Crystalline systems can be organized from several types of intermolecular interactions, among which classical and weak H-bonds are the most common, playing a very important role in the supramolecular assembly. However, in recent years a number of works have considered the influence of the homonuclear dihydrogen interaction, which had been neglected for a long time, to describe the supramolecular assembly of single crystals. In the C17H17N3O2 azine of the present study, a nonclassical dihydrogen interactions (C–H···H–C contact) have appeared in the crystal structure with a fundamental contribution toward the stability of crystalline packing. Nonetheless, an X-ray structural analysis is not conclusive to assess the real importance of the C–H···H–C contact. In order to characterize the nature and implications of C–H···H–C contacts concomitant with the classical interactions, the crystallized compound was evaluated by Hirshfeld surface, Quantum Theory of Atoms in Molecules, natural bond orbital, and Car–Parrinello molecular dynamics. The results establish that these interactions really exist, and their extension is responsible for the cooperative effect on the stability of crystalline packing. We expect that a more thorough understanding and description of homonuclear dihydrogen interactions in the supramolecular assembly of C17H17N3O2 can assist in the crystal engineering of small molecules, offering progress on physical–chemistry parameters of biological and material processes.

Extensive solid state characterization of a novel asymmetric azine and its environmental polarization effect is reported.

Organic molecules with electron acceptors or withdrawal substituents terminal at π-conjugated system are promising candidates to be explored as materials with high linear and nonlinear optical properties. On the basis of these features, a novel asymmetric azine (7E, 8E)-2-(3-methoxy-4-hydroxy-benzylidene)-1-(4nitrobenzylidene)hydrazineC 15 H 13 N 3 O 4 (NMZ) was synthesized. The molecular structure of NMZ was elucidated by X-ray crystallography and the supramolecular arrangement was analyzed from Hirshfeld surface methodology. An iterative electrostatic scheme using a super molecule approach, where neighboring molecules are represented by charge points, was employed to investigate optical dipole moment (μ), the linear polarization (α) and the first (β) and second (γ) hyperpolarizabilities. The NMZ crystallized in the centrosymetric space group P2 1 /n and packs viaand N•••π interactions. The macroscopic property of third order χ (3) found for the NMZ is 298.62 times greater than values reported for chalcone derivative (2E)-1-(3-bromophenyl)-3-[4 (methylsulfanyl)phenyl]prop-2en-1-one. The results for NMZ indicate a good nonlinear optical effect.

The multivalent effect of carbohydrates (glycoclusters) has been explored to study important biological targets and processes involving Trypanosoma cruzi (T. cruzi) infection. Likewise, CuAAC cycloaddition reactions (click chemistry) have been applied as useful strategy in the discovery of bioactive molecules. Hence, we describe the synthesis of 1,2,3-triazole-based tetravalent homoglycoclusters (1–3) and heteroglycoclusters (4 and 5) of d-galactopyranose (C-1 and C-6 positions) and sialic acid (C-2 position) to assess their potential to inhibit T. cruzi cell invasion and also its cell surface trans-sialidase (TcTS). The target compounds were synthesised in good yields (52–75 %) via click chemistry by coupling azidosugars galactopyranose and sialic acid with alkynylated pentaerythritol or tris(hydroxymethyl)-aminomethane (TRIS) scaffolds. T. cruzi cell invasion inhibition assays showed expressive low parasite infection index values (5.3–6.8) for most compounds. However, most glycoclusters proved to be weak TcTS inhibitors at 1 mM (<17 %), except the tetravalent sialic acid 3 (99 % at 1 mM, IC50 450 μM). Therefore, we assume that T. cruzi cell invasion blockage is not due to TcTS inhibition by itself, but rather by other mechanisms involved in this process. In addition, all glycoclusters were not cytotoxic and had significant trypanocidal activity upon parasite survival of amastigote forms.

Neglected Diseases (NDs) affect million of people, especially the poorest population around the world. Several efforts to an effective treatment have proved insufficient at the moment. In this context, triazole derivatives have shown great relevance in medicinal chemistry due to a wide range of biological activities. This review aims to describe some of the most relevant and recent research focused on 1,2,3- and 1,2,4-triazole-based molecules targeting four expressive NDs: Chagas disease, Malaria, Tuberculosis and Leishmaniasis.

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