Instability of a thermally inhomogeneous layer of weakly conducting liquid in an electric field

We give the results of a theoretical investigation of the hydrostatic stability of a plane horizontal layer of weakly conducting liquid for different constant temperatures and potentials on the thermally and electrically conducting capacitor plates bounding the layer. We found that the onset of electrothermal convection is of an oscillatory nature. The critical conditions for loss of stability were found.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 133–138, November–December, 1974.     

Supramolecular structure organization and the biological properties of [Co(DH)<Subscript>2</Subscript>(PP)<Subscript>2</Subscript>][BF<Subscript>4</Subscript>]

The coordination compound [Co(DH)₂(PP)₂][BF₄]₂ · 2H₂O (DH⁻ is the dimethylglyoxime residue, PP is nicotinamide) was synthesized and studied by X-ray diffraction. The equatorial plane of the octahedral Co(III) complex contains two DH⁻ residues combined by intramolecular hydrogen bonds O-H…O, while the apical positions are occupied by two PP molecules. A method for the optimal use of the complex for enhancement of the biosynthesis of standard and acid-stable amylases of the micromycete Aspergillus niger 33–19 CNMN FD 02A and lipases of the micromycete Rhizopus arrhizus Fischer CNMN FD 03L was depeloped. The introduction of the complex in a concentration of 1–5 mg/l into the culture medium of Aspergillus niger 33-19 CNMN FD 02A reduces the process cycle by 24 h. The stimulating effect of the introduction of the complex (5 mg/l) into the culture medium of the Rhizopus arrhizus Fischer CNMN FD 03L strain is 55.5%.     

The structure of polynuclear clusters based on zinc and copper compounds with thiosemicarbazidodiacetic acid

Polynuclear complexes were synthesized from Zn(II) and Cu(II) compounds and thiosemicarbazidodiacetic acid and their structures were studied. The formation of four-, five-, and nonanuclear clusters was shown to depend on the metal nature and the synthesis conditions.     

Crystal and molecular structure of the coordination compound of O-phenanthroline thiosemicarbazide diacetate of cadmium(II) monohydrate

Institute for Applied Physics, Moldavian Academy of Sciences. Moldavian Institute of Chemistry. Lazo Polytechnic Institute of Kishinev. Translated from Zhurnal Strukturnoi Khimii, Vol. 133, No. 6, pp. 197–201, November–December, 1992.     

Synthesis and Structure of the [Co(NioxH)2(Thio)2]2[SiF6] Complex

Anhydrous compound [Co(NioxH)₂(Thio)₂]₂[SiF₆] (I) was synthesized. Its structure was determined by X-ray diffraction analysis. The structures and character of intramolecular and intermolecular hydrogen bonds of complex Iand the previously studied [Co(NioxH)₂(Thio)₂]₂[SiF₆] · 3H₂O complex were compared.     

Cobalt(III) α-Dimethylglyoximates [Co(DH)2(Py)2]2SiF6 · 10H2O and [Co(DH)2(Thio)2]2SiF6 · 2H2O · C2H5OH: Synthesis and Structure

[Co(DH)₂(Py)₂]₂SiF₆ · 10H₂O and [Co(DH)₂(Thio)₂]₂SiF₆ · 2H₂O · C₂H₅OH complexes are synthesized and characterized by X-ray diffraction analysis. Two radicals of -glyoxime linked by hydrogen O–H···O bonds lie in the equatorial plane of the octahedral Co(III) complexes. Intramolecular (– and N–H···O) and intermolecular (O–H···F, O–H···O, N–H···F, N–H···O, N–H···S) interactions are discovered in the crystal. The influence of nonvalence interactions on the structures is discussed.     

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.     

Cobalt(III) dimethylglyoximates containing selenourea and an unusual diselenourea ligand: Synthesis and structures

The complexes [Co(DH)₂(Seu) _y (Se-Seu) _z ]₂X · mSolv (DH is the dimethylglyoxime monoanion, Seu is selenourea, and X is [TiF₆]²⁻, [ZrF₆]²⁻) were obtained from the system CoX · 6H₂O-DH₂-Seu in DMF-MeOH or MeOH-H₂O and examined by UV, IR, and NMR spectroscopy and X-ray diffraction. Unexpectedly, the ligand Se-Seu (the oxidized form of selenourea) was detected on the axial coordinate, partially replacing selenourea. The complexes were formulated as [Co(DH)₂(Seu)_1.75(Se-Seu)_0.25]₂[TiF₆] · H₂O (I) and [Co(DH)₂(Seu)(Se-Seu)]₂[ZrF₆] · 3H₂O (II). The complex cations in I and II have trans-octahedral structures. Their crystal structures are made up of the complex Co³⁺ cations and the outer-sphere MF₆²⁻ anions (M = Ti(IV) (I) and Zr(IV) (II)) held together by electrostatic interactions and hydrogen bonds; water of crystallization is also involved in hydrogen bonding.     

Synthesis and crystal structure of cobalt(III) α-dioximates with pyrazine

A series of new coordination compounds of cobalt(III) trans-dioximates with pyrazine [CoCl(DH)₂Pz] · H₂O (I), [CoBr(DH)₂Pz] · H₂O (II), [Co(DH)₂Pz₂]NO₃ · H₂O (III), [Co(DH)₂Pz₂][BF₄] (IV), [Co(MgH)₂Pz₂][BF₄] (V), and [Co(NioxH)₂Pz₂][BF₄] (VI), where DH, MgH, and NioxH are dimethylglyoxime, methylglyoxime, and 1,2-cyclohexanedionedioxime monoanions, respectively, Pz is a pyrazine molecule were synthesized. The structures of compounds I, II, and VI were determined by X-ray diffraction. The Co(III) environment in these compounds is octahedral and the pseudomacrocyclic (DioxH⁻)₂ fragment occurs in the equatorial plane. This fragment is stabilized by O-H…O hydrogen bonds. The neutral Pz ligand is monodentate in all three compounds.     

Crystal and molecular structure of chloro-bis(1,2-cyclohexanedione-dioxime)triphenylphosphinecobalt(III)

The structure of chloro-bis(1,2-cyclohexanedionediaxwte)triphenylphosphinecobalt(III) [Co(NioxH)₂PPh₃Cl] was determined by X-ray diffraction analysis. The crystal is monoclinic, a = 17.049(3), b = 15.223(3), c = 11.032(3) å, Β = 87.44(2)?, R(hkl) = 0.068 for 2739 reflections with I ≥2Σ(I). The structure is molecular. In the octahedral complex, the cobalt(III) atom is coordinated by two NioxH residues (av Co-N = 1.876 å), the phosphorus atom (Co-P = 2.307 å), and the Cl^- union (Co-Cl = 2.260 å). In the crystal, there are weak intermolecular interactions C-H…Cl and C-H…O.