Competition Between Intra and Intermolecular Triel Bonds. Complexes Between Naphthalene Derivatives and Neutral or Anionic Lewis Bases

Authors

Wiktor Zierkiewicz, Wrocław University of Science and Technology
Mariusz Michalczyk, Wrocław University of Science and Technology
Steve Scheiner, Utah State UniversityFollow

Document Type

Article

Journal/Book Title

Molecules

Publication Date

2-1-2020

Publisher

M D P I AG

Volume

25

Issue

3

First Page

1

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.

Last Page

15

Abstract

A TrF₂ group (Tr = B, Al, Ga, In, Tl) is placed on one of the α positions of naphthalene, and its ability to engage in a triel bond (TrB) with a weak (NCH) and strong (NC⁻) nucleophile is assessed by ab initio calculations. As a competitor, an NH₂ group is placed on the neighboring C^α, from which point it forms an intramolecular TrB with the TrF₂ group. The latter internal TrB reduces the intensity of the π-hole on the Tr atom, decreasing its ability to engage in a second external TrB. The intermolecular TrB is weakened by a factor of about two for the smaller Tr atoms but is less severe for the larger Tl. The external TrB can be quite strong nonetheless; it varies from a minimum of 8 kcal/mol for the weak NCH base, up to as much as 70 kcal/mol for CN⁻. Likewise, the appearance of an external TrB to a strong base like CN⁻ lessens the ability of the Tr to engage in an internal TrB, to the point where such an intramolecular TrB becomes questionable.

Recommended Citation

Zierkiewicz, W.; Michalczyk, M.; Scheiner, S. Competition between Intra and Intermolecular Triel Bonds. Complexes between Naphthalene Derivatives and Neutral or Anionic Lewis Bases. Molecules 2020, 25, 635.