Raw data for Figs 4 and 5.

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The Importance of Lone Pair Delocalizations: Theoretical Investigations on the Stability of <i>cis</i> and <i>trans</i> Isomers in 1,2-Halodiazenes

The relative and thermodynamic stabilities of cis and trans isomers of 1,2-dihalodiazenes (XNNX; X = F, Cl, or Br) were examined using high level ab initio and density functional theory (DFT) calculations. For 1,2-dihalodiazenes, it was found that the cis isomers were more stable than the corresponding trans isomers, despite the existence of several cis destabilizing mechanisms, such as steric exchange between halogen lone pairs and dipole−dipole electrostatic repulsions (Δtrans−cis = 3.15, 7.04, and 8.19 kcal mol−1, respectively, at BP86/6-311++G(3df,3pd)//B3LYP /6-311++G(3df,3pd) level). Their origin of the cis-preferred difference in energy was investigated with natural bond orbital (NBO) analysis to show that the “cis effect” came mainly from antiperiplanar interactions (AP effect) between the nitrogen lone pair and the neighboring antibonding orbital of the N−X bond (nN → σN′X′*). The delocalization of halogen lone-pair into the antibonding orbital of the NN bonds (the LP effects) was also found to enhance the cis preference by 1.20 to 6.58 kcal mol−1, depending on the substituted halogen atom. The total amount of the AP effect increased as the halogen atom became larger, and the increased AP effect promoted the triple-bond-like nature of the NN bond (shorter NN bond length and wider NNX angle). The greater AP effect also made the N′−X′ bond easier to cleave (longer N−X bond length), and a higher energy level than that of the nitrogen lone pair was found in the N−Br bonding orbital in 1,2-dibromodiazenes, thus indicating the significant instability of this molecule. The degradability of the N−Cl bond in 1,2-dichlorodiazenes and the fair stability of the N−F bond in 1,2-fluorodiazenes were also confirmed theoretically, and were found to be consistent with the previous experimental and theoretical reports. These results clearly indicate the dominance of lone-pair-related hyperconjugations on the basic electronic structure and energetic natures of 1,2-dihalodiazene systems

Regiospecific Synthesis of 2,6-Di-<i>O</i>- (α-d-mannopyranosyl)phosphatidyl-d-<i>myo</i>- inositol

Regiospecific Synthesis of 2,6-Di-O- (α-d-mannopyranosyl)phosphatidyl-d-myo- inosito

Aromatic Polyketide Production in <i>Cordyceps indigotica</i>, an Entomopathogenic Fungus, Induced by Exposure to a Histone Deacetylase Inhibitor

Cultivation of <i>Cordyceps indigotica</i>, an entomopathogenic fungus, in the presence of suberoyl bis-hydroxamic acid (an HDAC inhibitor) greatly activated its polyketide synthesis apparatus to afford six novel aromatic polyketides, indigotides C–F (<b>1</b>–<b>4</b>), 13-hydroxyindigotide A (<b>5</b>), and 8-<i>O</i>-methylindigotide B (<b>6</b>). The structures of these compounds were determined by NMR spectroscopic analyses. Among the compounds, indigotides C–E (<b>1</b>–<b>3</b>) possessed unprecedented dimeric polyketide frameworks possibly generated via a [4 + 2] cycloaddition or Michael type reaction

Photoreduction of Prussian Blue Intercalated into Titania Nanosheet Ultrathin Films

Photoreduction of Prussian Blue Intercalated into Titania Nanosheet Ultrathin Film

Amine-Functionalized Diamond Electrode for Boosting CO₂ Reduction to CO

Carbon capture, utilization, and storage (CCUS) have been attracting much attention as an initiative to achieve carbon neutrality. In the capture and storage strategy, amines are widely used for highly efficient separation and capturing of CO2 since amines react with CO2 to form carbamates. In the utilization strategy, CO2 electroreduction is a promising method to convert CO2 into value-added compounds because reaction conditions are relatively mild and easily controlled. In this work, toward combining CO2 capture and storage technologies and CO2 electroreduction, we focused on amine modification of the electrode surface, in which boron-doped diamond (BDD) was chosen as a sustainable electrode material. CO2 electroreduction using the amine-modified BDD was performed, and an applied potential dependence of the product selectivity was examined. In situ attenuated total reflectance-infrared measurements showed that the peak intensity of the stretching vibration of the carbonyl group at around 1640 cm–1 decreased as applied potentials became more negative. The effect of amine modification of the BDD surface lies in the formation of a C–N bond during CO2 electroreduction, resulting in the enhancement of the selectivity of CO production up to 8 times compared to the unmodified BDD

Quantitative Chemical State Analysis of Supported Vanadium Oxide Catalysts by High Resolution Vanadium Kα Spectroscopy

Oxidation states of vanadium species on Al2O3, SiO2, and TiO2 were quantitatively analyzed by least-squares fitting of V Kα spectra recorded with a two-crystal X-ray fluorescence spectrometer. Uncertainties of analytical results by the normalization procedure, and coefficient of validation and the reduction behavior of vanadium species by X-ray irradiation were discussed. The V5+/V4+/V3+ ratios on Al2O3, SiO2, and TiO2 calcined at 773 K in air were determined to be ca. 6/3/1, 3/6/1, and 5/4/1, respectively. The possible chemical states of vanadium species on supports were proposed

Observation of the Anisotropic Photoinduced Magnetization Effect in Co−Fe Prussian Blue Thin Films Fabricated by Using Clay Langmuir−Blodgett Films as a Template

Thin films of cobalt−iron cyanide (Co−Fe Prussian blue) have been fabricated by means of the modified Langmuir−Blodgett (LB) method using a smectite clay mineral (montmorillonite). In this combined method, clay LB films play a template role in the formation of the Co−Fe Prussian blue thin layer. The films were revealed to possess a well-organized structure not only in perpendicular directions to the film surface but also in parallel directions to the film surface. The photoinduced electron transfer from the iron ion to the cobalt through the bridging cyanide in the films occurred at low temperature (8 K), similar to that in the bulk Co−Fe Prussian blue. The films clearly exhibited magnetic anisotropy with regards to the direction of the applied magnetic field. Moreover, the photoinduced magnetization effect in the films was also found to be anisotropic

Strategy for <i>O</i>‑Alkylation of Serine and Threonine from Serinyl and Threoninyl Acetic Acids by Photoinduced Decarboxylative Radical Reactions: Connection between Serine/Threonine and Carbohydrates/Amino Acids at the Side Chain

O-Alkylations of serine and threonine derivatives at the hydroxy group were achieved using photoinduced decarboxylative radical reactions of serinyl and threoninyl acetic acids with an organic photocatalyst without racemization under mild conditions. Photoinduced decarboxylative radical additions of serinyl and threoninyl acetic acids to electron-deficient alkenes provided linked serine and threonine with carbohydrates and amino acids at the side chain. In addition, O-methylations containing deuterium and O-benzylation of serine were performed under similar photochemical conditions