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Selective two-electron reductive defluorination of 1-Me-CB(11)F(11-) and related anions: synthesis and characterization of salts of 1-Me-12-R-CB(11)F(10-) and related anions

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dc.contributor.authorKobayashi, Yoshihiro, author
dc.contributor.authorStrauss, Steven H., advisor
dc.date.accessioned2024-03-13T19:53:56Z
dc.date.available2024-03-13T19:53:56Z
dc.date.issued2008
dc.description.abstractIn this dissertation, a method to selectively defluorinate and functionalize the antipodal B-F bond in 1-R-CB11F11-anion is described. The defluorination reaction mechanism using sodium naphthalenide to form an intermediate anion was investigated by 19F{ 11B} NMR, cyclic voltammetry, and computational analysis. The stoichiometric amount of sodium naphthalenide to reduce 1-Me-CB11F11 - was determined to be two. 19F{11B} NMR of the intermediate did not show a peak due to the antipodal fluorine atom, which suggested that the B-F bond is broken. Cyclic voltammetry of 1-Me-CB 11F11- showed a reversible one-electron reduction. In presence of excess Na+, the reduction occurred as an irreversible two-electron process, but at the same potential as the one-electron process. The addition of excess 18-crown-6 restored the reversible one-electron process. This suggested that Na+ is probably incorporated in the structure of the intermediate. Based on these results, two structures were proposed, one with B···F···Na+ linkage the other with B···Na+···F - linkage at the antipodal position. The intermediate did not show electron-exchange between the intermediate and the starting material, 1-Me-CB 11F11-. This suggested that the structure with B···F···Na+ is unlikely. Computational analysis of the proposed structures predicted that the latter structure is 55 kJ/mol more stable than the former. From these results, the structure of the intermediate was suggested to be (1-Me-CB 11F11···Na+···F -)2-. Using various electrophiles, several derivatives of 1-Me-12-R-CB 11F10-. For example, when methyl iodide was added to the intermediate solution, the major product was 1,12-Me2-CB 11F10-. An isomer, 1-Me-7-X-CB11F 10- was formed as one of the byproducts, however, the isomeric ratio of the 12-isomer and the 7-isomer was 9:1. X-ray crystal structures of four new compounds NMe4(1,12-Me 2-CB11F10), Cs(1-Me-12-I-CB11 F10), Cs(1-Me-12-SiPh3-CB11F10), and Ag2(1-Me-12-SiPh3-CB11F 10)2·C6H6 were obtained. The characteristics of each structure are described. One of them, Ag2(1-Me-12-SiPh 3-CB11F10)2·C6H 6, contained two Ag+ with different coordination spheres. One of them was the first example of tetrahediral Ag(arene)4 +. In order to investigate the effect of substitution on the B12 vertex of 1-Me-CB11F11- on the coordinating and ion-pairing abilities of the anions, DFT calculations were performed with 1-Me-CB11F11-, 1,12-Me2-CB 11F10-, and 1-Me-12-H-CB11F 10-. The calculations predicted that both 1,12-Me 2-CB11F10- and 1-Me-12-H-CB 11F10- had slightly less ion-pairing ability than 1-Me-CB11F11-. Especially, significant change was observed on the B 12-X direction on the ion-pairing ability. The solution conductivities of N(n-Bu)4(1-Me-CB 11F11) and N(n-Bu)4(1,12-Me 2-CB11F10) also showed that N(n-Bu) 4(1,12-Me2-CB11F10) is 16% more conductive than N(n-Bu)4(1-Me-CB11F11). The DFT-predicted relative energies of the 12-, 7-, and 2-isomers of Fe(Cp)(CO) 2(1-Me-CB11F11), Fe(Cp)(CO)2(1,12-Me 2-CB11F10), and Fe(Cp)(CO)2(1-Me-12-H-CB 11F10) were also calculated. For Fe(Cp)(CO)2(1-Me-CB 11F10), the 12-isomer was predicted to be the most stable. This suggests that the B12-vertex is the most strongly coordinating. For Fe(Cp)(CO) 2(1,12-Me2CB11F10), the strongest coordinating site is on the B7-F7 direction, however, the difference between the 12- and 7-isomers was only 1.8 kJ/mol. For Fe(Cp)(CO)2(1-Me-12-H-CB 11F10), 12-isomer was the most stable, and 7- and 2- isomers were predicted to have much higher energies than the 12-isomer.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierETDF_Kobayashi_2008_3321288.pdf
dc.identifier.urihttps://hdl.handle.net/10217/237826
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.rights.licensePer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.
dc.subjectcarboranes
dc.subjectdefluorination
dc.subjectsodium naphthalenide
dc.subjecttwo-electron reduction
dc.subjectweakly coordinating anions
dc.subjectinorganic chemistry
dc.titleSelective two-electron reductive defluorination of 1-Me-CB(11)F(11-) and related anions: synthesis and characterization of salts of 1-Me-12-R-CB(11)F(10-) and related anions
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineChemistry
thesis.degree.grantorColorado State University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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