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.     

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.     

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.     

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.     

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.     

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 Use of Co(III) Dimethylglyoximates in the Biosynthesis of Rhizopus arrhizus Pectinases

Novel coordination compounds of Co(III) with dimethylglyoxime were synthesized, namely, [Co(DH)₂(Thio)₂]₃F[SiF₆] · 1.5H₂O (I) and [Co(DH)(Thio)₂]₂[SiF₆] · 3H₂O (II)], in which the central atom coordinates dimethylglyoxime moieties (DH), thiocarbamide (Thio), and hexafluorosilicate anions. These compounds were tested as stimulators in the biosynthesis of extracellular enzymes in the Rhizopus strain. It was established that the effect produced by complex compounds depends on the type of hydrolytic enzyme complex used, the composition of the complex, and its concentration in the cultivation medium.     

Carbodications. 4.(1) Hydrogen Isotope Exchange of Crotonyl Cations in Superacid

The title ion reacts in 1:1 DF-SbF(5) and exchanges up to five protium atoms with deuterium. The incorporation of label was measured by GC-MS analysis of the methyl crotonate formed by methanol quenching. The isotopomer distribution at about 60% conversion, which shows a minimum for the d(1) and a maximum for the d(4) species, indicates that the intermediate dication with the second charge at C(3) loses a proton faster from C(4) than from C(2). Formation of the pentadeuteriocrotonyl cation indicates that the 1,4-dication (acyl primary alkyl) or the 1,2-dication must intervene in the process. Computer modeling of the kinetics for the multiple exchange process to fit the experimental deuterium distribution allowed determination of the relative rate constants and isotope effects (KIEs) for the formation of the carbocations from alkenoyl cations (beta-secondary KIE) and elimination from carbodications to alkenoyl cations (primary KIE). An exceptionally large beta-secondary KIE of ca. 2.0/hydrogen was found for the formation of the dication. A small primary isotope effect of ca. 1.5 was found for elimination from the dications to the alkenoyl cations. Elimination from the 1,3-acylalkyl dication to form the nonconjugated 3-butenoyl cation is 6-7 times faster than elimination to the conjugated 2-butenoyl cation. The rate ratio for the conversion of 3-butenoyl cation to the 1,4-dication (primary alkyl cation) and 1,3-dication (secondary alkyl cation) is (0.025-0.030):1, whereas the relative rate of the formation of the 1,2-acylalkyl dication (the alternative route of achieving pentadeuteration) is zero.