Boronate avidity

Although the first report on boronic acids was published in 1862, boronate affinity materials have not been extensively investigated until recently. In recent years, various boronate-functionalized materials, " such as macroporous monoliths, " " nanoparticles, and mesoporous materials, have been developed into important tools for the facile selective extraction of cis-diol-containing compounds. With these matrices, several important materials with teamed boronate affinity and boronate avidity as well as boronate affinity-based molecularly imprinted polymers have been prepared. 

H. Wang, Z. Bie, C. Lu and Z. Liu, Magnetic nanoparticles with den-drimer-assisted boronate avidity for the selective enrichment of trace glycoproteins, Chem. ScL, 2013,4(11), 4298-4303. 

Borane, BH3, having only six valence electrons on boron, is an avid electron pair acceptor. Pure borane exists as a dimer in which two hydrogens bridge the borons. 

Ions besides (P +) which may act as the central coordinating atom to form 12-fold heteropoly acids with molybdate include arsenic (As +), silicon (Si +), germanium (Ge +) and under some conditions molybdenum (Mo +) and boron (B +). Tungstate can also be coordinated about P as central atoms but with less avidity. The heteropolycomplexes, before reduction give a yellow hue to their water solution. With high P concentrations, a yellow precipitate is formed. In solution of low enough concentration to be suitable for determination by reduction to form the blue colour, the yellow colour is so faint that, it is not noticed and spectrophotometric measurements is done without any problem. The molybdenum blue colour is produced when either molybdate or its heteropolycomplexes are partially reduced. Some of the molybdenum ions are reduced from h-6 to a low valence state, probably h-3 and/or h-5, involving unpaired electrons due to which spectrophotometric resonance (blue colouration) would be expected. 

Boron trifluoride is one of the most avid acceptors—that is, strongest Lewis acids-—known, and readily unites with water, ethers, alcohols, amines, phosphines, etc., to form adducts. BF3 is commonly available as its diethyl etherate, (C2H5)26bf3. Because of its potency as a Lewis acid and its greater resistance to hydrolysis compared with BC13 and BBr3, BF3 is widely used to... 

Another, similar, vesicle is the low-density hpoprotein (LDL), which is a major carrier of cholesterol. Cancer cells avidly absorb LDL as a source of cholesterol for their rapidly dividing cells. The LDL can be isolated and their cholesterol core replaced by hydrophobic carboranes. In vitro studies of hamster V-79 cancer cells have shown that such boronated LDLs resulted in intercellular concentrations of 240 (tg B/cell, which is about lOx the amount needed for effective BNCT. The use of drug laden vesicles, such as liposomes or LDLs, also take advantage of a general phenomenon of the enhanced permeability and retention (EPR) effect. ... 

Borane, BH3, is an avid electron pair acceptor because only a sextet of valence electrons is present at boron in the monomeric molecule. The pure material exists as a dimer. In aprotic solvents which act as electron pair donors such as ethers, tertiary amines, and sulfides, diborane forms stable Lewis acid-Lewis base... 

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