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Because of the extracellular acidic microenvironment of cancer cells, many pH-responsive molecules have become indispensable materials for bioanalysis and targeted therapy development. pH-Responsive DNA aptamers, which selectively bind to target proteins in cancer cells, have become a key research target in the therapeutic field. However, conventional pH-responsive aptamers have fatal drawbacks, such as complex structures, sequence limitation, and difficulties in mass production, as they require special nucleic acid structures, including the i-motif and DNA triplex. To address these issues, we utilized An C , which is an unnatural nucleobase with a p K a H of 5.9, to construct a simple pH-responsive DNA aptamer (CSL1-II) for selective binding to the c-Met protein expressed in cancer cells. CSL1-II in a weakly acidic environment had a stronger inhibitory effect on the HGF/c-Met pathway and exerted a strong controlling effect on the spreading and migration of cancer cells. Our strategy provides a simple and versatile method to develop pH-responsive DNA aptamers and represents the first example of a cancer-selective c-Met antagonist that inhibits cell migration., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We herein propose an approach to visualize the Menschutkin reaction at an interface between a self-assembled monolayer with nucleophilic properties and water containing alkyl halides. An organic field-effect transistor functionalized with a nucleophilic monolayer has detected in situ alkylation depending on differences in the leaving group ability and the bulkiness of electrophilic alkyls.

Association-controllable hemoprotein assemblies were constructed from a fusion protein containing two c-type cytochrome units using 3D domain swapping. The hemoprotein assembly exhibited a dynamic exchange between cyclic and linear structures and could be regulated by carbon monoxide (CO) and imidazole binding.

Solar energy storage technology ensures a sustainable and reliable energy supply. Herein, we show that electrons generated in semiconductor nanocrystals (NCs) of CsPbBr 3 by visible light excitation can be stored in polyoxometalates (POMs) of W 10 O 32 , and extracted as an electric current using a photoelectrochemical cell.

The chalcogen-bonding interactions formed at both sides of the thiocarbonyl group in thiourea were investigated. In particular, the role of these chalcogen-bonding interactions in the trans - trans conformation of thiourea was evaluated via single-crystal X-ray diffraction analysis and DFT calculations. The obtained results indicate that the Se⋯S⋯Se dual chalcogen-bonding interactions play a stronger role in controlling the planar structure than the S⋯S⋯S interactions.

The chiral recognition of a self-assembled structure of enantiopure ( M )-type 2,13-diphenyl[7]thiaheterohelicene (( M )-Ph-[7]TH) was investigated on a Ag(111) substrate by scanning tunnelling microscopy (STM) and tip-enhanced Raman spectroscopy (TERS). In contrast to previous research of thiaheterohelicene and its derivatives showing zigzag row formation on the Ag(111) substrate, the hexagonal ordered structure was observed by STM. The obtained TERS spectra of ( M )-Ph-[7]TH were consistent with the Raman spectra calculated on the basis of density functional theory (DFT), which suggests that ( M )-Ph-[7]TH was adsorbed on the substrate without decomposition. The sample bias voltage dependence of STM images combined with the calculated molecular orbitals of ( M )-Ph-[7]TH indicates that a phenyl ring was observed as a protrusion at +3.0 V, whereas the helicene backbone was observed at +0.5 V. From these results, a possible model of the hexagonal structure was proposed. Owing to the phenyl ring, the van der Waals interaction between ( M )-Ph-[7]TH and the substrate becomes strong. This leads to the formation of the hexagonal structure with the same symmetry as the substrate.

