dft and qtaim computations have been performed on numbers of pure nitrogen cluster speciesi.e. nn (n = 4, 6) for investigating the structure and bonding. this study is critical since thesemolecules have been nominated as the good synthetic targets of high energy materials (hem).0nthe other hand the decomposition mechanism is closely depends on the bonding pattern. thislatter concept was searche...

Motivated by the use of chitosan (Ch), and cellulose acetate (AC) as organic matrices in several therapeutic drugs, a theoretical study has been elaborated through density functional theory method (DFT) to investigate interaction mechanism between two essential ions for human body Ca2+, K+ (AC). Many physical chemical aspects have carried out after achievement structural optimization. This invo...

the main purpose of this research is to investigate computationally the tautomeric reaction pathway of 5-methyl-3-methylthio-1,2,4-triazole from the thermodynamical and mechanistical viewpoints. in this respect, density functional theory (dft) in conjunction with the quantum theory of atoms in molecule (qtaim) has been employed to model the energetic and electronic features of tautomeric mechan...

Dynamic and static behavior of the X-H-*-π interactions in X-H-*-π(C6H6) (X = F, Cl, Br, I, HO, MeO, H2N, MeHN and Me2N) is elucidated by QTAIM-DFA (QTAIM dual functional analysis), which we proposed recently, as the first step to clarify various types of X-H-*-π interactions. The asterisk * emphasizes the existence of the bond critical point (BCP) on the interaction in question. Total electron...

The conformational preferences of benznidazole were examined through the application of DFT, PCM and QTAIM calculations, whose results were compared with crystallography data. The geometries were fully optimized with minimum potential energy surface by means of the Relaxed Potential Energy Surface Scan (RPESS) at AM1, followed by the B3LYP/6-311++G(d,p) theoretical level. As a result, the s-cis...

[AnX(3)](2)(μ-η(2):η(2)-N(2)) (An = Th-Pu; X = F, Cl, Br, Me, H, OPh) have been studied using relativistic density functional theory. Geometric and vibrational data suggest that metal→N(2) charge transfer maximises at the protactinium systems, which feature the longest N-N bonds and the smallest σ(N-N), as a result of partial population of the N-N π* orbitals. There is very strong correlation o...

topological analysis has been performed on the total electron density of the two forms of ozonemolecule,c2v and d3h ,to investigate the nature of chemical bonds ,molecular structure , atomiccharges and electrical properties. while these concepts have been completely discussed usingclassical models the emphasize in this work is based on quantum theory of atoms in molecules(qtaim). because the d3...

The geometrical and electronic structures of Ln[(H2O)9]3+ and [Ln(BTP)3]3+, where Ln = Ce-Lu, have been evaluated at the density functional level of theory using three related exchange-correlation (xc-)functionals. The BHLYP xc-functional was found to be most accurate, and this, along with the B3LYP functional, was used as the basis for topological studies of the electron density via the quantu...

In this paper, NMR and QTAIM analysis for three substituted of T2SA complex was investigated in the gas and four solvents at DFT level. Intermolecular O–H…N hydrogen bonds between 1,2,4,5-Tetrazine and Sulphurous acids enhance the stability of complex.1,2,4,5-Tetrazine is a highly reactive diene for [4+2] inverse-Diels–Alder cycloaddition processes and an excellent precursor to attain the pyrid...

Following a previous study by de Courcy et al. (Interdiscip. Sci. Comput. Life Sci. 2009, 1, 55-60), we demonstrate in this contribution, using quantum chemistry, that metal cations exhibit a specific topological signature in the electron localization of their density interacting with ligands according to their “soft” or “hard” character. Introducing the concept of metal cation subvalence, we s...