Potentiometric investigations of some catechol derivatives of scandium

The equilibrium reactions of scandium(III) with some triprotic catechol derivatives (H₃L) were studied. The selected ligands that are 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), 3.4-dihydroxyhydrocinnamic acid (3,4-DHHCA), and 3,4-dihydroxyphenylacetic acid (3,4-DHPA) were investigated in aqueous solution by means of potentiometry in 0.1 M ionic medium at 25°C. The stability constants are reported for the ScL and ScL(H₂L)^– mononuclear complexes. 2,3-DHBA can bind to Sc³⁺ ion strongly and the salicylate mode (COO^–, O^–) is effective over the acidic pH range. But in higher pH range, 3,4-DHBA, 3,4-DHHCA, and 3,4-DHPA act more efficiently through catecholate groups (O^–, O^–).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 229–233.Original Russian Text Copyright © 2005 by Türkel, Özer.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis and crystal structure of 2′-(3,5-dioxo-1,2,4-triazinane-1-yl)acetic acid and the product of its reaction with copper(II) chloride

A new organic compound, 2-(3,5-dioxo-1,2,4-triazinane-1-yl)acetic acid, was prepared by transit template synthesis, and its crystal structure was determined. The ability of this compound to form stable metal complexes, where it acts as an N,O-chelating ligand, was demonstrated using its Cu(II) compound as an example.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 187–194.Original Russian Text Copyright © 2005 by Filippova, Bologa, Simonov, Gdaniec, Gerbaleu.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Complexation processes in KF-SbF<Subscript>3</Subscript>-H<Subscript>2</Subscript>O system studied by calorimetric titration

Complexation in a KF-SbF₃-H₂O system is studied in a range of molar ratios of fluorides KF : SbF₃= (0.1–2) : 1 by calorimetric titration. The equilibrium formation constants of complexes KSb₂F₇, KSbF₄, and K₂SbF₅ (5.8×10⁵±800, 3.3×10⁴±500, and 1.9×10⁶± 950, respectively) and the changes in enthalpy (–31.75± 0.74, –28.15±0.44, and –25.5±0.64 J mol^–1, respectively) and entropy (4±7, –8±5, and –35±9 J mol^–1 K^–1, respectively) are determined. The thermodynamic stability of the antimony(III) fluoride complexes is found to increase on going from KSb₂F₇ to K₂SbF₅.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 168–171.Original Russian Text Copyright © 2005 by Kovaleva, Zemnukhova, Lebedeva, Fedorishcheva.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

<Superscript>1</Superscript>H NMR study of complexation of α- and β-cyclodextrins with some biologically active acids

Reactions of - and -cyclodextrins with some biologically active acids were studied by ¹H NMR spectroscopy. Inclusion complexes are found to be formed only with aromatic amino acids (phenylalanine and tryptophan) and ascorbic acid. The complexes of cyclodextrin with citric acid are obtained through interactions between the polar groups of the guest molecule and the OH groups of the host molecule located on the outside.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 234–236.Original Russian Text Copyright © 2005 by Terekhova, Kulikov, Kumeev, Nikiforov, Alper.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis of Ru(II) complex with 3-(4,5-dihydroimidazol-1-yl)propyltriethoxysilane containing viologen group

The nanostructured metallopolymers consisting of the partially quaternized 3-(4,5-dihydroimidazol-1-yl)propyl having the viologen group linked covalently through the alkyl spacer and its Ru(II) complex have been prepared by sol-gel method. Structural elucidation was done with Fourier transform infrared spectroscopy, ultraviolet spectroscopy and differential thermal analysis.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 183–186.Original Russian Text Copyright © 2005 by Gürbüz, Seçkin, Özdemir, Çetinkaya.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Oxidation of 2-alkyl-5,10-dihydrophenazines

Oxidation of 2-alkyl-5,10-dihydrophenazines afforded 1:1 molecular complexes of the initial compounds with the corresponding 2-alkylphenazines.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1544–1545.Original Russian Text Copyright © 2004 by Bidman.This revised version was published online in April 2005 with a corrected cover date.     

Thermal dissociation of supramolecular complexes on the basis of 18-crown-6 and amino acids

The possibility of isolation of crystalline supramolecular complexes of 18-crown-6 with glycine, L-alanine, L-valine, L-leucine, L-phenylalanine, L-proline, L-hystidine, and L-threonine from aqueous solutions was studied. Comparative analysis of thermal decomposition of the complexes and their individual components and mechanical mixture was studied by means of thermogravimetry, differential thermal analysis, and differential scanning calorimetry. Crystaline complexes of 18-crown-6 with glycine, L-alanine, and L-hystidine were isolated and shown to be stable up to 140°C, which was additionally confirmed by IR spectroscopy.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1313–1317.Original Russian Text Copyright © 2004 by Terekhova, Kulikov, Barannikov.This revised version was published online in April 2005 with a corrected cover date.     