π-Conjugated polymers such as polythiophene provide intramolecular wire effects upon analyte capture, which contribute to sensitive detection in chemical sensing. However, inherent aggregation-induced quenching causes difficulty in fluorescent chemical sensing in the solid state. Herein, we propose a solid-state fluorescent chemosensor array device made of a paper substrate (PCSAD) for the qualitative and quantitative detection of metal ions. A polythiophene derivative modified by dipicolylamine moieties (1 poly ), which shows optical changes upon the addition of target metal ions ( i.e. , Cu 2+ , Cd 2+ , Ni 2+ , Co 2+ , Pb 2+ , Zn 2+ , and Hg 2+ ), was highly dispersed on the paper substrate using office apparatus. In this regard, morphological observation of the PCSAD after printing of 1 poly suggested the contribution of the fiber structures of the paper substrate to the homogeneous dispersion of 1 poly ink to suppress aggregation-induced quenching. The optical changes in the PCSAD upon the addition of metal ions was rapidly recorded using a smartphone, which was further applied to imaging analysis and pattern recognition techniques for high-throughput sensing. Indeed, the printed PCSAD embedded with 1 poly achieved the accurate detection of metal ions at ppm levels contained in river water. The limit of detection of the PCSAD-based sensing system using a smartphone (48 ppb for Cu 2+ ions) is comparable to that of a solution-based sensing system using a stationary spectrophotometer (16 ppb for Cu 2+ ions). Therefore, the methodology based on a combination of a paper-based sensor array and a π-conjugated polymer will be a promising approach for solid-state fluorescent chemosensors., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Although deuterium incorporation into pharmaceutical drugs is an attractive way to expand drug modalities, their physicochemical properties have not been sufficiently examined. This study focuses on examining the changes in physicochemical properties between flurbiprofen (FP) and flurbiprofen- d 8 (FP- d 8 ), which was successfully prepared by direct and multiple H/D exchange reactions at the eight aromatic C-H bonds of FP. Although the effect of deuterium incorporation was not observed between the crystal structures of FP and FP- d 8 , the melting point and heat of fusion of FP- d 8 were lower than those of FP. Additionally, the solubility of FP- d 8 increased by 2-fold compared to that of FP. Calculation of the interaction energy between FP/FP- d 8 and water molecules using the multi-component density functional theory method resulted in increased solubility of FP- d 8 . These novel and valuable findings regarding the changes in physicochemical properties triggered by deuterium incorporation can contribute to the further development of deuterated drugs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The pressure-induced amorphization (PIA) of ice and clathrate hydrates occurs at temperatures significantly below their melting and decomposition points. The PIA of type I clathrate hydrates containing methane and ethane as guest molecules was investigated using Raman and infrared (IR) spectroscopy. With isothermal compression at 100 K, methane hydrate (MH) underwent PIA at 2-3.5 GPa, whereas ethane hydrate (EH) underwent PIA at 4.0-5.5 GPa. The type I clathrate structure consists of small (5 12 ) and large (5 12 6 2 ) cages. The Raman results revealed that the collapsed small and large cages in the amorphous forms of MH and EH were not distinguishable. The collapsed cages, including the methane and ethane molecules, were similar to the small and large cages, respectively. Their water networks were folded or expanded during the PIA process so that the cavity sizes of the collapsed cages were compatible with those of the guest molecules. Peaks in the IR spectra of crystalline MH assignable to the ro-vibrational transition of methane in large cages were observed in the C-H stretching wavenumber region below 40 K. The ro-vibrational IR band disappeared after amorphization, suggesting that the rotational motion of the methane molecule in the large cage was frozen by the collapse, as reported in previous dielectric spectroscopic and simulation studies. This study contributes to a better understanding of the changes in the local structure around guest molecules during PIA and the dynamics of the guest molecules.

In this study, we demonstrated the direct synthesis of sodium dihydrogen phosphate (PA) containing palladium nanoparticles (PdNPs) supported on a metal-organic framework (MOF). The resulting composite containing PA molecules coexisting with PdNPs demonstrated improved hydrogenation catalytic performance compared to the composites without PA.

A self-assembled chemosensor prepared using off-the-shelf materials has shown various fluorescence responses including ratiometric and simple ON-OFF switching profiles by adding different toxic metal ions. The unique fingerprint-like responses have been applied to pattern recognition of metal ions in river water for environmental analysis.

We herein report an organic transistor functionalized with a phenylboronic acid derivative and graphene oxide for the quantification of plasma glucose levels, which has been achieved by the minimization of interferent effects derived from physical protein adsorption on the detection electrode.

Dissymmetrical α,α'-disubstituted tripyrrins have been prepared using a modified synthetic protocol. Tripyrrin 2a bearing 3,5-bis(trifluoromethyl)phenyl and 4-methoxyphenyl moieties showed an anti -type dimer arrangement in the solid state. In contrast, syn -type dimers were observed for tripyrrin 2b bearing 3,5-bis(trifluoromethyl)phenyl and 3,5-di- t -butylphenyl moieties. In addition, proton-exchange NH tautomerization was observed in 2b.

Phthalocyanine that has four peripheral 2-methoxyphenyl substituents at the α-position and its Zn(II) and Cu(II) complexes were synthesized. Chemical oxidation by the Cu(II) ion and electrochemical oxidation of these metal complexes were investigated spectrophotometrically in acetonitrile. The UV-visible absorption spectra of these metal complexes and their one-electron oxidized π-cation radicals showed no concentration dependence, indicating that these species exist as monomers in solution. Kinetics of the thermal electron transfer reaction from each phthalocyanine complex to Cu 2+ and the photoinduced electron transfer reaction of the Zn(II) phthalocyanine complex with V(V) and V(IV) Schiff base complexes were studied using conventional spectrophotometric and transient absorption techniques, and the electron transfer rate constants were analysed using the Marcus cross relationship. The obtained rate constants of the electron self-exchange reaction between the parent phthalocyanine complexes and their π-cation radicals were in the order of 10 9 to 10 11 M -1 s -1 at T = 298.2 K. These large electron self-exchange rate constants are consistent with the phthalocyanine-centred redox reactions where small reorganization energies are required with little structural change during the electron transfer process.

