Voltammetric Reductions of Ring-Substituted Acetophenones. 3. A Collaborative Sophomore-Level Molecular Modeling Exercise Correlating Experimental and Theoretical Electrochemical and Spectroscopic Data

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 8 Issue 2 (2003) pp 141-145

Voltammetric Reductions of Ring-Substituted Acetophenones. 3. A Collaborative Sophomore-Level Molecular Modeling Exercise Correlating Experimental and Theoretical Electrochemical and Spectroscopic Data

Grant N. Holder* and David Farrar

Department of Chemistry, Appalachian State University, Boone, NC 28608, holdergn@appstate.edu
Received December 17, 2002. Accepted January 22, 2003

Published online: 18 February 2003

Abstract. An experiment suitable for introductory organic chemistry students is described. In it, students perform relatively simple semi-empirical and ab initio calculations on a series of ring-substituted acetophenones. The calculated LUMO energies and bond-stretching frequencies derived from PM3, AM1, Hartree–Fock (3-21G*), and density functional theory (DFT) were compared against reduction potentials (E_1/2) acquired using differential pulse voltammetry at a glassy carbon electrode and stretching frequencies for selected bonds using either DRIFT or absorbance FT–IR data. Correlation for the LUMO energies ranged from excellent (3-21G*) to very poor (DFT); for the stretching frequencies, agreement was best using PM3 and worst using DFT, but all correlations could be called fair only.

Key Words: Laboratories and Demonstrations; organic chemistry; computational chemistry; voltammetry; FT-IR

(*) Corresponding author. (E-mail: holdergn@appstate.edu)

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