Tautomerism of Diisopropoxyphosphoryl Benzylisothiourea

Abstract

As part of our studies in preparation and physical properties of Potential ligands containing l-phosphoryl(P?O)-3-3-carbonyI(C?X, X?NH, O or S) group, we have investigated the intrdinta molecular hydrogen bonding of diisoproxy- phosphorylquanidine[l] as well as the tautomerism of phosphoryl benzylisothiourea. These are of interest as in interpretation of their chelation behavior as well as in development of other potential ligands for specific metal cations.     

Surface-plasmon-enhanced band emission of ZnO nanoflowers decorated with Au nanoparticles

A simple strategy was used to enhance band emission through the transfer of defect emission from ZnO to Au by using the energy match between the defect emission of ZnO and the surface plasmon absorbance of Au NPs through decorating the surface of ZnO nanoflowers with Au nanoparticles (Au NPs). The ZnO nanostructure, which was comprised of six nanorods that were attached on one side in a flower-like fashion, was synthesized by using a hydrothermal method. The temperature-dependent morphology and detailed growth mechanism were studied. The influence of the density of the Au NPs that were deposited onto the surface of ZnO on photoluminescence was investigated to optimize the configuration of the ZnO/Au system in terms of the maximum band emission. The sequential transfer of defect energy from ZnO to Au and electron transfer from excited Au to ZnO was proposed as a possible mechanism for the enhanced band emission.     

Fluorogenic sensing of CH3CO2- and H2PO4- by ditopic receptor through conformational change

Cyclo-bis-(urea-3,6-dichlorocarbazole) (1) forms a 1 : 2 complex with CH(3)CO(2)(-) and H(2)PO(4)(-) through hydrogen bonding with the two urea moieties, resulting in fluorescence enhancement via a combined photoinduced electron transfer (PET) and energy transfer mechanism. The binding mechanism involves a conformational change of the two urea receptors to a trans orientation after binding of the first anion, which facilitates the second interaction.     

Recent Advances in Aerosol‐Assisted Spray Processes for the Design and Fabrication of Nanostructured Metal Chalcogenides for Sodium‐Ion Batteries

Increasing demand for sodium‐ion batteries (SIBs), one of the most feasible alternatives to lithium ion batteries (LIBs), has resulted because of their high energy density, low cost, and excellent cycling stability. Consequently, the design and fabrication of suitable electrode materials that govern the overall performance of SIBs are important. Aerosol‐assisted spray processes have gained recent prominence as feasible, scalable, and cost‐effective methods for preparing electrode materials. Herein, recent advances in aerosol‐assisted spray processes for the fabrication of nanostructured metal chalcogenides (e.g., metal sulfides, selenides, and tellurides) for SIBs, with a focus on improving the electrochemical performance of metal chalcogenides, are summarized. Finally, the improvements, limitations, and direction of future research into aerosol‐assisted spray processes for the fabrication of various electrode materials are presented.     

AGR2, a mucinous ovarian cancer marker, promotes cell proliferation and migration

Ovarian cancer is a leading cause of death in women. Early detection of ovarian cancer is essential to decrease mortality. However, the early diagnosis of ovarian cancer is difficult due to a lack of clinical symptoms and suitable molecular diagnostic markers. Thus, identification of meaningful tumor biomarkers with potential clinical application is clearly needed. To search for a biomarker for the early detection of ovarian cancer, we identified human anterior gradient 2 (AGR2) from our systematic analysis of paired normal and ovarian tumor tissue cDNA microarray. We noted a marked overexpression of AGR2 mRNA and protein in early stage mucinous ovarian tumors compared to normal ovarian tissues and serous type ovarian tumors by Western blot analysis and immunohistochemistry. To further elucidate the role of AGR2 in ovarian tumorigenesis, stable 2774 human ovarian cancer cell lines overexpressing AGR2 were established. Forced expression of AGR2 in 2774 cells enhanced the growth and migration of ovarian cancer cells. AGR2 protein was detected in the serum of mucinous ovarian cancer patients by Western blot and ELISA analysis. Thus, AGR2 is a potential biomarker for the diagnosis of mucinous ovarian cancer and an ELISA assay may facilitate the early detection of mucinous ovarian cancer using patient serum.     

Fabrication of polymer nanotubes containing nanoparticles and inside functionalization

A polypyrrole nanotube containing nanoparticles is prepared by a dual template approach, and the inside of the nanotube is selectively functionalized with carboxyl and amine groups.     

Chromium porphyrin arrays as spintronic devices

Spintronic devices are very important for futuristic information technology. Suitable materials for such devices should have half-metallic properties so that only one spin passes through the device. In particular, organic half metals have the advantage that they may be used for flexible devices and have a long spin-coherence length. We predict that the one-dimensional infinite chromium porphyrin array, which we call Cr-PA(∞), shows half-metallic behavior when the spins on the chromium atoms are in a parallel alignment. Since the chromium atoms are separated by a large distance (>8 ?), the coupling between spins is small and thus their directions can be readily controlled by an external magnetic field. In the ferromagnetic state, the band gap for major spin electrons is 0.30 eV, while there is no band gap for the minor spin electrons, thus reflecting the half-metallic property. This unique property originates from the high spin state of Cr which results in the spin asymmetry of the conduction band in Cr-PA(∞). Electron transport of Cr-PA(1,2,3) is calculated with the nonequilibrium Green function technique in the presence of Au electrodes. It turned out that the spin-filtering ability appears from the dimeric Cr-PA(2). Thus, a new organometallic framework for designing a spin filter is proposed. Though many others have designed novel spintronic devices, none of them are realized due to the lack of a practical fabrication method at present. However, the porphyrin-based spintronic device provides a synthesizable framework.     

Induction-driven stabilization of the anion-π interaction in electron-rich aromatics as the key to fluoride inclusion in imidazolium-cage receptors

Intermolecular interactions that involve aromatic rings are key processes in both chemical and biological recognition. It is common knowledge that the existence of anion-π interactions between anions and electron-deficient (π-acidic) aromatics indicates that electron-rich (π-basic) aromatics are expected to be repulsive to anions due to their electron-donating character. Here we report the first concrete theoretical and experimental evidence of the anion-π interaction between electron-rich alkylbenzene rings and a fluoride ion in CH(3)CN. The cyclophane cavity bridged with three naphthoimidazolium groups selectively complexes a fluoride ion by means of a combination of anion-π interactions and (C-H)(+)···F(-)-type ionic hydrogen bonds. (1)H NMR, (19)F NMR, and fluorescence spectra of 1 and 2 with fluoride ions are examined to show that only 2 can host a fluoride ion in the cavity between two alkylbenzene rings to form a sandwich complex. In addition, the cage compounds can serve as highly selective and ratiometric fluorescent sensors for a fluoride ion. With the addition of 1 equiv of F(-), a strongly increased fluorescence emission centered at 385 nm appears at the expense of the fluorescence emission of 2 centered at 474 nm. Finally, isothermal titration calorimetry (ITC) experiments were performed to obtain the binding constants of the compounds 1 and 2 with F(-) as well as Gibbs free energy. The 2-F(-) complex is more stable than the 1-F(-) complex by 1.87 kcal mol(-1), which is attributable to the stronger anion-π interaction between F(-) and triethylbenzene.