A New Synthetic Route to (Trifluoromethyl)quinolines: Nickel-Catalyzed Insertion of an Alkyne into an Aromatic C–S Bond by Formation of a Thianickelacycle and Thermal Desulfidation

We have developed a nickel-catalyzed insertion reaction of an alkyne into a 2-(trifluoromethyl)-1,3-benzothiazole to give a seven-membered benzothiazepine that is converted into a 2-(trifluoromethyl)quinoline by thermal desulfidation. This process can be considered a formal substitution of a sulfur atom with an alkyne. The structure of the thianickelacycle intermediate formed through oxidative addition of a C–S bond in the benzothiazole to nickel(0) was confirmed by X-ray single-crystal structure analysis and in situ X-ray absorption fine-structure spectroscopy.

1,3-Dipolar [3+3] Cycloaddition of 1,4-Benzodiazepinone-Based Nitrones with α-Halohydroxamates for Diastereoselective Synthesis of Novel d-Edge Heterocycle-Fused 1,4-Benzodiazepinones

Promoted by K2CO3 (2.0 equiv), the 1,3-dipolar [3+3] cycloaddition between 1, 4-benzodiazepinone-based nitrones and α-halohydroxamates processed smoothly under the mild reaction conditions and delivered structurally novel and complex cis or trans-configured d-edge-heterocycle-fused 1,4-benzodiazepinones in up to >99% isolated yield with >20:1 dr. The relative configuration of the title chemical entities was clearly identified with the use of X-ray single crystal structure analysis. The reaction mechanism was assumed to interpret the diastereoselective production of the obtained cis or trans-configured d-edge-heterocycle-fused 1, 4-benzodiazepinones.

Stereoselective Synthesis of Multifunctionalized Nitrones via Conjugate Addition Between α-Halogeno Hydrazones and Nitroso Compounds

In the presence of Na2CO3, the conjugate addition between α-halogeno hydrazones and nitroso compounds proceeded readily, thus delivering multifunctionalized nitrones in the reasonable chemical yields with excellent strereoselectivities. The chemical structure and stereochemical configuration of title chemical entities were unambiguously identified by an X-ray single crystal structure analysis.

Diastereoselective synthesis of spiropyrazolones via 1,3-dipolar [3+2] cycloadditions between pyrazolone-based olefins and N, N’-cyclic azomethine imines

Under the catalysis of PhCO2H, the 1,3-dipolar [3+2] cycloaddition between pyrazolone-based olefins and N, N’-cyclic azomethine imines proceeded readily, thus delivering structurally novel spiropyrazolones with up to 98% yield and >20:1 dr. The relative stereochemical configuration of the obtained spiropyrazolones was unambiguously assigned by X-ray single crystal structure analysis. The diastereoselective formation of the title spiropyrazolones was interpreted by the hypothesized reaction mechanism.

Heterocyclic Schiff Bases of 3-Aminobenzanthrone and Their Reduced Analogues: Synthesis, Properties and Spectroscopy

New substituted azomethines of benzanthrone with heterocyclic substituents were synthesized by condensation reaction of 3-aminobenzo[de]anthracen-7-one with appropriate aromatic aldehydes. The resulting imines were reduced with sodium borohydride to the corresponding amines, the luminescence of which is more pronounced in comparison with the initial azomethines. The novel benzanthrone derivatives were characterized by NMR, IR, MS, UV/Vis, and fluorescence spectroscopy. The structure of three dyes was studied by the X-ray single crystal structure analysis. The solvent effect on photophysical behaviors of synthesized imines and amines was investigated. The obtained compounds absorb at 420–525 nm, have relatively large Stokes shifts (up to 150 nm in ethanol), and emit at 500–660 nm. The results testify that emission of the studied compounds is sensitive to the solvent polarity, exhibiting negative fluorosolvatochromism for the synthesized azomethines and positive fluorosolvatochromism for the obtained amines. The results obtained indicate that the synthesized compounds are promising as luminescent dyes.

