Session: Undergraduate Research Posters: Computational Chemistry:

Penicillins are a member of the β-lactam family of antibiotics. The β-lactams include the fungal-derived penicillins or “penams”, and the cephalosporins or “cephems”. In this study, the isomerization of the double bond (indicated in red) is currently the biggest hurdle in the development of new chemistry to make cephalosporin analogs. The molecular structures, vibrational frequencies, and Gibbs free energies of cephalosporin intermediates in are compared using different density functional methods and basis sets. The exchange functionals DFT employed in this study include local (SVWN), gradient corrected (PBEPBE) and hybrid (B3LYP), and basis sets include Pople basis set 6-311G+(d,p), 6-311++G(2df,2pd), and Dunning's correlation-consistent basis sets aug-cc-pVDZ and aug-cc-pVTZ. The results are compared with experimental observations and will aid in the development of new chemistry for synthesizing cephalosporin analogs by way of Suzuki coupling reactions on cephem compounds.

Ericka Barnes

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