Designing boron and metal complexes for fluoride recognition: a computational perspective

• Published in: Physical chemistry chemical physics : PCCP 2021-10, Vol.23 (39), p.22768-22778
• Main Authors: Orenha, Renato Pereira, Peixoto, Letícia Bermudes, Caramori, Giovanni Finoto, Piotrowski, Maurício Jeomar, de Araújo Batista, Krys Elly, Contreras-Garcia, Julia, Cardenas, Carlos, Morgon, Nelson Henrique, Mendizabal, Fernando, Parreira, Renato Luis Tame
• Format: Article
• Language: English
• Subjects: Anions; Antimony; Antimony compounds; Aqueous solutions; Boron; Chemical Sciences; Coordination compounds; Covalent bonds; Environmental effects; Fluorides; Nitrogen dioxide; or physical chemistry; Receptors; Tellurium; Theoretical and
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d1cp02514g

Fluoride anions (F − ) may have beneficial or harmful effects on the environment depending on their concentration. Here, we shed light on F − recognition by compounds containing boron, tellurium and antimony, which were experimentally demonstrated to be capable of interacting with the F − ion in a partially aqueous medium. Boron and metal complexes recognize F − anions primarily using electrostatic energy along with important contributions from orbital interaction energy. The natural orbitals for chemical valence (NOCV) methodology indicates that the main orbital interactions behind fluoride recognition are σ bonds between the receptors and the F − anions. The charged receptors, which provide (i) two B atoms, (ii) one B atom and one Sb atom, or (iii) one B atom and one Te atom to directly interact with the F − ions, appear to be some of the best structures for the recognition of F − anions. This is supported by the combination of favorable electrostatic and σ bond interactions. Overall, the presence of electron donor groups, such as -CH 3 and -OH, in the receptor structure destabilizes the fluoride recognition because it decreases the attractive electrostatic energy and increases the Pauli repulsion energy in the receptor F − bonds. Notably, electron acceptor groups, for example, -CN and -NO 2 , in the receptor structure favor the interaction with the F − ions, due to the improvement of the electrostatic and σ bond interactions. This study opens the way to find the main features of a receptor for F − recognition. Fluoride anions play important roles in the human body and environment. Thus, DFT calculations have been performed to design structures that can efficiently recognize this ion in aqueous media.