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 Cα, 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.
Article
Competition Between Intra and Intermolecular Triel Bonds. Complexes Between Naphthalene Derivatives and Neutral or Anionic Lewis Bases
Molecules
Document Type
Article
Publication Date
2-1-2020
Publisher
M D P I AG
Creative Commons License
Creative Commons Attribution 4.0
Disciplines
Abstract
Citation Information
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.