Surface and interface of Ti(film)/SiC(substrate) system: a soft X-ray emission and photoemission electron microscopy study

We have conducted a soft X-ray emission spectroscopy (SXES) and a photoemission electron microscopy (PEEM) study on the heat-treated Ti/4H–SiC system. This spectro-microscopy approach is an ideal surface and interface characterization techniques due to the non-destructive nature of SXES and the real-time surface imaging of PEEM.

The Si L_2,3 and C K soft X-ray emission spectra, which reflect Si (s+d) states and C p states, respectively, revealed formations of Ti₅Si₃ and TiC in the reacted interfacial region of Ti (50 nm)/4H–SiC(0 0 0 1) sample.

The surface of the Ti films on 4H–SiC samples during heat-treatment up to 850 °C was investigated by PEEM. The variation in brightness in the image of the sample was attributed to the surface deoxidation in the early stage of the treatment and to the formation of reacted region at the later stage. The darkening of the surface could be attributed to the formation of TiC and/or excess C atoms that could have migrated to the surface.     

Preparation of high-performance hydroxide exchange membrane by a novel ablation restriction plasma polymerization approach

A novel approach of ablation restriction plasma polymerization has been successfully demonstrated for the first time in hydroxide exchange membrane synthesis. The membrane possesses high hydroxide conductivity, alkaline stability, and the ability of fully encompassing catalyst particles, without solubility in low boiling point water-soluble solvents.     

Chiral ionic liquid-mediated photochirogenesis. Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid

Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (AC-H) and its lithium salt (AC-Li) in chiral ionic liquid (CIL), (R)-1-(2,3-dihydroxypropyl)-3-methylimidazolium acetate {[(R)-GLYMI][AcO]}, gave a mixture of two head-to-tail (HT) and two head-to-head (HH) cyclodimers in HT/HH ratios of 1.3-1.7 (for AC-H) and 2.2-4.3 (for AC-Li) with low enantiomeric excesses (ee) of 0-3% for chiral syn-HT and anti-HH dimers. In contrast, irradiation of AC-H in an aqueous solution, containing cucurbit[8]uril (CB[8]) as a host and [(R)-GLYMI][AcO] or [(R)-GLYMI][Tf(2)N] as a modifier of CB portals, afforded the HH dimers in 91-99% selectivity, although the anti-HH dimer was totally racemic. Interestingly, irradiation of AC-H in a dichloromethane solution, containing [(R)-GLYMI][AcO] as a chiral template, led to the formation of the HH-dimers in 98% selectivity with chiral anti-HH dimer in -14% ee, presumably by the dual ligation of two ACs to a CIL through electrostatic and hydrogen-bonding interactions.     

Epitaxial growth and electrochemical properties of Li4Ti5O12 thin-film lithium battery anodes

Epitaxial Li(4)Ti(5)O(12) thin-films were successfully synthesized on SrTiO(3) single-crystal substrates with (111), (110), and (100) lattice plane orientations using pulsed laser deposition (PLD). Thin-film X-ray diffraction (XRD) revealed that the Li(4)Ti(5)O(12) films had the same orientation as the SrTiO(3) substrates: Li(4)Ti(5)O(12) (111) on SrTiO(3) (111), Li(4)Ti(5)O(12) (110) on SrTiO(3) (110), and Li(4)Ti(5)O(12) (100) on SrTiO(3) (100). These epitaxial films contained island structures, and the morphology of the (111), (110), and (100) films, observed by field emission scanning electron microscopy (FE-SEM), exhibited angular, needle-like, and circular shapes, respectively. The electrochemical properties of 20 nm thick Li(4)Ti(5)O(12) (111) and (110) films were investigated by cyclic voltammetry. Reversible intercalation proceeded through both lattice planes due to the three-dimensional diffusion pathway of lithium in the spinel framework. Reduction peaks in the first cathodic scan appeared at different positions from those in subsequent scans, suggesting a surface reconstruction at the Li(4)Ti(5)O(12) surface due to interfacial reactions.     

Rhodium-catalyzed olefin isomerization/enantioselective intramolecular Alder-ene reaction cascade

The olefin isomerization/enantioselective intramolecular Alder-ene reaction cascade was achieved by using a cationic rhodium(I)/(R)-BINAP complex as a catalyst. A variety of substituted dihydrobenzofurans and dihydronaphthofurans were obtained from phenol- or naphthol-linked 1,7-enynes, respectively, with good yields and ee values.     

Synthetic Studies of the Zoanthamine Alkaloids: Total Synthesis of Zoanthenol Based on an Isoaromatization Strategy

The total synthesis of zoanthenol, a unique aromatic member of the zoanthamine alkaloids, which has exhibited potent anti‐platelet activities on human platelet aggregation, is described in full detail. The key step involves a Brønsted acid‐promoted isoaromatization in the AB ring system to install the crucial aromatic ring. We have not only succeeded in the first total synthesis of zoanthenol, but also established an alternative efficient synthetic route from the commercially available norzoanthamine hydrochloride to zoanthenol.     

Sulfur-substituted tetrahedranes

The stable sulfur-substituted tetrahedrane derivatives 2-4 were synthesized by the reaction of tris(trimethylsilyl)tetrahedranyllithium 1 with diphenyl disulfide, bis(4-nitrophenyl) disulfide, and bis(2,4-dinitrophenyl) disulfide, respectively, and characterized by both NMR spectroscopy and X-ray crystallography. Phenylsulfonyltetrahedrane 5 was prepared by the reaction of 2 and m-chloroperbenzoic acid. The UV-vis absorption spectra of 2-4 suggested an interaction of the σ orbital of the tetrahedrane core and the lone-pair electrons on the sulfur atom, whereas no interaction for 5 was found. Thermal reactions of 2 and 5 are also reported; 2 underwent fragmentation into two acetylene molecules, whereas 5 gave the corresponding cyclobutadiene.