Photochemical reductions of imidazole-conjugated quinones in acetonitrile solutions containing [Ru(bpy)3]2+ (bpy: 2.2′-bipyridine) as a photosensitizer and triethanolamine as an electron donor selectively afforded the corresponding hydroquinones. These conversions were accelerated by the presence of an imidazolyl N-H proton, suggesting that the proton-coupled electron transfer retards the back-electron transfer.
For liquid-based fluoride shuttle batteries, electrolyte composed of organic solvent and supporting electrolyte salt is developed. To increase the solubility of supporting electrolyte salt in organic solvent, anion acceptors (triphenylboroxine or triphenylborane) are added. The addition of anion acceptor greatly increases the solubility of supporting electrolyte salt, and discharge-charge reaction of BiF3 electrode is confirmed in the prepared electrolytes.
Cadmium sulfide (CdS) is one of the most promising electron-transporting materials (ETMs) in perovskite solar cells (PSCs). In the present study, an ultra-thin CdS layer was prepared as the ETL using N-methyl thiourea (NMT) and introduced into a planar PSC. This new CdS ETL effectively enhanced the current without sacrificing other parameters such as the open-circuit voltage and fill factor, resulting in superior photovoltaic performance.
To make an effective panchromatic photo-sensitizer unit, inorganic lead sulfide (PbS) and cadmium sulfide (CdS) quantum dots (QDs) were deposited sequentially over mesoporous TiO2 film by the successive ionic layer adsorption and reaction (SILAR) process and then two molecular dyes were adsorbed successively to boost the response in the near-IR and visible regions, respectively. Using a cobalt (II/III) redox mediator, the photovoltaic performances of these hybrid sensitizer-anchored photo-anodes were tested to demonstrate a gradual increase in panchromatic response after the addition of each sensitizer.
Cyclo-1,8-carbazolylene was found to undergo oxidative rearrangement by oxidation with 2,3-dichloro-5,6-dicyano-p-benzoquinone, giving a 9a-substituted carbazol-1-one derivative. This is the first example of a dearomative oxidative rearrangement of a carbazole or aniline derivative. The geometrical and electronic structures were elucidated by X-ray analysis, UV-vis absorption spectroscopy, and DFT calculations.
We developed an enantioselective desymmetrization of 1,3-diols by a chiral N,N-dimethyl-4-aminopyridine (DMAP) derivative containing a 1,1′-binaphthyl with tert-alcohol units. The reactions required only 0.1 mol % of catalyst and showed moderate to high chemoselectivity (monoacylation vs. diacylation) and enantioselectivity (14 examples, up to 95:5 er). Several control experiments revealed that diol units in both the substrate and the catalyst are important to achieve high enantioselectivity.
Photo decomposition and stability under acidic conditions were studied for photo base generators (PBGs) having a borate anion. Borate-type PBGs were unstable under acetic acid conditions and quickly decomposed. However, PBGs bearing electron-withdrawing groups on an aromatic ring of borate showed good stability. According to HOMO-LUMO energy calculated basis at the B3LYP/6-31G(d) level, PBGs that had lower HOMO levels showed higher stability. Photolysis of PBGs was also studied and free energy changes estimated based on the Rhem-Weller equation. A higher stability was observed under acidic conditions co-existing with a sensitizer. When PBGs were evaluated in a system consisting of epoxy resin, carboxylic oligomer, sensitizer and an m-fluorinated aromatic ring on borate, it showed good potential for use in photoresists.
An in-situ biosynthetic method was employed to prepare graphene-incorporated-bacterial-cellulose (G/BC) conductive nanohybrid. The electrical conductivity of G/BC was determined as high as 46 S/m. A G/BC-based heterogeneous catalyst, CoPc@G/BC, was fabricated by immobilizing tetraamino cobalt (II) phthalocyanine (CoPc) catalyst onto the G/BC nanohybrid. The catalytic activity of CoPc@G/BC, as determined by removal rate of rhodamine B (RhB) dye wastewater, was ca. 50% higher than that without graphene. Electron interaction between CoPc and graphene might be responsible for this enhancement.
Ammonium ions (NH4+) were intercalated into the lattice of octacalcium phosphate (OCP) via a hydrolysis reaction in a concentrated NH4+–PO43−–H+ solution at a low temperature. The NH4+ ions substituted for Ca2+ ions conjugated to P5-PO4. The formation of OCP-NH4 was indicated by an extra peak at 4.3° in the X-ray diffraction pattern.
