Stochastic model of tilting mode in nuclear fission

A model of induced nuclear fission was developed with consideration of thermodynamically fluctuating orientation degree of freedom (tilting) of deformed nuclei. This model was applied to analysis of the experimental angular anisotropy of fission fragments in the ¹⁶O + ²³²Th, ²³⁸U, ²⁴⁸Cm, ²⁰⁸Pb, ²⁰⁹Bi; ¹²C + ²³⁶U; ¹⁹F + ²⁰⁸Pb; and ¹¹B + ²³⁷Np reactions. Information on the equilibrating time of the tilting mode was obtained. The text was submitted by the authors in English.     

Synthesis,structure, and ESR spectra of the new heteronuclear complex {Li4(VO)2[(OOC)2C(H)Bu]4(H2O)8}·H2O

The reaction of an aqueous solution of vanadyl sulfate VOSO₄·3H₂O, butylmalonic acid (H₂Bumal = C₄H₁₀(COOH)₂), and lithium carbonate at pH ～4–5 gave crystals of the complex Li₄(VO)₂(Bumal)₄(H₂O)₈]·H₂O (1). The structure of complex 1 was established by X-ray diffraction analysis. The molecule of complex 1 consists of two mononuclear bischelate dianionic units {VO(Bumal)₂(H₂O)} linked by four lithium ions to form the hexanuclear heterometallic {V₂Li₄} structure. The crystals and an ethanolic solution of compound 1 were studied by ESR spectroscopy.     

Crystal structure and magnetic properties of a new heterometallic complex of Pd(II)-Cu(II) with 1-aminoethylidene-1,1-diphosphonic acid

A heterometallic complex of Pd(II)-Cu(II) with 1-aminoethylidene-1,1-diphosphonic (AEDP) acid (C₄H₂₂CuN₂O₁₆P₄Pd) _n (I) is synthesized. Single crystals of compound I are obtained; its crystal structure is determined by X-ray crystallography. The crystals are orthorhombic, space group Pbcn, a = 18.366(3) Å, b = 9.7661(17) Å, c = 20.198(4) Å, V = 3622.8(11) ų, Z = 8, d _x = 2.376 g/cm³. The compound crystallizes as a coordination polymer; the square environment of Pd(II) is formed by nitrogen atoms of amino groups and oxygen atoms of phosphonic groups, while at two non-equivalent copper atoms the octahedral environment is formed by oxygen atoms of phosphonic groups and water molecules. The crystal structure of compound I is characterized by the formation of a branched network of hydrogen bonds. Based on the analysis of the temperature dependence of the magnetic susceptibility it is found that for the heterometallic complex of Pd(II)-Cu(II) with AEDP antiferromagnetic interactions between the paramagnetic centers are dominant.     

XPS study of the electronic structure of heterometallic complexes Fe2MO(Piv)6(HPiv)3 (M = Ni, Co)

Heterometallic complexes Fe₂MO(Piv)₆(HPiv)₃ (M = Ni, Co) have been studied by XPS. The complexes are identified as high-spin complexes with metal atoms in oxidation states M(II) and M(III). A change in the ligand environment of metal atoms has an effect on both the energetic state of metal atoms and the XPS pattern. The substitution of a Co atom for the nickel atom in the heterometallic complexes changes the XPS pattern of iron and their magnetic state. For the Fe₂MO(Piv)₆(HPiv)₃ complexes, quantum-chemical calculations have been performed at the density functional theory (DFT) level. In combination with XPS and magnetochemistry data, the quantum-chemical calculation demonstrates that the Fe, Ni, and Co atoms in the trinuclear complexes are in the high-spin local state and that the ground state is dominated by antiferromagnetic exchange interaction.     

