Ionization of NO by superhalogens: DFT and QTAIM approaches

Recent progress on the design and applications of superhalogens

The research on superhalogens has successfully completed four decades. After their prediction in 1981 and experimental verification in 1999, such species have attracted attention due to their unusual structures and intriguing applications. Superhalogens are species whose electron affinity exceeds that of halogen or whose anions possess a larger vertical detachment energy than that of halides. Initially, these species were designed using s and p block atoms having a central electropositive atom as the core with excess electronegative atoms as ligands such as F, Cl, O etc. The last decade has witnessed enormous progress in the field of superhalogens. The transition metal atoms have played the role of the central core and a variety of new ligands have been explored. Further, new classes of superhalogens such as polynuclear superhalogens, magnetic superhalogens, aromatic superhalogens, etc. have been reported. The first application of superhalogens as strong oxidizers appeared much before their conceptualization. In the last decade, however, their applications have spanned a variety of fields such as energy storage, superacids, organic superconductors, ionic liquids, liquid crystals, etc. This makes research in the field of superhalogens truly interdisciplinary. This article is intended to highlight the progress on the design and applications of superhalogens in the last decade.

Computational analyses of Fe-Chelation by thiofavipiravir

Existence of iron (Fe) is important for cells of living systems; however, its level of magnitude for those patients infected by novel coronavirus disease (COVID-19) is still a challenging issue. Therefore, such mechanism of function was investigated in this work by assistance of thiofavipiravir (TFav) compounds generated by the well-known favipiravir (Fav) drug used for medication of COVID-19 patents. To this aim, sulfur-substitutions of oxygen atoms of Fav were done and the obtained parent structures were prepared for participating in Fe-chelation function. The results indicated that the modes were suitable for running such Fe-chelation processes, in which favorability and strength the models were ranged in this order: 1O2S-Fe > 1S2S-Fe > 1O2O-Fe > 1S2O-Fe. As a consequence, such idea of sulfur-substitution of Fav drug for more appropriate favorability of participating in Fe-chelation process was sensed by results of this work proposing 1O2S compound as the most favorable one for doing the function. Hence, information about capability of TFav compounds for participating in Fe-chelation processes were provided in this work regarding the challenging issue of Fe-chelation in medication of COVID-19 patients. All results of this work were obtained by performing computations using the density functional theory (DFT) approach

Investigating Functionalization Impacts on Structural Features of Barbituric Acid Derivatives: DFT Approach

Density functional theory (DFT) calculations were performed to investigate electronic and structural properties of barbituric acid (BA) and sixtheen of its derivatives to show impacts of structural functionalization on the features of parent BA. The models were optimized and the minimum energy structures were confirmed by frequency calculations. Molecular and atomic descriptors were evaluated for the optimized models, in which the results of formation binding strength and molecular orbital features indicated significance of such functionalization processes on the observed properties. The highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) and their related parameters all indicated magnitudes of changes from one molecule to another one. Furthermore, atomic scale quadrupole coupling constants (Cq) were evaluated for the nitrogen and oxygen atoms of BA compounds showing significance of structural functionalization impacts on the atomic properties of parent BA. As a consequence, such structural analyses of BA compounds could show their characteristic features for further developments especially for their efficient pharmaceutical applications.

Iron Chelation by thiocytosine: Investigating electronic and structural features for describing tautomerism and metal chelation processes

This work was performed regarding the importance of iron (Fe) chelation for biological systems. This goal was investigated by assistance of a model of thiocytosine (TC) for participating in Fe-chelation processes. First, formations of tautomeric conformations were investigated to explore existence of possible structures of TC. Next, Fe-chelation processes were examined for all four obtained tautomers of TC. The results indicated that thiol tautomers could be seen at higher stability than thio tautomers, in which one of such thiol tautomers yielded the strongest Fe-chelation process to build FeTC3 model. As a consequence, parallel to the results of original TC tautomers, Fe-chelated models were found to be achievable for meaningful chelation processes or sensing the existence of Fe in media. Examining molecular orbital features could help for sensing purposes. The results of this work were obtained by performing density functional theory (DFT) calculations proposing TC compounds suitable for Fe-chelation purposes.