Characterization of nanocrystals in laser condensates deposited through vanadium evaporation in an oxygen atmosphere

The influence of the substrate temperature T _sub (20–360°C) and the oxygen pressure P(O₂) (5 × 10⁻³−0.13 Pa) in an evaporation chamber on the structure and phase composition of films prepared through laser sputtering of a vanadium target is investigated by electron diffraction and in situ transmission electron microscopy (with the use of the bend extinction contour technique for determining the bending of the crystal lattice). It is demonstrated that the oxygen content in the films increases with an increase in the oxygen pressure P(O₂) at a fixed substrate temperature T _sub and decreases with an increase in the substrate temperature T _sub at a fixed oxygen pressure P(O₂). The conditions responsible for the formation and composition of the crystalline (VO_0.9) and amorphous (V₂O₃) phases in the films are determined. It is established that the phase composition of the film depends on the angle of condensation of the vapor-plasma flow. The crystallization of the V₂O₃ amorphous phase is accompanied by an increase in the density by 9.2%. It is revealed that the V₂O₃ spherulites growing in the amorphous film have a bent crystal lattice. The bending of the crystal lattice can be as large as ∼42 deg/μm.

     

Tetracyclines Communication 33. Synthesis of 8-chloro-5-methoxy-3,10-dioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene [5-chloro-1,3,4,4a,9a,10-hexahydro-8-methoxy-2,9-anthracenedione]

Summary 8-Chloro-5-methoxy-3,10-dioxo-1,2,3,4,4a,9,9a,10-octahydroanthracene (Ib) was synthesized; this can serve as an intermediary in the preparation of the tetracyclic analog (IIb) of aureomycin,Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 806–810, May, 1965 Original article submitted April 22, 1963For preceding communication see [1],The authors thank L. B. Senyavina for infrared spectrum measurements.     

Olivomycin and related antibiotics

Summary It has been shown that olivomycose has the structure of 3-C-methyl-2, 6-dideoxy-L-arabino-hexose. In olivomycins A and C, this sugar is present in the form of the 4-O-isobutyrate, and in olivomycin B in the form of the 4-O-acetate.Khimiya Prirodnykh Soedinenii, Vol. 3, No. 6, pp. 405–410, 1967For preliminary communication, see [1].     

Synthesis and spatial structure of the geometrical isomers of 4-substituted 1-tert-butyl-3-methyl-piperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines

In order to study the interrelationship between the structure, reactivity, and spectroscopic characteristics of the stereoisomeric piperidines, starting from 1-tert-butyl-3-methylpiperidin-4-one the synthesis has been performed of the geometric isomers of some 4-substituted 1-tert-butyl-3-methylpiperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines. The spatial structures of the compounds obtained have been determined by IR and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1056–1061, August, 1973.     

Synthesis and three-dimensional structures of geometrical isomers of some 4-substitute d 1,2,5-trimethyl-4-acetoxy- and 1,2,5-trimethyl-4-benzoxypiperidines

Stereoisomers of the corresponding 4-substituted 1,2,5-trimethyl-4-acetoxy- and 1,2,5-trimethyl-4-benzoxypiperidines were obtained by acylation of the geometrical isomers of 1,2, 5-trimethyl-4-piperidol and its 4-ethynyl, 4-ethyl, and 4-phenyl-substituted derivatives. The preferred conformations of the investigated esters were elucidated by means of the PMR and IR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No.1, pp. 50–55, January, 1973.     

EPR of magnetically diluted copper bis-[2,3-dichlorobenzene-(1-azo-1')naphthol-2'] monocrystal

Conclusions Noticeable coupling of the unpaired electron spin with the nuclear spins of the nitrogen atoms of the ligand is accomplished only with the two equivalent nitrogen atoms that are attached directly to the copper atom. An increase in the number of lines in the EPR spectra of solutions of copper azo complexes above 5 (up to 7, 8, and 9) is associated with the presence of a poorly resolved structure from the two copper isotopes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2120–2122, September, 1973.     

Zur Erhöhung der Reaktivität von apatitischen Rohphosphaten durch mechanische Aktivierung

Increase in the Reactivity of Apatitic Phosphates due to Mechanical Activation The lattice of natural apatitic phosphates was severely distorted by mechanical activation. At a high energy concentration in a centrifugal mill the crystals reach the X-ray amorphous state. The structural changes are investigated by infrared and X-ray methods. At increased degrees of activation the mechanically activated apatitic phosphates show enhanced solubility as a result of structural changes.     

Oxidation of phenol and chlorophenols on platinized titanium anodes in an acidic medium

A comparative study of oxidation of phenol, 3-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol on Pt/Ti and Ce,Pt/Ti electrocatalysts is performed via cyclic voltammetry. It is shown that the surface morphology and roughness of the anode do not change after modification with cerium. The formal kinetic orders of electrooxidation of all compounds are found to be less than one. It is shown that the β temperature coefficients of the rate of oxidation of chlorophenols grow by 10 to 50% when the Ce,Pt/Ti anode is used at a substrate concentration of 1 mM. A tenfold increase in concentration reduces the effect of cerium additive, except for 3-chlorophenol: the latter exhibits a 250% increase in the β value, compared to the Pt/Ti anode.