In situ synthesis of Cu nanocatalysts on ZnO whiskers embedded in a microstructured paper composite for autothermal hydrogen production

Cu nanoparticles (CuNPs) were successfully synthesized in situ on ZnO whiskers as a selective scaffold, which were supported in a microstructured paper matrix composed of inorganic fibers; as-prepared paper composites were easy to handle in practical use and demonstrated excellent catalytic performance in the methanol reforming process for effective hydrogen production.     

Synthesis, self-assembling properties, and atom transfer radical polymerization of an alkylated L-phenylalanine-derived monomeric organogel from silica: a new approach to prepare packing materials for high-performance liquid chromatography

The monomer N'-octadecyl-N(alpha)-(4-vinyl)-benzoyl-L-phenylalanineamide (4) based on L-phenylalanine has been simply but effectively synthesized, and its self-assembling properties have been investigated. FTIR and a variable-temperature (1)H NMR spectroscopic investigation demonstrated that the aggregation of compound 4 in various organic solvents is due to the formation of intermolecular hydrogen bonds among the amide moieties. UV/Vis measurements indicated that the multiple pi-pi interactions of the phenyl groups also contribute to the self-assembly. As was observed by (13)C cross-polarization magic-angle spinning (CP/MAS) NMR and variable-temperature (1)H NMR measurements, the ordered alkyl chains also played an important role in the molecular aggregation by van der Waals interactions. Compound 4 was polymerized by surface-initiated atom transfer radical polymerization from porous silica gel to prepare a packing material for HPLC. The results of thermogravimetric analysis showed that a relatively large amount of polymer was grafted onto the silica surface. The organic phase on silica was in a noncrystalline solid form in which the long alkyl chain exists in a less-ordered gauche conformation. Analysis of chromatographic performance for polyaromatic hydrocarbon samples showed higher selectivity than conventional reversed-phase HPLC packing materials.     

Separation efficiencies in hydrophilic interaction chromatography

Hydrophilic interaction chromatography (HILIC) is important for the separation of highly polar substances including biologically active compounds, such as pharmaceutical drugs, neurotransmitters, nucleosides, nucleotides, amino acids, peptides, proteins, oligosaccharides, carbohydrates, etc. In the HILIC mode separation, aqueous organic solvents are used as mobile phases on more polar stationary phases that consist of bare silica, and silica phases modified with amino, amide, zwitterionic functional group, polyols including saccharides and other polar groups. This review discusses the column efficiency of HILIC materials in relation to solute and stationary phase structures, as well as comparisons between particle-packed and monolithic columns. In addition, a literature review consisting of 2006-2007 data is included, as a follow up to the excellent review by Hemstr?m and Irgum.     

Preparation, telomerization, immobilization and application of N-alkyl L-phenylalanine-derived polymerizable organogelator for reversed-phase high-performance liquid chromatography

Silica-polymer hybrid materials (Sil-T1) have been successfully synthesized from a self-assembling polymerizable organogelator; N'-octadecyl-N(alpha)-(4-vinyl)-benzoyl-L-phenylalanineamide (C(18)-L-Phe-St or 1). Telomerization of compound 1 has been done with commonly used silane coupling agent; 3-mercaptopropyltrimethoxysilane (MPS), and the telomer (T1) was grafted onto porous silica surface to prepare a stationary phase (Sil-T1) for reversed-phase high-performance liquid chromatography. The composition of the new hybrid material (Sil-T1) was determined by elemental analysis, DRIFT-IR, TGA and by (13)C and (29)Si (CP/MAS) NMR spectroscopic measurements. The elemental analysis measurements revealed that the surface coverage by organic phase in Sil-T1 is significantly (about 135%) lower than commercial polymeric octadecylsilyalted silica (ODS-p). In addition, the results of (13)C CP/MAS NMR demonstrated that the N-alkyl moieties of the grafted polymers chain in Sil-T1 remained disordered, amorphous, and mobile represented by gauche conformational form. Furthermore, from the characterization data, the successful grafting process and unagglomerated state of the grafted particles (as observed by scanning electron microscopic, SEM measurements) prove the material to be suitable for HPLC application. The evaluation of chromatographic performance has been done from the retention studies of different size and shape PAHs and aromatic positional isomers. Significantly higher selectivity for PAHs was attributed by Sil-T1 than ODS-p regardless it has low surface coverage and lower order of alkyl chain. The enhancement of selectivity obtained by Sil-T1 can be explained by the contribution of multiple pi-pi interactions between the guest PAHs and the pi-electrons sources (carbonyls and aromatic moieties) of the organic phase of Sil-T1.     

