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Squeezing Fluoride out of Water with a Neutral Bidentate Antimony(V) Lewis Acid
Author(s) -
Hirai Masato,
Gabbaï François P.
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201410085
Subject(s) - fluoride , lewis acids and bases , chemistry , denticity , antimony , adduct , inorganic chemistry , titration , chelation , aqueous solution , stability constants of complexes , medicinal chemistry , crystallography , crystal structure , organic chemistry , catalysis
Because of hydration, fluoride ions in water typically elude complexation by neutral Lewis acids. Here, we show how this limitation can be overcome with a bidentate Lewis acid containing two antimony(V) centers. This derivative ( 2 ) is obtained by the simple reaction of 4,5‐bis(diphenylstibino)‐9,9‐dimethylxanthene ( 1 ) with two equivalents of 3,4,5,6‐tetrachlorobenzoquinone (o‐chloranil). It features two square‐pyramidal stiborane units oriented in a face‐to‐face fashion. Titration experiments show that this new bidentate Lewis acid binds fluoride in aqueous solutions containing 95 % water with a binding constant (K) of 700±30 M −1 . The structure of the fluoride adduct confirms fluoride anion chelation between the two antimony centers.