Photoinduced 1,3‐Dipolar Cycloadditions of Cyclic Enones and 2,5‐Disubstituted Tetrazoles: An Unprecedented Pathway to Polysubstituted Pyrazolines and Pyrazoles.

International audienceWe report herein the syntheses of original pyrazolines and pyrazoles through 1,3‐dipolar cycloaddition cyclic enones with 2,5‐disubstituted nitrile imines achieved via photochemical activation 2,5‐diaryl substituted tetrazoles. Monitoring reactions, similar to imine‐mediated tetrazole‐ene cycloadditions (NITEC), could be performed by means UV‐vis absorption emission measurements. The presence or absence substituents in alpha position ketone function makes it possible direct these reactions towards selective formation pyrazolines. choice tetrazoles proved crucial for fluorescence properties polycyclic derivatives obtained

Synthesis, Characterization, Antimicrobial Properties, and Antioxidant Activities of Silver-N-Heterocyclic Carbene Complexes

The emergence of antimicrobial resistance has become a major handicap in the fight against bacterial infections, prompting researchers to develop new, more effective, and multimodal alternatives. Silver and its complexes have long been used as antimicrobial agents in medicine because of their lack of resistance to silver, their low potency at low concentrations, and their low toxicity compared to most commonly used antibiotics. N-Heterocyclic carbenes (NHCs) are widely used for coordination of transition metals, mainly in catalytic chemistry. In this study, several N-alkylated benzimidazolium salts 2a–j were synthesized. Then, the N-heterocyclic carbene (NHC) precursor was treated with Ag2O to give silver (I) NHC complexes (3a–j) at room temperature in dichloromethane for 48 h. Ten new silver-NHC complexes were fully characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), elemental analysis, and LC-MSMS (for complexes) techniques. The antibacterial and antioxidant activities of salt 2 and its silver complex 3 were evaluated. All of these complexes were more effective against bacterial strains than comparable ligands. With MIC values ranging from 6.25 to 100 g/ml, the Ag-NHC complex effectively showed strong antibacterial activity. Antioxidant activity was also tested using conventional techniques, such as 2, 2-diphenyl-1-picrylhydrazine (DPPH) and hydrogen peroxide scavenging assays. In DPPH and ABTS experiments, compounds 3a, 3b, 3c, 3e, 3g, and 3i showed significant clearance

Design of Amorphous Thin Films of Azobenzene Containing Ruthenium Acetylides for Optical Data Storage

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From synthesis to biological impact of palladium bis(benzimidazol-2-ylidene) complexes: Preparation, characterization, and antimicrobial and scavenging activity

Palladium-based complexes with the ligand N-heterocyclic carbene have long received attention as active catalysts for many catalytic reactions. Recently, the biological activities of these air- and moisture-stable complexes have also been investigated. In our work, bis(benzimidazol-2-ylidene)palladium complexes 3a–d were synthesized by reacting benzimidazolium salts 2a–d with PdCl2 under reflux in tetrahydrofuran for 24 h and analyzed by spectroscopy (FT-IR [Fourier transform infrared], 1H NMR [proton nuclear magnetic resonance]) characterization, 13C NMR [carbon-13 (C13) nuclear magnetic resonance]), and elemental analysis. The in vitro antibacterial and antifungal activities of these complexes were studied against Gram-positive and Gram-negative microorganisms, and two different fungi showed their remarkable biological potential. In addition, the analysis of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals using spectrophotometry showed that they are an antioxidant. The potent antibacterial and antioxidant activities of the synthetic complexes suggest that they are more effective antibacterial agents. Our study extends the biological relevance of palladium bis(benzimidazol-2-ylidene) complexes with antibacterial and antioxidant activities. Furthermore, the main goal of the docking simulation is to provide a detailed analysis of the interaction between the complex and the protein of interest

Design of bis(acylamino)triazine containing ruthenium-acetylides as self-complementary supramolecular units

International audienceA series of systematically varied 'rigid-rod' octahedral ruthenium-acetylide complexes, bearing conjugated bis(acylamino)triazine (DAT) substituents capable of ADAD-DADA pairing, of general formula trans-[(dppe)2Ru(Cl)(Ctriple bond; length of mdashC-C6H4-DAT(R)2)] (R = Et, i-Pr, t-Bu, n-C5H11) have been synthesized and thoroughly characterized in solution by 1H NMR and in the solid state. trans-[Ru(-Ctriple bond; length of mdashC-C6H4-DAT(R)2)2(dppe)2] (R = n-C5H11) has also been designed to form discrete oligomeric chains in solution