Food protein-derived peptides with agonistic effects on receptors have great potential for treating anxiety, hypertension, and stress. In the present study, opioid peptides with agonistic activities for δ-receptor-expressing HEK293 cells were screened from casein hydrolysates prepared with five types of food grade proteolytic enzymes, among which casein hydrolysate with Aspergillus oryzae protease ASD showed the highest opioid activity. Eluted fractions showing potent opioid activity were further purified for active peptides by reverse phase-HPLC. The peptide in the active fraction was identified as YPFPGPIPNS, a member of β-casomorphin (CM-10) (β-casein 60-69). Various CM-10 derivative peptides were synthesized and their characteristic features for specificities towards δ- and μ-receptors were determined. Peptides 5 to 12 amino acids long showed relatively higher opioid activities for δ- and μ-receptors. CM-10 was docked into the optimized δ-receptor model. The CDOCKER energies of the CM-10 derivatives were consistent with their opioid activities. In the elevated plus-maze study, CM-10 showed a significant anti-anxiety effect in BALB/c mice at a dose of 10 mg per kg body weight when administered orally, but not via intravenous injection. Furthermore, intravital imaging revealed that Ca 2+ signaling was induced in the small intestinal villi of a Yellow Cameleon 3.60 (YC3.60)-expressing mouse upon injection with CM-10. However, this decreased in the presence of δ- or μ-receptor antagonists. These results suggest that the opioid peptide CM-10 prepared from casein with ASD has an anti-anxiety effect through interaction with gut δ- and/or μ-opioid receptors in the mouse gut.

This study proposes a chemical sensing approach for the selective detection of tropane alkaloid drugs based on an extended-gate-type organic field-effect transistor (OFET) functionalized with a molecularly imprinted polymer (MIP). From the viewpoint of pharmaceutical chemistry, the development of versatile chemical sensors to determine the enantiomeric purity of over-the-counter (OTC) tropane drugs is important because of their side effects and different pharmacological activities depending on their chirality. To this end, we newly designed an OFET sensor with an MIP (MIP-OFET) as the recognition element for tropane drugs based on a high complementarity among a template ( i.e. , ( S )-hyoscyamine) and functional monomers such as N -isopropylacrylamide and 2,2-dimethyl-4-pentenoic acid. Indeed, the MIP optimized by density functional theory (DFT) has succeeded in the sensitive and selective detection of ( S )-hyoscyamine (as low as 1 μM) by the combination of the OFET with highly selective recognition sites in the MIP. The MIP-OFET was further applied to determine the enantiomeric excess (ee) of commercially available ( S )-hyoscyamine, and the linearity changes in the threshold voltages of the OFET corresponded to the % ee values of ( S )-hyoscyamine. Overall, the validation with tropane alkaloids revealed the potential of the MIP combined with OFET as a chemical sensor chip for OTC drugs in real-world scenarios.

Chemical heterogeneous catalysis maximizes performance by controlling the interactions between the catalyst and the substrates. Steady-state catalytic rates depend on the heat of adsorption and the resultant coverage of adsorbates, which in turn reflects the electronic structure of the heterogeneous catalyst surfaces. This study aims to free the surface from high coverage of a kind of substance by externally controlling the electrochemical potential of the catalysts for improved thermal-catalytic rates. We employed aqueous CO oxidation at 295 K as a model reaction, where strong binding of chemisorbed CO (CO*) to the metal surfaces and its high coverage led to inhibition of O 2 accessing the surface site. Based on the establishment of coverage-potential-performance correlation, our potential-controlling experiments used an electrochemical configuration to identify the appropriate potentials of Pt/C catalysts that can drastically enhance the CO 2 formation rate through the thermal reaction pathway. An anodic potential was applied to suppress the high coverage of chemisorbed CO; consequently, the catalytic testing recorded a 5-fold increase in thermal CO 2 formation compared to the open-circuit counterpart with a faradaic efficiency (FE) of over 400%. In situ infrared spectroscopy corroborates the potential-coverage correlation, where the suppression of high CO* coverage due to pinning the catalyst potential triggered the enhancement of thermal-catalytic contribution to CO 2 formation. Our extended study employing other metal catalysts also exhibited FEs exceeding unity. This work establishes a universal methodology of electrochemical tools for thermal catalysis to precisely tune the electrochemical potential of solids and achieve green and innovative reactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A microfluidic organic transistor functionalized with phenylboronic acid firstly succeeded in reversible and real-time monitoring of H 2 O 2 at ppb/ppt levels in ultrapure water, which would be used not only as portable chemical sensors but also as monitoring tools to clarify unknown reaction mechanisms of phenylboronic acid with H 2 O 2 .

