An examination of the nature of localized molecular orbitals and their value in understanding various phenomena that occur in organic chemistry

• Published in: Journal of molecular modeling Vol. 25; no. 1; pp. 7 - 17
• Main Author: Stewart, James J. P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2019; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemical reactions; Chemistry; Chemistry and Materials Science; Computational chemistry; Computer Appl. in Life Sciences; Computer Applications in Chemistry; Molecular Medicine; Molecular orbitals; Organic chemistry; Original Paper; Theoretical and Computational Chemistry; Tim Clark 70th Birthday Festschrift; Banana bonds; Reactions; Lewis structures; Solids; Eigenvectors; Localized molecular orbitals; Canonical molecular orbitals; Delocalization; Rabbit ears
• ISSN: 1610-2940; 0948-5023
• DOI: 10.1007/s00894-018-3880-8

While canonical molecular orbitals have been used in computational chemistry for almost a century, the use of localized molecular orbitals is relatively new, and generating them has been difficult until recently. This has impeded their routine use in modeling chemical systems and reactions so that, even though localized molecular orbitals can now be generated easily, their usefulness in interpreting chemical phenomena has not been properly appreciated. Localized molecular orbitals can provide useful insights into chemical phenomena such as two-electron bonds, π delocalization, and lone pairs. A potentially important application would be interpreting the phenomena that occur in chemical reactions, in particular those reactions which can be described using the Lewis curly-arrow electron pushing convention. This paper considers how canonical and localized molecular orbitals are generated, their usefulness and limitations, and some issues that could be considered controversial regarding their nature, and it presents examples of the usefulness of LMOs in describing six chemical systems and one reaction.