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Metamagnetism and Single‐Chain Magnetic Behavior in a Homospin One‐Dimensional Iron(II) Coordination Polymer
Author(s) -
Boeckmann Jan,
Wriedt Mario,
Näther Christian
Publication year - 2012
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.201103416
Subject(s) - crystallography , metamagnetism , pyridine , chemistry , paramagnetism , spin crossover , ferromagnetism , ligand (biochemistry) , magnetic susceptibility , inorganic chemistry , magnetic field , magnetization , medicinal chemistry , condensed matter physics , biochemistry , physics , receptor , quantum mechanics
Reaction of FeCl 2 ⋅4 H 2 O with KNCSe and pyridine in ethanol leads to the formation of the discrete complex [Fe(NCSe) 2 (pyridine) 4 ] ( 1 ) in which the Fe II cations are coordinated by two N‐terminal‐bonded selenocyanato anions and four pyridine co‐ligands. Thermal treatment of compound 1 enforces the removal of half of the co‐ligands leading to the formation of a ligand‐deficient (lacking on neutral co‐ligands) intermediate of composition [Fe(NCSe) 2 (pyridine) 2 ] n ( 2 ) to which we have found no access in the liquid phase. Compound 2 is obtained only as a microcrystalline powder, but it is isotypic to [Cd(NCSe) 2 (pyridine) 2 ] n and therefore, its structure was determined by Rietveld refinement. In its crystal structure the metal cations are coordinated by two pyridine ligands and four selenocyanato anions and are linked into chains by μ‐1,3 bridging anionic ligands. Magnetic measurements on compound 1 show only paramagnetic behavior, whereas for compound 2 an unexpected magnetic behavior is found, which to the best of our knowledge was never observed before for a iron(II) homospin compound. In this compound metamagnetism and single‐chain magnetic behavior coexist. The metamagnetic transition between the antiferromagnetically ordered phase and a field‐induced ferromagnetic phase of the high‐spin iron(II) spin carriers is observed at a transition field H C of 1300 Oe and the single‐chain magnetic behavior is characterized by a blocking temperature T B , estimated to be about 5 K.