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A stereoselective, base-free Heck coupling between 1,4-naphthoquinone and 1H-1,2,3-triazole derivatives was reported for the first time. This study shows that depending on the 1,4-naphthoquinone, the use of an additional base is unnecessary to produce the naphthoquinone-triazole conjugates. This is also the first example of a Heck coupling of these two cores without using a base as an additive. In this work, sixteen new naphthoquinone-triazole hybrids were stereoselectively synthetized in good to excellent yields. The reaction mechanism was discussed based on DFT CAM−B3LYP calculations. The first step is the coordination of the arene to the palladium catalyst to form a palladacycle intermediate. After reorganization in this intermediate, the double bond in the arene is restored to proceed with the coupling step and formation of the C−C bond in the rate determining step. The Kozuchi-Shaik span model was employed to rationalize substituent effects.

Conformational stabilization mediated by hydrogen bonds can play an important role in the drug-target recognition process. Non-classical hydrogen bonding is receiving great attention, where C–H⋯Y hydrogen bonds are found in some biological systems and are important for molecular recognition, leading to the possibility of exploration of this interaction in drug design projects. Studies that identify and characterize new non-classical interactions in different systems can assist in the rational application of these interactions. In this paper, we describe the serendipitous identification and characterization of a new non-classical hydrogen bond donor moiety found in 3-acyl-substituted furan. We applied a theoretical and experimental approach in the study of several N-acylhydrazones containing 3-acyl-substituted furan, where we describe the presence of a hydrogen bond between the C(2)–H bond of 3-acyl-substituted furan with the imine nitrogen in the syn conformer of the N-acylhydrazone moiety. In addition, we evaluated the strength of this interaction with intermolecular models. Thus, we believe that the 3-acyl-substituted furan moiety can be rationally explored as a hydrogen bond donor moiety in drug design projects.

The water mol­ecule connects the mol­ecules in the crystal packing. The crystal structure exhibits N—H⋯O, O—H⋯O and O—H⋯N inter­actions, resulting in the formation of a three-dimensional framework., In the mol­ecular structure of the title compound, C10H10N4O2·H2O, the angle between the triazole and arene rings is 87.39 (5)°. The water of crystallization connects the mol­ecules in the crystal packing. The crystal structure exhibits N—H⋯O, O—H⋯O and O—H⋯N inter­actions, resulting in the formation of a three-dimensional framework. The inter­molecular inter­actions were identified and qu­anti­fied using Hirshfeld surface analysis.

In this work, a 8-hydroxyquinoline derivative, named 8-hydroxyquinoline-2-carboxaldehyde 2-furoyl hydrazone (HQFUH), was obtained. The respective compound was successfully synthesized as well as its respective Zn(II) coordination compound. Both compounds were structurally characterized, by experimental and theoretical IR and Raman spectra, XRD. Single crystal XRD showed that Zn(II) adopts a tetrahedral geometry, in which the neutral chelating ligand coordinates bidentaded by two N-atoms and the neutrality charge is achieved by two coordinated chloride ions. Topological analysis using Quantum Theory of Atoms in Molecules (QTAIM) was performed to investigate ligand interaction through O-atoms. This investigation is important regarding the determination of complex formation constant. The crystal structures of the ligand and complex are arranged according to an orthorhombic system with P212121 and Aea2 space groups, respectively. Ligand displays a E configuration around to C10 = N2 bond, while after the coordination of metal, a Z configuration is observed. Besides molecular structure description of complex, the intermolecular environment was analyzed by Hirshfeld Surface.

A new monohydrated polymorph of dexamethasone acetate was crystallized and its crystal structure characterized. The different analytical techniques used for describing its structural and vibrational properties were: single crystal and polycrystal X-ray diffraction, solid state nuclear magnetic resonance, infrared spectroscopy. A Hirshfeld surface analysis was carried out through self-arrangement cemented by H-bonds observed in this new polymorph. This new polymorph form appeared because of self-arrangement via classical hydrogen bonds around the water molecule.

