Simona Mitu, M. C. Baird
Sep 1, 2006
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0
Influential Citations
27
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Journal
Organometallics
Abstract
Carboxylic acids react with B(C6F5)3 in CH2Cl2 to form 1:1 adducts, which have been characterized by room-temperature IR and low-temperature (−30 °C) 1H, 19F, 13C, and 11B NMR spectroscopy. Coordination appears to occur via the carbonyl oxygen atom, and exchange between an adduct and its components is generally sufficiently slow that 1H, 19F, 13C, and 11B resonances of the adduct are readily distinguished from the 1H and 13C resonances of the corresponding free acid and the 19F and 11B resonances of free B(C6F5)3. The electron-withdrawing power of the highly electrophilic B(C6F5)3 increases the Bronsted acidity of the coordinated carboxylic acids sufficiently that they are able to protonate isobutene and thus initiate its carbocationic polymerization. The enhanced acidity also results in slow, partial cleavage of B−C6F5 bonds, and with benzoic acid the compound [(μ-C6H5CO2)(μ-OH){B(C6F5)2}2] has been isolated and characterized crystallographically. Because of slow B−C6F5 cleavage, crystallographically use...