Synthesis and structure of cobalt α-dioximate complexes with isonicotinamide

New cobalt trans-dioximate complexes with isoniconinamide have been synthesized: [Co^II(DmgH)₂(Inia)₂] (I), [Co^III(DmgH)₂(Inia)₂][PF₆] · 1.5H₂O (II), [Co^III(NioxH)₂ (Inia)₂][PF₆] · H₂O · CH₃OH (III), and [CoIIICl(DmgH)₂(Inia)] · H₂O (IV), where DmgH⁻ and NioxH⁻ are the dimeth-ylglyoxime and 1,2-cyclohexanedionedioxime monoanions, respectively; Inia is the isonicotinamide molecule. The structures of compounds I–IV have been determined by X-ray crystallography. In I–IV, Co(II) or Co(III) has an octahedral environment with the pseudomacrocyclic (DioxH⁻)₂ moiety (DioxH⁻ is the dioximate monoanion) in the equatorial plane. The latter is stabilized by O-H…O hydrogen bonds. The isonicotinamide molecules in all four complexes are monodentately bound to the metal ion through the heterocyclic nitrogen atom.     

Synthesis and structure of new thiourea-containing Cobalt(III) dioximates with the [TiF6]2− anion

The new Co(III) dioximates [Co(DH₂)(D)(Thio)₂]₂[TiF₆] ·2DMF (I), [Co(NioxH)₂(Thio)₂]₂[TiF₆] · 2.25H₂O (II), and [Co(DpgH)₂(Thio)₂]₂[TiF₆] · 4DMF · 1.5H₂O (III) have been synthesized and studied (DH₂ and D are, respectively, the dimethylglyoxime molecule and doubly charged anion; NioxH and DpgH are singly charged anions of 1,2-cyclohexanedione dioxime and diphenylglyoxime, respectively; Thio is thiourea; DMF is dimethylformamide). The composition and structure of the complexes have been studies by IR, UV, and NMR spectroscopy. The crystal structures have been determined by X-ray crystallography. The hydrogen bonds in the structures are formed by fluorine atoms of the [TiF₆]^2? anion with Co(III) complex cations and solvent molecules of crystallization. The amino groups of coordinated thiourea molecules are also involved in the hydrogen bond system, which is responsible for their different arrangement with respect to the equatorial planes of the Co(III) complex cations.     

Novel wet electrostatic precipitator for collection of fine aerosol

A novel wet electrostatic precipitator (WESP) is designed for effective control of fine aerosol from humid gases. It operates on the principle of unipolar particle charging in the corona discharge and particle precipitation under the field of their own space charge. The new precipitator is characterized by high gas velocity in the ionizing stage. Tests were carried out for gas with (NH₄)₂SO₄, HCl and (NH₄)Cl aerosol at particle number concentration up to 5·10⁷#/cm³ and mass concentration 10–1000 mg/Nm³. For test conditions one-field WESP ensures mass collection efficiency 90–97% and two-field electrostatic precipitator up to 99%.     

Hydrogen as a cause of doping in zinc oxide

Zinc oxide, a wide-band-gap semiconductor with many technological applications, typically exhibits n-type conductivity. The cause of this conductivity has been widely debated. A first-principles investigation, based on density functional theory, produces strong evidence that hydrogen acts as a source of conductivity: it can incorporate in high concentrations and behaves as a shallow donor. This behavior is unexpected and very different from hydrogen's role in other semiconductors, in which it acts only as a compensating center and always counteracts the prevailing conductivity. These insights have important consequences for control and utilization of hydrogen in oxides in general.     

Molecular and crystalline structure of 4-phenylthiosemicarbazidodiacetic acid monohydrate

Institute of Chemistry, Moldavian Academy of Sciences. Translated from Zhurnal Strukturnoi Khimii, Vol. 33, No. 2, pp. 177–180, March–April, 1992.     

Crystal and molecular structure of dimethyl 4-phenyl-S-methylisothiosemicarbazide diacetate and its complex with copper(II) bromide

The structure of dimethyl 4-phenyl-S-methylisothiosemicarbazide diacetate NH(C₆H₅)C(SCH₃)NN × (CH₂COOCH₃)₂ (Z) hydroiodide (I) (crystals I are triclinic, space group $P\bar 1$ , a=11.671(3), b=10.889(2), c=8.237(2) Å,α=78.59(2),β=77.63(2),γ=106.47(2)°, Z=2, final R=0.088) and a complex of Z with copper(II) bromide, CuBr₂Z (II) (crystals II are orthorhombic, space group Pbca, a=14.487(4), b=18.827(8), c=14.565(5) Å, Z=8, R=0.062) was determined by X-ray diffraction analysis. It is established that methylation of the sulfur atom changes the type of ligand attachment to the metal, namely, the ligand is transformed from the tripod S,N,O,O, into the N,N,O,O type (the sulfur atom is not involved in coordination). When coordinated, the ligand does not change conformation, and the thiosemicarbazide fragment retains the E-configuration. During complexation, Z topologically behaves as a classical complexon of the monoamine series.