Decarboxylierung cyclischer und acyclischer dicarboxylato-komplexe des platins

The interaction of (Ph₃P)₂PtO₂ (I) with the dicarboxylic acids HO₂C(CH₂)_nCO₂H (n = 1–3), phthalic acid and maleic acid gives the dicarboxylato complexes (Ph₃P)₂$\text{PtO(O)C(CH}{}_2\text{)}{}_{\mathrm{<mtext>n</mtext>}}\text{C(O)O}$ (II) (n = 1–3), (Ph₃P)₂$\text{PtO(O)CC}{}_6\text{H}{}_4\text{C(O)O}$ (III) and cis-[(Ph₃P)₂Pt(O(O)CCHCHC(O)OH)₂] (IV) in nearly quantitative yield. Thermal and photoinduced decarboxylation of III and IV yields the platina heterocycles (Ph₃P)₂$\text{PtC}{}_6\text{H}{}_4\text{C(O)O}$ (V) and (Ph₃P)₂$\text{PtCHCHC(O)O}$ (VI) with a carbon-platinum σ-bond. Complex VI has been characterized by an X-ray crystal structure determination.     

Hemorrhagic action of the venoms of Central Asian snakes

Collective characteristics of the venoms belonging to various taxons of Central Asian snakes, demonstrating levels of toxicity and efficiency of hemorrhagic action, together with proteolytic, esterase, and phospholipase activities, have been obtained. A comparative analysis of the collective characteristics (“portraits”) of the venoms and their changes on degradative treatment has shown that the hemorrhagic action of the venoms of viperine and crotalid snakes is connected with metalloproteins. In contrast to the venoms of the elapids (cobras) the toxicity of the venoms of the viperine and crotalid snakes exhibits a dependence on the hemmorhagic effect and the activity of the metalloproteins causing it.     

Mannich reaction in the series of 7-hydroxy-3-phenoxychromones and their derivatives

The Mannich condensation of amino acids with 3-phenoxychromones and polyhydroxy-α-phenoxyacetophenones has given a series of 8-carboxyalkylaminomethylchromones and 3-carboxymethylaminomethyl-2,4-dihydroxy-α-phenoxyacetophenones. Some features of the course of the Mannich reaction as a function of the structures of the chromones and acetophenones have been studied. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 475–481, July–August, 1998.     

Predicting discotic mesomorphism from molecular parameters for discogenic structures

Molecular parameters (M_m, M_r, K_p, K, K_c, and K_s) are calculated for polysubstituted cycloveratrilenes and cyclophanes as a continuation of our series of papers on prediction of discotic mesomorphism (DM). Histograms showing the distribution of 57 mesogenic and 28 nonmesogenic structures according to the first three parameters are constructed. Prediction probabilities are estimated at more than 50% for M_m and M_r. This approach is used to analyze 150 hypothetical structures of polysubstituted cycloveratrilenes and cyclophanes to examine the occurrence of a discophase. Several structures with predictable DM are selected for further research. Ivanovo State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 39, No. 3, pp. 473–477, May–June, 1998.     

Formation of furan derivatives in the course of the Stevens rearrangement of ammonium salts containing 4-allyloxy(phenoxy)-2-butynyl group

Ammonium salts containing phenacyl group in combination with 4-allyloxy(phehoxy)-2-butynyl group, when treated with a suspension of potassium hydroxide in benzene, undergo the 3,2-Stevens rearrangement with the formation of allenic amino ketones which under the reaction conditions give the furan derivatives.     

Phosphorus-containing Small Rings: X. Phosphorylation of Derivatives of 1-Methyl-2,2-dichlorocyclopropanecarboxylic Acid

Reaction of derivatives of 1-methyl-2,2-dichlorocyclopropanecarboxylic acid with three- and four-coordinate phosphorus acids was studied. It was established that the nucleophilic substitution on the carbonyl carbon atom proceeds without cleavage of the three-membered ring and leads to new types of phosphorus-containing cyclopropanes. The products were found to enhance the germination energy and laboratory germination of cereal, legume, and vegetable seeds.     

Plasma-Enhanced Chemical Vapor Deposition of Silicon Carbonitride Films from Volatile Silyl Derivatives of 1,1-Dimethylhydrazine

Silicon carbonitride films were synthesized from new volatile precursors by plasma-enhanced chemical vapor deposition. Based on a detailed study of the morphology of film surfaces, it was found that the layer material was an amorphous matrix with inclusions of nanosized crystals. Calculation of the structure of the crystalline phase from synchrotron X-ray diffraction patterns demonstrated that the entire set of the diffraction peaks detected is indexed by a tetragonal structure with the lattice parameters a = 9.6 Å and c = 6.4 Å. This is consistent with the fact that the carbon 1s and nitrogen 1s core level X-ray photoelectron spectra exhibited only sp ³ bonding, which was expected for superhard carbon nitride phases.     

Synthesis of β-Aminophosphonates and Study of Their Acid-Base Properties and Phase Distribution in Water-Organic Solvent Systems

New and previously known β-aminoethylphosphonates were synthesized by addition of primary and secondary amines to vinylphosphonates, and their IR and NMR spectra were examined. Diethyl 2-diethylaminoethylphosphonate and diethyl 2-morpholinoethylphosphonate were found to be stronger bases than the corresponding aminomethylphosphonates, but all these are weaker bases than their precursors, nonphosphorylated amines. Distribution constants of β-aminophosphonates between water and some organic solvents were determined and compared with those of their α-amino homologs.     

Hydrolysis of bis(chloromethyl)phosphonic acid p-nitroanilide in aqueous micellar surfactant solutions

The hydrolysis of bis(chloromethyl)phosphonic acid p-nitroanilide has been studied in the pH range 6.86–13.0 and the effects of ionic surfactant micelles on this process have also been examined. The nature of the micellar effects of cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) on this reaction lead us to conclude that both the neutral and anionic forms of the substrate are reactive, and that in the range of pH > pK_a hydrolysis of the ionic form of the anilide predominates, while at pH < pK_a the reaction of the neutral form is predominant. The binding constants for both the neutral and anionic forms of bis(chloromethyl)phosphonic acid p-nitroanilide in micellar CTAB and SDS solutions have been determined using a kinetic method, as well as by measuring the changes in the acid-base properties of the substrate resulting from the influence of micelles.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1718–1722, August, 1990.     

Catalytic properties of initial and thermosteamed faujasites in n-hexane aromatization

Regularities in n-hexane conversion on decationized Y zeolites under cracking and aromatization conditions have been studied. Possible formation of lower olefins and benzenes in parallel reactions following different mechanisms at low conversion degrees is suggested. The effect of thermosteam treatment on the activity and selectivity of Y zeolites in n-hexane conversion has been examined.

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