DFT prediction of ground-state spin multiplicity of cyclobutane-1,3-diyls: notable effects of two sets of through-bond interactions

Manabu Abe; Chizuko Ishihara; Masatomo Nojima

doi:10.1021/jo026345c

DFT prediction of ground-state spin multiplicity of cyclobutane-1,3-diyls: notable effects of two sets of through-bond interactions

J Org Chem. 2003 Feb 21;68(4):1618-21. doi: 10.1021/jo026345c.

Authors

Manabu Abe¹, Chizuko Ishihara, Masatomo Nojima

Affiliation

¹ Department of Materials Chemistry & Frontier Research Center (HANDAI FRC), Graduate School of Engineering, Osaka University (HANDAI), Suita 565-0871, Osaka, Japan. abe@ap.chem.eng.osaka-u.ac.jp

PMID: 12585920
DOI: 10.1021/jo026345c

Abstract

DFT calculations (UB3LYP/6-31+G**) have been performed to predict the substituent effect on the ground-state spin-multiplicity and the singlet-triplet energy gap in cyclobutane-1,3-diyls, CB-DR. The ground state is calculated to be largely dependent on the substituents (X, Y) at the C2 and C4 positions. The substituent effects can be reasonably explained by the two sets of through-bond (TB) interactions which result from the coupling between the symmetric nonbonding molecular orbital (Psi(S)) and the C-X (Y) sigma and sigma* orbitals.