МЕТАЛООРГАНІЧНІ МАГНЕТИКИ НА ОСНОВІ КОМПЛЕКСІВ ЗАЛІЗА З 1-НІТРОЗО-2-НАФТОЛОМ

Abstract

Providing macroscopic magnetism in organic materials is a very complex but quite promising scientific problem. The need to create an organic magnet is due to a number of expected advantages, such as lightness, transparency, flexibility, ability to switch under the influence of light (magneto-optics), or chemical influences (sensors), creation of modern toners for digital printing, materials for chemical power sources etc. To understand the mechanism of biological processes, in particular, human thinking and DNA functioning may help to study the state of spin glass, biomagnetism, the mechanism of action of paramagnetic probes in living tissues and others. In the present paper the peculiarities of the structure and magnetic behavior of the iron complex with 1-nitroso-2-naphthol Na[Fe(C10H6(NO2)3] have been studied. The powder X-ray diffraction method determined that the crystal structure of the complex is monoclinic with the space group P2/1. According to cyclic voltammetry, the electrochemical behavior of the complex anion Fe(C10H6(NO2)3] is characteristic of reversible electrochemical systems with one electron transfer. Optical absorption bands are observed in the electronic spectra of the complex at 389, 690, and 763 nm. The dependences of the magnetic susceptibility of the complex on the temperature, frequency and magnetic field strength in the temperature range 1.5–200 K in the external magnetic field up to 90 kE and in the frequency range from 95 to 2000 Hz are obtained and analyzed. At low temperatures, the peculiarities of magnetic behavior characteristic of the state of spin glass are revealed. The EPR spectrum of the complex is a superposition of two lines, the behavior of which is opposite when the temperature changes in the range of 4–293 K, which indicates the unusual dynamics of the molecular surrounding the Fe3+ ion. Such features may be due to the presence of two structurally inhomogeneous magnetic centers that exhibit opposite spin dynamics with changing temperature. The presence of this dynamic can have a significant impact on the properties of the substance.