Magneto-Structural Relationship on Strong Exchange Interactions between Chelating Nitroxide Radical and Transition-Metal Spins

4th International Conference on Advanced Materials Science and Technology

Okazawa, A.^1

Department of Basic Science, University of Tokyo, Komaba, Meguro-ku, Tokyo

153-8902, Japan^1

关键词: Chelating ligands;    Linear correlation;    Magnetic interactions;    Magnetostructural correlations;    Magnetostructural relationship;    Molecule based magnets;    Nitroxide radicals;    Radical complexes;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/202/1/012002/pdf
DOI  :  10.1088/1757-899X/202/1/012002

来源: IOP

【 摘 要 】

To develop room-temperature molecule-based magnets, metal-radical approach is one of the most promising strategies. Strong magnetic interactions beyond a thermal energy of room temperature are essential for achieving such coveted materials. We have developed 2-pyridyl tert-butyl nitroxide (2pyNO) derivatives as a chelating radical ligand with a copper(II) or nickel(II) ion. The torsion angle (φ) around M-O-N-C2pyis a useful metric in describing correlation between the structure and metal-radical exchange coupling 2J (defined as H = -2JΣSi•Si+1). Although we previously reported such a magneto-structural correlation, in this paper we updated the plot of 2J versus φ by dividing into two categories: the hexacoordinatenickel(II) and copper(II) complexes. An empirical linear correlation was formulated for both Cu and Ni categories, as 2J/kB= a + b|φ| with a = 503(112) K and b = -36(3) K deg-1and with a = 449(46) K and b = -21.0(17) K deg-1, respectively. In the latter plot we confirm that the relationship can be generalized for the oxoverdazyl and dithiadiazolyl systems as well as the 2pyNO systems. The results are supported by the calculations based on the density functional theory.