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The detection of toxic molecules has gained imperial attention to protect living organisms and their environment. The broadly explored sensor behaviour of triazine-based C3N4 reveals their ultra-high sensitivity towards numerous toxic molecules e.g., chemical welfare agents. However, another potential analogue of C3N4 composed of heptazine exhibits remarkable electrical and optical properties but has not been much explored in sensor technology, especially for toxic pollutants. Keeping this in mind, the sensing performance of heptazine-based g-C3N4 is explored for the detection of toxic amides by using First Principles calculations. In this context, acryloyl amide (C2H3CONH2), acryloyl chloride (C2H3COCl), fluoroacetic acid (C2H3FCOOH), flouroaceta amide (C2H2FONH2), flouroacetyl chloride (C2H2FOCl) are selected as toxic pollutants; herein, for the ease of understanding, these molecules are represented as AAM, ACl, FAAc, FAA, & FACl, respectively. The electrochemical sensitivity of g-C3N4 is determined via geometric, energetic, and electronic properties analysis, whereas the photochemical sensitivity is explored by UV–Vis absorption analysis based on TD-DFT calculations. The interaction energies of studied molecules on C3N4 range between − 9.09 and - 23.39 kcal/mol depending upon the type of interactions e.g., hydrogen bonding or dispersion, which are explained on the basis of Symmetry Adopted Perturbation Theory, Non-Covalent Interaction Index, and Quantum Theory of Atoms in Molecules analyses. The density of State analysis, Frontier Molecular Orbitals and NBO charge transfer characterized that the electronic behaviour of g-C3N4 can be an effective sensor material with a semiconducting nature and significant charge transfer. Lastly, UV–Vis absorption analysis confirms the photosensitivity of g-C3N4 upon interaction with toxic molecules. [ABSTRACT FROM AUTHOR]

In this study, for the first time, boron oxide nanoflake is analyzed as drug carrier for favipiravir using computational studies. The thermodynamic stability of the boron oxide and favipiravir justifies the strong interaction between both species. Four orientations are investigated for the interaction between the favipiravir and the B3O3 nanoflake. The Eint of the most stable orientation is −26.98 kcal/mol, whereas the counterpoise-corrected energy is −22.59 kcal/mol. Noncovalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses are performed to obtain insights about the behavior and the types of interactions that occur between B3O3 nanoflake and favipiravir. The results indicate the presence of hydrogen bonding between the hydrogen in the favipiravir and the oxygen in the B3O3 nanoflake in the most stable complex (FAV@B3O3-C1). The electronic properties are investigated through frontier molecular orbital analysis, dipole moments and chemical reactivity descriptors. These parameters showed the significant activity of B3O3 for favipiravir. NBO charge analysis transfer illustrated the charge transfer between the two species, and UV-VIS analysis confirmed the electronic excitation. Our work suggested a suitable drug carrier system for the antiviral drug favipiravir, which can be considered by the experimentalist for better drug delivery systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The drug carrier ability of B 3 O 3 toward Foscarnet is investigated via DFT. • The interaction is characterized by the geometric, energetic, electronic, and optical analyses. • Widely accepted ωB97XD/6-31+G(d,p) method of DFT is adopted for geometric analysis whereas for electronic properties B3LYP/6-31+G (d,p) method is used. • NCI and QTAIM analyses confirmed the nature of interactions. In this study, B 3 O 3 quantum dot is investigated via density functional theory (DFT) calculations as an antiviral drug carrier toward Foscarnet. Geometric analysis is carried out to find stable orientations of interaction between Foscarnet drug and the B 3 O 3 quantum dot. As a result, three stable orientations are proposed. The E int of the most stable orientation is –32.63 kcal/mol whereas the BSSE corrected energy is −26.98 kcal/mol. Noncovalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses are employed to understand the nature and the type of interactions taking place between drug and the B 3 O 3 quantum dot. Their results indicated the presence of hydrogen bonding in the most stable complex (orientation A). The HOMO-LUMO analysis