Dr. Kraig Wheeler, Department of Chemistry

Uploaded by catsEIU on 19.05.2011

[no dialogue].
Hi, my name is Kraig Wheeler, I'm an Associate Professor
in the Department of Chemistry, one of fifteen faculty
passionate about quality instruction, and engaging
students in meaningful research.
The research interests of this dedicated group span
a variety of areas, such as microfluidics, dynamics
of biological systems, environmental remediation,
surface absorption studies, and supramolecular chemistry.
The latter topic is related to chemical systems with function
created by the engineered alignment of molecules.
My research interests over the last two decades have focused
on the areas of crystal engineering,
and supramolecular chemistry.
The general principles that govern these science areas
center on organizing molecules in a predictable manner.
Becaues the property of a material is intimately connected
to the alignment of the building blocks, that is molecules
and atoms, advances in this area continue to make
important contributions to the development of
functional materials with optical properties, drug
discovery, and other materials of technological value.
During the first part of my career, student-led research
projects have centerd on exploring the factors
responsible for organizing molecules in materials.
While there are many types of materials to investigate,
crystalin materials have been a common thread
in our research investigations.
Crystals offer an important framework
in which to study materials.
Unlike other solids, crystalin solids are composed of
two-dimensional, and three-dimensional
rays of molecules or atoms.
And it's this organizational and periodic property
that lends itself for study.
Directing an X-ray beam at a crystal
produces X-ray defraction.
That, when assessed properly, gives us a clear picture
of the crystalin components, and their orientation.
This is a hugely powerful tool for
making important connections between
the property of the material, and material structure.
One can imagaine that, if you were interested in developing,
let's say, a better magnet, knowing the structure of the
material could help you suggest ways to adjust the
material components to improve that property.
Our work in this area initially set out to indentify the
structural features responsible for molecular alignment
in crystals, as well as establish that hydrogen bonds
provide a cohesive force for assembling molecules
in crystals and other materials.
And our investigations explored the competitive nature of
introducing several types of hypdrogen bonds
in a single chemical system.
This work showcased the complexity of predicting
the crystal structures of relatively simple components,
and hopefully offered some insight to important challenges
in crystal engineering.
An extension of that work followed, and looked beyond
the role of hydrogen bonds to molecular alignment,
by investigating the shapes of molecules and
their influence on crystal packing.
The materials of interest to us are commonly
referred to as quasiracemates.
These compounds consist of two chemical different molecules
that are similar in shape and size, but differ in their
three-dimensional shape.
These molecules are, more or less, mirror images of
each other, and only break this mirror symmetry by the
chemical fragment that is chemically unique.
Conceptually, this is similar to left and right hands.
If a finger on one hand is fitted with a ring, then the
two hands remain similar, but are not exactly identical.
By investigating the crystal structure of compounds with the
same chemical trait, new insight to material design is possible.
Current student-led research projects at my laboratory
exploit the properties of hydrogen bombs, and
molecular shape to drive chemical reactions in crystals.
Because these molecules are fixed in space,
the chemical process tends to have enhanced selectivity.
The particular reaction we are investigating mimics
that commonly identified in skin cancers by
over-exposure to sun's rays.
By varying the components of these chemical systems,
we can engineer the distance and, thus,
reactivity between the reacting centers.
This gives an important opportunity to explore
the structural requirements needed to conduct these
reactions and, in turn, shed some light on the
fundamental aspects related to DNA photo damage processes
that are often the origin on many skin cancers.
If you should have further questions regarding this
research, please feel free to contact me.
[no dialogue].