Crossover Sorption of C2H2/CO2 and C2H6/C2H4 in Soft Porous Coordination Networks

Porous sorbents are materials that are used for various applications, including storage and separation. Typically, the uptake of a single gas by a sorbent decreases with temperature, but the relative affinity for two similar gases does not change. However, in this study, we report a rare example of “crossover sorption,” in which the uptake capacity and apparent affinity for two similar gases reverse at different temperatures. We synthesized two soft porous coordination polymers (PCPs), [Zn₂(L1)(L2)₂]_n (PCP-1) and [Zn₂(L1)(L3)₂]_n (PCP-2) (L1= 1,4-bis(4-pyridyl)benzene, L2=5-methyl-1,3-di(4-carboxyphenyl)benzene, and L3=5-methoxy-1,3-di(4-carboxyphenyl)benzene). These PCPs exhibits structural changes upon gas sorption and show the crossover sorption for both C₂H₂/CO₂ and C₂H₆/C₂H₄, in which the apparent affinity reverse with temperature. We used in situ gas-loading single-crystal X-ray diffraction (SCXRD) analysis to reveal the guest inclusion structures of PCP-1 for C₂H₂, CO₂, C₂H₆, and C₂H₄ gases at various temperatures. Interestingly, we observed three-step single-crystal to single-crystal (sc-sc) transformations with the different loading phases under these gases, providing insight into guest binding positions, nature of host–guest or guest-guest interactions, and their phase transformations upon exposure to these gases. Combining with theoretical investigation, we have fully elucidated the crossover sorption in the flexible coordination networks, which involves a reversal of apparent affinity and uptake of similar gases at different temperatures. We discovered that this behaviour can be explained by the delicate balance between guest binding and host–guest and guest-guest interactions.     

Effect of vaccination against COVID-19 spreading

We continue (Ref. 1: Proc. Jpn. Acad. Ser. B 97, 22–49) to analyze the COVID-19 status. We concentrate on the following issues in this work:1. Effect of vaccination against the spreading of SARS-CoV-2.2. General landscape of the world situation concerning vaccinations.3. Some aspects of the new variants of SARS-CoV-2.Our findings include:1. With vaccinations, it is fair to say that we have entered a new phase in the fight against the virus SARS-CoV-2. We have analyzed some preliminary data to find how vaccinations can be effective against COVID-19 spreading. This analysis is based on, and is a continuation of, our first paper quoted in Ref. 1.2. If Tokyo (or Japan) continues to keep its vaccination schedule (starting in early April, 2021 and finishing it for elderly, 65 or older, in 4 months), it will see a sign of control of the virus in early June, 2021 although we see changes of this status due to new, more contagious variants.3. The strength (parameter β) of a new contagious variant can be estimated based on the initial data on the variant (Section 5).     

Synthesis of a new poly(carboxybetaine) with peptide main chain

A new poly(carboxybetaine) whose main chain is composed of peptide bonds was synthesized from poly(γ-methyl L -glutamate). The side chains of poly(γ-methyl L -glutamate) were exchanged to carboxybetaine structures by three reactions. Our new poly(carboxybetaine) has 84% carboxybetaine structures in the side chains, as determined by ¹H NMR measurements. The presence of betaine structures in the side chains was confirmed by viscosity measurements.