Saccharification of a glass surface has been performed using two grafting methods: grafting-from and grafting-onto, using a sugar-based cyclic sulfite as monomer. Central to the technique is a cationic ring-opening polymerization of the cyclic sulfite, which proceeds via the clean elimination of SO2 to yield 1,2-glucopyranan-grafted materials. The obtained glass surfaces exhibit different thermo-responsive behaviors, which could be attributed to features of each grafting method.
The influence of pH on the underpotential deposition of copper metal and the surface limited redox replacement with Pt2+ ions was studied. After 10 cycles of surface limited redox replacement between deposited Cu atoms and Pt ions, the roughness factor of the Pt multilayer prepared in near-neutral Na2SO4 was 1.5-fold smaller than in strongly acidic H2SO4. The small roughness factor of the Pt multilayer can be attributed to suppression of proton deposition at near-neutral pH.
A diindole-fused corannulene imide derivative was synthesized through two steps, Suzuki coupling and subsequent reductive cyclization reaction. Fusing indole rings to corannulene imide led to significantly red-shifted absorption, a lower HOMO–LUMO band gap, and a lower bowl-to-bowl inversion barrier than those of corannulene imide. The heterocycles also decreased the aromaticity of the rings of corannulene moiety adjacent to heterocycles.
A supramolecular hydrogel was prepared by the introduction of host-guest interactions between polyrotaxane (PRx) having guest parts and poly(acrylamide) with cyclodextrin hosts. Although the chemically cross-linked poly(acrylamide) hydrogels did not adhere to each other at the cut ends, the supramolecular hydrogels adhered to each other strongly even enduring their own weight. The recovery speed of rupture stress for the supramolecular hydrogels containing PRx was faster than that without PRx due to the movable cross-links.
A combination of simple π-conjugated molecules bearing a lone pair on heteroatom(s) and activators afforded new solid-state fluorescent materials. A solid-state red-emitting material that exhibits aggregation-induced emission was also synthesized by the present method.
A tetraphenylethylene-based diamidine for the recognition of dicarboxylic acids has been designed and synthesized. The diamidine shows a blue fluorescence after the addition of α,ω-dicarboxylic acids (C5–C10), such as pimelic acid (C7) and suberic acid (C8), due to the formation of a higher aggregate which is determined by a DLS analysis. For the recognition of the shorter and longer methylene chain lengths of α,ω-dicarboxylic acids (C3–C4, C11–C13), no fluorescence was observed, thus a narrow selectivity for the chain length of the α,ω-dicarboxylic acids was determined.
Immersing organometal halide perovskite crystals in CH3NH3I solution converts PbI2 impurities to CH3NH3PbI3 perovskite, yielding excellent carrier transport. Hence, the power conversion efficiency of perovskite solar cells is improved from 17.7% to 19.3% based on increased light absorption and decreased series resistance.
To evaluate the influence of polymers with similar chemical structures to polystyrene synthesized through soap-free emulsion polymerization on the indicator microorganism Micrococcus luteus, styrene derivative monomers were polymerized using a cationic initiator, namely 2,2′-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride. During bioassay, these polymers showed an inhibition zone against M. luteus. Hence, the supernatant containing polymers with lower molecular weights, which were toxic to M. luteus, obtained from soap-free emulsion polymerization should be treated carefully prior to discharge to the environment.
Herein, gefitinib-loaded nanoparticles are prepared based on the flash nanoprecipitation (FNP) approach, which lead to kinetically frozen nanoparticles featuring good size control and stability over time. Folic acid-modified amphiphilic Dex-b-PLA is applied as the protective copolymer, and the formed nanoparticles (NPs) display decent biocompatibility and efficient cellular uptake rate due to the presence of the dextran blocks and target groups, respectively. Our study demonstrates a novel method for preparing lung cancer drug-loaded NPs that show potential for further therapeutic applications.
