Water soluble boron

HMSO (1979) Method 8. Boron, water soluble in soil. The Analysis of Agricultural Materials, RB 427, 2nd edn., London. 

The Analysis of Agricultural Materials, 2nd edn, R.B. 427. HMSO, London, (1979) Method 2, p. 6. Preparation of Samples of soil Method 8, p. 21. Boron, water soluble in soil Method 57, p. 134. Nitrogen in soil Method 62, p. 148. Organic matter in soil Method 63, p. 151. Particle size distribution in soil... 

With sodium hydroxide as the base boron of the alkylborane is converted to the water soluble and easily removed sodium salt of boric acid... 

An expedient and stereoselective synthesis of bicyclic ketone 30 exemplifies the utility and elegance of Corey s new catalytic system (see Scheme 8). Reaction of the (R)-tryptophan-derived oxazaboro-lidine 42 (5 mol %), 5-(benzyloxymethyl)-l,3-cyclopentadiene 26, and 2-bromoacrolein (43) at -78 °C in methylene chloride gives, after eight hours, diastereomeric adducts 44 in a yield of 83 % (95 5 exo.endo diastereoselectivity 96 4 enantioselectivity for the exo isomer). After reaction, the /V-tosyltryptophan can be recovered for reuse. The basic premise is that oxazaborolidine 42 induces the Diels-Alder reaction between intermediates 26 and 43 to proceed through a transition state geometry that maximizes attractive donor-acceptor interactions. Coordination of the dienophile at the face of boron that is cis to the 3-indolylmethyl substituent is thus favored.19d f Treatment of the 95 5 mixture of exo/endo diastereo-mers with 5 mol % aqueous AgNC>3 selectively converts the minor, but more reactive, endo aldehyde diastereomer into water-soluble... 

Boron zirconimn chelates from ammonium hydroxide water-soluble amines sodium or potassimn zirconium and organic acid salts such as lactates, citrates, tartrates, glycolates, malates, gluconates, glycerates, and mandelates with polyols such as glycerol, erythritol, arabitol, xylitol, sorbitol, dulcitol, mannitol, inositol, monosaccharides, and disaccharides [463,464,1592,1593]... 

Rhodium-catalyzed Heck-type coupling of boronic acids with activated alkenes was carried out in an aqueous emulsion.82 The couplings between arylboronic acids and activated alkenes catalyzed by a water-soluble tm-butyl amphosrhodium complex were found to progress at room temperature to generate Heck-type products with high yields and excellent selectivity. It was necessary to add two equivalents of the... 

The use of other crosslinking metals developed simultaneously with the use of antimony, chromium, and boron(borate). Tiner, et al.(242) introduced titanium (IV) crosslinkers in 1975 as ammonium tetralactonate or bis(triethanolamine)bis(isopropyl)titanium(IV). Upon contact with water soluble titanium (IV) derivatives ordinarily form orthotitanic acid, Ti(0H)4, which rapidly forms oligimeric metatitanic acid, [Ti(0H)2] and titanium dioxide. Electron donors such as the hydroxyl groupsxof polysaccharides, if properly oriented, can participate in the sequence of titania reactions and a crosslinked gel network results. Various titanium metal crosslinkers remain in common use today. More will be said about titanium crosslinked gels later. 

Precise placement of metal complexing sites within the infrastructure of a cascade molecule is of importance from a variety of perspectives. In the construction of the above noted Micellane family (cf. Sect. 3.1), we reported the construction of dendrimers with four alkyne moieties at sites equidistant from each other in the interior (17, Fig. 8) [60]. These were treated with decaborane (B10H14) to afford 1,2-dicarba-closo-dodecaboranes (o-carboranes) [71]. Rendering boron clusters soluble in water is of interest because of their use in cancer treatment by Boron Neutron Cancer Therapy. First and second generation water-soluble dendrimers containing four and twelve precisely located boron cluster sites, respectively, were synthesized (e.g., 18). These water soluble dendrimers and their precursors were characterized by 13C-, and nB-NMR spectroscopy (Fig. 8). 

Boron complex azo dyes have also been reported. These include solvent soluble boron complexes, such as the red dye (32) used for dyeing polyester and coloring plastics25,26 and water-soluble dyes for the detection of boron (as boric acid) by a color change27 (Scheme 5). 

