Cluster ions in the secondary ion mass spectrometry of choline and acetylcholine halides

Liquid secondary ion mass spectra of choline and acetylcholine halides exhibit several series of cluster ions whose origins were investigated using B/E and B²/E linked-scan techniques. In the case of choline halides three series of cluster ions were identified as (Me₃$ \mathop {\rm N}\limits^ + $CH₂CH₂OH + nM), (Me₃$ \mathop {\rm N}\limits^ + $CH₂CH₂OMe + nM) and (Me₃N$ \mathop {\rm N}\limits^ + $CH₂CH₂OH · Me₃$ \mathop {\rm N}\limits^ + $CH₂CH₂O^? + nM), while (CH₃COOCH₂CH₂$ \mathop {\rm N}\limits^ + $Me₃ + nM), (Me₃$ \mathop {\rm N}\limits^ + $CH₂CH₂OH + nM) and (CH₂ = CH$ \mathop {\rm N}\limits^ + $Me₃ + nM) were observed in the spectra of acetylcholine halides. For these cluster ions, bimolecular reactions induced on ion bombardment under secondary ion mass spectrometric conditions are discussed.     

Development of Highly Active Chiral Titanium Catalysts for the Enantioselective Addition of Various Organometallic Reagents to Aldehydes

The catalytic enantioselective carbonyl addition reaction has long attracted the interest of chemists because of its synthetic importance. Although many highly enantioselective reactions have been developed, with few exceptions the reactions are carried out at relatively high catalyst loadings, making them less practical for scale‐up applications. In addition, organometallic reagents employed as carbon nucleophiles have been limited to those with relatively low reactivity, such as diorganozincs and arylboronic acids. In an effort to enhance the practicality, a highly active and enantioselective chiral titanium catalyst system was recently developed in our laboratory, enabling the enantioselective carbonyl addition reaction to aldehydes using various organometallic reagents (RM; M = MgX, Li, BY₂, ZnX, AlMe₂) at lower catalyst loadings (≤5 mol %).

     

Feasibility study to investigate diffusion of Fe in Si using a Mössbauer spectroscopic microscope

A prototype Mössbauer Spectroscopic Microscope is applied for the feasibility study of ⁵⁷Fe impurity diffusion in Si wafers. A 2nm- ⁵⁷Fe deposited Si wafer is annealed at 430 °C for 1 hour, and subsequently the 1/3 area of the wafer is further grinded with an angle of 6 degrees to the original surface to get a higher depth resolution for the mapping. Subsequently, the mapping images for Fe\(_{\text {sub}}^{\mathrm {0}}\), Fe\(_{\text {int}}^{\mathrm {0}}\), and Fe\(_{\text {int}}^{\mathrm {+}}\) states are measured separately for the two different areas: one area (A) along the grinded surface, and the other (B) along the original wafer surface crossing through the ⁵⁷Fe-deposition boundary. By integrating the mapping intensity the diffusivity of each Fe component along the two different directions can be evaluated and compared with an average Fe diffusivity in Si, which is measured by EDS mapping data obtained for the same area.     

3D-Mössbauer spectroscopic microscope for mc-Si solar cell evaluation

A 3D-Mössbauer Spectroscopic Microscope is developed to evaluate Fe impurities in multi-crystalline Si solar cells, which combines the Mössbauer spectroscopic microscope with a scanning electron microscope (SEM), an electron beam induced current (EBIC), an electron backscatter diffraction (EBSD), and an electron energy analyzer (HV-CSA). In addition, a new moving-coil-actuator with a liner encoder of 100 nm-resolution is incorporated for the operations with both a constant velocity and a constant acceleration mode successfully with the same precision as that obtained by the conventional transducers. Furthermore, a new multi-capillary X-ray lens is designed to achieve a γ-ray spot size less than 100 μm in diameter. The new microscope provides us to investigate the space correlation between Fe impurities and the lattice defects such as grain boundaries in multi-crystalline Si solar cells.     

Transformation of benzonitrile into benzyl alcohol and benzoate esters in supercritical alcohols

The reactions of benzonitrile in supercritical methanol, ethanol, and 2-propanol were investigated under non-catalytic conditions. In supercritical methanol, benzonitrile was converted to methyl benzoate in high yield. The esterification reaction also occurred in supercritical ethanol to afford ethyl benzoate in moderate yield. The esterification could occur via a route analogous to the Pinner reaction. On the other hand, benzonitrile in supercritical 2-propanol yielded no ester. Benzyl alcohol was the major product in supercritical 2-propanol. We investigated the reaction of the CN bond in supercritical 2-propanol. In supercritical 2-propanol, N-benzylideneaniline was transferred to the reduction product (N-benzylaniline) and hydrolysis products (benzyl alcohol and aniline). The hydrolysis reaction was restricted when the reaction was carried out in supercritical 2-propanol with a low water content. This indicates that the water in the 2-propanol acts as a reagent for the hydrolysis of the CN bond. These results suggested the following reaction process: C₆H₅CN→C₆H₅CHNH→C₆H₅CHO→C₆H₅CH₂OH.     

