First report on the electrooxidation of vinpocetine using a modification free sensing platform: application to pharmaceutical formulations.

This study presents the first insights into vinpocetine (VIN) behavior, a nootropic compound, on a glassy carbon electrode (GCE). Cyclic voltammetry (CV) revealed an irreversible oxidation peak at +1.0 V ( Ag/AgCl), with pH dependency indicating proton involvement in the electrochemical reaction.

The use of molecular electronic structure methods to investigate mechanically interlocked molecules.

Mechanically interlocked molecules (MIMs) show several applications as molecular machines, catalysts, and appear as potential structures for ion recognition. Importantly, the understanding of the nature of the mechanical bonds that support the interaction between the non-interlocked components of MIMs is still a poorly explored topic in the literature. Important discoveries in the field of MIMs have been made using molecular mechanics (MM) and, in particular, molecular dynamics (MD) methods.

Cation recognition controlled by protonation or chemical reduction: a computational study.

To control biochemical processes, non-covalent interactions involving cations are activated by protons or electrons. In the present study, the bonding situation between: (i) carboxylic acid or (ii) ferrocene-functionalized crown ether derivatives and cations (Li, Na or K) has been elucidated and, mainly, tuned by the substitution of hydrogen atoms by electron donor (-NH) or acceptor (-NO) groups. The deprotonation of the carboxyl groups improves the interaction with the cations through more favorable electrostatic O⋯cation interactions.

Tuning Mechanically Interlocked Molecules to Recognize Anions and Cations: A Computational Study.

Ions appear as active components in diverse materials. Here, the bonding energy between mechanically interlocked molecules (MIMs) or their acyclic/cyclic molecular derivatives and i) Cl and Br ions and/or ii) Na and K ions, have been investigated. The chemical environment provided by MIMs is less preferably to recognize ionic species compared to unconstrained interactions that are furnished by acyclic molecules.

Designing boron and metal complexes for fluoride recognition: a computational perspective.

Fluoride anions (F) may have beneficial or harmful effects on the environment depending on their concentration. Here, we shed light on F recognition by compounds containing boron, tellurium and antimony, which were experimentally demonstrated to be capable of interacting with the F ion in a partially aqueous medium. Boron and metal complexes recognize F anions primarily using electrostatic energy along with important contributions from orbital interaction energy.

Development of new dinuclear Fe(III) coordination compounds with nanomolar antitrypanosomal activity.

Chagas disease is a neglected tropical disease caused by the protozoan pathogen . The disease is a major public health problem affecting about 6 to 7 million people worldwide, mostly in Latin America. The available therapy for this disease is based on two drugs, nifurtimox and benznidazole, which exhibit severe side effects, including resistance, severe cytotoxicity, variable efficacy and inefficiency in the chronic phase.

The design of anion-π interactions and hydrogen bonds for the recognition of chloride, bromide and nitrate anions.

The role of anions in several biochemical processes has given rise to enormous interest in the identification/exploration of compounds with the potential ability to recognize anions. Here, an anthracene-squaramide conjugated compound, O2C4[NH(C14H10)][(NH(C6H6)], has been modified through the substitutions (i) H → F and (ii) H → OH at the anthracene and benzene rings to improve the capabilities of these structures for recognizing chloride, bromide, and nitrate anions. Through an energy decomposition analysis method, the recognition of the anions is chiefly identified as a non-covalent process.

The simultaneous recognition mechanism of cations and anions using macrocyclic-iodine structures: insights from dispersion-corrected DFT calculations.

The recent development of compounds for recognizing ions highlights the applicability of this area. In this work, the simultaneous recognition of cations (Li, Na and K) and anions (F, Cl and I) using a macrocycle comprising a simple crown ether and an iodine-triazole unit is investigated. The roles of the (i) cation radius, (ii) anion radius, and (iii) electron withdrawing (-CN) and donor (-OH) groups of the receptor in ionic recognition were evaluated.

Polar Order and Symmetry Breaking at the Boundary between Bent-Core and Rodlike Molecular Forms: When 4-Cyanoresorcinol Meets the Carbosilane End Group.

Two isomeric achiral bent-core liquid crystals involving a 4-cyanoresorcinol core and containing a carbosilane unit as nanosegregating segment were synthesized and were shown to form ferroelectric liquid-crystalline phases. Inversion of the direction of one of the COO groups in these molecules leads to a distinct distribution of the electrostatic potential along the surface of the molecule and to a strong change of the molecular dipole moments. Thus, a distinct degree of segregation of the carbosilane units and consequent modification of the phase structure and coherence length of polar order result.

Ru-NO and Ru-NO2 bonding linkage isomerism in cis-[Ru(NO)(NO)(bpy)2](2+/+) complexes - a theoretical insight.

Ruthenium nitrosyl complexes have received considerable attention due to the fact that they are able to store, transfer and release NO in a controlled manner. It is well-known that the NO reactivity of ruthenium nitrosyl complexes can be modulated with the judicious choice of equatorial and axial ligands. In this piece of research we elucidate the nature of the Ru-NO and Ru-NO2 bonding in a cis-[Ru(NO)(NO2)(bpy)2](2+) complex energy decomposition (Su-Li EDA) and topological (e.

Nanoparticle translocation through a lipid bilayer tuned by surface chemistry.

An enhanced understanding about the interactions between nanomaterials and cell membranes may have important implications for biomedical applications. In this work, coarse-grained molecular dynamics simulations of gold nanoparticles interacting with lipid bilayers were performed to evaluate the effect of hydrophobicity, charge density and ligand length on lipid bilayers. The simulations accomplished indicate that hydrophobic and anionic nanoparticles do not exhibit significant interactions and different charge densities may induce pore formation or nanoparticle wrapping, resembling first stages of endocytosis.

The nature of Ru-NO bonds in ruthenium tetraazamacrocycle nitrosyl complexes--a computational study.

Ruthenium complexes including nitrosyl or nitrite complexes are particularly interesting because they can not only scavenge but also release nitric oxide in a controlled manner, regulating the NO-level in vivo. The judicious choice of ligands attached to the [RuNO] core has been shown to be a suitable strategy to modulate NO reactivity in these complexes. In order to understand the influence of different equatorial ligands on the electronic structure of the Ru-NO chemical bonding, and thus on the reactivity of the coordinated NO, we propose an investigation of the nature of the Ru-NO chemical bond by means of energy decomposition analysis (EDA), considering tetraamine and tetraazamacrocycles as equatorial ligands, prior to and after the reduction of the {RuNO}(6) moiety by one electron.

Oxindole-Schiff base copper(II) complexes interactions with human serum albumin: spectroscopic, oxidative damage, and computational studies.

CD and EPR were used to characterize interactions of oxindole-Schiff base copper(II) complexes with human serum albumin (HSA). These imine ligands form very stable complexes with copper, and can efficiently compete for this metal ion towards the specific N-terminal binding site of the protein, consisting of the amino acid sequence Asp-Ala-His. Relative stability constants for the corresponding complexes were estimated from CD data, using the protein as competitive ligand, with values of log K(CuL) in the range 15.