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Trinuclear Cyanido‐Bridged [Cr 2 Fe] Complexes: To Be or not to Be a Single‐Molecule Magnet, a Matter of Straightness
Author(s) -
Pichon Céline,
Suaud Nicolas,
Jubault Valentin,
Duhayon Carine,
Guihéry Nathalie,
Sutter JeanPascal
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202102571
Subject(s) - pentagonal bipyramidal molecular geometry , crystallography , moiety , steric effects , single molecule magnet , chemistry , magnetization , molecule , magnetic anisotropy , magnet , relaxation (psychology) , trigonal bipyramidal molecular geometry , anisotropy , stereochemistry , crystal structure , physics , magnetic field , organic chemistry , psychology , social psychology , quantum mechanics
Trinuclear systems of formula [{Cr(L N3O2Ph )(CN) 2 } 2 M(H 2 L N3O2R )] (M=Mn II and Fe II , L N3O2R stands for pentadentate ligands) were prepared in order to assess the influence of the bending of the apical M−N≡C linkages on the magnetic anisotropy of the Fe II derivatives and in turn on their Single‐Molecule Magnet (SMM) behaviors. The cyanido‐bridged [Cr 2 M] derivatives were obtained by assembling trans ‐dicyanido Cr III complex [Cr(L N3O2Ph )(CN) 2 ] − and divalent pentagonal bipyramid complexes [M II (H 2 L N3O2R )] 2+ with various R substituents (R=NH 2 , cyclohexyl, S , S ‐mandelic) imparting different steric demand to the central moiety of the complexes. A comparative examination of the structural and magnetic properties showed an obvious effect of the deviation from straightness of the M−N≡C alignment on the slow relaxation of the magnetization exhibited by the [Cr 2 Fe] complexes. Theoretical calculations have highlighted important effects of the bending of the apical C−N−Fe linkages on both the magnetic anisotropy of the Fe II center and the exchange interactions with the Cr III units.