Bloch oscillations of a soliton in a molecular chain

This paper presents the results of numerical experiments simulating Bloch oscillations of solitons in a deformable molecular chain subject to a constant electric field. By using as an example a homogeneous polynucleotide chain, it is shown that the system under consideration can exhibit complicated dynamical behaviour: when subject to field intensities less than a certain critical value, a soliton exhibits oscillations as a whole, while at field intensities exceeding this threshold, the soliton becomes a breather that oscillates. It is shown that the motion of a charge in a deformable chain is infinite, which in contrast to that in a rigid chain.     

Copper,cobalt, and nickel complexes of azomethine compounds containing phenylazo group in the amine fragment: Syntheses,structures, and magnetic properties

The Cu, Ni, and Со complexes based on the following new azomethine compounds containing azobenzene groups in the ortho- or para-positions of the amine fragment are synthesized: 2-allyl-6-[(E)-[4-(E)-phenylazophenyl]iminomethyl]phenol (HL¹), 2-allyl-6-[(E)-[4-methyl-2-[(E)-phenylazo]-p-tolylazo] iminomethyl]phenol (HL²), 5-methoxy-2-[(E)-[4-[(E)-phenylazo]phenyl]iminoethyl]phenol (HL³), and 5-methoxy-2-[(E)-[4-methyl-2-[(E)-p-tolylazo]phenyl]iminomethyl]phenol (HL⁴). The structures of the complexes are determined by the data of IR and ¹Н NMR spectroscopy (for the azomethine compounds), X-ray absorption spectroscopy, and magnetochemistry. The coordination centers of all Cu complexes have a distorted square structure. A direct dependence of the geometry of the coordination polyhedron on the position of azobenzene groups in the amine fragments of the ligands is found for the Ni and Co complexes. The octahedral environment of the nickel and cobalt ions takes place in the case of the ortho-position of the amine fragment, whereas the square environment for the Ni complexes or the tetrahedral environment for the Co complexes is observed at the para-position. The molecular structures of two azomethines HL¹ and HL⁴ are determined by X-ray diffraction analysis (CIF files CCDC nos. 1552836 (HL¹) and 1552837 (HL⁴)).     

Disulfide derivatives of thiosemicarbazones of 4-formyl-5-thiopyrazole

The reaction of 4-formyl-5-mercaptopyrazole with thiosemicarbazides in methanol has afforded novel disulfide derivatives of thiosemicarbazones, and their structure has been studied by NMR and IR spectroscopy. X-ray diffraction analysis of [5,5'-dithiobis(4-formyl-3-methyl-1-phenylpyrazole)]-4-allylthio-semicarbazone has shown that it exists as a dimer with two molecules linked via the disulfide S–S bridge between the heterocycles in the crystal.     

Exchange and dative coordinate bonds in binuclear zinc complex

The high-resolution X-ray diffraction study of dizinc bis(pyridine)-bis{[μ₂-(2-oxybenzylidene)amino]-4,6-di(tert-butyl)phenoxide} and the analysis of the structures of related compounds refuted the data on the effect of the exchange or dative mechanism of the metalbridging ligand bond formation on the bond strength and revealed the factors controlling the energy of these bonds.     

New copper(II), nickel(II), and cobalt(II) chelates derived from 2-methyl-3-{[3-methyl-5-oxo-1-phenylpyrazol-4- ylidene)methyl]amino}-quinazolin-4-one

Ligand system derived from pyrazolone-5 and N-aminoquinazolinone was prepared, its structure was studied. Metal chelates ML₂ were prepared by reaction of the obtained ligand with copper(II), nickel(II), and cobalt(II) acetates. The complexes were studied by IR, electronic, and ESR spectroscopy, magnetochemistry, X-ray diffraction. Copper(II) complex was shown to have pseudo-tetrahedral structure, nickel(II) and cobalt(II) complexes are octahedral.