Properties of Prussian Blue Materials Manifested in Molecular Complexes: Observation of Cyanide Linkage Isomerism and Spin-Crossover Behavior in Pentanuclear Cyanide Clusters
- 25 April 2007
- journal article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 129 (19), 6104-6116
- https://doi.org/10.1021/ja066273x
Abstract
Pentanuclear, cyanide-bridged clusters [M(tmphen)2]3[M‘(CN)6]2 (M/M‘ = Zn/Cr (1), Zn/Fe (2), Fe/Fe (3), Fe/Co (4), and Fe/Cr (5); tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) were prepared by combining [M‘III(CN)6]3- anions with mononuclear complexes of MII ions with two capping tmphen ligands. The clusters consist of a trigonal bipyramidal (TBP) core with three MII ions in the equatorial positions and two M‘III ions in the axial positions. Compounds 1−4 are isostructural and crystallize in the monoclinic space group P21/c. Complex 5 crystallizes in the enantiomorphic space group P3221. The magnetic properties of compounds 1 and 2 reflect the contributions of the individual [CrIII(CN)6]3- and [FeIII(CN)6]3- ions. The FeII ions in compounds 3 and 4 exhibit a gradual, temperature-induced spin transition between high spin (HS) and low spin (LS), as determined by the combination of Mössbauer spectroscopy, magnetic measurements, and single-crystal X-ray studies. The investigation of compound 5 by these methods and by IR spectroscopy indicates that cyanide linkage isomerism occurs during cluster formation. The magnetic behavior of 5 is determined by weak ferromagnetic coupling between the axial CrIII centers mediated by the equatorial diamagnetic FeII ions. Mössbauer spectra collected in the presence of a high applied field have allowed, for the first time, the direct experimental observation of uncompensated spin density at diamagnetic metal ions that bridge paramagnetic metal ions.Keywords
This publication has 32 references indexed in Scilit:
- Pressure-Induced Sequential Magnetic Pole Inversion and Antiferromagnetic−Ferromagnetic Crossover in a Trimetallic Prussian Blue AnalogueJournal of the American Chemical Society, 2006
- Observation of an Fe(II) Spin-Crossover in a Cesium Iron HexacyanochromateJournal of the American Chemical Society, 2005
- A Charge-Transfer-Induced Spin Transition in the Discrete Cyanide-Bridged Complex {[Co(tmphen)2]3[Fe(CN)6]2}Journal of the American Chemical Society, 2004
- Sol−Gel Synthesis of KVII[CrIII(CN)6]·2H2O: A Crystalline Molecule-Based Magnet with a Magnetic Ordering Temperature above 100 °CJournal of the American Chemical Society, 1999
- High-Temperature Molecular Magnets Based on Cyanovanadate Building Blocks: Spontaneous Magnetization at 230 KScience, 1995
- X.alpha.-SW calculations for naked actinide dimers: existence of .vphi. bonds between metal atomsInorganic Chemistry, 1984
- Dynamic intersystem crossing in solid bis(phenanthroline)bis(cyanotrihydroborato)iron(II)Inorganic Chemistry, 1984
- Magnetic isomers of iron(II). Bis(C-cyanotrihydroborate)bis(phenanthroline)iron - a spin tripletInorganic Chemistry, 1977
- Kinetics of complex formation between hexacyanoferrate(III) ions and iron(III) to form FeFe(CN)6 (Prussian brown)Inorganic Chemistry, 1968
- The Mechanism of the Piezochromism of Hexaphenyl-biimidazolylBulletin of the Chemical Society of Japan, 1965