Novel ruthenium(ii) N-heterocyclic carbene complexes: Synthesis, characterization, and evaluation of their biological activities

A series of ruthenium(ii) complexes with N-heterocyclic carbene (NHC) ligands of the general type (arene)(NHC)Ru(ii)X2 (where X = halide) (3a–3d) were synthesized and characterized in order to compare their antibacterial activities with benzimidazolium salts 2. Our comparison revealed that ruthenium(ii) NHC complexes 3 were more active than benzimidazolium salts 2. Furthermore, the two complexes 3b and 3d had a potent inhibitory effect against acetylcholinesterase with an IC50 of 4.52 and 4.04 g·mL−1 and against tyrosinase with an IC50 of 20.77 and 25.84 g·mL−1, respectively. In addition, screening of benzimidazolium salts (2a–2d) and their ruthenium(ii) complexes (3a–3d) against colon carcinoma cell lines (HCT-116) and hepatocellular carcinoma cell lines (HepG-2) were studied. The obtained results revealed that complex 3a is the most active against vinblastines

Supramolecular Ruthenium–Alkynyl Multicomponent Architectures: Engineering, Photophysical Properties, and Responsiveness to Nitroaromatics

A series of H-bonded supramolecular architectures were built from monofunctional M–CC–R and bifunctional R–CC–M–CC–R <i>trans</i>-alkynylbis­(1,2-bis­(diphenylphosphino)­ethane)­ruthenium­(II) complexes and π-conjugated modules containing 2,5-dialkoxy-<i>p</i>-phenylene. Incorporation on each partner of a cyanuric end and of the complementary Hamilton receptor provided the necessary means to keep the constituents together via strong hydrogen bonding. Characterization of all architectures has been performed on the basis of NMR and photophysical methods. In particular, the formation of a Hamilton receptor/cyanuric acid complex has been exemplified by an X-ray single-crystal structure determination. Both self-assembly and accurate modification of the complementary blocks were ensured in such a way that the resulting materials maintain the responsiveness of the electron-rich 2,5-dialkoxy-<i>p</i>-phenylene spacers toward nitroaromatics

Supramolecular Ruthenium–Alkynyl Multicomponent Architectures: Engineering, Photophysical Properties, and Responsiveness to Nitroaromatics

A series of H-bonded supramolecular architectures were built from monofunctional M–CC–R and bifunctional R–CC–M–CC–R <i>trans</i>-alkynylbis­(1,2-bis­(diphenylphosphino)­ethane)­ruthenium­(II) complexes and π-conjugated modules containing 2,5-dialkoxy-<i>p</i>-phenylene. Incorporation on each partner of a cyanuric end and of the complementary Hamilton receptor provided the necessary means to keep the constituents together via strong hydrogen bonding. Characterization of all architectures has been performed on the basis of NMR and photophysical methods. In particular, the formation of a Hamilton receptor/cyanuric acid complex has been exemplified by an X-ray single-crystal structure determination. Both self-assembly and accurate modification of the complementary blocks were ensured in such a way that the resulting materials maintain the responsiveness of the electron-rich 2,5-dialkoxy-<i>p</i>-phenylene spacers toward nitroaromatics

Supramolecular Ruthenium-Alkynyl Multicomponent Architectures: Engineering, Photophysical Properties, and Responsiveness to Nitroaromatics

International audienceA series of H-bonded supramolecular architectures were built from monofunctional M-C≡C-R and bifunctional R-C≡C-M-C≡C-R trans-alkynylbis(1,2-bis(diphenylphosphino)ethane)ruthenium(II) complexes and π-conjugated modules containing 2,5-dialkoxy-p-phenylene. Incorporation on each partner of a cyanuric end and of the complementary Hamilton receptor provided the necessary means to keep the constituents together via strong hydrogen bonding. Characterization of all architectures has been performed on the basis of NMR and photophysical methods. In particular, the formation of a Hamilton receptor/cyanuric acid complex has been exemplified by an X-ray single-crystal structure determination. Both self-assembly and accurate modification of the complementary blocks were ensured in such a way that the resulting materials maintain the responsiveness of the electron-rich 2,5-dialkoxy-p-phenylene spacers toward nitroaromatics