Extra-Annulated Chlorophyll Derivatives by Scholl Reaction.

The ferric chloride assisted Scholl reaction of methyl (3,5-dimethoxyphenyl)carbonyl-pyropheophorbide- produced an extra-annulated, didehydrogenated chlorophyll derivative with a six-membered ring fused at the pyrrole A-ring. The steric interaction of the substituents on the additional tetralone and B-rings induced molecular helicity. The helically cyclized stereoisomers were separated by recrystallization, and their (/)-stereochemistry was confirmed by circular dichroism spectra.

Chiroptical Response Control of Planar and Axially Chiral Polymethylene-Vaulted Platinum(II) Complexes Bearing 1,1'-Binaphthyl Frameworks.

In this study, the synthesis, structure, and chiroptical response control of planar chiral polymethylene-vaulted -bis[(β-iminomethyl)aryloxy]platinum(II) complexes bearing axially chiral 1,1'-binaphthyl ligands are described. A series of enantiopure polymethylene ( = 4-10)-vaulted complexes were prepared in 6 steps using commercially available ()- or ()-BINOL as the starting material without an optical resolution process. The -coordination and three-dimensional vaulted structures of the platinum complexes were elucidated from X-ray diffraction (XRD) studies.

Chiral B-N AIEgens: Intense Blue Circularly Polarized Luminescence and Piezochromism.

We present a new class of blue circularly polarized luminescent emitters based on tetraarylaminoborane (TAAB) with considerable dissymmetry factor in the solid state. The chiral pendant 1-phenylethylamine in and imparts chirality to the core chromophore, resulting in circularly polarized luminescence signals ( = 0.8 × 10) with a quantum yield of 33% in the crystalline state.

Data on the solution and processing time reached when constructing a phylogenetic tree using a quantum-inspired computer.

Phylogenetic trees provide insight into the evolutionary trajectories of species and molecules. However, because (2n-5)! Phylogenetic trees can be constructed from a dataset containing n sequences, but this method of phylogenetic tree construction is not ideal from the viewpoint of a combinatorial explosion to determine the optimal tree using brute force. Therefore, we developed a method for constructing a phylogenetic tree using a Fujitsu Digital Annealer, a quantum-inspired computer that solves combinatorial optimization problems at a high speed.

Phylogenetic tree reconstruction via graph cut presented using a quantum-inspired computer.

Phylogenetic trees are essential tools in evolutionary biology that present information on evolutionary events among organisms and molecules. From a dataset of n sequences, a phylogenetic tree of (2n-5)!! possible topologies exists, and determining the optimum topology using brute force is infeasible. Recently, a recursive graph cut on a graph-represented-similarity matrix has proven accurate in reconstructing a phylogenetic tree containing distantly related sequences.

Helical Oligophenylene Linked with [2.2]Paracyclophane: Stereogenic π-Conjugated Dye for Highly Emissive Chiroptical Properties.

A stereogenic π-system based on dimer (2) and trimer (3) of [2.2]paracyclophane (PC) and biphenyl was prepared and its structural, photophysical, and chiroptical properties were investigated. X-ray analysis revealed that the quaterphenyl moieties in 2 adopt a double helical structure anchoring [2.

Sign dependence of MCPL spectra on type and position of substituent groups of pyrene and phenanthrene derivatives.

Diamagnetic achiral pyrene and phenanthrene derivatives substituted with electron-donating hydroxyl/methoxy groups and electron-withdrawing carboxylic acid groups exhibited clear magnetic circularly polarised luminescence (MCPL) spectra at 360-460 nm in dilute solvents upon the application of N-up and S-up Faraday geometries under an external magnetic field of 1.6 T. Their MCPL signs were also susceptible upon application of the same Faraday geometry.

Small Figure-Eight Luminophores: Double-Twisted Tethered Cyclic Binaphthyls Boost Circularly Polarized Luminescence.

Invited for the cover of this issue are Masashi Hasegawa, Yoshitane Imai and co-workers at Kitasato University and Kindai University. The image depicts the reported figure-eight molecule as an M. C.

Small Figure-Eight Luminophores: Double-Twisted Tethered Cyclic Binaphthyls Boost Circularly Polarized Luminescence.

