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Symmetry Breaking and Two-Step Spin-Crossover Behavior in Two Cyano-Bridged Mixed-Valence {Fe III 2 (μ-CN) 4 Fe II 2 } Clusters.

Authors :
Zheng C
Jia S
Dong Y
Xu J
Sui H
Wang F
Li D
Source :
Inorganic chemistry [Inorg Chem] 2019 Nov 04; Vol. 58 (21), pp. 14316-14324. Date of Electronic Publication: 2019 Oct 17.
Publication Year :
2019

Abstract

Two new cyano-bridged mixed-valence {Fe <superscript>III</superscript> <subscript>2</subscript> (μ-CN) <subscript>4</subscript> Fe <superscript>II</superscript> <subscript>2</subscript> } clusters, {[(Tp)Fe <superscript>III</superscript> (CN) <subscript>3</subscript> ] <subscript>2</subscript> [Fe <superscript>II</superscript> (Py <subscript>2</subscript> N <subscript>2</subscript> )] <subscript>2</subscript> }·(ClO <subscript>4</subscript> ) <subscript>2</subscript> ·MeCN·Et <subscript>2</subscript> O ( 1 ·MeCN·Et <subscript>2</subscript> O), its solvent-free form ( 1 ), and {[(Tp)Fe <superscript>III</superscript> (CN) <subscript>3</subscript> ] <subscript>2</subscript> [Fe <superscript>II</superscript> (Me <subscript>2</subscript> Py <subscript>2</subscript> N <subscript>2</subscript> )] <subscript>2</subscript> }·(ClO <subscript>4</subscript> ) <subscript>2</subscript> ·5MeOH ( 2 ·5MeOH), were obtained [Tp = hydrotris(pyrazol-1-yl)borate; N , N '-bis(2-pyridylmethyl)- N , N '-bis(4-X-benzyl)-1,2-ethanediamine, Py <subscript>2</subscript> N <subscript>2</subscript> , X = H; Me <subscript>2</subscript> Py <subscript>2</subscript> N <subscript>2</subscript> , X = Me]. Complexes 1 and 2 ·5MeOH exhibit gradual thermally induced two-step spin-crossover behavior (SCO) at two Fe <superscript>II</superscript> metal centers, and the transformation of high-spin (HS) to low-spin (LS) Fe <superscript>II</superscript> ions with temperature was confirmed by a combination of X-ray crystallography, variable-temperature Fourier transform infrared, variable-temperature magnetic susceptibility, and <superscript>57</superscript> Fe Mössbauer spectroscopy. Moreover, complexes 1 ·MeCN·Et <subscript>2</subscript> O and 1 exhibit a reversible single-crystal-to-single-crystal transformation, and complex 1 undergoes two-step SCO behavior with T <subscript>1/2</subscript> = 178 and 93 K accompanied by symmetry breaking in the structure.

Details

Language :
English
ISSN :
1520-510X
Volume :
58
Issue :
21
Database :
MEDLINE
Journal :
Inorganic chemistry
Publication Type :
Academic Journal
Accession number :
31622084
Full Text :
https://doi.org/10.1021/acs.inorgchem.9b00544