Light-Induced Magnetostructural Anomalies in a Polymer Chain Complex of Cu(hfac)2 with tert-Butylpyrazolylnitroxides

Light-Induced Magnetostructural Anomalies in a Polymer Chain Complex of Cu(hfac)2 with tert-Butylpyrazolylnitroxides Full article

Journal

The Journal of Physical Chemistry A
ISSN: 1089-5639

Output data

Year: 2013, Volume: 117, Number: 30, Pages: 6483-6488 Pages count : 6 DOI: 10.1021/jp403977n

Authors

Drozdyuk Irina Yu. ¹ , Tolstikov Svyatoslav E. ¹ , Tretyakov Evgeny V. ¹ , Veber Sergey L. ¹ , Ovcharenko Victor I. ¹ , Sagdeev Renad Z. ¹ , Bagryanskaya Elena G. ^1,2 , Fedin Matvey V. ¹

Affiliations

1	International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
2	N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Pr. Lavrentjeva 9, 630090 Novosibirsk, Russia

We report the study of light-induced magnetostructural anomalies in a polymer chain complex of Cu(hfac)2 (hfac = hexafluoroacetylacetonate) with an unusual acyclic tert-butylpyrazolylnitroxide radical (LtertMe) using EPR. This complex ([Cu(hfac)2LtertMe]n) belongs to the family of thermo- and photoswitchable molecular magnets “breathing crystals”. Compared to previously studied breathing crystals with nitronyl nitroxides, [Cu(hfac)2LtertMe]n shows much weaker absorption bands in the visible spectral region and therefore is superior for optical manipulation of the spin states. Illumination with light (λ ≈ 540 nm) at cryogenic temperatures leads to formation of a metastable weakly coupled spin state, which relaxes to the ground strongly coupled spin state on a time scale of hours. These phenomena are in many aspects similar to the light-induced excited spin state trapping (LIESST) well-known for spin-crossover compounds. Remarkably, the photoinduced spin state in [Cu(hfac)2LtertMe]n is metastable at temperatures up to TLIESST ≈ 60 K, which is a significant improvement compared to that of previously studied breathing crystals with nitronyl nitroxides (TLIESST ≈ 20 K). We describe LIESST-like behavior observed in [Cu(hfac)2LtertMe]n and discuss possible reasons for the increased stability of the photoinduced spin state.

Drozdyuk I.Y. , Tolstikov S.E. , Tretyakov E.V. , Veber S.L. , Ovcharenko V.I. , Sagdeev R.Z. , Bagryanskaya E.G. , Fedin M.V.
Light-Induced Magnetostructural Anomalies in a Polymer Chain Complex of Cu(hfac)2 with tert-Butylpyrazolylnitroxides
The Journal of Physical Chemistry A. 2013. V.117. N30. P.6483-6488. DOI: 10.1021/jp403977n WOS Scopus

Accepted:

Jul 11, 2013

Web of science:	WOS:000322807300009
Scopus:	2-s2.0-84881175378

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Scopus	20
Web of science	20