UNLV Theses, Dissertations, Professional Papers, and Capstones
5-1-2013
Strategic Electronic Property Control of Self-Assembling Pyrazine-
Acenes
Lacie Brownell
University of Nevada, Las Vegas
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Repository Citation
Brownell, Lacie, "Strategic Electronic Property Control of Self-Assembling Pyrazine-Acenes" (2013). UNLV
Theses, Dissertations, Professional Papers, and Capstones. 1807.
http://dx.doi.org/10.34917/4478203
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,STRATEGIC ELECTRONIC PROPERTY CONTROL OF SELF-
ASSEMBLYING PYRAZINE-ACENES
by
Lacie V. Brownell
Bachelor of Science in Biochemistry
University of Nevada, Las Vegas
2008
A thesis submitted in partial fulfillment
of the requirement for the
Master of Science in Chemistry
Department of Chemistry
College of Sciences
The Graduate College
University of Nevada, Las Vegas
May 2013
,THE GRADUATE COLLEGE
We recommend the thesis prepared under our supervision by
Lacie Brownell
entitled
Strategic Electronic Property Control of Self-Assemblying Pyrazine-Acenes
be accepted in partial fulfillment of the requirements for the degree of
Master of Science in Chemistry
Department of Chemistry
Dong-Chan Lee, Ph.D., Committee Chair
David Hatchett, Ph.D., Committee Member
Kathleen Robins, Ph.D., Committee Member
Monika Neda, Ph.D., Graduate College Representative
Tom Piechota, Ph.D., Interim Vice President for Research &
Dean of the Graduate College
May 2013
ii
, ABSTRACT
Strategic Electronic Property Control of Self-Assembling Pyrazine-Acenes
by
Lacie V. Brownell
Dr. Dong-Chan Lee, Exam Committee Chair
Associate Professor of Chemistry
University of Nevada- Las Vegas
Control of electronic properties in organic semiconductor materials is essential for
electro-optical applications such as field-effect transistors, light-emitting diodes, and
photovoltaic devices. This work is focused on two systems that highlight different
approaches for the manipulation of electronic properties: (I) the development of electron-
deficient (n-type) materials by selective lowering of ELUMO and (II) low energy gap
materials by controlling both ELUMO and EHOMO.
To specifically lower ELUMO, a pyrazine-acene π-platform was extended using
electron-withdrawing moieties. These include: pyridine, pyrazine, and benzothiadiazole
(system I). From the base pyrazine-acene, the most significant change in ELUMO of 0.83
eV was observed with benzothiadiazole π-extender, while pyridine and pyrazine lowered
ELUMO by 0.15 eV and 0.42 eV, respectively. EHOMO was relatively unaffected by these π-
extenders.
The mechanism for ELUMO control in this system was illustrated by theoretical
evaluation. We found that the LUMO orbital localized on the more electron deficient
part of the pyrazine-acene including the π-extenders, while the HOMO orbital localized
on the more electron rich portion, away from the π-extenders. This enabled us to achieve
specific control of ELUMO depending on the type of π-extenders.
iii
