Spherical Amides with Symmetry: Improved Synthetic Approach and Structural/Optical Analysis.

A spherical amide with symmetry was synthesized by a one-step cyclization reaction using triphenylphosphine and hexachloroethane as coupling reagents. This method enabled synthesis of -benzyl and -allyl derivatives, which could not be obtained by the previously reported method. The optical resolution of each compound was measured, and their electronic circular dichroism spectra revealed that they were mirror images.

Chiral spherical aromatic amides: one-step synthesis and their stereochemical/chiroptical properties.

Macrocyclic aromatic amides 2, in which the -positions of all four benzene rings are linked by tertiary amide bonds, were successfully synthesized by a one-step condensation reaction of two monomers using dichlorotriphenylphosphorane or triphenylphosphine/hexachloroethane (dehydration-condensation reagents for carboxy and amino groups), or LiHMDS (aminolysis for esters) as coupling reagents. Single crystal X-ray analyses of the -methyl and -ethyl derivatives were performed and revealed that each compound adopted a spherical structure with chirality because of the fixed axis rotation and combined polarity of the amide bonds. Enantiomers of each spherical macrocycle were separated by chiral column chromatography and showed mirror-imaged CD spectra to each other.

Silver to Gold Metallic Luster Changes in Stimuli-Responsive Diacetylene Derivatives Uniquely Arranged within Crystals.

Eye-catching metallic luster materials, especially those whose colors can be controlled by external stimuli, have many potential applications. Here, we present a silver luster material that changes color to gold upon UV irradiation. Diacetylene (DA) derivatives with stilbenes introduced via linkers at both ends ( ( = 1-6)) exhibited significantly different metallic luster and color change behaviors depending on the linker carbon number ().

Magnetic Supramolecular Spherical Arrays: Direct Formation of Micellar Cubic Mesophase by Lanthanide Metallomesogens with 7-Coordination Geometry.

Here, an unprecedented phenomenon in which 7-coordinate lanthanide metallomesogens, which align via hydrogen bonds mediated by coordinated HO molecules, form micellar cubic mesophases at room temperature, creating body-centered cubic (BCC)-type supramolecular spherical arrays, is reported. The results of experiments and molecular dynamics simulations reveal that spherical assemblies of three complexes surrounded by an amorphous alkyl domain spontaneously align in an energetically stable orientation to form the BCC structure. This phenomenon differs greatly from the conventional self-assembling behavior of 6-coordinated metallomesogens, which form columnar assemblies due to strong intermolecular interactions.

Enhanced Circularly Polarized Luminescence by a Homochiral Guest-Host Interaction in Gyroidal MOFs, [Ru(bpy)] [M(ox)] (bpy = 2,2'-Bipyridyl, ox = Oxalate, M = Zn, Mn).

We report the circularly polarized luminescence (CPL) for [Ru(bpy)]I () and [Ru(bpy)][M(ox)] (M = Zn (), Mn ()). Whereas compound is a simple salt of [Ru(bpy)], and are MOFs in which the chiral [Ru(bpy)] ions are encapsulated in a homochiral gyroidal skeleton of [M(ox)]. Whereas the solution of exhibited weak CPL with a luminescence dissymmetry factor of || ∼ 10, the CPL was significantly enhanced in solid-state - with || = 2 × 10 for , 4 × 10 for , and 1 × 10 for .

Solvent-Dependent Conformational Switching of N-Methyl-N,N'-diarylsquaramide.

,'-Diarylsquaramide and ,'-dialkylsquaramide are conformationally stable linkers with extended (trans, trans) and folded (cis, cis) structures, respectively, independently of external conditions. Here, we show that -monomethylated ,'-diarylsquaramides generally take a (trans, cis) structure in the crystal but show a solvent-dependent conformational equilibrium in solution. In particular, the stable conformer of -methyl-,'-bis(1-naphthyl)squaramide () changes depending upon the solvent.

