Crystal structure of 2-[(E)-2-(4-bromophenyl)diazen-1-yl]-4,5-bis(4-methoxyphenyl)-1H-imidazole: The first example of a structurally characterized triarylazoimidazole

The title compound, C23H19BrN4O2, is a product of an azo coupling reaction between 3,4-bis(4-methoxyphenyl)imidazole and 4-bromophenyldiazonium tetrafluoroborate. Its crystal structure was determined using data collected at 120 K. The molecule adopts a trans configuration with respect to the N=N double bond. The imidazole and aryl rings attached to the azo linkage are coplanar within 12.73 (14)°, which indicates significant electron delocalization within the molecule. In the crystal, the molecules form centrosymmetric dimers via pairs of N - H⋯O hydrogen bonds. © 2021

Combined analysis of chemical bonding in a Cu(II) dimer using QTAIM, Voronoi tessellation and Hirshfeld surface approaches

Interaction of 1-(1 H -pyrazol-5-yl)ethanone oxime (H 2 PzOx) with copper(II) chloride in the presence of pyridine afforded a binuclear discrete [Cu 2 (HPzOx) 2 Cl 2 py 2 ] complex, which was characterized by Fourier transform???IR and electron paramagnetic resonance (EPR) spectra, magnetochemistry and high-resolution X-ray diffraction experiments. Multipole refinement of X-ray diffraction data and density-functional theory (DFT) calculations of an isolated molecule allowed charge and spin distributions to be obtained for this compound. Magnetochemistry data, EPR spectra and DFT calculations of an isolated molecule show antiferromagnetic coupling between copper(II) ions. The spin distribution suggests an exchange pathway via the bridging pyrazole ring in the equatorial plane of the CuN 4 Cl coordination polyhedron, thus providing support for the classical superexchange mechanism; the calculated value of the magnetic coupling constant ???2 J is equal to 220???cm ???1 , which compares well with the experimental value of 203????????2???cm ???1 . Chemical connectivity was derived by Bader's `quantum theory of atoms in molecules' and compared with Voronoi tessellation and Hirshfeld surface representations of crystal space. All methodologies gave a similar qualitative and semi-quantitative description of intra- and intermolecular connectivity

High-Nuclearity (Cu8-Based) Cage Silsesquioxanes: Synthesis and Structural Study

We herein report a study of Cu(II)-silsesquioxanes' self-assembly in the presence of two possible template agents (acetonitrile and acetone). This results in the isolation of unusual high-nuclearity cluster CuII 8 cage silsesquioxanes [(Ph8Si8O16)2Cu8(DMF)8][Ph8Si8O12]·2MeCN 1 and [(Me8Si8O16)2Cu8(Me2CO)4]2[MeCOO-]2[Na+]2·2(H2O)·3(Me2CO) 2. In the case of 1, acetonitrile indeed serves as a template being incorporated into the inner void of the prism-like cage of the crystalline product. To the contrary, in the case of complex 2, acetone molecules just play the role of external solvates. An inner void of the prism-like cage in 2 is occupied by sodium acetate groups. The latter, most likely, are produced via the mild oxidation of ethanol during the synthesis of 2. Finally, the sodium centers of these acetate groups caused an unprecedented "cage connectivity" (dimerization of two octacopper cage silsesquioxanes in 2). © 2018 American Chemical Society

Heptanuclear Cage CuII-Silsesquioxanes: Synthesis, Structure and Catalytic Activity

Two prismatic phenyl- (PhSiO1.5)14(CuO)7 (1, 29 % yield) and methyl- (MeSiO1.5)14(CuO)7 (2, 19 % yield) heptacoppersilsesquioxanes were obtained by the interaction of Cu,Na-based cage silsesquioxanes [(RSiO1.5)12(CuO)4(NaO0.5)4] (R = Ph, Me) with 4,4′-bipyridine and pyrazine, respectively, acting as “silent witness” ligands. Unusual molecular topologies of both compounds 1 and 2, which are the first representatives of cage silsesquioxanes with seven metal ions in their cores, were established by X-ray diffraction studies. Complex 1 was found to be an active precatalyst in the oxidation of alkanes and 1-phenylethanol to alkyl hydroperoxides and acetophenone, respectively. Alkanes were oxidized by hydrogen peroxide, and the alcohol was oxidized by tert-butyl hydroperoxide. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Tridecanuclear CuII 11Na2 Cagelike Silsesquioxanes

