Syntheses of highly lipophilic and stable organic anions of poly-fluoroalkyl-substituted tetraphenylboron ate-complex tipe.

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The present research project is to investigate the formation of bulky and lipophilic stable tetraarylborate ions substituted by many polyfluoroalkyl groups, their solubilities in a range of hydrophobic solvents, and chemical stabilities under acid conditions. Research results are as follows : 1) Convenient methods were developed for the preparation of perfluoro- and polyfluoro-alkyl-substituted iodobenzenes which were useful as precursors for the corresponding tetraarylborates. 2) Efficient Grigrlard reaction methods were developed for the formation of tetraarylborate-s substituted by 3-perfluoroalkyl, 3, 5-bis (polyfluoroalkyl), and 3-trifluoromethyl-5-polyfluoroalkyl on each phenyl group. 3) Introduction of branched polyfluoroalkyl substituents with an increased number of terminal trifluoromethyl groups enhanced the solubilities of tetramethylammonium tetraarylborates in polyhalomethane solvents, especially effective in polyfluorocarbon solvents. Straight-chained perfluoroalkyl substituents seemed to depress the solubility. 4) Chemical stabilities measured in dichloromethane/sulfuric acid two-phases and in methanolic sulfuric acid solutions were in accordance with the electron-withdrawing effect of substituents, among which. trifluoromethyl groups was most effective as presumed. 5) Counter lithium ion, which was dried at higher temperature under high vacuum, was most electrophilic in dichloromethane to accelerate the Diels-Alder reaction and to affect the exo/endo selectivity of the adducts.