Double-twisted cyclic binaphthyls, in which two naphthalenes are tethered by -O(CH ) O- linkage (n=1-3), have been synthesized. X-ray analyses and DFT calculations revealed a tightly constrained stereogenic figure-eight geometry. Tethering of two naphthalenes by short linkage forces a small dihedral angle, and the cyclic binaphthyls with short tether (n=1, 2) exhibit remarkable boosting of the g value (1.

Sign inversion in magnetic circularly polarised luminescence of fused aromatics with 1.6 T N-up/S-up Faraday geometry.

Although 12 diamagnetic fused aromatics with or without substituents exhibit mirror-symmetric magnetic circularly polarised luminescence (MCPL) through N-up and S-up Faraday geometries under a magnetic field intensity of 1.6 T, their signs (single and multiple) and magnitudes depend strongly on either the aromatic structures or the peripheral positions of the substituents.

Circularly Polarized Luminescence of a Stereogenic Curved Paraphenylene Anchoring a Chiral Binaphthyl in Solution and Solid State.

Invited for the cover of this issue are Masashi Hasegawa, Yoshitane Imai, Yasuhiro Mazaki and co-workers at Kitasato University, Kindai University and Osaka University. The image depicts a stereogenic twisted cycloparaphenylene that exhibits circularly polarized luminescence in a polymethyl methacrylate thin film. Read the full text of the article at 10.

Circularly Polarized Luminescence of a Stereogenic Curved Paraphenylene Anchoring a Chiral Binaphthyl in Solution and Solid State.

A curved stereogenic [6]paraphenylene ([6]PP), anchoring a chiral binaphthyl scaffold at 7,7'-positions, was prepared and investigated for its properties as a solid-state circularly polarized luminescence (CPL) dye. X-ray analysis revealed a helically twisted structure of PP units induced by axial chirality of binaphthyl framework. The curved [6]PP exhibits fluorescence in powder and polymethyl methacrylate (PMMA) film as well as solution.

Multiple Fused Anthracenes as Helical Polycyclic Aromatic Hydrocarbon Motif for Chiroptical Performance Enhancement.

Polycyclic aromatic hydrocarbons consisting of three fused anthracene units were designed as new π-conjugated compounds having helical structures. These expanded helicenes were synthesized by Pt-catalyzed cycloisomerization of the corresponding ethynyl-substituted precursors. The nonplanar and helical structure was confirmed by X-ray analysis and DFT calculations, and the barrier to helical inversion was estimated to be 34 kJ mol .

Excimer-origin CPL vs. monomer-origin magnetic CPL in photo-excited chiral binaphthyl-ester-pyrenes: critical role of ester direction.

Two chiral binaphthyl (BNp) derivatives bearing oppositely oriented ester linkers to two pyrene (Py) moieties [(R)/(S)-1 and (R)/(S)-2] enabled Py-origin circularly polarized luminescence (CPL), magnetic CPL (MCPL), and circular dichroism (CD). (R)-1 that exhibited (-)-sign CD showed (+)-sign Py-excimer CPL but did not exhibit MCPL. Conversely, (R)-2, with (-)-sign CD, did not show excimer-origin CPL, but exhibited clear Py-monomer MCPL.

Inter- and intramolecular excimer circularly polarised luminescence of planar chiral paracyclophane-pyrene luminophores.

Two types of planar chiral [2,2]paracyclophane-pyrene luminophores (1 and 2) with different binding positions of the fluorescent pyrene units were synthesised. ()/()-1 with 1-pyrene units exhibited green intermolecular excimer circularly polarised luminescence (CPL) at 530 nm in the KBr-pellet, but exhibited no CPL signal in dilute CHCl solution. In contrast, ()/()-2 with 2-pyrene units exhibited a blue intramolecular excimer CPL at 450 nm in CHCl solution.

Circularly polarised luminescence from planar-chiral Phanephos/Tb(iii)(hfa) hybrid luminophores.

Planar-chiral Phanephos, containing the coordinatable P(iii), formed P(iii)/Tb(iii)(hfa) hybrid luminophores that successfully emitted characteristic circularly polarised luminescence (CPL) due to D→F transitions in solution. On the other hand, BINAP, containing P(iii)[double bond, length as m-dash]O as axially chiral ligand, exhibited no detectable CPL with Tb(iii)(hfa).

Solid-state AIEnh-circularly polarised luminescence of chiral perylene diimide fluorophores.