Herein, we report an extended-gate-type organic field-effect transistor (OFET) sensor for oxytocin. The fabricated OFET-based immunosensor has successfully detected oxytocin at a ppt level in human saliva with high recovery rates (96-102%). We believe our sensor would pave the way for the realization of portable sensors for healthcare monitoring.

We herein report the quantitative detection of biogenic amines using a gold nanoparticle-based colorimetric chemosensor array for food analysis. The gold nanoparticles are functionalized with carboxylate derivatives, which capture target amines through hydrogen bonds and electrostatic interactions. The simultaneous discrimination of 10 amine derivatives was achieved by a linear discriminant analysis with a 100% correct classification based on the multi-colorimetric response pattern of structural differences. Furthermore, a real sample analysis for raw fish ( i.e ., tuna) demonstrated highly accurate determination of histamine concentrations by a support vector machine, the result of which was matched with high-performance liquid chromatography. Most importantly, the chemosensor array succeeded in detecting the time-dependent concentration change of histamine in the raw fish, meaning that the decomposition of the fish could be monitored by the colorimetric changes. Hence, the proposed chemosensor array combined with pattern recognition techniques can be a user-friendly analytical method for food freshness monitoring., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The development of efficient fuel cells greatly promotes reducing the consumption of fossil energy, and it is crucial to enhance the platinum (Pt) catalytic activity by optimizing both the nanoparticle size and support effect. In this study, we generate a smaller and uniform size of naked Pt nanocluster (NC) catalysts via a dry process in the gas phase, and using the direct powder embedded trapping method, the Pt NCs are spatioselectively supported on Marimo carbon (MC) that comprises a high density of carbon nanofilaments. At a minimum Pt loading of 0.05 mg Pt cm -2 for both the anode and cathode in a single cell configuration, a membrane-electrode assembly (MEA) formed by the dry-deposition Pt-NC( d )/MC exhibits superior power density (rated) of 0.105 g Pt kW -1 at a current density of 1.2 A cm -2 , which is better output power density than the conventional MEA formed by Pt catalysts via a wet process. The origin of the improved performance is investigated using transmission electron microscopy; dry-deposition Pt catalysts that are monodispersely loaded on the outer surface of MC can facilitate not only the gas reaction but also leaving the generated water. The present results demonstrate that the dry deposition of Pt NCs on MC can be used as a scalable catalyst synthesis method to reduce the Pt loading., Competing Interests: The authors declare the following competing financial interest(s): K. T. and A. N. are inventors on JAPAN patent JP 5493139, submitted by JST agency and Ayabo Corp., which covers nanocluster generator., (This journal is © The Royal Society of Chemistry.)

The first phosphinoboronic ester bearing a fused bicyclic framework was synthesised by either deprotonation and hydride abstraction or Rh-catalysed dehydrogenation of a hydrophosphineboronic ester. The phosphinoboronic ester reacted as a Lewis acid with KF/18-crown-6, pyridine and DMAP to give the corresponding adducts. Furthermore, its crystal structure shows a remarkably short P-B bond in comparison with other P-B bonded derivatives in spite of the trigonal pyramidal geometry of the phosphorus. Consistent with the phosphorus pyramidality, the π-type donor-acceptor interaction of the P-B bond is small as revealed by the DFT calculations. The P-B bond shared within the fused six-membered rings has to shorten because of the geometrical requirement and high s-character of the boron.

The thermal decomposition of spherically granulated malachite particles was investigated to unveil the specific kinetic features of the reaction in samples in granular form toward the improvement of the thermal processing of malachite as a precursor of functional CuO. Granular malachite underwent thermal decomposition via a partially overlapping two-step mass loss process upon heating the sample in a stream of dry N2 gas. Morphologically, the process was characterized by swelling of the granular particles and cleavage divisions of the surface layer. The kinetics of the thermal decomposition was investigated through step-by-step kinetic analyses of the systematically recorded thermoanalytical curves. Finally, the kinetics of the component reaction steps was separately characterized by performing a kinetic deconvolution analysis. The first reaction step, which contributed approximately 25% to the overall reaction and followed pseudo-first-order kinetics, was attributed to the thermal decomposition of the granular particle surface. The as-produced surface product layer impeded the diffusional removal of the gaseous products, i.e., CO2 and water vapor, from the interior of the granular particles, which caused swelling of the granular particles owing to an increase in the internal gaseous pressure and the cleavage division of the surface product layer by crack formation. The second mass loss step occurred inside the granular particles under significant variations in the self-generated reaction conditions and geometrical constraints and reached its maximum rate midway through the reaction. Possible causes of the observed specific rate behavior are discussed from the viewpoint of physico-geometrical kinetics in the solid-gas system.

