Centro UTN QUITEX - Difusión Científica - Artículos de Revista

Permanent URI for this collectionhttp://48.217.138.120/handle/20.500.12272/3851

Browse

Subject: search.filters.subject.hydrogen bonds

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Augmentation of inductive effects through short range intramolecular hydrogen bonds for the improvement of cooperativity of trimeric rosettes
    (2024-02-26) Petelski, Andre Nicolai; Bundrea, Tamara; Peruchena, Nélida María
    Three key design elements improve the binding strength of trimeric rosettes: the direction of hydrogen bonds, the addition of groups with inductive effects, and the presence of ambifunctional intramolecular hydrogen bonds between the substituents.
  • Thumbnail Image
    Item
    Understanding the influence of alkali cations and halogen anions on the cooperativity of cyclic hydrogen-bonded rosettes in supramolecular stacks
    (2022-11-07) Petelski, Andre Nicolai; Fonseca Guerra, Célia
    Hydrogen-bonded supramolecular systems are known to obtain extra stabilization from the complexation with ions, like guanine quadruplex (GQ). They experience strong hydrogen bonds due to cooperative effects. To gain deeper understanding of the interplay between ions and hydrogen-bonding cooperativity, relativistic dispersion-cor rected density functional theory (DFT-D) computations were performed on triple layer hydrogen-bonded rosettes of ammeline interacting with alkali metal cations and halides. Our results show that when ions are placed between the stacks, the hydrogen bonds are weakened but, at the same time, the cooperativity is strengthened. This phenomenon can be traced back to the shrinkage of the cavity as the ions pull the monomers closer together and therefore the distance between the monomers becomes smaller. On one hand this results in a larger steric repulsion, but on the other hand, the donor-acceptor interactions are enhanced due to the larger overlap between the donating and accepting orbitals leading to more charge donation and therefore an enhanced electrostatic attraction.
  • Thumbnail Image
    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 Laura
    Melamine (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.
  • Thumbnail Image
    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 María
    Due 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.