Water-Soluble Polymers and Their Polymer-Metal Ion-Complexes as Antibacterial Agents

Summary: Natural and synthetic polymers with heteroatom, such as oxygen, nitrogen, sulfur or phosphorous, potentially can efficiently remove metal ions from aqueous solutions. The ability of synthetic polymers derived from imino diacetic acid, acrylamido glycolic copolymer, and the natural polymer alginic acid to remove metal ions from dilute solution in conjunction with ultrafiltration membranes was studied. The maximum retention capacity was determined and its polymer-metal ion-complexes were studied as possible antibacterial agents.     

Oxidation of aliphatic alcohols with the lead tetraacetate—metal halide system under mechanical activation

The mechanochemical oxidation ofn-pentanol,n-hexanol, andn-octanol with the Pb(OAc)₄-MHal system (M=Li, K; Hal=Cl, Br) in the absence of a solvent affords esters. and secondary alcohols with the composition C₈H₁₇OH and C₉H₁₉OH give ketones. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1870–1873, November, 2000.     

Rhodium-Catalyzed Amination of Aromatic Olefins [1]

Summary.  The oxidative amination of styrene with secondary amines in the presence of cationic rhodium catalysts yields regiospecifically the corresponding anti-Markovnikov enamines. Styrene as the hydrogen acceptor gave concomitantly ethylbenzene. In the presence of 1,5-cyclooctadiene (cod) preferential reduction to cyclooctene takes place. The addition of cod reduces the rate of the reaction, but also the amount of ethylbenzene produced. Here, for the first time the ratio of enamine: ethylbenzene is > 1, which is favourable in case of more expensive styrene derivatives. A screening of various ligands for oxidative amination reveals that hemilabile 2-(ω-phosphino-n-alkyl)-pyridines are superior ligands for this reaction compared to simple alkyl and aryl phosphines. Received May 30, 2000. Accepted July 11, 2000     

Specific features of the interaction of components in the DMSO−HBr−Pd0 system

The products of interaction of components in the donor-acceptor electron-transport (DAET) DMSO−HBr system and their complex formation with the metallic palladium surface were studied. H₂O and Me₂S (main reaction products) and CO, CS₂, C₂H₆, MeBr, H, and CH₄ (minor reaction products) were found in the gas phase by mass spectrometry (MS). The samples of metallic palladium treated with the DAET system with a components ratio corresponding to the minimum and maximum rates of metal dissolution were studied by the methods of thermoprogrammed desorption with MS detection (TPD-MS) and XPS. According to the TPD-MS data, two forms of Me₂S are present on the metal surface, whereas the XPS method detected two complexes with the molecular compositions Pd^IIBr₄S_1.26 and Pd^IIBr_3.86S_1.42. The addition of an aqueous solution of NaOH to the system results in the formation of HCOONa, which indicates that compounds (CH₂O, HCOOH) capable of reducing the palladium complexes are present in the DAET system. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1740–1743, October, 2000.     

Synthesis of Polymer-Bonded Quaternary Ammonium Type Metal Porphyrins

Synthetic metalloporphyrin are efficient models of the cytochrome P-450 family ofmono-oxygen enzymes and have been largely used as catalysts in oxidation of alkanesand epoxidation of alkenesl. Polymer-bonded metalloporphyrin reveal many advantageson the catalytic reaction, where the catalysts can be easily separated from the products,recovered, and reused2. Quaternary ammonium salts as phase transfer catalysts werewide used in aqueous-organic two-phase conditions. Unfortunately, most porphyrin…     

Si-O and P-O motifs in inorganic rings and clusters

This article presents a brief overview of different kinds of silanols and the important reactions of N-bonded silanetriols. The synthesis and characterization of silanediols containing Si-N and Si-C bonds, (2,4,6-Me₃C₆H₂)N(SiMe₃)Si(Me)(OH)₂ (1e) is described. 1e shows a polymeric crinkled tape type of structure due to extensive intermolecular hydrogen bonding. We also describe the formation of a neutral copper(II) complex derived from the reaction of CuCl₂ with (O)P(3,5-Me₂Pz)₃ where the ligand undergoes a facile P-N bond cleavage and functions as an N₂O type of tridentate ligand.     

Acidity and Catalytic Activity of Sulfate Modified Mixed Oxides of Tin and Praseodymium

A comparitive study of the acid-base properties and physico-chemical characteristics of pure SnO₂, sulfated SnO₂ and sulfated binary oxides of Sn and Pr was done. The data were correlated with the catalytic activity of the oxides towards benzoylation of toluene.