Fig. 3 Above Spontaneous gelation mechanism between the phenylboronic acid moiety (boronate ion) in water-soluble PMBV and the hydroxyl groups (diol units) in PVA. Below Photoimages of spontaneously forming PMBV/PVA hydrogel, before gelation (left), after gelation...

Spectrophotometric methods have been used to determine water soluble boron in soils. In one method [1] the soil is extracted with boiling water then converted to fluoroborate which is evaluated spectrophotometrically as the methylene blue complex. 

A further spectrophotometric method [3, 4] for water soluble boron in soil, boron is extracted from soil with boiling water. Borate in the extract is converted to fluoroborate by the action of orthophosphoric acid and sodium fluoride. The concentration of fluoroborate is measured spectrophotometrically as the blue complex formed with methylene blue and which is extracted into 1, 2-dichloroethane. Nitrates and nitrites interfere they are removed by reduction with zinc powder and orthophosphoric acid. 

Xue C, Cai F, Liu H (2008) Ultrasensitive fluorescent responses of water-soluble, zwitter-ionic, boronic acid-bearing, regioregular head-to-tail polythiophene to biological species. ChemEur J 14 1648-1653... 

DiCesare N, Pinto MR, Schanze KS, Lakowicz JR (2002) Saccharide detection based on the amplified fluorescence quenching of a water-soluble poly(phenylene ethynylene) by a boronic acid functionalized benzyl viologen derivative. Langmuir 18 7785-7787... 

Yinghuai Z, Peng AT, Carpenter K, Maguire JA, Hosmane NS, Takagaki M (2005) Substituted carborane-appended water-soluble single-wall carbon nanotubes New approach to boron neutron capture therapy drug delivery. J. Am. Chem. Soc. 127 9875-9880. 

Boron rods provide an alternative wood preservative, which is considered safe for people and the environment. They are made of boron compounds that have been subjected to high temperatures to form water-soluble, glassllke rods. These rods are Inserted Into drilled holes In the wood, strategically positioned where decay is most likely the holes are then plugged to keep the rods In place. When the wood becomes wet, boric acid is released, which prevents fungal decay. Boron pastes have a similar effect. Manufacturers of boron rods are seeking to make these rods available for home use. 

Boron deficiency is particularly prevalent in light-textured soils in which water-soluble borates are gradually leached down the soil profile and become unavailable to plants. Heavier, more loamy soils tend to retain more boron because they contain an abundance of compounds, such as humic acids, that can complex boron. Certain crop types have higher boron requirements and benefit most from supplementation. These include soybeans, cotton, peanuts, oil palm, apples, and almonds. 

A similar approach was taken for the synthesis of 45 by Miyaura. " Shaughnessy and Booth synthesized the water-soluble alkylphosphine 46, and found it to provide very active palladium catalysts for the reaction of aryl bromides or chlorides with boronic acids. The more sterically demanding ligand 47 was shown to promote the reactions of aryl chlorides with better results than 46. Najera and co-workers recently reported on the synthesis of di(2-pyridyl)-methylamine-palladium dichloride complexes 48a and 48b, and their use in the coupling of a variety of electrophiles (aryl bromides or chlorides, allyl chlorides, acetates or carbonates) with alkyl- or arylboronic acids very low catalyst loadings at Palladium-oxime catalysts 8a and 8b) have also been developed. In conjunction with... 

Boron exists in several forms in the soil (USEPA 1975) in soil solntion, it exists largely as the undissociated weak monobasic acid that accepts hydroxyl gronps (Gnpta and Macleod 1982). Most plant-available boron in soils is associated with soil organic matter (Gnpta and Macleod 1982), with the hot-water soluble boron fraction (Hingston 1986), and with soil solntion pH ranges of... 

Based on the excellent solubility and reducing properties of amine boranes, they are often used for the stabilization and purification of industrial materials. Further, they are applied as additives in hydrocarbon fuels and in lubricating oils, as polymerization catalysts, as ingredients in photographic processing and in the electroplating industry.169 High stability towards hydrolysis and oxidation makes cationic boron chelates useful as water-soluble dyes.170... 

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