Novel continuous carboxylation using pressurized carbon dioxide by immobilized decarboxylase

Novel continuous flow carboxylation system was constructed using pressurized CO₂ at 6.5 MPa and immobilized enzyme, Bacillus megaterium PYR 2910 decarboxylase. The decarboxylase catalyzed the backward reaction, carboxylation, to convert pyrrole to pyrrole-2-carboxylate at the improved space-time yield by 25 times compared to the corresponding batch reaction.     

Removal of structurally different dyes in submerged membrane fungi reactor—Biosorption/PAC-adsorption,membrane retention and biodegradation

The long-term performance of a submerged membrane fungi reactor was observed while a synthetic textile wastewater containing either or both of the two structurally different azo dyes was continuously fed. Compared to the Acid Orange II dye (simpler structure), higher biosorption but slower biodegradation of the polymeric dye (Poly S119) was observed in sterile batch tests. In the membrane bioreactor (MBR), although a relative abundance of fungi (66%) without any specific control of bacterial contamination could be maintained, unlike in pure fungus culture, enzymatic activity was below detection limit. Nevertheless, >99% removal of Poly S119 was consistently achieved under a dye loading of 0.1 g L⁻¹ d⁻¹ (HRT = 1 d). Comparison of the reactor-supernatant (SQ) and the membrane-permeate (PQ) qualities (31% improvement) revealed the significant contribution of the membrane to the overall removal (biosorption, cake layer filtration, biodegradation) of Poly S119. Contrary to the faster removal of Orange II in batch test, membrane-permeate quality revealed 93% removal of the dye in MBR (corresponding SQ = 82%). However, excellent (>99%) stable removal of Orange II or of both the dyes together, as well as stable enzymatic activity was observed following addition of powdered activated carbon (PAC) in the MBR. In accordance with real textile wastewater, dye contributed only 5% of the TOC loading (0.944 g L⁻¹ d⁻¹) in this study. In contrast to low TOC removal by fungi alone, the MBR containing mixed microbial community steadily achieved >98% removal, which improved further to >99% after PAC addition.     

X-ray diffraction analysis of photochromic reaction of fulgides: crystalline state reaction induced by two-photon excitation

Although most fulgides show their photochromism in the solid state, crystal structure changes accompanying the photochromism have not been previously observed. The photochromic reactions have been so far considered to take place on surfaces or at defects of the crystals or to proceed with destruction of the crystals. In this study we have succeeded in observing crystal structure changes accompanying the photochromism of fulgides using X-ray diffraction analysis. Detection of the photoproducts in the crystal structures was not possible when the single crystals of the fulgides were irradiated with steady UV light. Two-photon excitation by pulsed laser light was essential to produce a sufficient amount of the photoproducts without significant deterioration in the quality of the crystals.     

Fabrication and characterization of a novel inclusion complex of chiral monomer derived from (+)-camphor with beta-cyclodextrins

In order to develop a highly ordered polymer dopant to improve the physical properties of polymer materials for microsystems, a novel supramolecular inclusion complex (IC) of chiral bornyl 4-(6-acryloyloxyhexyloxy) phenyl-4'-benzoate ( BAPB) threaded with beta-cyclodextrins (beta-CDs) was synthesized. The inclusion complex was identified using Fourier transform infrared (FTIR), UV, 13C cross-polarization/magic-angle spinning (CP/MAS) NMR, 1H NMR, and X-ray diffraction (XRD). The construction of the fibrous self-assembled inclusion complex was confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The highly ordered polymerized inclusion complex beta-CD-BAPB revealed significant birefringence and was confirmed using polarized optical microscopy (POM). Polymerization of self-assembled nanofibrous monomers with methyl methacrylate was carried out, and the distribution of the nanofibers in the polymer matrix was confirmed using POM. This investigation demonstrates a novel method for the fabrication of polymeric nanofibers with highly ordered, self-assembled functional monomers. The polymeric nanofibers are expected to improve the physical properties of polymer films in the field of microelectric and micromachine systems (MEMS).