Synthesis of tetramethylammonium phenyltrialkylborate salts by the addition of alkyllithium reagents to a triorganylborane or organoboranylhalides

Several new tetraorganylborate salts have been synthesized by the addition of alkyl or phenyllithium reagents to a triorganylborane or organoboranylhalides. The chemical structure of the borates was confirmed by 1H, 13C NMR and IR spectroscopic measurements and elemental analysis. Solubility, spectroscopic and electrochemical properties of these salts have been investigated as well. The structures of the phenyltrialkylborates were varied systematically to control their oxidation potential. These compounds are the trimethyl-, triethyl-, n-tributyl- and sec-tributylborate derivatives and form a series of substituted phenyltrialkylborates containing either electron-withdrawing or electron-donating substituents in the para position of phenyl ring. The oxidation potential of these borates has been found to be a function of Hammett constant.

Graphical abstractThe products of reactions of alkyl or phenyllithium reagents with triorganylborane or organoboranylhalides were studied by NMR, IR spectroscopy and elemental analysis. Solubility, spectroscopic and electrochemical properties of these phenyltrialkylborate salts were investigated as well.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Dichlorophenylborane reacts with alkyllithium giving phenyltrialkylborate salts. ► Addition of alkyl or phenyllithium to triorganylborane gives phenyltrialkylborates. ► Chemical structure of the borates was confirmed. ► Oxidation potential of these borates is a function of Hammett constant.