Magnetic Properties of Weakly Exchange-Coupled High Spin Co(II) Ions in Pseudooctahedral Coordination Evaluated by Single Crystal X-Band EPR Spectroscopy and Magnetic Measurements

• DOI: 10.1021/ic402797t
• Publication Date: 2014-02-14T19:20:08Z
• Authors: Nicolás I. Neuman; Elín Winkler; Octavio Peña; Mario C. G. Passeggi; Alberto C. Rizzi; Carlos D. Brondino
• Keywords: Ions; Models, Molecular; Magnetic Phenomena; Single Crystal Epr; Electron Spin Resonance Spectroscopy; Cobalt; Crystallography, X-Ray; 01 natural sciences; 0104 chemical sciences; Coordination Complexes; Exchange Interaction; https://purl.org/becyt/ford/1.4; https://purl.org/becyt/ford/1; Zero Field Splitting

We report single-crystal X-band EPR and magnetic measurements of the coordination polymer catena-(trans-(μ2-fumarato)tetraaquacobalt(II)), 1, Co(II)-doped Zn(II) analogue, 2, in different Zn:Co ratios. 1 presents two magnetically inequivalent high spin S = 3/2 Co(II) ions per unit cell, named A B, a distorted octahedral environment coordinated to four water oxygen atoms trans carboxylic from fumarate anions, which are linked by hydrogen bonds molecules. Magnetic susceptibility magnetization indicate weak antiferromagnetic exchange interactions between spins crystal lattice. Oriented single experiments 2 were used evaluate molecular g-tensor coupling constants ions, assuming an effective S′= 1/2. Unexpectedly, eigenvectors not lying along any preferential bond direction, indicating that, roughly geometry with approximately axial signals, presence pseudo axes metal site does determine directions for g-tensor. The experiment measurements, together theoretical analysis relating obtained both techniques, allowed us selectively constant associated that connect (|JAB1/2| 0.055(2) cm–1) bridge connecting equivalent (|JAA1/2| ≈ 0.25 (1) cm–1), good agreement average J3/2 value determined measurements.