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Tetrahydroxydiboron
Tetrahydroxydiboron is a chemical reagent which can be used to prepare boronic acids. Synthesis The reaction of boron trichloride with alcohol (chemistry), alcohols was reported in 1931, and was used to prepare dimethoxyboron chloride, B(OCH3)2Cl. Egon Wiberg and Wilhelm Ruschmann used it to prepare tetrahydroxydiboron by first introducing the boron–boron bond by redox, reduction with sodium and then hydrolysis, hydrolysing the resulting tetramethoxydiboron, B2(OCH3)4, to produce what they termed sub-boric acid. The methanol used in this process can be recycled: ::BCl3 ->[\text \ce][- \text \ce] B(OCH3)2Cl ->[\text \ce][- \text \ce] B2(OCH3)4 ->[\text \ce][- \text \ce] B2(OH)4 Overall: 2 boron trichloride, BCl3 + 2 sodium, Na + 4 water, H2O → B2(OH)4 + 2 sodium chloride, NaCl + 4 hydrochloric acid, HCl Reactions When heated to over 90 °C, tetrahydrox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boronic Acid
A boronic acid is an organic compound related to boric acid () in which one of the three hydroxyl groups () is replaced by an alkyl or aryl group (represented by R in the general formula ). As a compound containing a carbon–boron bond, members of this class thus belong to the larger class of organoboranes. Boronic acids act as Lewis acids. Their unique feature is that they are capable of forming reversible covalent complexes with sugars, amino acids, hydroxamic acids, etc. (molecules with vicinal, (1,2) or occasionally (1,3) substituted Lewis base donors (alcohol, amine, carboxylate)). The p''K''a of a boronic acid is ~9, but they can form tetrahedral boronate complexes with p''K''a ~7. They are occasionally used in the area of molecular recognition to bind to saccharides for fluorescent detection or selective transport of saccharides across membranes. Boronic acids are used extensively in organic chemistry as chemical building blocks and intermediates predominantly in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
