Molecular and crystal structure of 2-(N-benzyl-N-phenylhydrazinoethylidene)-3-(2H)-benzo[b]-thiophenone

X-ray structural analysis was used to determine the molecular and crystal structure of 2-(N-benzyl-N-phenylhydrazinoethylidene)-3-(2H)-benzo[b]thiophenone. The crystals are monoclinic, the space group isC2/c,a=16.022(6),b=11.202(3),c=22.111(4) Å, =81.08(3)°, and andZ=8. It was shown that the ability of hydrazones of a similar class to exhibit photochromic properties is a function of the steric stresses in the molecules and their confirmation.Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, 142432 Chernogolovka. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2805–2809, December, 1992.     

Preparation and reactivity of metal-containing monomers

Mono- and disubstituted cluster metal-containing monomers were obtained under mild conditions on interaction of Rh₆(CO)₁₆ with 4-vinylpyridine (4-ViPy) in the presence of N-trimethylaminoxide. These products were characterized by IR and¹H NMR spectroscopy and by elemental and X-ray analyses. Rh₆(CO)₁₅(4-ViPy) was found to be an octahedral cluster with eleven terminal and four ₃-bridging carbonyl ligands. 4-ViPy is linked with the Rh(3) atom through the N atom and occupies the coordination site of the twelfth CO terminal ligand. The mean value of the Rh-Rh bond length is 2.762 Å. The unsaturated ligand has little or no effect on the geometry of the starting cluster and its double bond retains the ability to undergo addition reactions.For part 28, seeRuss. Chem. Bull., 1993, 453.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 975–979, May, 1993.     

Comparative investigation of the intramolecular interaction of the chromophores in diketones and dihydroxydicarbonium and dicarbonium ions

The intramolecular interaction of the chromophores in the systems of the dichalcone (I) and its dihydroxydicarbonium (II) and dicarbonium (III) ions with the general formula

X-ray and IR spectroscopic studies of specific intermolecular interactions inN′-substituted isonicotinohydrazides

_N-Thenylidene- andN-(o-nitrobenzylidene)hydrazides of isonicotinic acid have been studied by X-ray structural analysis and IR spectroscopy. In the crystalline state, these molecules are linked through intermolecular N—H ... Np_y hydrogen bonds. Carbonyl groups are not involved in intermolecular hydrogen bonds. However, it was found that the C=O group participates in an attractive interaction with the sulfur atom of the thiophene group. The energy of this interaction is comparable with the energies of intermolecular C=O ... H—N hydrogen bonds in amides.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 896–900, April, 1996.     

Nutations of magnetizations of sublattices and their role in the formation of Mössbauer spectra of antiferromagnetic nanoparticles

A law determining the dispersion shift of the anti-Stokes band of the supercontinuum of a light bullet in a filament of a femtosecond laser pulse in transparent dielectrics has been established. The dispersion equation theoretically obtained for the anti-Stokes shift has been confirmed by spectroscopic studies of the filamentation of the near and middle infrared ranges in fused silica and fluorides.     

Quantum model of the magnetic dynamics of single-domain particles for describing their magnetization curves and Mössbauer spectra in a weak magnetic field

A universal approach to describing the equilibrium magnetization curves and relaxation Mössbauer spectra of magnetic nanoparticles is proposed for consistent analysis of magnetometry and gamma-resonance experimental data, based solving a quantum-mechanical problem for a particle with spin S that has intrinsic magnetic anisotropy and is positioned in an external magnetic field.     

Mössbauer spectroscopy of magnetic nanoparticles: From universal qualitative treatment to realistic models of magnetic dynamics for particles of different magnetic nature and nanomaterial diagnostics

A unified phenomenological model of the magnetic dynamic of an ensemble of nanoparticles of different magnetic nature is developed. The model can be applied to the numerical analysis of Mössbauer spectra as functions of the temperature and external field. The model allows us to describe nonstandard features of the temperature evolution of the spectrum shape, particularly the macroscopic quantum effects often observed in the spectra of ⁵⁷Fe nuclei in antiferromagnetic nanoparticles.     

Synthesis of oligoorganosilsesquioxanes via acidohydrolytic polycondensation

Methyl acrylate oligosilsesquioxanes based on γ-methacryloxypropyltrimethoxysilane and its mixtures with phenyltrimethoxysilane have been synthesized through acidohydrolytic polycondensation and studied via NMR spectroscopy and MALDI-TOF mass spectrometry. It is shown that the addition of the aforementioned oligosilsesquioxanes to a dental composition based on 2,2-bis[p-(3-metacryloyloxy-2-hydroxypropoxy)phenyl]propane and triethylene glycol dimethacrylate improves the mechanical characteristics of cured polymer composites.     

Phase problem in three-beam X-ray diffraction

It is shown that, apart from the purely elastic scattering of X-rays, their inelastic coherent scattering by phonons can play, in some cases, a significant part in the formation of reflection curves for multiple X-ray diffraction. This process may affect the interference pattern for weak reflection, and it must be taken into account when extracting the triplet phase, as was demonstrated by an analysis of the experimental rocking curves obtained for the coplanar three-beam diffraction by a KDP crystal.