Neomacrophorin I,II, and III,novel drimenyl cyclohexanes with hydroxylated butanoates from Trichoderma sp. 1212-03

Neomacrophorins I (1), II (2), and III (3) were isolated from the culture broth of Trichoderma sp. 1212-03, which was collected at Shirakami Mountainous area in Japan. Structural analyses disclosed that these resemble known macrophorins but possess axial-hydroxy group at C3 as well as different side chains at C7′. These are diastereomeric forms of macrophorins for 5′,6′-epoxide functionality. The NMR analyses suggested their relative configurational relationship between the C1–C15 drimene and C1′–C7′ epoxyquinone moieties. ECD spectral discussions verified them particularly for C5′,C6′-epoxyquinone (1), C5′,C6′-epoxysemiquinone (2 and 3), and 2″,3″-dihydroxybutanoate moiety in 1 and 2. The configuration of C3″-stereocenter of 3 was determined by chiral GC–MS after converting into methyl (S)-3″-hydroxybutanoate by basic of 3 methanolysis. Biological assays disclosed that 1 induces hyphal branching of Cochliobolus miyabeanus as well as cytotoxicity against human colorectal cancer COLO 201.     

Rate constant measurements for initial addition reactions of radicals at the propagation step of photo‐polymerization as studied by pulsed EPR spectroscopy

Pulsed EPR spectroscopy was employed to determine reaction rate constants at an early stage of addition reactions in radical polymerizations triggered by four initiator radicals, which were generated by photodissociation of four parent molecules. Two monomers (tert‐butylacrylate and tert‐butylmethacrylate) were examined as reactant. Stern–Volmer analysis on the measured decay time of electron spin echo intensity of reacting radicals provides rate constants for addition reactions. We focused on rate constants for the second step reaction between monomer and adduct radical that is produced by the first step addition reaction between initiator radical and monomer. The rate constant measured by pulsed EPR was evaluated by theoretical calculations in the light of (1) enthalpy difference between product radical and reactants and (2) charge transfer interaction between reacting radical and monomer. Copyright © 2016 John Wiley & Sons, Ltd.     

Design of Ratiometric Fluorescent Probes Based on Arene–Metal‐Ion Interactions and Their Application to CdII and Hydrogen Sulfide Imaging in Living Cells

Non‐coordinative interactions between a metal ion and the aromatic ring of a fluorophore can act as a versatile sensing mechanism for the detection of metal ions with a large emission change of fluorophores. We report the design of fluorescent probes based on arene–metal‐ion interactions and their biological applications. This study found that various probes having different fluorophores and metal binding units displayed significant emission redshift upon complexation with metal ions, such as Ag^I, Cd^II, Hg^II, and Pb^II. X‐ray crystallography of the complexes confirmed that the metal ions were held in close proximity to the fluorophore to form an arene–metal‐ion interaction. Electronic structure calculations based on TDDFT offered a theoretical basis for the sensing mechanism, thus showing that metal ions electrostatically modulate the energy levels of the molecular orbitals of the fluorophore. A fluorescent probe was successfully applied to the ratiometric detection of the uptake of Cd^II ions and hydrogen sulfide (H₂S) in living cells. These results highlight the utility of interactions between arene groups and metal ions in biological analyses.     

Organic Dicarboxylate Negative Electrode Materials with Remarkably Small Strain for High‐Voltage Bipolar Batteries

As advanced negative electrodes for powerful and useful high‐voltage bipolar batteries, an intercalated metal–organic framework (iMOF), 2,6‐naphthalene dicarboxylate dilithium, is described which has an organic‐inorganic layered structure of π‐stacked naphthalene and tetrahedral LiO₄ units. The material shows a reversible two‐electron‐transfer Li intercalation at a flat potential of 0.8 V with a small polarization. Detailed crystal structure analysis during Li intercalation shows the layered framework to be maintained and its volume change is only 0.33 %. The material possesses two‐dimensional pathways for efficient electron and Li⁺ transport formed by Li‐doped naphthalene packing and tetrahedral LiO₃C network. A cell with a high potential operating LiNi_0.5Mn_1.5O₄ spinel positive and the proposed negative electrodes exhibited favorable cycle performance (96 % capacity retention after 100 cycles), high specific energy (300 Wh kg^?1), and high specific power (5 kW kg^?1). An 8 V bipolar cell was also constructed by connecting only two cells in series.     

Enantiodifferentiating Photodimerization of a 2,6-Disubstituted Anthracene Assisted by Supramolecular Double-Helix Formation with Chiral Amines

A novel 2,6-anthrylene-linked bis(m-terphenylcarboxylic acid) strand ( 1 ) self-associates into a racemic double-helix. In the presence of chiral mono- and diamines, either a right- or left-handed double-helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face-selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo- (anti or syn) and enantiodifferentiating way to afford the chiral anti-photodimer with up to 98 % enantiomeric excess when (R)-phenylethylamine was used as a chiral double-helix inducer. The resulting optically active anti-photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines.     

Enantiodifferentiating Photodimerization of a 2,6‐Disubstituted Anthracene Assisted by Supramolecular Double‐Helix Formation with Chiral Amines

A novel 2,6‐anthrylene‐linked bis(m‐terphenylcarboxylic acid) strand ( 1 ) self‐associates into a racemic double‐helix. In the presence of chiral mono‐ and diamines, either a right‐ or left‐handed double‐helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face‐selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo‐ (anti or syn) and enantiodifferentiating way to afford the chiral anti‐photodimer with up to 98 % enantiomeric excess when (R)‐phenylethylamine was used as a chiral double‐helix inducer. The resulting optically active anti‐photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines.     

Pyrolysis of Polymer Complexes Leading to Air-Stable Ultrafine Metal Particles Uniformly Dispersedin a Carbon Matrix

New types of air-stable metal-carbon composites which contain ultrafine metal particles (Fe, Co, Ni, Pd, Pt, Rh, Cu, etc.) uniformly dispersed in a carbon matrix were obtained by pyrolysis of a variety of soluble organometallic polymers, macromolecular-metal complexes, and blends of coal pitch with metal complexes at 400-1400°C in N₂. Some of their unique physical properties and functions are noted.