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Structure of a rare monomeric boron hydride, R = i-Pr. [4] The most-studied class of organoboron compounds has the formula BR n H 3−n. These compounds are catalysts, reagents, and synthetic intermediates. The trialkyl and triaryl derivatives feature a trigonal-planar boron center that is typically only weakly Lewis acidic.
Triethylborane is strongly pyrophoric, with an autoignition temperature of −20 °C (−4 °F), [13] burning with an apple-green flame characteristic for boron compounds. Thus, it is typically handled and stored using air-free techniques.
The rhodium-catalyzed hydroboration reaction is thought to be initiated with the dissociation of a triphenylphosphine from the Rh(I) centre. Oxidative addition of the B-H bond of the borane reagent to this 14 e − species is then followed by coordination of the alkene to the 16e − Rh(III) hydride complex.
The discovery of an efficient route was a significant technological achievement. The multistep process uses aluminium, hydrogen gas, and ethylene, summarized as follows: [4] 2 Al + 3 H 2 + 6 C 2 H 4 → Al 2 Et 6. Because of this efficient synthesis, triethylaluminium is one of the most available organoaluminium compounds.
Borane makes a strong adduct with triethylamine; using this adduct requires harsher conditions in hydroboration. This can be advantageous for cases such as hydroborating trienes to avoid polymerization. More sterically hindered tertiary and silyl amines can deliver borane to alkenes at room temperature. Borane(5) is the dihydrogen complex of
Ball-and-stick model of the tetrahydroborate anion, [BH 4] −. Borohydride refers to the anion [B H 4] −, which is also called tetrahydridoborate, and its salts. [1] Borohydride or hydroborate is also the term used for compounds containing [BH 4−n X n] −, where n is an integer from 0 to 3, for example cyanoborohydride or cyanotrihydroborate [BH 3 (CN)] − and triethylborohydride or ...
9-Borabicyclo[3.3.1]nonane or 9-BBN is an organoborane compound. This colourless solid is used in organic chemistry as a hydroboration reagent.The compound exists as a hydride-bridged dimer, which easily cleaves in the presence of reducible substrates.
The simplest borirene, (CH) 2 BH, which was prepared via a reaction between an atomic boron atom and ethylene, was first identified using matrix isolation spectroscopy by Lanzisera et al. in 1997, and later confirmed with the crossed molecular beam method by Balucani et al. [12] [13] Substituted borirenes are typically prepared starting from an alkyne, and are prepared through either a ...