Coordination compounds of neodymium(III) with acyldihydrazones of saturated dicarboxylic acids and 3-methyl-1-phenyl-4-formylpyrazol-5-one

Coordination compounds of neodymium(III) with acylhydrazones of saturated dicarboxylic acids and 3-methyl-1-phenyl-4-formylpyrazol-5-one are synthesized and studied. The structure of complex [Nd₂(H₂L²)₃] · Me₂SO · CH₃OH · 6H₂O is determined from the X-ray diffraction data for the isostructural lanthanum complex. The complex is binuclear and contains nine-vertex coordination polyhedra bound by three hydrocarbon spacers. Solid samples of the studied neodymium complexes exhibit luminescence in the near-infrared spectral range (λ = 874, 904, and 1059 nm) characteristic of this ion.     

Dynamical model of fission fragment angular distributions

A dynamical model of fission fragment angular distributions is developed. The experimental data on the angular anisotropy of fission fragments is analyzed for the ¹⁶O + ²⁰⁸Pb, ²³²Th, ²³⁸U, and ²⁴⁸Cm reactions at energies of the incident ¹⁶O ions ranging from 90 to 160 MeV. This analysis allows us to extract the relaxation time for the tilting mode. It was also demonstrated that the angular distributions are sensitive to the deformation dependence of the nuclear friction.

     

Influence of the steric properties of pyridine ligands on the structure of complexes containing the {LnCd2(bzo)7} fragment

The reaction of Cd(NO₃)₂ · 4H₂O and Eu(NO₃)₃ · 6H₂O or Tb(NO₃)₃ · 6H₂O with potassium 3,5-di-tert-butylbenzoate (Kbzo) and N-donor ligands (1,10-phenanthroline (phen), 2,4-lutidine (2,4-lut), 3,4-lutidine (3,4-lut), phenanthridine (phtd), 2,3-cyclododecenopyridine (cdpy), acridine (acr)) afforded heterometallic LnCd₂ complexes: [EuCd₂(bzo)₇(EtOH)₂(phen)] (2), [LnCd₂(bzo)₇(2,4-lut)₄] (Ln = Eu (3), Tb (4)), [EuCd₂(bzo)₇(H₂O)₂(2,4-lut)₂] · MeCN (5), [EuCd₂(NO₃)(bzo)₆(EtOH)₂(2,4-lut)₂] (6), [EuCd₂(bzo)₇(H₂O)(EtOH)(3,4-lut)₂] · 5EtOH (7), 3[EuCd₂(bzo)₇(H₂O)₂(phtd)₂] · 4phtd (8), [EuCd₂(bzo)₇(EtOH)₃(cdpy)] (9), 2[EuCd₂-(bzo)₂(EtOH)₄] · acr (10). The structures of complexes 2, 3, and 5–10 were determined by single-crystal X-ray diffraction. The isostructurality of complexes 3 and 4 was confirmed by powder X-ray diffraction. The structure of the trinuclear {Ln₂Cd} metal core is stable and independent of the type of peripheral ligands coordinated to cadmium atoms. Photoluminescent properties of compounds 3 and 4 were studied.

     

Synthesis of fluorodinitromethane and 2-fluoro-2, 2-dinitroethanol

Conclusions The authors have obtained fluorodinitromethane and 2-fluoro-2, 2-dinitroethanol and studied some of their physiocochemical properties.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 912–914, April, 1968.     

NMR study on the interaction of 1,4-cubanedicarboxylic acid and its esters with elemental fluorine. The synthesis of dimethyl 2-fluorocubane-1,4-dicarboxylate

Elemental fluorine can be successfully used for fluorination of cubane derivatives. The nature of the products depends on the fluorination conditions: in CH3CN at -20 to -30 degrees C, dimethyl 2-fluorocubane-1,4-dicarboxylate was obtained from dimethyl ester of 1,4-cubanedicarboxylic acid; in CF3COOH at -12 to -15 degrees C in the presence of alkali metal acetates, 1,4-cubanedicarboxylic acid and its dimethyl and diethyl esters gave complex mixtures of fluorinated cubane products. Our investigation by 1H and 19F NMR spectroscopy and spectra computer simulation revealed production of mono- and difluorinated cubanes. Fluorine-containing cubane derivatives were also found with extra substituents in other than 1 and 4 positions.