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Assistant Professor, Physical Organic Chemistry
2625 Campus Box
Elon, NC 27244
Voice: (336) 278-6267
Fax: (336) 278-6258
I grew up and attended high school in a small city in Oregon. I earned a B.S. degree in chemistry with a minor in mathematics at the University of Puget Sound--a small liberal arts school in Tacoma, Washington. I then entered the Ph. D. program at Stanford University, working for Dr. John I. Brauman. My research there was in the area of Physical-Organic Chemistry, which primarily involved spectroscopic studies of organic molecular negative ions in the gas phase. Specifically, I was interested in the influence of molecular geometry on the thermochemistry and kinetics of certain organic functional groups. I earned my Ph. D. in 2001, after which I took the position here at Elon. I have a wonderful wife, Valerie, and two wonderful sons, Joshua and Jacob.
Courses Taught at Elon
Chem 101: Basic Concept in Chemistry
Chem 111: General Chemistry I
Chem 113: General Chemistry I Lab
Chem 116: Advanced General Chemistry Lab
Chem 211: Organic Chemistry I
Chem 212: Organic Chemistry II
Chem 213: Organic Chemistry I Lab
Chem 214: Organic Chemistry II Lab
Chem 332L: Physical Chemistry I Lab
Chem 334: Physical Chemistry II
Chem 334L: Physical Chemistry II Lab
Chem 432: Physical Organic Chemistry
My research interests lie in answering fundamental questions in chemistry, spanning two major areas. The first involves a phenomenon called periodic precipitation. As students learn in General Chemistry, a precipitation reaction that occurs in aqueous medium forms a cloud of the solid product--the precipitate--that eventually settles to the bottom. However, if the precipitation reaction is set up according to the figure below, where one reactant salt (the inner electrolyte) is dissolved in a gel medium, and the other (outer electrolyte) is aqueous, then the precipitate product forms in patterns. Depending on the initial setup, either concentric rings (left), called Liesegang rings, or bands (right), called Liesegang bands, will form. This phenomenon has been studied for over 100 years; however, the mechanism behind the pattern formation is still unclear. Therefore, our lab performs physical chemistry experiments to understand WHY these patterns form the way they do.
My second major area of research focuses on understanding the effects of resonance and induction on reactions that involve relatively simple organic molecules. Resonance and induction are conceptual models that are commonly employed in Organic Chemistry to explain why two molecules might have significantly different reactivities. Often times, however, both of these phenomena contribute simultaneously toward the stability of a given molecule, and it is difficult to determine their individual effects on a reaction. A classic example is the contribution by resonance and inductive effects toward the enhanced acidity of carboxylic acids (RCO2H) over similar looking alcohols (RCH2OH). The carboxylate anion (RCO2‾) enjoys both resonance stabilization and inductive stabilization (the C=O) group withdraws electron density away from the oxygen atom bearing the negative charge). To examine these and other systems, we developed a new computational methodology using a quantum mechanical calculation software package, which enables us to obtain independent measures of the contribution by resonance and inductive effects. Applying this methodology toward the carboxylic acid question, for example, suggests that about 1/3 is due to resonance, and 2/3 is due to inductive effects. These results are at odds with the traditional view described in most undergraduate Organic textbooks, that the acidity enhancement of carboxylic acids is due entirely to resonance effects. Currently, we are examining other systems.
Karty, Joel (2005). The Nuts and Bolts of Organic Chemistry: A Student's Guide to Success. San Francisco, Benjamin Cummings.
Peer Reviewed Publications
(* denotes Elon University undergraduate co-authors)
Walthall, D. A.; Karty, J. M.; Brauman, J. I. "Molecular Rotations and Dipole Bound State Lifetimes." J. Phys. Chem., 2005 (in press).
Walthall, D. A.; Karty, J. M.; Romer, B.; Ursini, O.; Brauman, J. I. "Enolate Structure and Electron Affinity." J. Phys. Chem., 2005 (in press).
Kim, J.; Liu, Y.; Ahn, S. J.; Zauscher, S.; Karty, J. M.; Yamanaka, Y.; Craig, S. L. "Self-Assembly and Properties of Main Chain Reversible Polymer
Brushes." Adv. Mat. 2005, 17(14), 1749-1753
Naumann, R.*; Dworkin, A.*; Seigfred, C.*; Karty, J. M. "Y-Aromaticity: Why is the Trimethylenemethane Dication More Stable than the Butadienyl
Dication?" J. Org. Chem., 2005 (ASAP article).
Barbour, J. B.*; Karty, J. M. "Resonance and Field/Inductive Substituent Effects on the Gas Phase Acidities of para-Substituted Phenols: A Direct
Approach Employing Density Functional Theory." J. Phys. Org. Chem., 2004, 18(3), 210-216.
Barbour, J. B.*; Karty, J. M. "Resonance Energies of the Allyl Cation and Allyl Anion: Contribution by Resonance and Inductive Effects toward
the Acidity and Hydride Abstraction Enthalpy of Propene." J. Org. Chem., 2004, 69(3), 648-654.
Holt, J.*; Karty, J. M.. "Origin of the Acidity Enhancement of Formic Acid over Methanol: Resonance versus Inductive Effects." J. Am. Chem.
Soc. 2003, 125(9), 2797.
Karty, J. M.; Janaway, G. A.; Brauman, J. I. "Conformation Dependent Thermochemistry: A Study of Lactones and Lactone Enolates in the Gas
Phase." J. Am. Chem. Soc., 2002, 124(18), 5213.
Karty, J. M.; Wu, Y.; Brauman, J. I. "The RS...HSR Hydrogen Bond: Acidities of a,wDithiols and Electron Affinities of their
Monoradicals" J. Am. Chem. Soc., 2001, 123(40), 40, 9800.
National ACS Meeting, Washington, DC, 2005, oral presentation: "How do you get organic chemistry students to embrace the reaction mechanism?
A tale of two pedagogies."
National ACS Meeting, San Diego, 2005, oral presentation: "Resonance and inductive contributions toward that gas phase acidities of
Y=CH−X-H (X,Y = CH2, NH, O)."
National ACS Meeting, New York City, 2003, poster presentation: "Resonance energies of the allyl cation and allyl anion."
Southeast Regional Meeting of the ACS, Charleston, 2002, poster presentation: "Origin of the acidity enhancement of formic acid over methanol:
Resonance vs. inductive effects."
$35,000 from the American Chemical Society--Petroleum Research Fund. 9/1/2003 - 8/31/2005
$34,000 from Research Corporation. Fall 2003.