pages: 13440-13449 Pages count : 10 DOI: 10.1021/acs.jpcb.5b06792 | ||||||||
| Tags | Ionic liquids; Magnetic resonance; Organic solvents; Paramagnetic resonance; Polarization; Probes; Solvents; Spin dynamics; Spin polarization | ||||||||
| Authors |
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| Affiliations |
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Funding (1)
| 1 | Russian Science Foundation | 14-13-00826 |
Abstract:
Unusual physicochemical properties of ionic liquids (ILs) open vistas for a variety of new applications. Herewith, we investigate the influence of microviscosity and nanostructuring of ILs on spin dynamics of the dissolved photoexcited molecules. We use two most common ILs [Bmim]PF6 and [Bmim]BF4 (with its close analogue [C10mim]BF4) as solvents and photoexcited Zn tetraphenylporphyrin (ZnTPP) as a probe. Time-resolved electron paramagnetic resonance (TR EPR) is employed to investigate spectra and kinetics of spin-polarized triplet ZnTPP in the temperature range 100–270 K. TR EPR data clearly indicate the presence of two microenvironments of ZnTPP in frozen ILs at 100–200 K, being manifested in different spectral shapes and different spin relaxation rates. For one of these microenvironments TR EPR data is quite similar to those obtained in common frozen organic solvents (toluene, glycerol, N-methyl-2-pyrrolidone). However, the second one favors the remarkably slow relaxation of spin polarization, being much longer than in the case of common solvents. Additional experiments using continuous wave EPR and stable nitroxide as a probe confirmed the formation of heterogeneities upon freezing of ILs and complemented TR EPR results. Thus, TR EPR of photoexcited triplets can be effectively used for probing heterogeneities and nanostructuring in frozen ILs. In addition, the increase of polarization lifetime in frozen ILs is an interesting finding that might allow investigation of short-lived intermediates inaccessible otherwise
Cite:
Ivanov M.Y.
, Veber S.L.
, Prikhodʹko S.A.
, Adonin N.Y.
, Bagryanskaya E.G.
, Fedin M.V.
Probing Microenvironment in Ionic Liquids by Time-Resolved EPR of Photoexcited Triplets
The Journal of Physical Chemistry B. 2015. V.119. N42. P.13440-13449. DOI: 10.1021/acs.jpcb.5b06792 WOS Scopus РИНЦ OpenAlex ANCAN PMID
Probing Microenvironment in Ionic Liquids by Time-Resolved EPR of Photoexcited Triplets
The Journal of Physical Chemistry B. 2015. V.119. N42. P.13440-13449. DOI: 10.1021/acs.jpcb.5b06792 WOS Scopus РИНЦ OpenAlex ANCAN PMID
Dates:
| Submitted: | Jul 15, 2015 |
| Published online: | Oct 7, 2015 |
| Published print: | Oct 22, 2015 |
Identifiers:
| ≡ Web of science: | WOS:000363916400023 |
| ≡ Scopus: | 2-s2.0-84945282663 |
| ≡ Elibrary: | 24966966 |
| ≡ OpenAlex: | W2474081784 |
| ≡ Chemical Abstracts: | 2015:1588749 |
| ≡ Chemical Abstracts (print): | 163:553484 |
| ≡ PMID: | 26421723 |