A new complex involving 1,3-bisbenzyl-2-oxoimidazoline-4,5-dicarboxylic acid (H2L) and a cobalt(II) metal ion designated [Co(L)(H2O)2]n has been synthesized under solvothermal conditions and characterized by elemental analyses, IR spectra, thermogravimetric analysis, single crystal X-ray diffraction and magnetization. The new compound crystallizes as pink crystals in an orthorhombic system with space group Pbca. A unit cell with 8 asymmetric units is present, each containing a Co(II) center with distorted octahedral geometry and a coordination sphere consisting of one nitrogen and five oxygen ligands. Bridging carboxylate groups are responsible for the formation of a 1D polymer. Adjacent chains are connected through OH⋯O hydrogen bonds involving coordinated water molecules leading to the formation of supramolecular arrangement. Low-temperature electron paramagnetic resonance (EPR) measurements identified that Co ions are in the divalent charge state in orthorhombic or less symmetry in high-spin (HS) configuration with principal values of g tensor of g1 = 5.5(2), g2 = 3.0(2) and g3 = 2.0(1). Magnetic susceptibility measurements as a function of temperature were analyzed by the standard Curie–Weiss law including diamagnetic contributions. Magnetic data were consistently explained by HS configuration of Co2+ ions with very small contribution of anti-ferromagnetic coupling.

A new EuIII β-diketonate complex [Eu(btfa)3(dmbpy)] containing the btfa (4,4,4-trifluoro-1-phenyl-1,3-butanedione) and the p,p′-disubstituted bipyridine ligand dmbpy (4,4′-dimethyl-2,2′-bipyridine) have been synthesized and fully characterized. The X-ray crystal structure reveals that the compound crystallize in monoclinic system of space group P21/n, with a classical structure observed in other similar compounds. The molecular structure of the EuIII complex was calculated using the Sparkle/PM6 model, and your optimized ground state geometry were used to calculated all details involved in the energy transfer process and compared with photoluminescence experimental data. These data shows that the triplet → 5D1 and triplet → 5D0 are the main energy transfer channels and that the photoluminescence mechanism in this complex is proposed to be a ligand sensitized luminescence process. Additionally, red organic light emitting diode (OLED) devices were fabricated using this complex, presenting the characteristic EL emission bands due to 5D0 → 7FJ (J = 0–4) transitions, which gives evidence that the “antenna effect” is operative. Due to its intense red photo/electroluminescence emission, this complex have potential applications as light-conversion molecular devices (LCMDs), mainly to fabricate new OLEDs.

We reported experimental and theoretical investigation of conformers of 1,2,3-triazole derivatives, substances of exclusively synthetic origin, subject of extensive studies, because of several biological properties, such as antiviral, antimicrobial and antileishmaniasis. We reported molecular/supramolecular X-ray structures of antiophidian compounds I and II. For I and II there are two crystallographic different molecules in the unit cell (A and B). To explore the causes of the similarities in the compound’s crystal structures, intermolecular interactions were explored using the Hirshfeld surface as the fingerprint plots. In addition, density functional theory (DFT) calculations were carried out at the ωB97x-D/6-31G(d,p)-PCM-CHCl3 level aiming to contribute to the interpretation of the experimental data and complement the experimental findings. Two structures named 2A and 5B were found in good agreement with the respective X-ray solid state ones (A and B). Theoretical 1H nuclear magnetic resonance (NMR) spectra calculated for 5B rotated structure (torsion angles deviation around 40° to 90°) was in fine agreement with experimental results (in CDCl3) indicating that the solution molecular structure is considerably different from optimized equilibrium geometries and solid-state structure. Therefore, care is needed when using X-ray structures or DFT geometries to model interaction of drugs with biological targets since significant conformational changes may take place in solution.

