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Acceptor strength of co-ordinated boron halides

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Item Summary

Title: Acceptor strength of co-ordinated boron halides
Authors: Ronan, Richard Joseph
Keywords: Boron compounds
Halides
Issue Date: 1970
Publisher: [Honolulu]
Abstract: The Bronsted and Lewis basicity of R2NBX3- (where R=H, CH3 and X=Cl, F) has been measured using aqueous, non-aqueous, and tensimetric titrations of R2NBX3- or R2HNBX3. Neither (CH3)2HNBF3 nor (CH3)2NBF3- could be successfully titrated in aqueous solution implying a pK for both compounds of about 7. H3NBF3 , CH3H2NBF3 , and (CH3)2HNBF3 could be titrated in pyridine. The experimental half neutralization potentials of 172 mv, 133 mv, and 189 mv respectively demonstrate that the acidity of the amine-BF3 complexes go through a minimum at CH3H2NBF3. This behavior has been rationalized by analogy to the methylammonium ions whose acidity goes through a minimum at (CH3)2NH2+. The methylamine-BH3 complexes could not be titrated in pyridine demonstrating that they are much weaker acids than the corresponding BF3 complexes. Low temperature tensimetric titrations of (CH3)2NBF3- and (CH3)2NBCl3- using as reference acid BF3 indicate that a weak complex, (CH3)2N(BF3)2-, forms while (CH3)2N(BC13)(BF3) cannot be observed. Thus, (CH3)2NBF3- is a stronger Lewis base than is (CH3)2NBC13-. These data have been interpreted to imply that the relative acceptor strengths of the BX3 groups BH3
Description: Typescript.
Thesis (Ph. D.)--University of Hawaii, 1970.
Bibliography: leaves [112]-116.
x, 116 l illus., tables
URI/DOI: http://hdl.handle.net/10125/11416
Rights: All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections:Ph.D. - Chemistry



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