Asymmetry and magnetism in bis(oximato)-bridged heterobimetallic compounds: a computational approach

A density functional study of exchange coupling was carried out for a series of heterobinuclear oximato-bridged transition metal complexes. Model calculations were used to examine the influence of the electronic configuration of the metal atoms on the coupling constants. This analysis was complemented by a study of the variation of the coupling constant with the most usual structural distortions within this family of compounds. The influence of the nature of the terminal ligands as well as that of the symmetry on the bridge were also investigated.     

Reversible temperature-induced transformations of poly(N-ethyl-4-vinylpyridinium) complexes with dodecyl sulfate in aqueous salt solutions

Supramolecular organization of complexes formed by poly(N-ethyl-4-vinylpyridinium bromide) and sodium dodecylsulfate in aqueous salt solutions was studied as a function of temperature and concentration of the complexes. It was shown that a decrease in temperature and/or concentration of complexes led to their reversible disaggregation into a molecularly dispersed (“unipolymer”) state. The ratio between the components in complex particles remained unchanged in this case. It was first found that phase separation in aqueous solutions of the complexes upon temperature elevation is accompanied by the precipitation of a nonstoichiometric complex.     

Action of nucleophilic agents on the pyrimidine ring

It is shown that 2-alkylpyrimidine methiodides in which the alkyl group is activated by electron-acceptor substituents undergo recyclization to the corresponding 2-methylaminopyridines in an alcohol solution of methylamine. Similar recyclization also takes place without quaternization of the pyrimidine ring when there is a strong electron-acceptor substituent (a nitro group) in the ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1405, October, 1978.     

Mixed-metal ethylenediaminetetraacetates of neodymium and alkaline earths

Conclusions In solution, the complexes M^II(NdA)₂ do not have a polynuclear structure. In the conditions studied, hydroxo polynuclear complexes including EDTA and M^II and Nd³⁺ ions are also not formed. Our results are not inconsistent with the hypothesis that the solid complex Ca(NdA)₂·17H₂O has a polynuclear structure and that the polynuclear character is successively weakened as Ca²⁺ is replaced by Sr²⁺ and Ba²⁺.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1235–1239, June, 1977.     

Stereochemistry of the synthesis of 1,2,3,4-tetrahydrocinnolines from aryldiazenium salts and olefins

It follows from the PMR spectra that the reaction of 1-methyl-, 1-phenyl-, 1-ethyl-,1-phenyl-, and 1,1-diphenyldiazenium salts with cis- and trans-d-styrenes, which leads to the corresponding 3-d-4-phenyl-1,2,3,4-tetrahydrocinnolines, takes place with retention of the configuration in the starting styrenes. It is therefore proposed that this reaction be regarded as a special case of [4⁺_s + 2_s]-cycloaddition.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1658–1661, December, 1977.