SINGLE CRYSTAL EPR FOR THE STUDY OF ELECTRONIC AND MAGNETIC PROPERTIES IN TRANSITION METAL SYSTEMS

ANA LAURA PÉREZ; NICOLÁS I. NEUMAN; ALBERTO C. RIZZI; CARLOS D. BRONDINO

Santa Fe

Workshop; III Taller de Resonancia Magnética. NMR and EPR at the Forefront of Research; 2016

Departamento de Física - Facultad de Bioquímica y Cs. Biológicas - Universidad Nacional del Litoral

P10: SINGLE CRYSTAL EPR FOR THE STUDY OF ELECTRONIC ANDMAGNETIC PROPERTIES IN TRANSITION METAL SYSTEMSAna Laura Pérez, Nicolás I. Neuman, Alberto C. Rizzi and Carlos D. BrondinoDepartamento de Física, FBCB, UNL Santa Fe, Argentinalaura24_89@hotmail.comKeywords: Single-crystal EPR, transition metals, magnetic interactions.Magnetic interactions between paramagnetic transition metal ions or non-metalcentered radicals are relevant to the fields of solid-state magnetism (including nanoandmolecular magnetism), bioinorganic chemistry (metalloproteins) and polymer andmacromolecular science (through the use of spin-labels). Most magnetic interactions inparamagnetic systems, which can be studied by electron paramagnetic resonance(EPR) are anisotropic and defined by matrices which contain information on orbitaloccupations of the unpaired electrons, delocalization or covalency, interspin distances,identity of bonding atoms, amongst other properties. In fluid samples some of theseinteractions are partially or totally averaged, while in polycrystalline (powder) or frozensolutin samples, the spectra are summed over all possible molecular orientations,obscuring part of the information. Therefore to fully understand the magnetic propertiesof some systems and to obtain correlations between magnetic interactions and subtleelectronic structure factors it becomes necessary to perform EPR experiments onoriented single crystal samples. The angular variations of the resonance positions allowdetermination of many interactions (g-matrix, hyperfine matrix, zero-field splitting, andexchange interactions), sometimes providing information that cannot be extracted byany other technique. Our group has applied this technique to studies of copper(II) (S =1/2) and cobalt(II) (S = 3/2) compounds presenting isolated, dimeric and chaintopologies, developing in many cases new physical models to interpret the data. Someof these results are discussed here.REFERENCES1) Kahn O., Molecular Magnetism (1993).2) Weil, J. A. y Bolton, J. R. (2007) Electron Paramagnetic Resonance: Elementary Theory andPractical Applications. John Wiley & Sons, New Jersey.3) Neuman N.I. et al., J. Phys. Chem. A (2010), 114(59):13069-13075.4) Neuman N.I. et al., Inorg. Chem. (2014), 53(5): 2535?2544.5) Neuman N.I. et al., Inorg. Chem. Front. (2015), 2: 837-8456.6) Rizzi A.C. et al., Eur. J. of Inorg. Chem. (2016), 2: 192-207.ACKNOWLEDGEMENTSCONICET, ANPCYT, UNL-CAI+D