A largely π-expanded thienoacene molecule, dinaphtho[2,3-d:2′,3′-d′]anthra[1,2-b:5,6-b′]dithiophene (DNADT) has been successfully synthesized and characterized. Its fabricated OFET device exhibited the maximum hole mobility of up to 8.5 × 10−2 cm2 V−1 s−1 which is three times higher than that of our previously reported nine-ring annulated compound, BBTADT. A detailed solid-state structure of DNADT by GIWAXS and AFM analyses have also been investigated.
To detect ammonia using an electrochemical method, we developed a sensor chip consisting of l-glutamate dehydrogenase, l-glutamate oxidase, and a Prussian blue–carbon electrode. When the enzyme electrode was applied to potentiometric and amperometric ammonia measurements, the limits of detection were 0.2 µM and 2,100 µM, respectively. Thus, potentiometric measurements, in which the charge produced by the enzymatic reaction accumulates on the electrode, allow more sensitive detection of ammonia than amperometric measurements, in which the charge passes through the electrode.
To achieve electrode performance with both high capacity and long cycle life, we investigated the effect of the anion structure in an ionic liquid electrolyte on the electrochemical performance of an annealed Ni–P/(etched Si) negative electrode for Li-ion batteries. The electrode maintained a discharge capacity of 1890 mA h g−1 after 250 cycles in bis(fluorosulfonyl)amide-based ionic liquid electrolyte, which was approximately three times higher than that in bis(trifluoromethanesulfonyl)amide-based electrolyte.
In this work, new pore-filled anion-exchange membranes (PFAEMs) are prepared and characterized for the successful application to all-vanadium redox flow batteries (VRBs). Particularly, filling ionomer is designed to have high crosslinking degree and ion-exchange capacity (IEC), simultaneously. As a result, the PFAEMs are shown to possess very low electrical resistance due to the thin film thickness and high IEC values. Furthermore, the VRBs utilizing the PFAEMs exhibit excellent energy efficiencies which are superior to those of the commercially available membranes (i.e. Nafion 117 and AMX) due to the low electrical resistance and reduced crossover rate of vanadium cations.
A CuGaS2 thin film was formed by annealing of spray-deposited precursor films in a sulfur atmosphere. The film worked as a photocathode for photoelectrochemical CO2 reduction in a neutral aqueous solution saturated with CO2 by applying a bias potential lower than that needed for inducing the reaction under a dark condition.
Co-loading of Pt and Fe on H-type *BEA zeolite (H-*BEA) helped us to stabilize Pt in a highly dispersed state, while Pt was aggregated on the outer surface of H-*BEA in the absence of Fe. Since highly dispersed Pt caused by Fe co-addition resulted in preferred balance between hydrogenating and acidic functions, Pt and Fe co-loaded H-*BEA provided high isomer selectivity in n-heptane conversion in comparison with only Pt loaded H-*BEA.
Automatic molecule design with machine learning and simulations has shown a remarkable ability to generate new and promising drug candidates. We propose a new population-based approach using a grammatical evolution named ChemGE, that can update a large population of molecules concurrently and evaluate with multiple simulators in parallel. In computational experiments, ChemGE succeeded in finding hundreds of candidate molecules whose affinity for thymidine kinase is better than that of known binding molecules in a database (DUD-E).
Temperature-dependent vibrational circular dichroism (VCD) measurements were performed in situ during the sol-gel transformation of a chiral low-molecular weight gelator, N,N′-diperfluoroheptanoyl-1,2(R,R)- or -1,2(S,S)-diaminocyclohexane in CD3CN. No VCD signal was detected for an isotropic acetonitrile solution of the gelator above 45 °C, while clear peaks appeared on the onset of gelation below 45 °C. They were assigned to the C=O stretching, NH bending and stretching vibrations related to perfluoroalkyl groups. The signal enhancement induced by gelation was ascribed to the occurrence of intermolecular vibrational coupling among the gelator molecules asymmetrically arranged within a fibril.
Rutin acts to protect the cardiovascular system, and thus it is of great significance to detect rutin. CdSe quantum dots combined with poly(diallyldimethylammonium chloride)-modified reduced graphene oxide nanocomposites (CdSe QDs/PDDA-rGO) were synthesized and used to detect rutin. The linear detection range for rutin is 0.1 to 10.0 µM and the detection limit is 0.03 µM. Furthermore, the CdSe QDs/PDDA-rGO/glassy carbon electrode (GCE) can quickly detect rutin in tablets. The new sensor is available to detect rutin in tablet samples.