Solid-state organic fluorescent materials are important for the development of electroluminescent sensing devices. Herein, we report that ,-bis(()-1-phenylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(,)-BPP] and its antipode [(,)-BPP], which contain extended π-electrons through planar perylenes, emit solid-state aggregation-induced-enhanced (AIEnh) circularly polarised luminescence (CPL) in inorganic (KBr) pellets and organic-polymer-film (PMMA- and -IPU-film) states; this CPL is difficult to observe in solution. These chiral perylene fluorophores emit AIEnh-CPL with high dissymmetry factors ( ) (up to 2.

Stereogenic cyclic oligonaphthalenes displaying ring size-dependent handedness of circularly polarized luminescence (CPL).

A series of cyclic oligomers with Dn symmetry (n = 2-5) based on chiral (R)/(S)-binaphthyl exhibiting intensive chiroptical properties were synthesized by using a Ni(0)-catalyzed coupling reaction. The intensity and the handedness of circularly polarized luminescence (CPL) were dependent on the ring size of the cyclic oligomers, in which the 1,1'-binaphthyl moieties form s-cis (n = 2, 3) or s-trans (n = 4, 5) conformers in the excited state. The relationship between the structure and chiroptical properties is discussed with the aid of X-ray analysis and DFT calculations.

Synthesis and Photochemical Properties of Axially Chiral Bis(dinaphthofuran).

Both enantiomers of axially chiral bis(dinaphthofuran) were prepared in only two steps from 1'-hydroxy-4'-methoxy-2,2'-binaphthalenyl-1,4-dione, followed by optical resolution via high-performance liquid chromatography (HPLC) using a chiral stationary phase (CSP). The absolute configurations were determined by comparison of experimental and calculated vibrational circular dichroism (VCD) spectra. Synthetic bis(dinaphthofuran) exhibited a broad and unstructured emission derived from an intramolecular excimer in both solution and solid state.

Inhibition of Polymorphic Property of Naphthoquinonepigment Derived from Vitamin K.

Organicpigment, 2-Methyl-3-(4-fluorophenylthio)-1,4-naphthalenedione (2), that is a new Vitamin K derivative bearing a fluorine group, did not show any polymorphism disregard of three different solvents. For comparison, its naphthoquinone analogue with a bromine group (1) showed clearly polymorphism susceptible to these solvents.

Solvent-sensitive signs and magnitudes of circularly polarised luminescence and circular dichroism spectra: probing two phenanthrenes as emitters endowed with BINOL derivatives.

A C-symmeric binaphthyl framework bearing phenanthrene as the emitter exhibited circularly polarised luminescence (CPL) in dilute solutions. The CPL and circular dichroism signs of the luminophores were altered by solvents (chloroform, methanol, acetonitrile, and dimethylformamide). DFT and TD-DFT calculations indicated that the dihedral angle between the phenanthrene and naphthyl rings was responsible for the apparent sign inversion.

Complexes of Eu(iii)(hfa) with a planar chiral P(iii) ligand (Phanephos): solvent-sensitive sign inversion of circularly polarised luminescence.

Complexes of Eu(iii)(hfa) with a C-symmetric planar P(iii) ligand exhibited intense circularly polarised luminescence (CPL) due to D → F and D → F transitions, with the signs and shapes of CPL signals depending on the choice of solvent (acetone or chloroform).

Chemical Composition and Characteristic Odor Compounds in Essential Oil from Alismatis Rhizoma (Tubers of Alisma orientale).

Chemical composition and potent odorants that contribute to the characteristic odor of essential oil from Alismatis Rhizoma (tubers of Alisma orientale) were investigated by gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GC-O), aroma extract dilution analysis (AEDA) and relative flavor activity (RFA) methods. Fifty components, representing 94.5% of the total oil, were identified.

Chemical Composition and Aroma Evaluation of Essential Oils from Skunk Cabbage (Symplocarpus foetidus).

Two sample preparation methods, namely hydrodistillation (HD) and solvent-assisted flavor evaporation (SAFE), have been used to investigate the essential oils of the aerial parts (leaves and stems) of Symplocarpus foetidus, a plant with a characteristic odor, by gas chromatography mass spectrometry (GC-MS). Characteristic aroma-active compounds in the oils were detected by GC-Olfactometry (GC-O) and aroma extract dilution analysis (AEDA). From the HD method, the main compounds in the oil were found to be p-vinyl-guaiacol (15.