Changes in the State of Silver Sol Particles after Low-Temperature Treatments

The influence of the low-temperature treatment of Ag hydrosol on the properties of silver particles was studied by electron absorption spectroscopy over the temperature range 77–230 K. Low-temperature treatment caused the aggregation of particles because of an increase in the number of defects on the surface of Ag observed as an increase in the damping coefficient of electron plasma oscillations. These processes depended on the temperature and initial concentration of disperse silver. Defect formation is explained taking into account the tunnel mechanism of the interaction of low-atomic mobile H⁺(H₂O) _n and OH⁻(H₂O) _n clusters with the surface of silver particles at low temperatures. Original Russian Text ? E.A. Kononova, I.I. Mikhalenko, V.D. Yagodovskii, 2008, published in Zhurnal Fizicheskoi Khimii, 2008, Vol. 82, No. 4, pp. 774–779.     

Imines of α-(Thiophosphoryl)Thioketones in the Synthesis of Thiophosphorylamidovinylsulfides

Abstract

It was found that N-phenylimine of a-dithiophosphorylace-tophenone in the presence of bases undergoes the isomer-isation into the corresponding thiophosphorylamidovinil-sulphides.     

Effect of low-temperature treatment on the state of gold hydrosol particles

A shift of the Plasmon absorption spectrum into the long-wave region, which increases with decreasing temperature and increasing duration of low-temperature treatment (LTT), was revealed after LTT at 217–77 K of Au hydrosol with a particle size of 10–11 nm. It was demonstrated that a decrease in the effective concentration of conduction electrons (N _e) after LTT is accompanied by an alteration in the damping coefficient of plasma resonance oscillations (γ) and the volume fraction of Au particles (N _V ). The temperature dependences of γ and N _V , just as for silver sol, are stipulated by the tunnel mechanism of the formation of low-temperature defects in the presence of two-dimensionally mobile positively charged aqua complexes X⁺(H₂O) _n . A feature of Au sol was revealed: the maximum on dependences of γ and N _V on the duration of LTT and the linear γ-N _e correlation.     

Aromatic polysulfone imides and membranes based on them

Aromatic polyimides containing diphenyl sulfone fragments in the backbone were prepared. Asymmetric microporous films of the synthesized polymers were prepared by wet forming under the conditions of a phase-inversion process. The morphologies and the mechanical and transport properties of nonporous and phase-inversion films as materials for pervaporation membranes were studied. Multilayer composite membranes with diffusion layers of an aromatic polyether imide were prepared on the basis of microporous polyamido imide films. These membranes showed high performance in pervaporation separation of ethanol-cyclohexane mixtures of various compositions.     

Boronated protohaemins: synthesis and in vivo antitumour efficacy

The conjugates of porphyrin macrocycles with boron-containing polyhedra are under investigation as agents for binary treatment strategies of cancer. Aiming at the design of photoactive compounds with low-to-zero dark toxicity, we synthesized a series of carboranyl and monocarbon-carboranyl derivatives of protohaemin IX using the activation of porphyrin carboxylic groups with di-tert-butyl pyrocarbonate or pivaloyl chloride. The water-soluble 1,3,5,8-tetramethyl-2,4-divinyl-6(7)-[2'-(closo-monocarbon-carborane-1'-yl)methoxycarbonylethyl]-7(6)-(2'-carboxyethyl)porphyrin Fe(III) (compound 9) exerted no discernible cytotoxicity for cultured mammalian cells, nor did it cause general toxicity in rats. Importantly, 9 demonstrated dose-dependent activity as a phototoxin in photodynamic therapy of M-1 sarcoma-bearing rats. In animals injected with 20 mg kg(-1) of 9, the tumours shrank by day 3 after one single irradiation of the tumour with red laser light. Between 7 and 14 days post-irradiation, 88.9% of rats were tumour-free; no recurrence of the disease was detectable within at least 90 days. Protohaemin IX alone was without effect, indicating that boronation is important for the phototoxic activity of 9. This is the first study that presents the synthesis and preclinical in vivo efficacy of boronated derivatives of protohaemin as phototoxins. The applicability in photodynamic treatment broadens the therapeutic potential of boronated porphyrins beyond their conventional role as radiosensitizers in boron neutron capture therapy.     

Carbolines. 14. Synthesis of 5-azaellipticine

3-Acetyl-4-methylaminopyridine was obtained by cyanation of 3-acetylpyridine ethyleneketal N-oxide and subsequent chemical transformations of the nitrile group. Condensation of this product with oxindole led to the synthesis of 5H-5,11-dimethylindolo [3,2-j]-1,4-naphthyridine — the aza analog of the alkaloid ellipticine.See [1] for communication 13.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1211–1214, September, 1982.     

Interaction between carbon dioxide and magnesium oxide prepared by low-temperature thermal decomposition of magnesium hydroxide and carbonate

The interaction of CO₂ with MgO has been studied. The reaction mechanism is discussed with special attention to the important catalytic role of the surface hydroxy groups of the active oxide.

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CO₂ MgO. , .

     

Researches on quinones

When anthra[1,2,5]oxadiazole-6, 11-dione reacts with sodium bisulfite, the sulfonic group enters at position 4 in the ring, giving 6, 11-dihydroxyanthra[1,2-c][1,2,5]oxadiazole-4-sulfonic acid. The latter compound is also formed by treating with bisulfite anthra[1,2-c]-[1,2,5]oxadiazole-6, 11-dione-5-sulfonic acid, obviously initially converted to the 4-sulfonic acid by addition-elimination of a molecule of bisulfite. The formation of sulfuric monoester observed in the course of the work in the reaction of quinone with bisulfite, is an example of an addition of a type unusual for carbonyl compounds, where a nucleophilic reagent, the sulfite ion, adds to carbonyl oxygen.For Part II see [1].     

Vibrational spectra and structure of cesium salts of icosahedral monocarba-closo-dodecarborate anion, [CB11H12]–, and its nido-derivative, [CB100H13]–

The Raman and IR spectra of the cesium salts of monocarbon carboranes, [closo-CB₁₁H₁₂]^– and [nido-CB₁₀H₁₃]^–, are reported and the assignment of the normal modes is given. Quantum-chemical calculations of the geometry of undistorted closo-anions B₁₂H₁₂ ^2– and CB₁₁H₁₂ ^– were carried out and normal coordinate analysis for the latter was performed. Structural parameters and spectral characteristics of isoelectronic closo-polyhedra [B₁₂H₁₂]^2–, [CB₁₁H₁₂]^–, and p-C₂B₁₀H₁₂ and those of the closo- and nido-structures were compared.