A series of three unprecedented heterometallic copper(II) sodium silsesquioxanes were isolated (i) via the unusual rearrangement process during synthesis of coordination polymers or (ii) via the self-assembly reaction using 2,2′-bipyridine. The unique type of these products' molecular topology consists of an unusual fusion of two sandwich-like components (each including five copper and one sodium sites) via a central copper ion. These compounds correspond to the highest nuclearity among Cu(II)-based cage silsesquioxanes reported to date. Copyright © 2018 American Chemical Society

Hydrogen bonding in the crystal of 1,1'-((1E,1'E)-(pyridine-3,4-diylbis(azanylylidene))bis(methanylylidene))-bis(naphthalen-2-ol) acetonitrile solvate: combined experimental and theoretical study

The title compound, 1,1'-((1E,1'E)-(pyridine-3,4-diylbis(azanylylidene))bis(methanylylidene))bis(naphthalen-2-ol) (1), was synthesized and structurally characterized. The compound cocrystallized with one MeCN molecule. Interestingly, one of two salicylaldehyde Schiff base fragments exists in enol form, while the other one - in a ketone form. Moreover, cocrystallized acetonitrile molecule forms hydrogen bonding with three hydrogen atoms of the dye molecule. The nature and energies of intermolecular and intramolecular hydrogen bonds were studied theoretically using DFT calculations and topological analysis of the electron density distribution within the formalism of Bader¢s theory (QTAIM method)

High-Nuclearity (Cu8-Based) Cage Silsesquioxanes: Synthesis and Structural Study

We herein report a study of Cu(II)-silsesquioxanes' self-assembly in the presence of two possible template agents (acetonitrile and acetone). This results in the isolation of unusual high-nuclearity cluster CuII 8 cage silsesquioxanes [(Ph8Si8O16)2Cu8(DMF)8][Ph8Si8O12]·2MeCN 1 and [(Me8Si8O16)2Cu8(Me2CO)4]2[MeCOO-]2[Na+]2·2(H2O)·3(Me2CO) 2. In the case of 1, acetonitrile indeed serves as a template being incorporated into the inner void of the prism-like cage of the crystalline product. To the contrary, in the case of complex 2, acetone molecules just play the role of external solvates. An inner void of the prism-like cage in 2 is occupied by sodium acetate groups. The latter, most likely, are produced via the mild oxidation of ethanol during the synthesis of 2. Finally, the sodium centers of these acetate groups caused an unprecedented "cage connectivity" (dimerization of two octacopper cage silsesquioxanes in 2). © 2018 American Chemical Society

HYDROGEN BONDING IN THE CRYSTAL OF 1,1′-((1E,1′E)-(PYRIDINE-3,4-DIYLBIS (AZANYLYLIDENE))BIS(METHANYLYLIDENE))- BIS(NAPHTHALEN-2-OL) ACETONITRILE SOLVATE: COMBINED EXPERIMENTAL AND THEORETICAL STUDY

Abstract: The title compound, 1,1′-((1E,1′E)-(pyridine-3,4-diylbis(azanylylidene))bis(methanylylidene))bis (naphthalen-2-ol) (1), was synthesized and structurally characterized. The compound cocrystallized with one MeCN molecule. Interestingly, one of two salicylaldehyde Schiff base fragments exists in enol form, while the other one - in a ketone form. Moreover, cocrystallized acetonitrile molecule forms hydrogen bonding with three hydrogen atoms of the dye molecule. The nature and energies of intermolecular and intramolecular hydrogen bonds were studied theoretically using DFT calculations and topological analysis of the electron density distribution within the formalism of Bader′s theory (QTAIM method). [Figure not available: see fulltext.] © 2022, Pleiades Publishing, Ltd

Triarylazoimidazole-ZnII, CdII, and HgII Complexes: Structures, Photophysics, and Antibacterial Properties

Novel triarylazoimidazoles containing strong electron donors (p-NEt2) or acceptors (p-NO2) by the azoaryl group, and their group 12 metal complexes were synthesized and fully characterized, including X-ray analysis for several complexes. Novel complexes exhibit red photo-luminescence emission (Φ up to  0.21) in a solution. Moreover, the antibacterial activity of complexes was tested against Gram-positive microorganism S. aureus and Gram-negative microorganism