is performed to study the electronic properties of the interacting moieties. The lowest E gap is observed in case of orientation A. The value of dipole moments and chemical descriptors showed the significant activity of B 3 O 3 quantum dot toward Foscarnet drug molecule. The overall findings from this study suggest the B 3 O 3 quantum dot as a potential drug carrier system for antiviral drugs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption of hazardous CH 3 X (X = F, Cl & Br) molecules on C 4 H 4 NH, C 4 H 4 O, C 4 H 4 S and C 6 H 6 monomer units has been studied. • The adsorption behaviors are evaluated by the geometric conformations, adsorption energies, SAPT and QTAIM topological analyses. • The effect of fluorination on the adsorption behavior is quantified. • The increase in adsorption strength is observed for the fluorinated adsorbents. Despite the numerous publications describing the synthesis and electronic properties of fluorinated furan, thiophene and pyrrole, the systematic overview of their adsorption applications is still lacking. In this study, the effect of fluorination on the adsorption properties of furan (C 4 H 4 O), thiophene (C 4 H 4 S), pyrrole (C 4 H 4 NH) and benzene (C 6 H 6) are investigated with the help of density functional theory (DFT) calculations. Herein, the adsorption energies of CH 3 X (X = F, Cl & Br) on C 4 H 4 O, C 4 H 4 S, C 4 H 4 NH and C 6 H 6 and their fluorinated analogues are calculated using ωB97XD/6-31+G(d, p) level of theory. The results of the adsorption energies and symmetry adapted perturbation theory (SAPT0) reveal that the adsorption affinity of adsorbent is enhanced upon fluorination due to the increasing dispersion forces. To comprehensively investigate the variation in the electronic properties of nonfluorinated and fluorinated systems, the HOMO, LUMO orbitals and NBO charges are analyzed. The isosurfaces of orbitals show that the electron density is more localized onto the fluorinated adsorbents which are probably due to the presence of multiple electronegative fluorine atoms. Owing to the electron-withdrawing nature of fluorine, the electronic charges are transferred from CH 3 X to fluorinated adsorbents while the charges are shifted from nonfluorinated adsorbents to CH 3 X. Furthermore, the TD-DFT calculations reveal that the electronic transition energies are significantly decreased in most of the fluorinated complexes especially, CH 3 X@C 4 F 4 S and CH 3 X@C 4 F 4 NH. With these findings, it can be postulated that fluorine substitution can significantly surge the electronic and adsorption properties of sensor materials. [ABSTRACT FROM AUTHOR]

The chemical warfare agents (CWAs) are highly toxic for living systems and environment. These diverse effects of CWAs, especially blistering agents, need the development of highly selective sensors for their rapid and effective detection. Herein, by using density functional theory calculations, we explained the adsorption of nitrogen (NM) and sulphur mustard (SM) blistering agents on graphdiyne (GDY) sheet. The calculated adsorption energies illustrate the physisorption of blistering (SM & NM) agents on the graphdiyne surface. The symmetry adopted perturbation theory (SAPT) analysis predicts that the dispersion is a dominating component of interaction energy. Reduced density gradient (RDG) and quantum theory of atoms in molecules (QTAIM) analyses are performed to justify the nature of interactions. Based on QTAIM analysis, the interaction energies between graphdiyne and blistering agents are noncovalent in nature. Furthermore, RDG results reveals that the van der Waals interactions i.e., dispersion forces dominate in the complexes. The %sensitivity and average energy gap variations are illustrated by HOMO-LUMO gaps. The detection ability of graphdiyne is further studied using UV–Vis analysis, NBO charge transfer and density of state analysis. These properties depict the appreciable sensitivity of graphdiyne towards blistering agents (SM and NM). We believe that the results of this study are fruitful for experimentalist to design highly sensitive CWAs sensors using graphdiyne sheet. Unlabelled Image • The adsorption of blistering agents on GDY is studied by ωB97XD/6-31+G(d,p) method of DFT. • Adsorption behaviour is elucidated by SAPT, RDG and QTAIM analyses. • The dispersion forces dominate between BA-GDY complexes. • This study shows that GDY sheet has high sensitivity towards blistering agents. [ABSTRACT FROM AUTHOR]