SPIN-CROSSOVER IN COMPLEXES OF IRON(II) CARBORANES WITH TRIS(PYRAZOL-1-YL)METHANE
O. G. Shakirova1, V. A. Daletskii2, L. G. Lavrenova2,3, V. A. Varnek2, D. A. Rudakov4, V. I. Potkin4
1Komsomolsk-on-Amur State Technical University, Komsomolsk-on-Amur
2A. V. Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences, Novosibirsk
3Novosibirsk State University, Novosibirsk
4Institute of Physico-Organic Chemistry, National Academy of Sciences of Belarus, Minsk
Keywords: synthesis, iron(II) complexes, carboranes, tris(pyrazol-1-yl)methane, spin-crossover, magnetochemistry, electron, IR, and Mössbauer spectroscopy
Abstract
Synthesis procedures for coordination compounds of iron(II) 1,5,6,10-tetra(R)-7,8-dicarba- nido-undecaborates(-1) (carboranes) with tris(pyrazol-1-yl)methane (HC(pz)3) of the composition [Fe{HC(pz)3}2]A2· nH2O (А = (7,8-С2B9H12)– ( I), (1,5,6,10-Br4-7,8-С2B9H8)– ( II), (1,5,6,10-I4-7,8-С2B9H8)– ( III), n = 0-2) are developed. The compounds are studied by static magnetic susceptibility in the temperature range of 160-500 K, electron (diffuse reflectance spectra), IR, and Mössbauer spectroscopy methods. It is shown that the complexes have high-temperature spin-crossover 1А1 ⇔ 5Т2. Transition temperatures ( Тс ) for I-III are 370 K, 380 K, and 400 K respectively. Spin-crossover is accompanied by thermochromism (color change: pink ⇔ white).
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