Electronic absorption spectra and the structure of the ligand in metal complexes with purpurin

Purpurin complexes with metals are formed due to metal coordination at the peri- or ortho-hydroxycarbonyl group involving anthraquinoid tautomers. The _l,* bands of metal purpurinates correspond to 1,10- and 1,4-anthraquinoid anions, 9,10-anthraquinoid structures are not typical of them.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 237–240.Original Russian Text Copyright © 2005 by Fain, Zaitsev, Ryabov.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

1,2,4-Thiadiazole derivatives of cytisine

Several new derivatives were prepared by reaction of 3-alkylthio-5-chloroacetamido-1,2,4-thiadiazoles with cytisine.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 479–480, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Host-guest complexes of crown ethers with HN-proton-donor molecules

Crown ethers were reacted with HN-proton-donor molecules to obtain crystalline molecular host-guest complexes. It was found that complexes with crown ethers of different structure are formed, depending on the linear dimensions and mode of steric shielding of active centers of the proton-donor molecules.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 12, 2004, pp. 2030–2033.Original Russian Text Copyright © 2004 by Wang, Ganin.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis of the lupinine ester of betulonic acid

The lupinine ester and 3-oxime of betulonic acid were prepared for the first time.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 467–468, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

On the hyperfine coupling in tetragonal copper(II) complexes

The vibronic effect on the hyperfine coupling (HFC) parameters in tetragonal copper(II) complexes was studied. The parameters of the vibronic contributions from the - and 4s-AOs of the Cu²⁺ ion to the ground-state function were estimated. The anomalous behavior of the isotropic HFC was analyzed in terms of the static model with consideration of the vibronic coupling. The static and vibronic contributions to the anisotropic portions of the components of the HFC tensor were estimated.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 204–206.Original Russian Text Copyright © 2005 by Muravev.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Spectral study of the catalytic reaction of hydrosiloxanes with vinylsiloxanes

¹H, ¹³C, and IR spectroscopy and gas chromatography-mass spectrometry were used to study addition of hydrosiloxanes to vinylsiloxanes in the presence of Pt(II) complexes. Along with hydrosilylation, dehydrocondensation and disproportionation of hydrosiloxanes occur.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1426–1433.Original Russian Text Copyright © 2004 by de Vekki, Viktorovskii, Skvortsov.This revised version was published online in April 2005 with a corrected cover date.     

New synthetic approaches to 6(7)-R-4-methyl-2-sulfanylquinazolines and their transformations

New synthetic approaches to 6(7)-R-4-methyl-2-sulfanylquinazolines are developed and certain transformations of the products are studied.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 10, 2004, pp. 1714–1719.Original Russian Text Copyright © 2004 by Shikhaliev, Zolotykh, Cherkasova, Solovev.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis of the racemic analog of a honeybee (<Emphasis Type="Italic">Apis mellifera</Emphasis>) breeding pheromone component

The synthesis of 1-palmitoyl-2,3-dioleoylglycerine, the racemic analog of a honeybee breeding pheromone component, from 1,2-O-isopropylideneglycerine was proposed.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 488–489, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Modified coumarins. 15. Condensed psoralen derivatives based on substituted dibenzo[<Emphasis Type="Italic">b,d</Emphasis>]pyran-6-ones

Benzo[c]furo[3,2-g]chromen-5-ones, modified psoralen analogs containing a substituted benzene ring annelated at the 5,6-position of the furo[3,2-g]chromen-7-one system, were prepared by the MacLeod method.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 441–445, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Development of methods of ligand control in Pd-catalyzed hydrosilylation of 1,3-alkadienes

The catalytic activity of palladium(II) complexes in trichlorosilane reactions with 1,3-alkadienes (isoprene and 2,3-dimethyl-1,3-butadiene) is strongly affected by the nature of the phosphorus-containing ligand.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 10, 2004, pp. 1639–1643.Original Russian Text Copyright © 2004 by Reznikov, Skvortsov.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis of 30-amino derivatives of 3,28-di-O-acetylbetulin

30-Amino derivatives of the lupane group were prepared by reaction of 3,28-di-O-acetyl-30-bromolup- 20(29)-ene with L-valine methyl ester and aliphatic amines.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 469–471, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Phytoecdysteroids from the <Emphasis Type="Italic">Silene</Emphasis> genus

Research results on the isolation and identification of ecdysteroids from plants of the Silene L. genus were presented.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 472–475, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Influence of the structure of the macroheterocyclic ligand on the catalytic properties of metal tetraarenoporphyrazine complexes: III. Oxidative decarboxylation of oxalic acid

The catalytic activity of cobalt complexes of a series of tetraarenoporphyrazines in oxidative decarboxylation of oxalic acid under heterogeneous conditions was studied. The structure of the macroheterocycle exerts a significant effect on the catalytic properties of the metal complexes.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1898–1901.Original Russian Text Copyright © 2004 by Korzhenevskii, Shikova, Koifman, Bykova.For communication II, see [1].This revised version was published online in April 2005 with a corrected cover date.