1-(4-Chloro­phen­yl)-3-(2-meth­oxy­anilino)propan-1-one

In the title compound, C16H16ClNO2, the mol­ecule adopts a bowed conformation, with a dihedral angle of 39.9 (2)° between the aromatic rings. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, generating C(6) chains propagating in [010]. Very weak aromatic π–π stacking is also observed [centroid–centroid distance = 4.040 (2) Å]

8-Methoxy-4-(4-Methoxyphenyl)Quinoline

In the title compound, C 17H 15NO 2, the dihedral angle between the quinoline and benzene ring systems is 62.17 (1)°. In the crystal, zigzag chains propagating in c are linked by C-H⋯O hydrogen bonds, and weak C-H⋯π inter-actions link the chains

8-Meth­oxy-4-(4-methoxy­phen­yl)quinoline

In the title compound, C17H15NO2, the dihedral angle between the quinoline and benzene ring systems is 62.17 (1)°. In the crystal, zigzag chains propagating in c are linked by C—H⋯O hydrogen bonds, and weak C—H⋯π inter­actions link the chains

Synthesis, characterization and catecholase biomimetic activity of novel cobalt(II), copper(II), and iron(II) complexes bearing phenylene-bisbenzimidazole ligand

Transition metal complexes of Co(II), Cu(II), and Fe(II) bearing a rigid symmetrical 2,20 -(1,2-phenylene)bis (1H-benzimidazole) ligand, PhBIm2, were synthesized and fully characterized by ESI-MS, FT-IR, 1 H NMR (for paramagnetic species), UV–Vis spectroscopy and microanalytical techniques. Besides the cobalt complex was subject of X-ray structural analysis. The molecular crystal structure of the PhBIm2Co(II)Cl2 complex revealed the metal center in a pseudo-tetrahedral environment with not significant lengthening or compressing of the bonds in the PhBIm2 framework upon chelation of the ligand. All complexes catalyze the aerobic oxidation of o-catechol to o-quinone under mild conditions. The results show that the oxidation rate depends on the electronic stabilizing effect to the metal center rather than the steric hindrance of the ligand. Kinetic parameters (Vmax, kcat, KM) were estimated by mean of the Michaelis–Menten model and Lineweaver–Burk plot. Catechol oxidation rates of complexes 2–4 are in the same order of magnitudes of mononuclear and dinuclear Cu(II) complexes bearing imidazole-based ligands but lower than observed for the catecholase enzym

Estudio cinético de la interconversión de Astilbina mediante espectroscopia de 1H-rmn

La cinética de interconversión de astilbina a una mezcla de sus respectivos diasteroisómeros fue estudiada por espectroscopia de resonancia magnética nuclear empleando experimentos de irradiación selectiva (TOCSY) en dimetilsulfóxido. Se planteó un modelo que permitió establecer una tendencia al equilibrio para H-3 (interconversión de astilbina a neoisoastilbina)[email protected] interconversion kinetics of astilbin to a mixture of their respective diasteroisomers was studied by nuclear magnetic resonance spectroscopy using selective irradiation experiments (TOCSY) in dimethylsulfoxide. It is proposed a model which allowed establishing a trend to equilibrium for H-3 (astilbin interconversion to neoisoastilbin

Assessment Of The Tautomeric Population Of Benzimidazole Derivatives In Solution: A Simple And Versatile Theoretical-Experimental Approach

Herein, we present a simple and versatile theoretical-experimental approach to assess the tautomeric distribution on 5(6)-aminobenzimidazole (5(6)-ABZ) derivatives in solution via one-photon absorption. The method is based on the optimized weighted sum of the theoretical spectra of the corresponding tautomers. In this article we show how the choice of exchange-correlation functional (XCF) employed in the calculations becomes crucial for the success of the approach. After the systematic analysis of XCFs with different amounts of exact-exchange we found a better performance for B3LYP and PBE0. The direct test of the proposed method on omeprazole, a well-known 5(6)-benzimidazole based pharmacotherapeutic, demonstrate its broader applicability. The proposed approach is expected to find direct applications on the tautomeric analysis of other molecular systems exhibiting similar tautomeric equilibria. Graphical abstract: Using a weighted sum of the corresponding individual tautomer theoretical spectra, the tautomeric population of benzimidazole derivatives in solution and at room temperature is directly determined through the theoretical-experimental fitting of the UV-Vis spectra of the tautomeric mixture at equilibrium. The reliability of the proposed method is based on the existent spectral difference between the two species.[Figure not available: see fulltext.

