Syntheses and characterization of dinuclear and tetra­nuclear Ag^I supra­molecular com­plexes generated from symmetric and asymmetric mol­ecular clips containing oxa­diazole rings

A new asymmetric ligand, 5-{3-[5-(4-methyl­phen­yl)-1,3,4-oxa­diazol-2-yl]phen­yl}-2-(pyridin-3-yl)-1,3,4-oxa­diazole (L5), which contains two oxa­diazole rings, was synthesized and characterized. The self-assembly of symmetric 2,5-bis­(pyridin-3-yl)-1,3,4-oxa­diazole (L1) and asymmetric L5 with AgCO₂CF₃ by the solution–diffusion method produced the novel Ag^I com­plexes [Ag₂(μ₂-O₂CCF₃)₂(L1)₂]_n and [Ag₂(μ₃-O₂CCF₃)₂(L5)]₂·CH₂Cl₂.

[Leu²]Gramicidin S preserves the structural properties of its parent peptide and forms helically aligned β-sheets

[Leu]Gramicidin S could be a novel scaffold for studying β-turn and sheet structures.

Modified polyoxometalate: a novel monocapped bi-supporting and reduced α-Keggin structure {PMo₁₂O₄₀[Cu(2,2′-bpy)]}[Cu(2,2′-bpy)(en)(H₂O)]₂

The structural analysis of a novel modified polyoxometalate reveals that it contains the reduced Keggin polyanion [PMo₁₂O₄₀]⁶⁻ as the parent unit, which is monocapped by [Cu(2,2′-bpy)]²⁺ fragments via four bridging O atoms on a {Mo₄O₄} pit and bi-supported by two [Cu(2,2′-bpy)(en)(H₂O)]²⁺ coordination cations simultaneously (2,2′-bpy is 2,2′-bipyridyl and en is ethyl­enedi­amine).

Tolerance factor and phase stability of the garnet structure

A tolerance factor of the garnet structure is provided to predict phase stability and investigate crystal chemistry.

Analysis of solvent-accessible voids and proton-coupled electron transfer of 2,6-bis­(1H-imidazol-2-yl)pyridine and its hydro­chloride

The crystallization of a twofold symmetric mol­ecule in a trigonal space group resulted in an atypical formation of solvent-accessible voids in the solid state. Proton-coupled electron-transfer reactions were investigated using a theoretical–experimental approach.

A new luminescent anionic metal–organic framework based on heterometallic zinc(II)–barium(II) for selective detection of Fe³⁺ and Cu²⁺ ions in aqueous solution

A new luminescent heterometallic zinc(II)–barium(II)-based anionic metal–organic framework, (ImH)[BaZn₃(BTC)₃(H₂O)₃]·4H₂O (ImH is imidazolium and BTC is benzene-1,3,5-tri­carboxyl­ate), presents a three-dimensional framework with an unprecedented (3,5)-connected topology of the point symbol (3.9²).(3³.4².5.9³.10), and exhibits `turn-off' luminescence responses for the Cu²⁺ and Fe³⁺ ions in aqueous solution based on significantly different quenching mechanisms.

Synthesis, characterization, and crystal structures of organonickel(II) com­plexes coordinated to novel 1-bromo-2,6-bis­{[(λ⁵-phosphanyl­idene)imino]­meth­yl}benzene NCN-pincer ligands

A novel family of four 1-bromo-2,6-bis­{[(λ⁵-phosphanyl­idene)imino]­meth­yl}benzene ligands has been synthesized and each ligand has been com­plexed with nickel(II). The phosphinimine substituents incrementally change from all-phenyl to all-cyclo­hexyl across this family and these ligands represent a useful opportunity to investigate the impact of changing sterics on com­plex structure and reactivity.

Coordination of a triazine ligand with Cu^II and Ag^I investigated by spectral, structural, theoretical and docking studies

Copper and silver com­plexes of 5-phenyl-3-(pyridin-2-yl)-1,2,4-triazine were prepared and the ability of the ligand and com­plexes to inter­act with ten selected biomacromolecules was investigated by docking studies. The results show that the studied com­pounds can inter­act with eight of the ten proteins better than doxorubicin.

A new biologically active mol­ecular scaffold: crystal structure of 7-(3-hy­droxy­phen­yl)-4-methyl-2H-[1,2,4]triazolo[3,2-c][1,2,4]triazole and selective anti­proliferative activity of three isomeric triazolo–triazoles

We have considered a set of three isomeric 7-(hy­droxy­phen­yl)-4-methyl-2H-[1,2,4]triazolo[3,2-c][1,2,4]triazole mol­ecules differing in the position of the hy­droxy group in the phenyl ring (ortho, meta and para). The three com­pounds were tested for anti­proliferative activity against some cancer cell lines, showing different activities and, in one case, i.e. the meta isomer, a certain degree of selectivity between cancer cell lines and normal cell lines.

A concise and efficient synthesis of amino-substituted (1H-benzo[d]imidazol-1-yl)pyrimidine hybrids: synthetic sequence and the mol­ecular and supra­molecular structures of six examples

Syntheses are reported for a series of amino-substituted (1H-benzo[d]imidazol-1-yl)pyrimidines and structures are reported for six products of this type. Multiple hydrogen bonds generate supra­molecular structures in two or three dimensions.

Polymorphism and photoluminescence properties of K₃ErSi₂O₇

The crystal structures of two tripotassium erbium disilicate, K₃ErSi₂O₇, polymorphs synthesized by high-temperature flux crystal growth were determined by single-crystal X-ray diffraction analysis. Powder X-ray diffraction, photoluminescence spectroscopy and scanning electron microscopy equipped with an energy dispersive X-ray spectrometer elucidated differences between the two polymorphs.

The synergistic co-operation of N—H⋯O=P hydrogen bonds and C—H⋯OX weak inter­molecular inter­actions (X is =P or —C) in the (CH₃O)₂P(O)(NH–NHC₆F₅) amido­phospho­ester: a combined X-ray crystallographic and theoretical study

N—H⋯O=P, C—H⋯O=P and C—H⋯O—C hydrogen bonds were studied, both theoretically and experimentally, in a new amido­phospho­ester structure with a (C—O)₂(N)P(O) skeleton.

Two precatalysts for application in propargylic CH activation

The complexes [Rh(NBD)(DPEPhos)]BF₄ and [Rh(COD)(DPEPhos)]BF₄·CH₂Cl₂ {DPEPhos is bis­[(2-di­phenyl­phosphan­yl)phen­yl] ether, NBD is norborna-2,5-diene and COD is cyclo­octa-1,5-diene} are applied as precatalysts. In addition, the catalytically inactive penta­coordinated 18-electron complex [RhCl(NBD)(DPEPhos)] was synthesized, which forms in the presence of chloride in the reaction system.

How the oxazole fragment influences the conformation of the tetra­oxazocane ring in a cyclo­hexane­spiro-3′-(1,2,4,5,7-tetra­oxazocane): single-crystal X-ray and theoretical study

The tetra­oxazocane ring in a cyclo­hexa­nespiro-3′-(1,2,4,5,7-tetra­oxazocane) compound adopts a boat–chair conformation in the crystalline state, which is due to intra­molecular inter­actions. Conformational analysis of the tetra­oxazocane fragment showed that there are three minima on the potential energy surface, one of which corresponds to the conformation realized in the solid state, but not to a global minimum.