Synthesis and liquid-crystalline properties of substituted β-aminovinyl ketones and their complexes with copper(ii)

Mesogenic complexes were synthesized by the reaction of -aminovinyl ketones with copper(ii) acetate. On going from the ligands to complexes, the temperature of phase transitions increases and the nematic phase disappears. The initial members of the homological 1-(4-nonyloxyphenyl)-3-(4-methoxyphenylamino)-1-propen-1-one series demonstrate the alternation of clearing temperatures, which is absent for the corresponding copper(ii) complexes.     

Liquid crystalline N-aryl-β-aminovinyl ketones and their complexes with lanthanides

Liquid crystalline lanthanide complexes with N-aryl-substituted β-aminovinyl ketones were synthesized for the first time. The complexes give rise to smectic A mesophase and are stable only in the solid state; in going to solution, they dissociate with formation of the initial ligand.     

The Study of the Magnetic Properties of a Fe(III) Complex Solution by the NMR Method of “Stationary Coaxial Ampoule”

For the first time, the nuclear magnetic resonance method of “stationary coaxial ampoule” was used to study the temperature dependence of the paramagnetic contribution of iron-containing complex molecules to the volume magnetic susceptibility of a solution of this complex. It was found that when the complex [Fe(salten)Cl] is dissolved in the chloroform/toluene mixture (1:1), this dependence obeys the Curie–Weiss law. On the basis of the obtained dependence the value of the effective spin of the Fe(III) ion was calculated with high accuracy. The obtained value of S _eff for the Fe(III) ion agrees with the value found in the EPR study of the vitrified solution of this complex.     

Intermolecular interactions and spin states of complexes [Fe(3-MeO-Qsal)<Subscript>2</Subscript>]Y (Y = PF<Subscript>6</Subscript>, BF<Subscript>4</Subscript>)

Compounds [Fe(3-MeO-Qsal)₂]Y (Y = PF₆, BF₄) have been prepared by diffusion method and studied in temperature range 5–300 K by EPR and magnetic susceptibility methods. The coexistence of spatially separated high-spin (solvated) and low-spin (unsolvated) fractions in the studied compounds has been established. It has been shown that change in the type of outer-sphere anion leads to change in the character of intermolecular interactions in the high-spin fraction and has no effect on the parameters and character of interactions of paramagnetic centers in the low-spin fraction.     

Effect of the chemical structure of a tetradentate equatorial ligand on the spin-crossover properties of the Fe (III) complexes chain structures: Electron paramagnetic resonance study

The effect of the chemical structure of the equatorial ligand on the spin state of the Fe (III) ion in a series of 1-D chain complexes of the general formula [Fe(L)(tvp)]BPh₄·nCH₃OH, where L = dianions of Schiff base containing a different number of aromatic groups: N,N′-ethylenebis (salicylaldimine) (salen) 1 , N,N′-ethylenebis (acetylacetone)2,2′-imine (acen) 2 , N,N′-ethylenebis (benzoylacetylacetone)2,2′-imine (bzacen) 3 , and tvp = 1,2-di(4-pyridyl)ethylene, was studied by ultraviolet–visible (UV–vis) and electron paramagnetic resonance (EPR) methods. The values of exchange interactions, thermodynamic parameters of spin-crossover, and electronic structure features of the Fe (III) complexes were estimated from the EPR data. The substitution of a fragment of the equatorial ligand L in the series salen–acen–bzacen changes the local symmetry of the complex in the 1-D chain, thereby affecting the spin variable properties.     

On light scattering in transformer oil

GK transformer oil is studied using the methods of UV and visible spectroscopy, dynamic light scattering, small-angle light scattering, scanning electron microscopy, and element analysis. The effect exerted on the optical properties of transformer oil by colloidal, micelle-like, and solid particles formed in oil during its exploitation is investigated.