C2 and C1-Symmetric Camphopyrazole Dioxomolybdenum(VI) Complexes catalyze the Epoxidation of Cyclic Olefins

Dioxomolybdenum(VI) complexes (1‐6) were prepared in good yields (≥79 %) using enantiopure C$_{2}$ and C$_{1}$‐symmetric bidentate N,N‐ligands (L$_{1}$‐L$_{6}$) derived from (+)‐camphor. The ligands and complexes were characterized by NMR spectroscopy, IR, and elemental analysis. Single crystal X‐ray diffraction analyses of complexes 3, 4 and 6 confirmed the bidentate coordination modes of ligands L$_{3}$, L$_{4}$, and L$_{6}$ and revealed distorted octahedral coordination geometries around the metal center. Complexes 3 and 6 form conformational isomers depending on the orientation of the substituents of the ligand aryl groups. Preliminary evaluation of the complexes as catalysts for the epoxidation of cyclohexene (81–93 % conversion) and cis‐cyclooctene (66–94 % conversion) with cumyl hydroperoxide and 35 % w/w aqueous hydrogen peroxide (39–73 %) demonstrated their activity for oxygen atom transfer reactions, opening the way for asymmetric epoxidations

“Chiral-at-Metal” Hemilabile Nickel Complexes with a Latent d¹⁰-ML₂ Configuration: Receiving Substrates with Open Arms

Complexes with highly reactive stereogenic metal centers are of great interest to asymmetric synthesis. Thus, by reacting [Ni­(COD)₂] with 2 equiv of the P-alkene ligand (<i>S</i>)-<b>5</b> ((<i>S</i>)-(+)-<i>N</i>-(3,5-dioxa-4-phosphacyclohepta­[2,1-<i>a</i>;3,4-<i>a</i>′]­dinaphthalen-4-yl)­dibenz­[<i>b</i>,<i>f</i>]­azepine) or (<i>S</i>_<i>P</i><i>,S</i>_<i>C</i>)<i>-</i><b>6</b> ((2<i>S</i>,5<i>S</i>)-(-)-<i>N</i>-(aza-3-oxa-2-phosphabicyclo­[3.3.0]­octan-4-on-2-yl)­dibenz­[<i>b</i>,<i>f</i>]­azepine), the diastereomerically and enantiomerically pure tetrahedral complexes (Δ,<i>S,S</i>)-[Ni­(<b>5</b>-κ<i>P</i>,η²-alkene)₂] (<b>2a</b>) and (Δ,<i>S</i>_P<i>,S</i>_C<i>,S</i>_P<i>′</i><i>,S</i>_C<i>′</i>)-[Ni­(<b>6</b>-κ<i>P</i>,η²-alkene)₂] (<b>2b</b>) were obtained in almost quantitative yields on multigram scales. The Ni atoms showed in both cases stable Δ configurations. Even though these Ni(0) complexes were air stable in the solid state, once dissolved, complex <b>2a</b> readily activated CS₂, alkynes, and enones as the formal d¹⁰-ML₂ fragment [Ni­(<b>5</b>-κ<i>P</i>)₂] (<b>4</b>) to form adducts <b>8</b>–<b>11</b>. This is possible thanks to the decoordination of the hemilabile alkene arms of the P-alkene ligands, and the X-ray crystal structures of the CS₂ and 4-ethynyltoluene adducts confirmed the η² coordination modes of the substrates and the concomitant opening up of the alkene arms of ligand <b>5</b>. The coordination of α,β-unsaturated carbonyl compounds in complexes <b>11a</b>–<b>c</b> was reversible

“Chiral-at-Metal” Hemilabile Nickel Complexes with a Latent d¹⁰-ML₂ Configuration: Receiving Substrates with Open Arms

Complexes with highly reactive stereogenic metal centers are of great interest to asymmetric synthesis. Thus, by reacting [Ni­(COD)₂] with 2 equiv of the P-alkene ligand (<i>S</i>)-<b>5</b> ((<i>S</i>)-(+)-<i>N</i>-(3,5-dioxa-4-phosphacyclohepta­[2,1-<i>a</i>;3,4-<i>a</i>′]­dinaphthalen-4-yl)­dibenz­[<i>b</i>,<i>f</i>]­azepine) or (<i>S</i>_<i>P</i><i>,S</i>_<i>C</i>)<i>-</i><b>6</b> ((2<i>S</i>,5<i>S</i>)-(-)-<i>N</i>-(aza-3-oxa-2-phosphabicyclo­[3.3.0]­octan-4-on-2-yl)­dibenz­[<i>b</i>,<i>f</i>]­azepine), the diastereomerically and enantiomerically pure tetrahedral complexes (Δ,<i>S,S</i>)-[Ni­(<b>5</b>-κ<i>P</i>,η²-alkene)₂] (<b>2a</b>) and (Δ,<i>S</i>_P<i>,S</i>_C<i>,S</i>_P<i>′</i><i>,S</i>_C<i>′</i>)-[Ni­(<b>6</b>-κ<i>P</i>,η²-alkene)₂] (<b>2b</b>) were obtained in almost quantitative yields on multigram scales. The Ni atoms showed in both cases stable Δ configurations. Even though these Ni(0) complexes were air stable in the solid state, once dissolved, complex <b>2a</b> readily activated CS₂, alkynes, and enones as the formal d¹⁰-ML₂ fragment [Ni­(<b>5</b>-κ<i>P</i>)₂] (<b>4</b>) to form adducts <b>8</b>–<b>11</b>. This is possible thanks to the decoordination of the hemilabile alkene arms of the P-alkene ligands, and the X-ray crystal structures of the CS₂ and 4-ethynyltoluene adducts confirmed the η² coordination modes of the substrates and the concomitant opening up of the alkene arms of ligand <b>5</b>. The coordination of α,β-unsaturated carbonyl compounds in complexes <b>11a</b>–<b>c</b> was reversible