Molecular Dynamics Studies of the Ho(III) Aqua-tris(dibenzoylmethane) Complex: Role of Water Dynamics.

The seven-coordinate Ho(III) aqua-tris(dibenzoylmethane)(DBM) complex, referred to as Ho-(DBM)·HO, was first reported in the late 1960s. It has a threefold symmetric structure, with Ho at the center of three dibenzoylmethane ligands and hydrogen-bonded water to ligands. It is considered that the hydrogen bonds between the water molecule and the ligands surrounding Ho play an important role in the formation of its symmetrical structure.

Asymmetric Friedel-Crafts-Type Reaction of 2-Vinylindoles to -Boc Imines Using a Chiral Imidazolidine-Containing NCN-Pincer Pd Catalyst.

A chiral imidazolidine-containing NCN-pincer Pd-OTf complex () promoted the asymmetric nucleophilic addition of unprotected 2-vinylindoles to -Boc imines in a Friedel-Crafts-type manner. The chiral (2-vinyl-1-indol-3-yl)methanamine products become nice platforms for constructing multiple ring systems.

Conformational Properties of Aromatic Amides Bearing Imidazole Ring and Acid-Induced - Amide Switching.

Aromatic amides bearing secondary amide bond exist in trans conformation both in the crystal and in solution, whereas the conformation of the -methylated derivatives is cis in the crystal and predominantly cis in various solvents. The cis conformational preference of -alkylated benzanilide provides access to aromatic foldamers such as oligo(-alkyl--benzamide)s, which adopt dynamic helical structures. Here, the conformational properties of imidazole-substituted amide in the crystal and in solution were examined.

Borocyclic Radicals Prepared from Orthoquinone-Containing Polycyclic Aromatics by Photoirradiation.

Borocyclic radicals with highly conjugated aromatics were generated from orthoquinone-containing polycyclic aromatic compounds by trapping the photoinduced triplet state with simple boron halide under irradiation with light of appropriate wavelength. The picene-based borocyclic radical was remarkably stable when stored at 23 °C in a desiccator for over 1 year. The crystal structure of this stable radical had a stacking structure of a planar π-conjugated system, and the electrical conductivity was higher than those of ordinary organic radical systems.

Development of Helical Aromatic Amide Foldamers with a Diphenylacetylene Backbone.

We designed and synthesized aromatic polyamides with a diphenylacetylene backbone, and , bearing ()-α- and ()-β-methyl-substituted triethyleneglycol (TEG) side chains, respectively, and examined their conformations in solution. Both polymers exhibit strong, solvent polarity-dependent circular dichroism spectra, which indicated that they take helical conformations in low-polarity solvents. The spectra were mirror images, depending on the chiral position of the side chains.

Synthesis and chiroptical properties of cylindrical macrocycles comprising two calix[3]aramide moieties.

Calix[3]aramide-based cylindrical macrocycles were synthesized by the one-step amide coupling reaction of a monomer containing two meta-alkylaminobenzoic acid units linked by para-phenylene bridges. The major products included a meso-form and an enantiomeric pair, with stereochemistry derived from the direction of the amide bonds and their fixed conformation. Mirror-image ECD, VCD, and CPL spectra were observed in the enantiomeric pair and the absolute structure was determined by comparing measured and calculated ECD and VCD spectra.

Catalytic Asymmetric Synthesis of Chiral Bis(indolyl)methanes Using a Ts-PyBidine-Nickel Complex.

A chiral tosyl-substituted bis(imidazolidine)pyridine Ts-PyBidine-nickel complex was an efficient catalyst for Friedel-Crafts reaction of indoles with methylene indolinones to give bisindolylmethane compounds having differently oxidized indole units with high enantioselectivities. Alkylation of the products proceeded smoothly in a highly diastereoselective manner, providing an all-carbon quaternary carbon center without significant loss of enantiomeric excess.

Crystal structure of butane-1,4-diyl bis-(furan-2-carboxyl-ate).

