Honors Theses

Date of Award

2014

Document Type

Undergraduate Thesis

Department

Chemistry and Biochemistry

First Advisor

Gregory Tschumper

Relational Format

Dissertation/Thesis

Abstract

This study focuses on boron tetrahalides of the form BFXClY, where X + Y = 4, using the B3LYP, M06-2X, and MP2 methods with the aug-cc-pVTZ basis set. The various neutral and anionic species were constructed and optimized using the Gaussian 09 software package, and the equilibrium geometries, harmonic vibrational frequencies, and energetics (specifically the electron affinity, vertical attachment and detachment energies, and stability with respect to dissociation) of each system are presented. The anionic species, due to their closed-shell electron configurations, have relatively high symmetry: Td for BF4- and BCl4-, C3v for BF3Cl- and BFCl3-, and C2v for BF2Cl2-. The symmetries of the open-shell neutral species, which consist of two isomers (one featuring a non-covalent interaction between the boron and the fourth halogen and one marked by completely covalent bonds) are lower: including C1, Cs, and C2v. B—F and B—Cl covalent bond distances range between 1.30 to 1.45 Å and 1.70 to 2.00 Å, respectively, while the non-covalent B!!!Cl bond distances range between 2.9 and 4.0 Å. All neutral van der Waals isomers are metastable with respect to dissociation, and covalent isomers are less stable, or unstable in the case of BF4. The electron affinities and vertical attachment energies generally increase with increasing number of chlorine atoms, after an initial decrease between BF4 and BF3Cl, while the vertical detachment energies generally decrease with increasing number of chlorine atoms, with a dramatic increase at BCl4.

Accessibility Status

Searchable text

Included in

Chemistry Commons

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.