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We present a data set of quantum topological properties of atoms of 44K randomly selected molecules from the GDB-9 data set. These atomic properties were obtained as defined by the quantum theory of atoms in molecules (QTAIM) within an atomic basin, a region of real space bounded by zero-flux surfaces in the electron density gradient vector field. The wave function files were generated through DFT static calculations (B3LYP/6-31G), and the atomic properties were calculated using QTAIM. The calculated atomic properties include the energy of the atomic basin, the electronic population, the magnitude of the total dipole moment, and the magnitude of the total quadrupole moment. The atomic properties allow one to understand the chemical structure, reactivity, and molecular recognition. They can be incorporated into force fields for molecular dynamics or for predicting reactive sites. We believe that this data set could facilitate new studies in chemical informatics, machine learning applied to chemistry, and computational molecular design., (© 2024. The Author(s).)

The kinetic energy (KE) density plays an essential role in the stabilization mechanism of covalent, polar covalent, and ionic bondings; however, its role in metal-ligand bindings remains unclear. In a recent work, the energetic contributions of the spin densities α and β were studied to explain the geometrical characteristics of a series of metal-ligand complexes. Notably, the KE density was found to modulate/stabilize the spin components of the intra-atomic nucleus-electron interactions within the metal in the complex. Here, we investigate the topographic properties of the spin components of the KE density for a family of high-spin hexa-aquo complexes ([M(H 2 O) 6 ] 2+ ) to shed light on the stabilization of the metal-ligand interaction. We compute the Lagrangian, G ( r ), and Hamiltonian, K ( r ), KE densities and analyze the evolution of its spin components in the formation of two metal-ligand coordination complexes. We study K α/β ( r ) along the metal-oxygen (M-O) internuclear axis as a function of the metal. Our results indicate that K ( r ) is a more distance-sensitive quantity compared to G ( r ) as it displays topographic features at larger M-O distances. Furthermore, K ( r ) allows one to identify the predominant interaction mechanism in the complexes.

In this paper, we present a novel approach to track the origin of the metal complex structure from the topology of the α and β spin densities as an extension of the Linnett-Gillespie model. Usually, the theories that explain the metal-ligand interactions consider the disposition and the relative energies of the empty or occupied set of d orbitals, ignoring the spin contribution explicitly. Our quantum topological approach considers the spatial distribution of the α and β spin valence shells, and the energy interaction between them. We used the properties of the atomic graph, a topological object that summarises the charge concentrations and depletions on the valence shell of an atom in a molecule, and the interacting quantum atoms (IQA) energy partition scheme. Unlike the Linnett-Gillespie model, which is based on electron-electron repulsion, our approach states that the ligands provoke a redistribution of the electron density to maximize the nuclear-electron interactions in each spin valence shell to bypass the concentration of electron-electron interactions, resulting in a polarization pattern which determines the position of the ligands.

Quantum Chemical Topology (QCT) is a well established structural theoretical approach, but the development of its reactivity component is still a challenge. The hypothesis of this work is that the reactivity of an atom within a molecule is a function of its electronic population, its delocalization in the rest of the molecule, and the way it polarizes within an atomic domain. In this paper, we present a topological reactivity predictor for cabonyl additions, κ. It is a measure of the polarization of the electron density with the carbonyl functional group. κ is a model obtained from a QSAR procedure, using quantum-topological atomic descriptors and reported hydration equilibrium constants of carbonyl compounds. To validate the predictive capability of κ, we applied it to organic reactions, including a multicomponent reaction. κ was the only property that predicts the reactivity in each reaction step. The shape of κ can be interpreted as the change between two electrophilic states of a functional group, reactive and non-reactive.