The asymmetric unit of the title compound, CHO, a monomeric compound of poly(butyl-ene 2,5-furandi-carboxyl-ate), consists of one half-mol-ecule, the whole all- mol-ecule being generated by an inversion centre. In the crystal, the mol-ecules are inter-connected C-H⋯O inter-actions, forming a mol-ecular sheet parallel to (10). The mol-ecular sheets are further linked by C-H⋯π inter-actions.

Modifications in coordination structure of Mg[TFSA]-based supporting salts for high-voltage magnesium rechargeable batteries.

To achieve a sustainable-energy society in the future, next-generation highly efficient energy storage technologies, particularly those based on multivalent metal negative electrodes, are urgently required to be developed. Magnesium rechargeable batteries (MRBs) are promising options owing to the many advantageous chemical and electrochemical properties of magnesium. However, the substantially low working voltage of sulfur-based positive electrodes may hinder MRBs in becoming alternatives to current Li-ion batteries.

Synthesis and Conformational Analysis of Alternately N-Alkylated Aromatic Amide Oligomers.

Alternately N-alkylated aromatic amides such as 1-3 bearing various side chains were designed and synthesized as novel helical foldamers. The CD spectra of oligomers with chiral side chains showed a positive Cotton effect, which indicates that these oligomers take helical conformations in solution. The CD intensity gradually increased with increasing chain length, and pentamer 3d showed remarkably strong CD signals in chloroform.

Coculture of a Pathogenic Actinomycete and Animal Cells To Produce Nocarjamide, a Cyclic Nonapeptide with Wnt Signal-Activating Effect.

A coculture method with a pathogenic actinomycete of the genus Nocardia and an animal cell line was designed to reconstruct and emulate the initial infection state, and a new cyclic nonapeptide, named nocarjamide (1), was obtained by coculture of Nocardia tenerifensis IFM 10554 and the mouse macrophage-like cell line J774.1 in a modified Czapek-Dox medium. Nocarjamide (1) exhibited Wnt signal-activating effects.

Frustrated Helicity: Joining the Diverging Ends of a Stable Aromatic Amide Helix to Form a Fluxional Macrocycle.

Macrocyclization of a stable two-turn helical aromatic pentamide, that is, an object with diverging ends that are not prone to cyclization, was made possible by the transient introduction of disruptors of helicity in the form of acid-labile dimethoxybenzyl tertiary amide substituents. After removal of the helicity disruptors, NMR, X-ray crystallography, and computational studies show that the macrocycle possesses a strained structure that tries to gain as high a helical content as possible despite being cyclic. Two points of disruption of helicity remain, in particular a cis amide bond.

Conformational Properties of Aromatic Oligoamides Bearing Pyrrole Rings.

N-Alkylbenzanilides generally exist in cis conformation both in the crystalline state and in various solvents, and this cis conformational preference can be utilized to construct dynamic helical oligoamides. Here, we synthesized the pyrrole-containing amides 2-5 and their oligomers 6-8 and examined their conformations in the crystalline state and in solution. All the N-methylated amides showed cis conformational preference in solution, but the ratio of the cis isomer was decreased when the amide bond was attached at the 4-position of the pyrrole ring, probably because the destabilization of the trans conformer due to electronic repulsion between the pyrrole π electrons and the amide carbonyl lone-pair electrons is reduced due to the small torsion angle between the 5-membered N-pyrrole and the amide bond.

Morphological and Physicochemical Evaluation of Two Distinct Glibenclamide/Hypromellose Amorphous Nanoparticles Prepared by the Antisolvent Method.