Molecular oxygen plays an important role in living organisms. Its concentration and fluctuation in cells or tissues are related to many diseases. Therefore, there is a need for molecular systems that can be used to detect and quantify oxygen levels in vitro and in vivo . In this study, we synthesized phosphonated mesoporous silica nanoparticles bearing ruthenium complexes in their pores (pM-Rus) and evaluated their photophysical and biological properties. The pM-Rus were highly soluble in water and showed robust phosphorescence under hypoxic conditions, while the addition of oxygen suppressed this emission. Cellular experiments revealed that pM-Rus with a size of 100 nm showed efficient cellular uptake to emit phosphorescence in hypoxic cells. In addition, pM-Rus have negligible toxicity to cells due to the blockage of direct contact between ruthenium complexes and intracellular biomolecules and the deactivation of singlet oxygen ( 1 O 2 ) generated by photoexcitation of ruthenium complexes before leaking out of the pores. Animal experiments confirmed that pM-Rus showed robust emission at hypoxic regions in mice. Thus, pM-Rus are promising oxygen probes for living systems., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Aqueous solubility is a key requirement for small-molecule drug candidates. Here, we investigated the regioisomer-physicochemical property relationships of disubstituted benzenes. We found that meta-isomers bearing non-flat substituents tend to possess the lowest melting point and the highest thermodynamic aqueous solubility among the regioisomers. The examination of pharmaceutical compounds containing a disubstituted benzene moiety supported the idea that the introduction of a non-flat substituent at the meta position of a benzene substructure would be a promising approach for medicinal chemists aiming to improve the thermodynamic aqueous solubility of drug candidates, even though it might not be universally effective.

The first asymmetric total synthesis of isolinearol has been achieved with high stereoselectively. The synthetic method includes enatio- and diastereoselective reductive desymmetrization, stereocontrolled introduction of the methallyl group, regio- and stereocontrolled allylation and introduction of the side chain carbonyl group using olefin cross-metathesis with a pinacol vinyl boronic ester.

In this communication, we report a chiral copper/NHC-catalyzed reaction between aromatic aldehydes and propargylic phosphates using a silylboronate, providing enantioenriched chiral α-allenic alcohols with complete regioselectivity and moderate to high enantioselectivity. The reaction pathway involves the catalytic formation of a nucleophilic α-alkoxylalkylcopper(i) species from aldehydes followed by its S N 2' type substitution reaction with propargylic phosphates.

Hybrids of reduced graphene oxide (rGO) and metal/metal oxide (Pt, NiO/Ni(OH) 2 , CoO, Fe 3 O 4 ) nano particle were prepared by reduction of graphene oxide (GO) and metal ion (Pt 2+ , Ni 2+ , Co 2+ , Fe 2+ ) hybrids. The M-rGO hybrids (M = Pt, Ni-, Co and Fe) were justified for the transformation of glucose to 5-hydroxymethylfurfural (5-HMF). High glucose → 5-HMF conversion was yielded depending on the nature of the M-rGO catalyst. The Ni-rGO showed the highest 5-HMF yield. The conversion reaction tuned to the optimized state under a microwave-assisted reaction accomplished by using Ni-rGO. In such case, the conversion rate was 99% with a 5-HMF yield of 75%. In order to improve both the conversion and yield, NiGO-FD was prepared by a freeze-dry method. The NiGO-FD remarkably showed the highest conversion of 99% and 5-HMF yield of 95%. Beside the biomass transformation process, the physico-chemical strategy employed herein for multiplying the catalytic efficiency might be justified for catalyzing similar reactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

(+)-5-Thiosucrose 1, a novel isosteric sulfur analog of sucrose, was synthesized stereoselectively for the first time via indirect β-d-fructofuranosidation involving selective β-d-psicofuranosidation, followed by stereo-inversion of the secondary hydroxy group at the C-3 position on the furanose ring. Glycosidation of protected 5-thio-d-glucose with a d-psicofuranosyl donor provided β-d-psicofuranosyl 5-thio-α-d-glucopyranoside and that with d-fructofuranosyl donor gave α-d-fructofuranosyl 5-thio-α-d-glucopyranoside. Two anomeric stereocenters of the glycosyl donor and acceptor were controlled correctly to provide a single disaccharide among four possible anomeric isomers in the glycosylation. Conversion of the resulting disaccharides afforded (+)-5-thiosucrose 1 and (+)-5-thioisosucrose 2 in excellent yields, respectively. Inhibitory activities of 1 and 2 against α-glucosidase in vitro were also examined., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