Stimuli-Responsive Luminescent Supramolecular Assemblies and Co-assemblies by Orthogonal Dipole-Dipole Interaction and Halogen Bonding

This article reports π-chromophore assemblies from three structurally related dipolar naphthalene monoimide (NMI) luminogens (M1, M2 and M3) by underexplored orthogonal dipole-dipole interaction and halogen bonding. Single crystal structure analysis...

Lu-atom-ordered oxonitridoaluminosilicate Ba0.9Ce0.1LuAl0.2Si3.8N6.9O0.1

A single crystal of Ba0.9Ce0.1LuAl0.2Si3.8N6.9O0.1 (barium cerium lutetium aluminosilicate nitride oxide) was obtained by heating a mixed powder of Ba3N2, Si3N4, Al, Lu2O3, and CeO2 at 2173 K for 1 h under N2 gas at 0.85 MPa. X-ray single-crystal structure analysis revealed that the title oxynitride is hexagonal (lattice constants: a = 6.0378 (5) Å, c = 9.8133 (9) Å; space group: P63 mc) and isostructural with BaYbSi4N7. (Ba,Ce) and Lu atoms occupy twelvefold and sixfold coordination sites, respectively.

Crystallization of metastable monoclinic carnallite, KCl·MgCl2·6H2O: missing structural link in the carnallite family

During evaporation of natural and synthetic K–Mg–Cl brines, the formation of almost square plate-like crystals of potassium carnallite (potassium chloride magnesium dichloride hexahydrate) was observed. A single-crystal structure analysis revealed a monoclinic cell [a = 9.251 (2), b = 9.516 (2), c = 13.217 (4) Å, β = 90.06 (2)° and space group C2/c]. The structure is isomorphous with other carnallite-type compounds, such as NH4Cl·MgCl2·6H2O. Until now, natural and synthetic carnallite, KCl·MgCl2·6H2O, was only known in its orthorhombic form [a = 16.0780 (3), b = 22.3850 (5), c = 9.5422 (2) Å and space group Pnna].

Autonomous flipping of azobenzene assemblies under light irradiation (II)

<p>To create autonomous microrobots which move in the presence of a constant energy source, their mechanical motion must have a capacity for self-control. This is realized when a structural change occurs with conversion of energy facilitated by cofactors, with a self-regulation component to prevent reaching a static state. Here, we present a single crystal structure analysis of azobenene derivatives which reveals a mille-feuille-like layered structure of sparse and dense layers of six independent azobenzene moieties. In this anisotropic structure, a specific azobenzene molecule acts as a reaction center for a light-to-mechanical function process. The other molecules in the crystal act as modulators. Moreover, depending on the photoisomerisation process activated by a polarized light source, different cyclic motions are observed. We clarify the mechanism by which the self-organized mechanical behavior of these azobenzene molecules is achieved at the molecular level. Thus, the present results demonstrate that autonomously driven molecular materials can exhibit information-responsive and self-sustainable motion by incorporating stimulus-responsive sensors. </p>

Autonomous flipping of azobenzene assemblies under light irradiation (II)

<p>To create autonomous microrobots which move in the presence of a constant energy source, their mechanical motion must have a capacity for self-control. This is realized when a structural change occurs with conversion of energy facilitated by cofactors, with a self-regulation component to prevent reaching a static state. Here, we present a single crystal structure analysis of azobenene derivatives which reveals a mille-feuille-like layered structure of sparse and dense layers of six independent azobenzene moieties. In this anisotropic structure, a specific azobenzene molecule acts as a reaction center for a light-to-mechanical function process. The other molecules in the crystal act as modulators. Moreover, depending on the photoisomerisation process activated by a polarized light source, different cyclic motions are observed. We clarify the mechanism by which the self-organized mechanical behavior of these azobenzene molecules is achieved at the molecular level. Thus, the present results demonstrate that autonomously driven molecular materials can exhibit information-responsive and self-sustainable motion by incorporating stimulus-responsive sensors. </p>