Graduation Year

2024

Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts

Department

Chemistry

Reader 1

Mary Hatcher-Skeers

Reader 2

Ethan Van Arnam

Rights Information

© 2024 Mia Zonies

Abstract

This study investigated whether pyridine carboxamides participate in aromatic pi-stacking interactions and the effect these interactions may have on carboxamide molecular dynamics. Nuclear Magnetic Resonance Spectroscopy, 1H-NMR, was used to investigate the effect of pi-stacking on the pyridine carboxamide, nicotinamide, when dissolved in aromatic solvents compared to non-aromatic solvents. This analysis was performed in, ethylene glycol-D₆ (D, 98%) methanol-D₄ (D, 99.8%), nitrobenzene-D₅ (D, 99%), and pyridine-D₅ (D, 99.5%). Aromaticity was found to impact nicotinamide’s electronic structure, as evidenced by the aromatic protons having differing chemical shifts in aromatic versus non-aromatic solvents. We further aimed to discern if pi-stacking between carboxamides and aromatic solvents alters the free energy of amide bond rotation. Data on nicotinamide and its regioisomer, picolinamide, dissolved in non-aromatic and aromatic solvents of different polarities were analyzed. Interestingly, pi-stacking effects were found to decrease the barrier to amide bond rotation for nicotinamide but increase the barrier to amide bond rotation for picolinamide. These findings highlight the significant yet nuanced role of aromatic pi-stacking interactions in modulating the molecular dynamics of pyridine carboxamides.

Download

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.

Share

COinS