High-surface-area β-MnO2 (β-MnO2-HS) nanoparticles could act as effective heterogeneous catalysts for the one-pot oxidative sulfonamidation of various aromatic and heteroaromatic thiols to the corresponding sulfonamides using molecular oxygen (O2) and ammonia (NH3) as respective oxygen and nitrogen sources, without the need for any additives.

A tough and transparent norbornene copolymer film affixing an imidazolyl iron-salen complex catalyst exhibited an ultra-high, humidity-independent, and monthly paced oxygen-scavenging capacity up to 300 mL (oxygen gas at STP)/g(film). The homogeneously dispersed and immobilized iron complex in the polymer matrix catalytically contributed to the exceptionally high-yield oxidative consumption of polymer allylic bonds.

We developed a procedure for direct patterning of graphene with arbitrary position, size, and shape on silicon substrates from a solid-state carbon source without dry etching processing. Our light emitting graphene devices perform on a par with those based on high crystallinity graphene obtained via mechanical exfoliation or chemical vapor deposition., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)

The adsorption of Cs + ions by the precipitation bands of a Mn-Fe based Prussian blue analogue (Mn-Fe PBA) that form spontaneously in agarose gel was investigated by X-ray absorption fine structure spectroscopy coupled with scanning electron microscopy (SEM) and X-ray fluorescence (XRF) distribution analysis. Two gel samples were prepared by contacting a gel containing 0.05 M [Fe(CN) 6 ] 3- and 2.3 mass% agarose with a 0.50 M MnSO 4 solution, into one of which a 0.10 M CsCl solution was introduced. The SEM images and the XRF intensity distributions reveal that Mn-Fe PBA forms cubic crystallites (approx. 3 × 3 × 3 μm in size) in the gels that trap Cs + ions with considerably high affinity. Cs L 3 -edge and Mn K-edge X-ray absorption near-edge structure (XANES) spectra, which were analyzed with the aid of FEFF simulations, strongly suggest that Cs adsorption occurs at relatively large defect sites close to the sub-cube faces in the PBA. This suggestion is supported by Cs L 3 -edge extended X-ray absorption fine structure spectroscopy, which suggested that the first and second coordination shells around the Cs + ions are at a Cs-O distance of 0.35 ± 0.02 nm and a Cs-N distance of 0.43 ± 0.01 nm, respectively, with coordination numbers of 1.5 ± 0.5 and 3.0 ± 0.5. The Mn K-edge XANES data also suggest that H 2 O molecules, which initially occupy many cubic centers in the Mn-Fe PBAs, are mostly displaced during Cs adsorption. These findings provide valuable insight toward fully understanding Cs adsorption by Mn-Fe PBA.

Tumor-selective accumulation of gold nanorods (GNR) has been demonstrated for visualization of tumor hypoxia by photoacoustic imaging. We prepared GNRs with hypoxia-targeting nitroimidazole units (G-NI) on their surface. Biological experiments revealed that G-NI produced a strong photoacoustic signal in hypoxic tumor cells and tissues., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Among several theories proposed for the origin of homochirality, absolute asymmetric synthesis is unique because it produces chiral compounds without the intervention of any chiral factor. Here we report on the kinetically controlled heterogeneous solid-vapor phase absolute asymmetric synthesis in conjunction with asymmetric autocatalysis with amplification of chirality. Each reaction, carried out in a test tube, between achiral powder crystals of pyrimidine-5-carbaldehyde and the vapor of diisopropylzinc, is controlled kinetically to afford either (S)- or (R)-pyrimidyl alkanol.

Fine control of the band gap of single-walled carbon nanotubes (SWNTs) has been achieved by the functionalization with dibromoalkanes, namely, 1,3-dibromopropane (1a), 1,4-dibromobutane (1b), 1,5-dibromopentane (1c), and 1,8-bis(bromomethyl)naphthalene (1d). Red-shifted photoluminescence (PL) peaks observed at 1215-1242 nm were assigned to the local band gaps of the chemically functionalized SWNTs 2a, 2b, 2c, and 2d, respectively. Density functional theory (DFT) and time-dependent DFT calculations for 2a-2d suggest that "local strain" induced by cycloaddition plays an important role in tuning the local band gap energies of functionalized SWNTs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A spiral-type chiral Eu(iii) coordination polymer showed strong luminescence (emission quantum yield Φf-f = 57% and photosensitized energy transfer efficiency ηsens = 53%) and effective CD and CPL properties (gCPL = 0.17) when compared with a mono-nuclear chiral Eu(iii) complex in the solid state (Φf-f = 36%, ηsens = 14%, and gCPL = 0.09).

