Decarboxylative Fluorination of 2-Pyridylacetates

Syntheses of substituted pyridines and fluorinated compounds, which are often pharmaceutical targets, are important objectives in organic chemistry. Herein, we found that decarboxylative fluorination of lithium 2-pyridylacetates occur under catalyst-free conditions. The phenomenon can be applied to one-pot transformation of substituted methyl 2-pyridylacetate to 2-(fluoroalkyl)pyridine by decarboxylative fluorination of the intermediate lithium 2-pyridylacetate. This method was also applied to the syntheses of 2-(difluoroalkyl)pyridines.     

Thermal decomposition of acrylamide from polyacrylamide

Ion-attachment mass spectrometry with a temperature-programed direct probe allows the detection of intact pyrolysis products. It, therefore, offers the opportunity to monitor directly thermal byproducts on a real-time basis and potentially to detect thermally unstable products. With this technique, we investigated the thermal decomposition of polyacrylamide (PAA). Pyrolysis of PAA at around 450?°C produces many products (e.g., amides, imides, nitriles, ketones, aldehydes, and acrylamide oligomers). Acrylamide, which is a possible carcinogen, is produced abundantly in various industries, and, therefore, continues to be a cause for concern. We also investigated the kinetics of the thermal decomposition of PAA, and observed that the degradation of acrylamide obeys Arrhenius kinetics, which allowed us to correlate the rate constant with the absolute temperature and the activation energy. The activation energy of thermal decomposition was calculated from selected ion-monitoring curves of acrylamide.     

Creation of Circularly Polarized Luminescence from an Achiral Polyfluorene Derivative through Complexation with Helix‐Forming Polysaccharides: Importance of the meta‐Linkage Chain for Helix Formation

A circularly polarized luminescence (CPL) material has been created by polymer–polymer complexation between a helix‐forming polysaccharide, schizophyllan (SPG), and a meta‐phenylene‐linked polyfluorene derivative (mPFS). Computational modeling revealed that mPFS can adopt a helical structure although a conventional polyfluorene derivative with a para‐phenylene linkage tends to enjoy a rigid rodlike conformation. Our detailed experimental examination showed that mPFS forms a chiral nanowire complex through cohelix formation with SPG. We have found, as expected, that this cohelical complex emits highly efficient CPL even in an aqueous solution. The appearance of the high CPL property is due to 1) a high quantum yield of the fluorene unit and 2) immobilization of the helically twisted conformation of mPFS in an isolated manner through cohelix formation with SPG. One can propose, therefore, that the SPG/mPFS complex acts as a new high‐performance CPL material with a solvent‐dispersible nanowire structure.     

H2 and O2 Activation—A Remarkable Insight into Hydrogenase

This article summarizes the development of a range of organometallic, biomimetic analogues of [NiFe]hydrogenases and their employment in a new generation of H₂‐O₂ fuel cells. It begins with a summary of O₂‐sensitive and O₂‐tolerant enzyme chemistry before detailing the properties and functionality of our biomimetic complexes, including: the first ever fully functional model, selective H₂ and O₂ activation, and the first catalyst using only common metals. These systems are centered on Ni–Fe, Ni–Ru, Ir–Ir, and Rh–Rh cores and use a range of ligands that all follow a set of design principles described herein.     

Dielectric Multilayer Including Azobenzene Polymer Liquid Crystal with Non-quarter-wave Stack

Dielectric multilayer including azobenzene polymer liquid crystal acts as a one-dimensional photonic crystal and has optical-switchable reflection bands. The reflection intensity can be controlled by irradiation of ultraviolet (UV) or visible light, in which the optical switch is based on cis-trans photoisomerization. An increase in the number of layers prevents photoresponse in the multilayer including azobenzen layers because UV or visible light for control cis-trans isomerization hardly reach the bottom of the multilayer due to exponential decay of light intensity. In this study, the multilayer consisting of thin azobenzene layers is investigated. According to numerical calculations, the non-quarter-wave structured multilayer has multiwavelength reflection band. Angular dependence of reflection color from multiwavelength stopband is also studied using the XYZ color space. The non-quarter-wave multilayer suppresses reflection color change compared with conventional quarter-wave multilayer.     

Recognition of gram-negative and gram-positive bacteria with a functionalized conducting polymer film

In this work, we successfully developed bacterial templates on the surface of an overoxidized polypyrrole film using both gram-negative and gram-positive bacteria in which bacterial surface chemical structures are precisely transferred at a molecular level. The sensor film identified target bacteria within minutes through a unique combination with dielectrophoresis. The bacterial cavities had high selectivity for distinguishing specific target bacteria in bacterial mixtures containing gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria. This rapid and specific recognition system will enable not only bacterial sensing but also analysis of various biological species.     

Intracellular in vitro probe acylcarnitine assay for identifying deficiencies of carnitine transporter and carnitine palmitoyltransferase-1

Mitochondrial fatty acid oxidation (FAO) disorders are caused by defects in one of the FAO enzymes that regulates cellular uptake of fatty acids and free carnitine. An in vitro probe acylcarnitine (IVP) assay using cultured cells and tandem mass spectrometry is a tool to diagnose enzyme defects linked to most FAO disorders. Extracellular acylcarnitine (AC) profiling detects carnitine palmitoyltransferase-2, carnitine acylcarnitine translocase, and other FAO deficiencies. However, the diagnosis of primary carnitine deficiency (PCD) or carnitine palmitoyltransferase-1 (CPT1) deficiency using the conventional IVP assay has been hampered by the presence of a large amount of free carnitine (C0), a key molecule deregulated by these deficiencies. In the present study, we developed a novel IVP assay for the diagnosis of PCD and CPT1 deficiency by analyzing intracellular ACs. When exogenous C0 was reduced, intracellular C0 and total AC in these deficiencies showed specific profiles clearly distinguishable from other FAO disorders and control cells. Also, the ratio of intracellular to extracellular C0 levels showed a significant difference in cells with these deficiencies compared with control. Hence, intracellular AC profiling using the IVP assay under reduced C0 conditions is a useful method for diagnosing PCD or CPT1 deficiency.