Date of Award

8-2008

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Chemistry

Advisor

Pennington, William T

Committee Member

McNeill , Jason

Committee Member

Stuart , Steve

Committee Member

VanDerveer , Don

Abstract

Halogen bonding is the donation of electron density from an electron donor, such as N, O, S, Se atoms, to an electron acceptor such as a dihalogen or organohalogen. This interaction plays an important role in biological systems, such as the thyroid gland and is useful in many other fields such as drug design, crystal engineering, synthetic chemistry, material science and bioinorganic chemistry. However, currently there is a lack of information for this interaction in systems involving organoiodines with sulfur and selenium electron donors.
A variety of sulfur and selenium Lewis base donors were investigated with various organoiodines. The main goal of this research was to better understand how different types of Lewis base donors affected the formation and strength of halogen bonds. This study investigated two classes of sulfur and selenium donors which included; thiones and selenones and tertiary phosphine sulfides and selenides. These donors were used with a variety of organoiodine acceptors which included 1,4-diiodotetrafluorobenzene, tetraiodoethylene, 1,2-diiodotetrafluorobenzene, and iodoform.
Single crystal X-ray diffraction analysis is by far the best method to study these interactions, however single crystals suitable for analysis cannot always be obtained. It has been shown that advanced algorithms such as Monte Carlo and the genetic algorithm can be used to elucidate crystal structures from X-ray powder diffraction data which would be advantageous in investigating halogen bonding.
Our research focused on the application of a program, OCEANA (developed by Dr. C.W. Padgett), to elucidate crystal structures from X-ray powder diffraction data. This program was tested against a variety of organic molecules in different space groups to determine the effectiveness of the program. In addition to this, the crystal structure of bis(5-quinoline) diacetylene was elucidated completely from X-ray powder diffraction data.

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