Centro UTN QUITEX - Difusión Científica - Artículos de Revista
Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/3851
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Item Impact of covalent modifications on the hydrogen bond strengths in diaminotriazine supramolecules(2022-04-14) Petelski, Andre Nicolai; Pamies, Silvana Carina; Márquez, María Josefina; Peruchena, Nélida María; Sosa, Gladis LauraMelamine (M) is a popular triamine triazine compound in the field of supramolecular materials. In this work, we have computationally investigated how substituents can be exploited to improve the binding strength of M supramolecules. Two types of covalent modifications were studied: the substitution of an H atom within an amine group NHR, and the replacement of the whole NH2 group (R=H, F, CH3 and COCH3). Through our dispersion-corrected density functional theory computations, we explain which covalent modification will show the best self-assembling capabilities, and why the binding energy is enhanced. Our charge density and molecular orbital analyses indicate that the best substituents are those that generate a charge accumulation on the endocyclic N atom, providing an improvement of the electrostatic attraction. At the same time the substituent assists the main N H···N hydrogen bonds by interacting with the amino group of the other monomer. We also show how the selected group notably boosts the strength of hexameric rosettes. This research, therefore, provides molecular tools for the rational design of emerging materials based on uneven hydrogen-bonded arrangements.Item How procyanidin C1 sticks to collagen : the role of proline rings(2021-05-29) Petelski, Andre Nicolai; Pamies, Silvana Carina; Sosa, Gladis LauraMolecular interactions between proteins and polyphenols are responsible for many natural phenomena like colloidal turbidity, astringency, denaturation of enzymes and leather tanning. Although these phenomena are well known, there are open questions about the specific interactions involved in the complexation process. In this work, Molecular Dynamic (MD) simulations and the topology of the electron density analysis were used to study the interactions between the flavonoid procyanidin C1 and a collagen fragment solvated in water. Root mean square deviation; root mean square fluctuation and hydrogen bonds occupancy were examined after 50 ns. The interactions were also analyzed by means of the quantum theory of atoms in molecules. Our results show that the main interactions are hydrogen bonds between –OH groups of the polyphenol and C––O groups of the peptide bond. Stacking interactions between proline rings and phenol rings, that is C–H⋯π hydrogen bonds, also stabilize the dynamic structure of the complex.Item Understanding the chloride affinity of barbiturates for anion receptor design(2021-02-25) Petelski, Andre Nicolai; Márquez, María Josefina; Pamies, Silvana Carina; Sosa, Gladis Laura; Peruchena, Nélida MaríaDue to their potential binding sites, barbituric acid (BA) and its derivatives have been used in metal coordination chemistry. Yet their abilities to recognize anions remain unexplored. In this work, we were able to identify four structural features of barbiturates that are responsible for a certain anion affinity. The set of coordination interactions can be finely tuned with covalent decorations at the methylene group. DFT-D computations at the BLYP-D3(BJ)/aug-cc-pVDZ level of theory show that the C—H bond is as effective as the N—H bond to coordinate chloride. An analysis of the electron charge density at the C—H···Cl— and N—H···Cl— bond critical points elucidates their similarities in covalent character. Our results reveal that the special acidity of the C—H bond shows up when the methylene group moves out of the ring plane and it is mainly governed by the orbital interaction energy. The amide and carboxyl groups are the best choices to coordinate the ion when they act together with the C—H bond. We finally show how can we use this information to rationally improve the recognition capability of a small cage-like complex that is able to coordinate NaCl.Item Impact of confinement in multimolecular inclusion compounds of melamine and cyanuric acid(2019-02-25) Petelski, Andre Nicolai; Pamies, Silvana Carina; Sejas, Agustín Gabriel; Peruchena, Nélida María; Sosa, Gladis LauraSupramolecular cavities can be found in clathrates and self-assembling capsules. In these computational experiments, we studiedthe effect of folding planar hydrogen-bonded supramolecules of melamine (M) and cyanuric acid (CA) intostablecage-like quartets. Based on dispersion-corrected density functional theory calculations at the wB97XD/6-311++G(d,p) level, we show the flexibility of M and CA molecules to form free confined spaces. Our bonding analysis indicatesthat only CA can form a cage which is more stable than their planar systems. We then studied the capacity of the complexes to host ionic and neutral monoatomic species like Na+, Cl-and Ar. The encapsulation energies range from -2 to -65 kcal mol-1. A detailed energy decomposition analysis (EDA) support the fact that the triazine ring of CA is superior to the M one to capture chloride ions. In addition, the EDA and the topology of the electron density, by means of the Atoms in Molecules (AIM) theory and electrostatic potential maps, reveal the nature of the host-guest interactions in the confined space. The CA cluster appears to be the best multimolecular inclusion compound because it can host the three species by keeping its cage structure, and therefore could also act as a dual receptor of the ionic pair Na+Cl-. We think these findings could inspire the design of new heteromolecular inclusion compounds based on triazines and hydrogen bonds.