An atom trapped in a crystal vacancy, metal cage, or fullerene might have many immediate neighbors. Then, the familiar concept of valency even coordination number seems inadequate to describe environment that atom. This difficulty terminology is illustrated here by four systems: H atoms tetragonal-pyramidal rhodium cages, an octahedral cobalt MgO hole, and C20 fullerenes. Density functional the...

CASSCF calculated wavefunctions are presented for three f-element metallocenes, MCOT2 (M = Ce, Th, Pu; COT = η(8)-C8H8). The configurational admixture of these systems is investigated and, where the ThCOT2 ground state is well-defined as a monodeterminantal Th(IV) state, the cerocene ground state is found to be strong multiconfigurational and to bear strong similarities to that of plutonocene. ...

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...

The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were studied experimentally in the solid state via ³⁵Cl NQR, ¹H-¹⁷O and ¹H-¹⁴N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O-H···N hydrogen bonds linking dimers and π-π stacking interactions were described wit...

Vibrational modes ascribed to the stretching of X-H bonds from donor monomers (HXdonor) in complexes presenting hydrogen bonds (HF···HF, HCl···HCl, HCN···HCN, HNC···HNC, HCN···HF, HF···HCl and H2O···HF) exhibit large (4 to 7 times) infrared intensity increments during complexation according to CCSD/cc-pVQZ-mod calculations. These intensity increases are explained by the charge-charge flux-dipol...

In this work, we used microwave irradiation conditions to synthesize β-enaminonitrile (4), which was affirmed using single crystal X-ray diffraction and the different spectral data. Two tumor cell lines, MCF-7 MCF-7/ADR, as well two normal HFL-1 WI-38, were assess anticancer activity of compound 4. The studied molecule exhibited potent efficacy against MCF-7/ADR lines compared with reference dr...

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...