Prostate cancer is an important cause of death in the male population and for which there is no satisfactory chemotherapy. Herein a new series of chalcone hybrids containing 2H-1,2,3-triazole core as the ring B has been synthesized and evaluated in vitro against PC-3 prostate cancer cell line. Compounds 4a, 4c and 4e significantly reduced cell viability and showed IC50 of 28.55, 15.64 and 25.56 µM, respectively. The structure-activity relationship supported by computational chemistry points that the polarity of the molecular surface area should have some relevance to the efficiency of the compounds, in particular the ratio of the partial positive charge sites and the total molecular surface area exposed to the cell environment.

With the increasing life expectancy of the world’s population, neurodegenerative diseases, such as Alzheimer’s disease (AD), will become a much more relevant public health issue. This fact, coupled with the lack of efficacy of the available treatments, has been driving research directed to the development of new drugs for this pathology. Metal-protein attenuating compounds (MPACs) constitute a promising class of agents with potential application on the treatment of neurodegenerative diseases, such as AD. Currently, most MPACs are based on 8-hydroxyquinoline. Recently, our research group has described the hybrid aroylhydrazone containing the 8-hydroxyquinoline group INHHQ as a promising MPAC. By studying the known structure-related ligand HPCIH, which does not contain the phenol moiety, as a simplified chemical model for INHHQ, we aimed to clarify the real impact of the aroylhydrazone group for the MPAC activity of a compound with potential anti-Alzheimer’s activity. The present work describes a detailed solution and solid-state study of the coordination of HPCIH with Zn2+ ions, as well as its in vitro binding-ability towards this metal in the presence of the Aβ(1–40) peptide. Similar to INHHQ, HPCIH is able to efficiently compete with Aβ(1–40) for Zn2+ ions, performing as expected for an MPAC. The similarity between the behaviors of both ligands is remarkable. Taken together, the data presented herein point to aroylhydrazones, such as the compounds HPCIH and the previously published INHHQ, as encouraging MPACs for the treatment of AD. Fil: Cukierman, Daphne S.. Pontifícia Universidade Católica do Rio de Janeiro; Brasil Fil: Accardo, Elio. Pontifícia Universidade Católica do Rio de Janeiro; Brasil Fil: Gomes, Rosana Garrido. Pontifícia Universidade Católica do Rio de Janeiro; Brasil Fil: De Falco, Anna. Pontifícia Universidade Católica do Rio de Janeiro; Brasil Fil: Miotto, Marco César. Universidad Nacional de Rosario; Argentina Fil: Freitas, Maria Clara Ramalho. Universidade Federal do Rio de Janeiro; Brasil Fil: Lanznaster, Mauricio. Universidade Federal Fluminense; Brasil Fil: Fernández, Claudio O.. Universidad Nacional de Rosario; Argentina Fil: Rey, Nicolás A.. Pontifícia Universidade Católica do Rio de Janeiro; Brasil

Summary Purpose To investigate which muscular maneuvers provide larger electric activity (EA) of the suprahyoid (SH) and infrahyoid (IH) muscles to be used as surface electromyography (SEMG) signal normalization reference. Methods The electrical potentials of the SH and IH muscles of 12 subjects were evaluated using six muscular maneuvers, involving the position of the tongue and effort. It was selected as maximum voluntary sustained activity maneuver, the one having the minor coefficient of variation and the smallest value for each muscle group. The EA signal was converted using the root mean square in microvolts. It was considered then the maximum signal of each maneuver as the difference between the mean of three measures and the resting potential. Results The maneuvers that provided higher mean potentials with minor coefficient of variation and smallest P value were incomplete swallowing (IS) with effort (mean potential equal to 56.73±8.68 with coefficient of variation of 15.30%) in SH group, and tongue retracted with mouth open (TROM, mean potential equal to 46.57±7.83 with coefficient of variation of 16.81%) in IH group. Conclusion The IS with effort and TROM maneuvers should be considered for signal normalization in these muscles, respectively, and may provide conditions for using the SEMG in voice clinic. Significance The use of normalization standards in researches of SH and IH muscles in the voice area will allow comparisons among future works.