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...

The nature of the E-E' bonds (E, E' = S and Se) in glutathione disulfide (1) and derivatives 2-3, respectively, was elucidated by applying quantum theory of atoms-in-molecules (QTAIM) dual functional analysis (QTAIM-DFA), to clarify the basic contribution of E-E' in the biological redox process, such as the glutathione peroxidase process. Five most stable conformers a-e were obtained, after app...

[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...

We show that the use of the quantum theory of atoms in molecules (QTAIM) in electronically excited states allows expanding the knowledge that the molecular orbital (MO) framework provides about electronic rearrangements. Despite that historical prejudice seemed to preclude the use of QTAIM beyond the electronic ground state, this paper evidences that QTAIM is versatile enough to deal with excit...

We introduce a development of next generation quantum theory atoms in molecules (NG-QTAIM) for an investigation the chirality ethane. A new isomer type Qσ is discovered addition to Sσ and Rσ stereoisomers stress tensor trajectory Uσ-space. The defined be ‘null-isomer’ since value chirality-helicity function ≈ 0. presence chiral contributions suggests that steric effects, rather than hyper-conju...

The diuranium(III) compound [UN''2]2(μ-η(6):η(6)-C6H6) (N''=N(SiMe3)2) has been studied using variable, high-pressure single-crystal X-ray crystallography, and density functional theory . In this compound, the low-coordinate metal cations are coupled through π- and δ-symmetric arene overlap and show close metal-CH contacts with the flexible methyl CH groups of the sterically encumbered amido li...

A ferramenta de Gassman-Fentiman da demanda crescente de elétrons foi usada para identificar íons carbênios e íons carbônios. Contudo, devido ao seu entendimento ambíguo, ela foi pivô de uma disputa histórica. Nós aplicamos a metodologia da Teoria Quântica de Átomos em Moléculas QTAIM para caracterizar íons carbênios e íons carbônios de uma forma mais eficaz e mais fácil. Essa metodologia pode ...

Substances known as nitrogen mustards turn into aziridinium ion through the intramolecular cyclization SN1. This ion reacts with the DNA preferably at the N7 position of the guanine, and because of this, it is an important antineoplastic agent. Based on this, the objective of this study is to quantify the interaction between the nitrogen mustard mechlorethamine and the guanine, using the NBO an...

Методом DFT B3LYP 6-311++G(3df,3pd) найдено распределение электронной плотности молекулы нафталина свободных радикалов - нафталил-1 и нафталил-2. В рамках квантовой теории атомов в молекуле (QTAIM) проведено исследование внутреннего строения выбранных соединений. Выявлены особенности радикалов, относительно места отрыва водорода. The method has been used to find the electron density distributio...

The observation that some properties attributed to atoms and functional groups are transferable from one molecule to another has played a key role in the development of chemistry. This observation provides a basis for group additivity schemes and is exemplified by the constancy of group contributions to thermodynamic and spectroscopic properties. But what is the electronic basis of this empiric...