Showing papers by "Matvey S. Gruzdev published in 2013"

Binding ability of Zn-tetraarylporphyrins with two, four and eight 4-(4-(3,6-bis(t-butyl)carbazol-9-ylphenyl)-1,2,3-triazole end groups towards N-containing substrates of different nature

Abstract: The binding ability of Zn-tetraarylporphyrins with two, four and eight 4-carbazolylphenyl-1,2,3-triazole end groups towards 1,4-diazabicyclo[2.2.2]octane, pyridine and 1,2,3-triazole in toluene was studied by spectrophotometric and 1H NMR titration. It was determined that due to a good geometric match of the ligand size to the size of the intramolecular cavities of the porphyrinic receptor, and by the existence of additional π–π and/or hydrogen bonding interactions between the ligand and the triazole fragments of the porphyrin, the Zn-tetraarylporphyrin with eight 4-carbazolylphenyl-1,2,3-triazole end groups could be used as an effective receptor for 1,2,3-triazole and other small heterocycles such as pyridine. Taking into account the fact that binding is accompanied by a clear and easily identifiable response in the UV–vis spectra of the reaction mixture, this metalloporphyrin could be considered as a molecular optical sensing device for small heterocyclic substrates.

Mesomorphic azomethine complexes of Iron(III) based on 4,4′-dodecyloxybenzoyloxybenzoyl-4-salicylidene-2-aminopyridine

Abstract: A new series of liquid crystalline (LC) complexes Fe(III) based on azomethine 4,4′-dodecyloxybenzoyloxybenzoyl-4-salicylidene-2-aminopyridine with counter-ions PF6−, NO3−, Cl−, BF4−, ClO4−, CNS− and SO42– was synthesised. According to elemental analysis, FT-IR, 1H-NMR and mass spectrometry (MALDI ToF), it was found that bi(ligand) Fe(III) complexes were formed with octahedral packing of the metal ion. The presence of the counter-ion in the complexes was confirmed by Infrared spectroscopy. The thermotropic LC properties were investigated by differential scanning calorimetry (DSC) and polarising optical microscopy (POM). All the seven complexes in this series exhibit thermotropic mesophases.

Stepwise magnetic behavior of the liquid crystal iron(III) complex

Abstract: EPR and Mossbauer spectroscopy is used to study a new liquid crystal complex of iron(III) with a Schiff base: 4,4′-dodecyloxybenzoyloxybenzoyl-4-oxysalicylidene-2-aminopyridine with a PF 6 − counterion. It is shown that Fe(III) ions exist only in the high-spin (HS, S = 5/2) state. It is found that under the influence of temperature the system demonstrates the stepwise behavior of the product of the integrated intensity of EPR lines (I) and temperature (proportional to χ T, where χ is the magnetic susceptibility) with an inflection point at ∼80 K. Above 80 K a new EPR spectrum is detected due to the excited S = 2 state and the formation of dimeric molecules (through oxygen bridges) with a strong intramolecular antiferromagnetic exchange interaction J 1 = 162.1 cm−1. Below 80 K iron(III) complexes are organized in 1D chains where the exchange value J 2 = 2.1 cm−1. At 80 K there is a structural phase transition in the system: the transition from a 1D chain organization of HS Fe(III) centers to dimeric molecules. Based on quantum chemical calculations a model of the binuclear iron(III) complex is proposed.

Synthesis and study of vitrescent materials based on the alkoxybenzoic acids derivatives and triethanolamine

Abstract: Fifteen new branched triethanolamine esters of the benzoic acid derivatives were designed and the mesomorphism typical of discotic mesogens was forecast for them. In eight of the obtained compounds a manifestation of liquid crystal properties was predicted, for four derivatives equiprobable prognosis was given, and only three compounds were predicted not to form a mesophase. The obtained esters were characterized by elemental analysis, NMR and IR spectroscopy, gas chromatography-mass spectrometry. The main thermal characteristics that allow accounting for their phase behavior were determined.