L. V. Stepakova

Reaction of vinylidenecyclopropanes with aromatic imines in the presence of Lewis acids

Abstract1-Methyl-2-(2-methylpropenylidene)-1-phenylcyclopropane, 7-(2-methylpropenylidene)bicyclo[4.1.0]heptane, and (Z)-9-(2-methylpropenylidene)bicyclo[6.1.0]non-4-ene react with N-benzylideneanilines in the presence of boron trifluoride-ether complex to give pyrrolidine derivatives. Reactions of 1-methyl-1-phenyl-2-diphenylvinylidenecyclopropane with N-benzylideneanilines in the presence of BF3·Et2O, Yb(OTf)3, or Sc(OTf)3 lead to the formation of substituted 1,2,3,4-tetrahydroquinolines. 7-Diphenylvinylidenebicyclo[4.1.0]heptane in the presence of BF3·Et2O undergoes isomerization into 5-phenyl-8,9,10,11-tetrahydro-7H-cyclohepta[a]naphthalene.

Influence of Acido Ligands on the Structure of Copper Dihalide Solvates with Dimethyl Sulfoxide and N,N-Dimethylformamide

Structures of copper dihalide solvates with dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) were determined by XRD single crystal analysis. The existence of two DMSO solvates with CuBr2, but only one with CuCl2, was attributed to a lower Cu-Br bond strength in comparison with Cu-Cl, and, as a consequence, by its easier breaking to form a bond with a solvent molecule. Fundamentally different structures of CuX2·2DMF (X = Br, Cl) solvates are caused by different donor power of the acido ligands.

Organic solvent effect on the solution-solid phase equilibria in the systems CuCl2-L-H2O (L = DMSO, DMF, acetonitrile) at 25°C

A solution-solid equilibrium in ternary water-organic systems CuCl2-L-H2O (L = dimethyl sulfoxide, N,N-dimethyl formamide, and acetonitrile) at 25°C was studied. The expansion of crystallization branches of individual solvates CuCl2·xL varies in parallel to the donor power of organic solvents. The existence of the mixed crystal-solvates CuCl2·2H2O·2(CH3)2SO, CuCl2·2H2O·2(CH3)2NCHO, CuCl2·H2O·(CH3)2NCHO, CuCl2·2H2O·CH3CN, and CuCl2·3H2O·2CH3CN in the studied systems was proved. Various donor power of oxygen-containing solvents determines the composition of the first coordination sphere of the copper ion in the specified compounds: the coordination of the both solvents in the mixed crystal-solvates with DMF and the absence of water in the nearest environment of the copper(II) ions in the CuCl2·2H2O·2(CH3)2SO compound.

Effect of the oxidation state of copper on the solution-solid phase equilibria in CuClx-MCl-H2O systems

The effect of the oxidation state of the metal on the solubility was analyzed using the example of CuClx-MCl-H2O (x = 1, 2; M = Li-Cs, NH4) ternary systems. The prevalence of acido complex formation is responsible for an essential similarity of the solubility isotherms: the presence of crystallization branches of complex salts and salting-in (or weak salting-out) of copper(I) and (II) chlorides, that increases in the order LiCl < NaCl < KCl < CsCl. The different stability of copper(I) and (II) chloride complexes results in that the chemical individuality of alkali metal cations is differently reflected in the shape of the solubility isotherms: The stronger complex formation in copper(I) systems results in leveling of this effect and the weaker complex formation with copper(II), in its differentiation.

Effect of Alkali Metal Chlorides on the Solubility in Ternary Water-Salt Systems Containing Copper Monochloride

Solubility in the systems of CuCl-LiCl-H2O and CuCl-CsCl-H2O at 25°C was studied by the method of isothermal removal of oversaturation. The results were examined in terms of the competition between hydration and complex formation processes in water-salt systems.

Comparative analysis of solubility in CuCl-MCl-H2O systems at 25°C (M+ = Li+, Cs+, NH 4 + )

Solubility in the ternary system CuCl-NH4Cl-H2O at 25°C was determined by the method of isothermal lifting of oversaturation. A comparative analysis of solubility in this system and the previously studied systems CuCl-MCl-H2O (M+ = Li+, Na+, K+, Cs+) was made. The results obtained were interpreted in terms of competition between hydration, association, and complexation processes in water-salt systems.