FTIR Study of Thermally Induced Magnetostructural Transitions in Breathing Crystals

FTIR Study of Thermally Induced Magnetostructural Transitions in Breathing Crystals Full article

Journal

Inorganic Chemistry
ISSN: 0020-1669

Output data

Year: 2015, Volume: 54, Number: 7, Pages: 3446-3455 Pages count : 10 DOI: 10.1021/ic5031153

Authors

Veber Sergey L. ^1,4 , Suturina Elizaveta A. ^4,2 , Fedin Matvey V. ^1,4 , Boldyrev Kirill N. ⁵ , Maryunina Kseniya Y. ¹ , Sagdeev Renad Z. ^1,6 , Ovcharenko Victor I. ¹ , Gritsan Nina P. ^4,2 , Bagryanskaya Elena G. ^1,4,3

Affiliations

1	International Tomography Center SB RAS, 630090 Novosibirsk, Russia
2	Institute of Chemical Kinetics and Combustion SB RAS, 630090 Novosibirsk, Russia
3	N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, SB RAS, 630090 Novosibirsk, Russia
4	Novosibirsk State University, 630090 Novosibirsk, Russia
5	Institute of Spectroscopy, RAS, 142190 Troitsk, Russia
6	Kazan (Volga Region) Federal University, Kremlevskaya St. 18, 420008 Kazan, Russia

Breathing crystals based on copper(II) hexafluoroacetylacetonates and pyrazolyl-substituted nitronyl nitroxides comprise the exchange-coupled clusters within the polymeric chains. Owing to an interplay of exchange interaction between copper(II) and nitroxide spins and Jahn-Teller nature of copper(II) complex, the breathing crystals demonstrate thermally and light-induced magnetostructural transitions in many aspects similar to the classical spin crossover. Herewith, we report the first application of variable temperature (VT) far/mid Fourier transform infrared (FTIR) spectroscopy and mid FTIR microscopy to breathing crystals. This VT-FTIR study was aimed toward clarification of the transitions mechanism previously debated on the basis of superconducting quantum interference device, X-ray diffraction, and electron paramagnetic resonance data. VT-FTIR showed the onset of new vibrational bands during phase transitions occurring at the expense of several existing ones, whose intensity was significantly reduced. The most pronounced spectral changes were assigned to corresponding vibrational modes using quantum chemical calculations. A clear-cut correlation was found between temperature-dependent effective magnetic moment of studied compounds and the observed VT-FTIR spectra. Importantly, VT-FTIR confirmed coexistence of two types of copper(II)-nitroxide clusters during gradual magnetostructural transition. Such clusters correspond to weakly coupled and strongly coupled spin states, whose relative contribution depends on temperature. The pronounced difference in the VT-FTIR spectra of two states in breathing crystals is a fingerprint of magnetostructural transition, and understanding of these characteristics achieved by us will be useful for future studies of breathing crystals as well as their diamagnetic analogues.

Veber S.L. , Suturina E.A. , Fedin M.V. , Boldyrev K.N. , Maryunina K.Y. , Sagdeev R.Z. , Ovcharenko V.I. , Gritsan N.P. , Bagryanskaya E.G.
FTIR Study of Thermally Induced Magnetostructural Transitions in Breathing Crystals
Inorganic Chemistry. 2015. V.54. N7. P.3446-3455. DOI: 10.1021/ic5031153 WOS Scopus РИНЦ OpenAlex

Published online:	Mar 11, 2015
Published print:	Apr 6, 2015

Web of science:	WOS:000352518600046
Scopus:	2-s2.0-84926483141
Elibrary:	24021537
OpenAlex:	W2324210139

DB	Citing
Web of science	23
Scopus	23
Elibrary	24
OpenAlex	23