O. A. Turanova

The first mesogenic derivative of boron difluoride β-diketonate

Boron difluoride β-diketonate exhibiting liquid crystalline as well as photoluminescence properties was prepared for the first time. It is the promising material for creating supramolecular organized luminescent media.

Liquid crystal polymorphism of boron difluoride β-diketonates

Boron difluoride 2-alkyl-β-diketonates possessing liquid crystal polymorphism and luminescence properties were first obtained. Influence of the ligand structure on the liquid crystal properties of the boron difluoride complexes was demonstrated.

First mesogenic derivative of boron difluoride β-enaminoketonate

Boron difluoride complexes possessing liquid crystalline and luminescent properties were synthesized for the first time on the basis of non-mesogenic β-enaminoketones.

Synthesis and photoisomerization of mesogenic 4-alkoxystyrylpyridines

Introduction of long-chain alkoxy substituents into molecules of styrylpyridines as potential ligands for photosensitive metal complexes endows them with liquid crystalline properties over a wide temperature range. trans-cis Photoisomerization of 4-alkoxystyrylpyridines in solution was revealed by NMR and electronic absorption spectroscopy, and the kinetics of transformations of their molecular forms after irradiation were estimated. Photoinduced trans→cis isomerization of 4-alkoxystyrylpyridines is characterized by a higher rate, and intramolecular cyclization of their cis isomers after irradiation is slower, as compared to unsubstituted analog.

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.

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

Mesogenic complexes were synthesized by the reaction of β-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.

Preparation and liquid-crystalline properties of mono- and binuclear complexes of Fe(III) with pentadentate Schiff’s base

Liquid-crystalline mono-and binuclear complexes of Fe(III) based on pentadentate Schiff’s base, N,N′-bis(2-hydroxy-4-octadecyloxybenzyliden)-1,7-diamino-4-azaheptane, have been prepared for the first time. The effects of counterions of the binuclear complexes and of the monodentate ligand in the mononuclear complexes on formation of the mesophase as well as phase transitions temperatures and the range of the mesophase existence have been demonstrated. EPR studies have revealed the possibility of spin-crossover properties of the complexes.

Thermo- and photoinduced properties of the Fe(III) complexes with the pentadentate ligand according to the EPR data

Compounds [Fe(Salten)L]BPh4 (Salten = N,N-bis[(2-oxyphenyl)methylene]-4-azaheptane-1,7-diamine; L = Him (I) and Pic (II)) were studied by the EPR method in the temperature range from 5 to 300 K. The thermoinduced spin transition is observed in compound II. Its thermodynamic parameters and parameters of the ground electronic low-spin state were determined. The effect of decreasing the intensity of the stationary EPR signal upon laser pulse irradiation at λ = 532 nm was observed in the studied samples.

Factors affecting photoisomerization of 4-styrylpyridine

Photoisomerization of 4-styrylpyridine at different irradiation wavelengths (λ 365 and 254 nm) and in different solvents was studied by UV and 1H NMR spectroscopy. A procedure for recording the UV spectra of 4-styrylpyridine dissolved in liquid crystalline films freely suspended within a frame. The results of quantum-chemical calculations of the geometry and UV spectra of 4-styrylpyridine isomers are presented.

Study of liquid-crystalline copper(II) β-enaminoketonates by EPR

The structure of the chelate unit and magnetic properties of the homologous series of liquid-crystalline bis{1-[4-(4-alkoxybenzoyloxy)phenyl]-3-amyl-1-aminoprop-1-en-3-onate)copper(II) complexes was studied by EPR. The direction of the orientation of liquid crystal molecules in an external magnetic field in the mesophase state was determined. The complexes have a square-planar structure of the chelate unit determining their mesomorphic properties.