We herein propose a novel sensing strategy for biogenic amines using an electrolyte-gated polythiophene transistor. This ultra-low voltage operatable device responds to amines on the basis of the molecular recognition ability of a polythiophene pendant with a carboxy side-chain, which indicates that the sensing platform can contribute to the realisation of easy-to-fabricate and integrated chemical sensors.

The energy metabolism and embryogenesis of fertilized Japanese medaka eggs were investigated in vivo at the molecular level using near-infrared (NIR) spectroscopy and imaging. Changes in chemical components, such as proteins and lipids, in yolk sphere and embryonic body were studied over the course of embryonic development. Metabolic changes that represent variations in the concentrations and molecular compositions of proteins and lipids in the yolk part, particularly on the 1 st day after fertilization and the day just before hatching, were successfully identified in the 4900-4000 cm -1 wavenumber region. The yolk components were shown to have specific functions at the very early and final stages of the embryonic development. Proteins with α-helix- or β-sheet-rich structures clearly showed the different variation patterns within the developing egg. Furthermore, the distribution of lipids could be selectively visualized using data from the higher wavenumber region. Detailed embryonic structures were clearly depicted in the NIR images using the data from the 6400-5500 cm -1 region in which the embryo parts had some characteristic peaks due to unsaturated fatty acids. It was made clear that yolk and embryo parts had different components especially lipid components. The present study provides new insights into material variations in the fertilized egg during its growth. NIR imaging proved to be valuable in investigating the embryogenesis in vivo at the molecular level in terms of changes in biomolecular concentrations and compositions, metabolic differentiation, and detailed information about embryonic structures without the need for staining.

We propose a novel strategy for a high-throughput sensing of metal ions using a molecular self-assembled colourimetric chemosensor array. The proposed colourimetric assay has been achieved by only using the combination of commercially available materials. Importantly, the easy-to-prepare assay can be utilised to quantitatively detect metal ions under competitive conditions.

Temperature dependent inversion of enantioselectivity in asymmetric catalysis is an interesting and somewhat unusual phenomenon. We have observed temperature dependent inversion of enantioselectivity in the asymmetric autocatalysis reaction when triggered by a wide scope of enantioenriched alcohols and amines. The addition reaction of diisopropylzinc to pyrimidine-5-carbaldehyde in the presence of enantiopure alcohols or amines affords the pyrimidyl alkanol product at 0 °C with high ee. However, lowering the reaction temperature to -44 °C affords the opposite enantioselectivity.

A series of monooxotungsten(iv) and dioxotungsten(vi) benzenedithiolates, (NEt 4 ) 2 [W IV O(1,2-S 2 -3-RCONHC 6 H 3 ) 2 ] (1-W; R = CH 3 (a), t-Bu (b), or CF 3 (c)) and (NEt 4 ) 2 [W VI O 2 (1,2-S 2 -3-RCONHC 6 H 3 ) 2 ] (2-W), were synthesized and compared with the corresponding molybdenum analogues. Single crystals of trans-1b-W were successfully obtained, and the crystal structure was determined by X-ray analysis although 1b-Mo could not be crystallized. The NHS hydrogen bonds shifted the potential of the W(iv/v) redox couple to more positive values, and the strength of the hydrogen bond and the positive shift value were strongly correlated. The hydrogen bonds in both 1-W and 2-W were weaker than those in the corresponding molybdenum analogues; however, the effect of the hydrogen bonds on the redox potential was greater in 1-W.

Herein, we report an organic field effect transistor (OFET) with an extended-gate modified by an artificial receptor for the detection of mercury(II) ions (Hg(2+)) in water. The sensor device is easy to fabricate, reusable, disposable, and portable. Thus OFET sensors could be applied for low-cost on-site detection of Hg(2+).

