Derivatives of Dodecahalo-Closo-Dodecaborate Di-Anion
- Author(s): Avelar, Amy Cindy
- Advisor(s): Reed, Christopher A
- et al.
ABSTRACT OF THE DISSERTATION
Derivatives of the Dodecahalo-Closo-Dodecaborate Di-Anion
Doctor of Philosophy, Graduate Program in Chemistry
University of California, Riverside, December 2009
Dr. Christopher A. Reed, Chairperson
The di-anion, dodecahalo-closo-dodecaborate, B12X122-, where the X = Cl or Br, has been determined to be a useful weakly coordinating anion, WCA. Despite the di- negative charge, several elusive and reactive cationic species were stabilized with B12X122- as the counterion. Of particular interest was the synthesis of the di-protic acid, H2(B12X12),1 H2(B12X12) is the di-protic analogue to the recently developed strongest isolable mono-protic Brønsted acid, H(CHB11Cl11).2 The basicity of the di-anion, B12Cl122-, was shown to be surprisingly similar to basicity of the carborane anion, CHB11Cl111-, based on the ν N-H anion basicity scale.3
The methodology used to synthesize the carborane acids was modified in order to successfully synthesize the di-protic acids, H2(B12X12). Several of the precursors to the acids are new compounds, and the precursors display remarkably similar properties as the analogous carborane compounds. The di-protic acids themselves are superacids due to their ability to protonate arenes, such as benzene and toluene.1 Also investigated was the stabilization of elusive di-cations with B12X122- counterions, and preliminary data are discussed in Chapter 6, including future work.
1. "Superacidity of Boron Acids H2(B12X12) (X= Cl, Br)" Avelar, A.; Tham, F.S.; Reed, C.A. Angew. Chem. 2009, 121, 3543-3545.(Angew Chem., Int. Ed. 2009, 48, 3491- 3493.)
2. "The Strongest Isolable Acid," Juhasz, M.; Hoffmann, S.; Stoyanov, E.; Kim, K.-C.; Reed, C.A. Angew. Chem. Int. Ed. 2004, 43, 5352-5255.
3. "An Infrared ν NH Scale for weakly basic anions. Implications for Single-Molecule Acidity and Superacidity," Stoyanov, E.S.; Kim, K.-C.; Reed, C.A. J. Am. Chem. Soc. 2006, 128, 8500-8508.