Theoretical study of the interaction of the potentially toxic contaminants Hg2+, CH3Hg+, CH3CH2Hg+, and C6H5Hg+ with a B3O3 monolayer matrix

Abstract

Context

The mercury ion Hg²⁺, and its derivatives, organomercurials are high toxicity to humans due their ability to bioaccumulate. In view of these problems, studies of the interaction of these potentially toxic compounds with matrices allow verify if they can be detected, or help determine their adsorptive capacity. In this context, the work aims to theoretically evaluate the interaction between the B₃O₃ matrix and the potentially toxic compounds Hg²⁺, CH₃Hg⁺, CH₃CH₂Hg⁺, and C₆H₅Hg⁺. The binding energy values showed that the interaction occurs effectively; being spontaneous and exothermic for all the interactions evaluated. The structural properties demonstrate that mercury interacts with the oxygen atoms of the B₃O₃ matrix, with bond lengths ranging from 2.365 to 3.777 Å and that all organomercurials form hydrogen bonds. The topological parameters of quantum theory of atoms in molecules (QTAIM) categorized the nature of the interactions in electrostatic for Hg^…O. The non-covalent interaction analyses presented a bluish color, between Hg and matrix oxygen indicating a strong attraction interaction and Van der Waals interactions ( green color) for the interaction of the organic group and B₃O₃. Thus, it can be confirmed that the study showed that the B₃O₃ matrix is efficient for the interactions, enabling future experimental studies of the application of this matrix in adsorptive processes or for molecular filters.

Methods

All calculations of density functional theory were performed using the program Gaussian 16 and the structures of B₃O₃ matrix, Hg²⁺, CH₃Hg⁺, CH₃CH₂Hg⁺, and C₆H₅Hg⁺ were generated using the GaussView program. The optimization and vibrational frequency calculations were performed using the functional ωB97XD and 6-31G(d,p) basis set for the H, B, C, and O atoms, while for the Hg atom the basis set used was CEP-31G with compact effective pseudopotential. All analyses were conducted at this level of theory. The quantum theory of atoms in molecules analysis were performed using AIMALL software. Non-covalent interaction calculations were carried out using Multiwfn software, and the structures were visualized using the visual molecular dynamics program.