نتایج جستجو برای: boron compounds
تعداد نتایج: 243622 فیلتر نتایج به سال:
The organo-boron species formed from the reactions of boron atoms with acetylene in solid neon are investigated using matrix isolation infrared spectroscopy with isotopic substitutions as well as quantum chemical calculations. Besides the previously reported single C-H bond activation species, a cyclic-HBC2BH diboron species is formed via double C-H bond activation of acetylene. It is character...
Plasmids determining resistance to arsenic, mercury, silver, and tellurium compounds in Escherichia coli and Pseudomonas aeruginosa were tested for resistance to 40 other metal compounds. Resistance to trivalent boron and hexavalent chromium compounds was a property of certain P. aeruginosa plasmids.
Boron is an interesting element with unusual polymorphism. While three-dimensional (3D) structural motifs are prevalent in bulk boron, atomic boron clusters are found to have planar or quasi-planar structures, stabilized by localized two-center-two-electron (2c-2e) σ bonds on the periphery and delocalized multicenter-two-electron (nc-2e) bonds in both σ and π frameworks. Electron delocalization...
In the course of attempts to find water-soluble derivatives of riboflavin, a study was made of the complexes formed between riboflavin and compounds of boron. The discovery was made that when proper pH control is exercised stable solutions of riboflavin-boron complex can be prepared of at least 25 times the natural solubility of riboflavin; i.e., a concentration of about 0.3 per cent as against...
This review is an attempt to bring together the data from literature on synthesis and properties of icosahedral carborane derivatives, in which exo-polyhedral three- four-coordinated boron substituents are attached directly cage through boron–carbon or boron–boron bonds. Various classes compounds considered, including carboranyl aryl boranes, boronic acids their boroles, diazaboroles, etc. Part...
The oral toxicity of boron compounds to the Argentine ant, Linepithema humile (Mayr), was evaluated in laboratory tests. The ants were provided 25% sucrose water containing 0.5 and 1% boric acid, disodium octaborate tetrahydrate, and borax. Lethal times of these solutions were a function of the concentration of boron. In field tests, the ants showed no discrimination between disodium octaborate...
The present communication reports the chemistry of three linear triborane(5) compounds possessing bulky diamino substituents on the terminal boron atoms. Fluorotriborane 2 was synthesized by a reaction of boryllithium and BF(3)·OEt(2). Halogen exchange reaction of 2 took place by a treatment with ClSiMe(3) to give the corresponding chlorotriborane(5) 3. Addition of silver tetraarylborate to 3 i...
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