A monooxotungsten(iv) benzenedithiolate complex containing two intramolecular NHS hydrogen bonds, (NEt4)2[W(IV)O(1,2-S2-3-t-BuNHCOC6H3)2] (1-W), was synthesized via a ligand-exchange reaction between a new starting complex, (NEt4)2[W(IV)O(SC6F5)4], and a partially deprotonated dithiol. When dithiol was used in solution, the oxo ligand was protonated and removed to afford (NEt4)2[W(IV)(1,2-S2-3-t-BuNHCOC6H3)3]. The trans isomer, trans-1-W, was crystallized, and the molecular structure was determined via X-ray analysis. Trans-1-W was gradually isomerized by heating it in solution and it eventually achieved an approximately 1 : 1 mixture of trans/cis isomers after 48 days. However, a slightly excess amount of trans isomer remained, so the isomerization rate was considerably slower than that of the molybdenum analogue. In the presence of NEt4BH4, deuteration of the NH protons was observed in acetonitrile-d3. The oxidation of both trans- and cis-1-W by Me3NO afforded the corresponding dioxotungsten(vi) complex, (NEt4)2[W(VI)O2(1,2-S2-3-t-BuNHCOC6H3)2] (2-W), as a single isomer. The contributions of the NHS hydrogen bonds to the bond distances, vibrational data, and electrochemical properties are described via comparisons with their molybdenum analogues. The results of this comparative study yielded insights into both tungsten and molybdenum enzymes.

Raman spectroscopy has previously been applied for studying lipid metabolism. In this study, a ball lens-installed hollow optical fiber Raman probe (BHRP) was used for the noninvasive measurement of skin lipids in hamsters. Our analysis suggested that multi-unsaturated lipids, once converted into a structure containing conjugated double bonds, were oxidized to form peroxides. These results were applied for analyzing lipid metabolism in adipose and skin tissues in hamsters fed tricaprin, saturated medium-chain triglyceride and trilinolein, unsaturated long-chain triglyceride fat diets. Unsaturated lipids formed conjugated structures in skin tissue but not in adipose tissue. Principal component analysis (PCA) revealed that the dietary fat intake correlated strongly with lipid composition in body and skin tissues. Hence, the present results successfully demonstrate that Raman spectroscopy with a BHRP can be a powerful tool for analyzing lipid metabolism.

Electrolyte is a key material for success in the research and development of next-generation rechargeable batteries. Aluminium rechargeable batteries that use aluminium (Al) metals as anode materials are attractive candidates for next-generation batteries, though they have not been developed yet due to the lack of practically useful electrolytes. Here we present, for the first time, non-corrosive reversible Al electrolytes working at room temperature. The electrolytes are composed of aluminium chlorides, dialkylsulfones, and dilutants, which are realized by the identification of electrochemically active Al species, the study of sulfone dependences, the effects of aluminium chloride concentrations, dilutions and their optimizations. The characteristic feature of these materials is the lower chloride concentrations in the solutions than those in the conventional Al electrolytes, which allows us to use the Al metal anodes without corrosions. We anticipate that the sulfone-based electrolytes will open the doors for the research and development of Al rechargeable batteries.

Crystalline peptide Ni(ii)-macrocycles (BF4(-) salt) exhibited moderate CO2 gas adsorption (ca. 6-7 CO2 molecules per macrocycle) into very narrow cavities (narrowest part <2 Å), accompanied by the expansion of the cavities. The BF4(-) salt demonstrated selective uptake of CO2 gas in preference to CH4 and N2 gases.

Five halogen substituted pyrazolates, 4-chloro-3,5-diisopropylpyrazole (4-Cl-3,5-iPr2pzH), 4-bromo-3,5-diisopropylpyrazole (4-Br-3,5-iPr2pzH), 4-iodo-3,5-diisopropylpyrazole (4-I-3,5-iPr2pzH), 4-chloro-3,5-diphenylpyrazole (4-Cl-3,5-Ph2pzH), and 4-bromo-3,5-diphenylpyrazole (4-Br-3,5-Ph2pzH), were conveniently prepared by halogenation of the appropriate pyrazoles with N-halosuccinimides (NXS) (X = Cl, Br, and I) followed by complexation of the pyrazolate anions with silver(i) nitrate. Single crystal X-ray analysis revealed either dimeric trinuclear {[Ag(μ-4-X-3,5-R2pz)]3}2 (R = iPr, X = Cl, Br, and I) or trinuclear [Ag(μ-4-X 3,5-R2pz)]3 (R = iPr, X = I; R = Ph, X = Cl, R = Ph, X = Br) structures, the latter held together with argentophilic interactions (AgAg interactions) that could also be observed in the Raman spectra. The electronegativity of the halogen substituent could be correlated with the strength of the AgAg interaction and the wavelength of solid-state photoluminescence. All complexes were emissive on UV irradiation at low temperatures, with the colour of emission from the diisopropyl substituted analogues red shifted by the halogens in the order Cl (red) > Br (orange) > I (yellow). Emission from the diphenyl substituted analogues was dominated by the extended aromatic system and was largely invariant to the halogens.