The morphology and stability of amorphous nanoparticles of glibenclamide (GLB) prepared by the antisolvent method using different methods of adding hypromellose (HPMC) were evaluated. Nano-A was prepared by the injection of a dimethyl sulfoxide (DMSO) solution of GLB into the HPMC solution, whereas nano-B was obtained by the injection of a DMSO solution of GLB and HPMC into water. Cryogenic transmission electron microscopy, field-emission scanning electron microscopy, and field-emission transmission electron microscopy, including energy dispersive X-ray spectrometry, revealed that the particles of the nano-A and nano-B samples are hollow spheres and nonspherical nanoparticles, respectively.

Chemosynthetic homologues of Mycoplasma pneumoniae β-glycolipid antigens for the diagnosis of mycoplasma infectious diseases.

Mycoplasma pneumoniae expresses β-glycolipids (β-GGLs) in cytoplasmic membranes, which possess a unique β(1 → 6)-linked disaccharide epitope, which has high potential in biochemical and medicinal applications. In the present study, a series of β-GGLs homologues with different acyl chains (C12, C14, C16, and C18) were prepared from a common precursor. An ELISA assay using an anti-(β-GGLs) monoclonal antibody indicated that the synthetic homologues with long acyl chains had greater diagnostic potential in the order C18 > C16 > C14 > C12.

Dinuclear PhosphoiminoBINOL-Pd Container for Malononitrile: Catalytic Asymmetric Double Mannich Reaction for Chiral 1,3-Diamine Synthesis.

A phosphoiminoBINOL ligand was designed to form a dinuclear metal complex that could hold a malononitrile molecule. The dinuclear bis(phosphoimino)binaphthoxy-Pd(OAc) complex catalyzed a double Mannich reaction of N-Boc-imines with malononitrile to give chiral 1,3-diamines with high enantioselectivity. The rational asymmetric catalyst, which smoothly introduces the first coupling product to the second coupling reaction while avoiding the reverse reaction, facilitates the over-reaction into a productive reaction process.

Crystal structures of 2-(benzene-carbo-thio-yloxy)ethyl benzene-carbo-thio-ate and 2-(benzene-carbo-thio-yloxy)ethyl benzoate.

The title compounds, CHOS and CHOS, which are monomeric models (models and ) for a polythio-noester and a poly(ester--thio-noester), respectively, crystallize in the space group 2/ and are isostructural with each other. The mol-ecule in each crystal is located on an inversion centre and has an all- structure. The asymmetric unit comprises one half-mol-ecule.

Synthesis and Optical Properties of Excited-State Intramolecular Proton Transfer Active π-Conjugated Benzimidazole Compounds: Influence of Structural Rigidification by Ring Fusion.

Two excited-state intramolecular proton transfer (ESIPT) active benzimidazole derivatives (1 and 2) were synthesized by acid-catalyzed intramolecular cyclization. The steady-state fluorescence spectrum in THF revealed that ring-fused derivative 1 exhibits a dual emission, namely, the major emission was from the K* (keto) form (ESIPT emission) at 515 nm with a large Stokes shift of 11 100 cm and the minor emission was from the E* (enol) form at below 400 nm. In contrast, the normal emission from the E* form was dominant and the fluorescence quantum yield was very low (Φ ∼ 0.

Adamantane-based Bidendate Metal Complexes in Crystalline and Solution State.

Bidentate organic molecules with imidazole or benzimidazole moieties connected to a rigid 1,3-diphenyladamantane spacer are simple and unique building blocks that facilitate the assembly of supramolecular architectures in the solid state via metal-coordination. Single-crystal X-ray analysis revealed that the complexation of bidentate ligand-bearing imidazole moieties with cobalt(II) or cadmium(II) ions in methanol/chloroform produced complexes that showed doubly-interpenetrated two-dimensional (2D) sheets through the formation of coordination bonds between the cobalt or cadmium metal centers and the nitrogen atoms of the imidazole groups. In the complexation of another ligand bearing a bulky benzimidazole group with cobalt(II) ion generated in methanol/chloroform, extended zigzag one-dimensional (1D) chains were formed, indicating that the molecular shape and bulkiness of the ligand design are crucial in the control of coordination polymers.