bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Synthesis of Methylenecyclopropane Spiro-Linked with Cycloalkanes via a Cyclization of Allylic Epoxides and Its Application to a Synthesis of Fused 3-Methylfurans
Authors: Satoh Tsuyoshi , Kawase Yasushi , Yamakawa Koji
Published: July 2006

Ring closure of allylic epoxides derived from 1-chloroalkyl phenyl sulfoxides and cyclic ketones with lithium diisopropylamide (LDA) in 3-Exo-Tet mode gave spiro-linked methylenecyclopropanes having a hydroxyl group in good yields. Oxidation of these compounds gave ketones, which were then treated with p-toluenesulfonic acid in 1,4-dioxane or DMSO at 100°C to give fused 3-methylfurans in good overall yields. This procedure was applied to a synthesis of menthofuran from 4-methylcyclohexanone.
Rates and Mechanism for the Solvolyses of 2,2-Dimethyl-2-sila-1-indanyl Bromide and α-Trialkylsilylbenzyl p-Toluenesulfonates. α-Silicon Effect on the Stability of Benzylic Cations in Solution
Authors: Shimizu Nobujiro , Osajima Erika , Tsuno Yuho
Published: July 2006

α-Silicon effect on the benzylic solvolysis has been investigated. The solvolysis of 2,2-dimethyl-2-sila-1-indanyl bromide in aq acetone exhibits a linear response to the solvent ionizing power YBr with a slope m close to unity (m=0.93) and gives the corresponding alcohol without skeletal rearrangement indicative of a kc mechanism; it solvolyzes 4.98×102 times less rapidly than a carbon reference, 2,2-dimethyl-1-indanyl bromide, in 60% aq acetone at 25°C suggesting that solvolytic generation of the α-silylated benzylic cation is electronically about 4 kcal mol−1 less favorable than that of the corresponding α-alkylated benzylic cation. A more pronounced rate-retardation of 1.65×104 by an α-SiMe3 group relative to Me is observed in the solvolysis of an open benzylic system due to the additional steric effect. Mechanism for the solvolysis of α-trialkylsilylbenzyl p-toluenesulfonates including SiMe3, SiEt3, and Si(t-Bu)Me2 groups has been also examined on the basis of the solvent effect, salt effect, and ethanol/water selectivity as well as product analysis; a kc mechanism including a product forming step via preferential front side solvent attack is suggested.
Redox Reaction of Aromatic Aldehydes with Fe3(CO)12
Authors: Itoh Keiji , Nakanishi Saburo , Otsuji Yoshio
Published: July 2006

Aromatic aldehydes react with Fe3(CO)12 in refluxing benzene ultimately to give arylmethyl alcohols and 1,2-diaryl-1,2-ethanedione in a 1:1 ratio. In some cases, small amounts of 2,4,5-triaryl-1,3-dioxolanes are formed as minor products. Dinuclear iron complex (1,2-diphenyl-1,2-ethanedioxido)Fe2(CO)7 has been isolated as an intermediate in the reaction of benzaldehyde with Fe3(CO)12. The mechanism of this redox reaction of aromatic aldehydes are discussed on the basis of the kinetic study of the reaction and also of the reactivity of the isolated dinuclear iron complex.
ESR and Magnetic Susceptibility Studies on High-Spin Tetrahedral Cobalt(II)–Thiolate Complexes: An Approach to Rubredoxin-Type Active Sites
Authors: Fukui Kouichi , Ohya-Nishiguchi Hiroaki , Hirota Noboru
Published: July 2006

Magnetic susceptibility and ESR studies on high-spin (S=3⁄2) tetrahedral cobalt(II)–thiolate complexes were performed for A2[Co(SPh)4]; A=Me4N (1a), Et4N (1b), Ph4P (1c) and (Et4N)2[Co(SR)4]; R=C6H4-p-Me (2), C6H4-p-Cl (3), C6F5 (4). It was found that the magnitude of zero-field splitting and the anisotropy of g-factor are exceptionally large for 1c as D≈−100 cm−1, E≈0, gx≈gy<gz. This parameter set shows that Co(SPh)42− in 1c is strongly affected by an axial distortion. On the contrary, a rhombic distortion with moderate magnitude was found for 1a (D*=6.5 cm−1, E⁄D=−0.21) and 1b (D*=5.0 cm−1, E⁄D=0.19). The results for the other compounds are D*=7.0 cm−1, E⁄D=0.14 for 2, D*=12 cm−1, E⁄D=0.10 for 3, and D*=2.0 cm−1, E⁄D=0.02 for 4. Attempts were made to correlate the magnetic properties and the coordination geometry for 1a–c by use of available X-ray data. As a result, the importance of the orientation of the thiolate ligands was confirmed.
1 : 1 Adduct Ion Formation of Permethylated Monosaccharides with Organic Cations in FAB Mass Spectrometry
Authors: Sawada Masami , Ouyang Li , Takai Yoshio , Yamada Hitoshi , Shizuma Motohiro , Kinoshita Takeshi , Mochizuki Tomoko , Hanafusa Terukiyo
Published: July 2006

The 1 : 1 adduct ion formation between a series of permethylated monosaccharides (M; Ia–Ih) and an organic or a metallic cation (A+) has been examined in quantitative FAB mass spectrometry. In a careful comparison under the same FABMS conditions, the relative (M+A)+ peak intensities increase in the following order of the monosaccharides, and further increase at nearly the same extents in spite of using three different cations such as octylammonium, (methoxycarbonyl) methylammonium, and potassium ions:

β-Glc<α-Glc<α-Gal<β-Gal≤α-Man<β-Man<α-Tal<β-Tal.

The order and cation-independency clearly indicate the OCH3 configurational effects of M on (M+A)+ adduct ion formation. The findings can be interpreted in terms of multisite electrostatic interaction of oxygens with the cation. Coupled with the results of gas-phase behavior by FABMS/MS(CAD), solution behavior by 1H NMR, and model calculations by MNDO, the characteristic structure of the 1 : 1 adduct ion is deduced as host-guest type association between permethylated monosaccharides and cationic species in particular cases, at least β-Tal and α-Tal cases.
Electrode Kinetics of the [Fe(CN)6]4−⁄3− Complex Confined in Cationic Perfluoropolymer Films on Electrode Surfaces
Authors: Okajima Takeyoshi , Ohsaka Takeo , Oyama Noboru
Published: July 2006

A heterogeneous electron-transfer process of the [Fe(CN)6]4−⁄3− complex confined electrostatically in cationic perfluoropolymer (CPFP) films on graphite electrodes and a homogeneous charge-transport process within the films were examined by potential-step methods. The relevant kinetic parameters (i.e., standard rate constant; k°/cm s−1 and transfer coefficient; α) of the heterogeneous electron-transfer process and the apparent diffusion coefficient (Dapp/cm2 s−1) of the homogeneous charge-transport process within the films were evaluated at various concentrations (C°) of the complex within the film. The values of Dapp and k° slightly decreased with an increase in C°. The value of α was independent of C° (cathodic transfer coefficient, αc=0.20, anodic transfer coefficient; αc=0.80), The values of k°, α, and Dapp were compared with those obtained previously for protonated poly(4-vinylpyridine) (PVPH+)–[Fe(CN)6]4−⁄3− system and poly(N,N-dimethylaniline) (PDMA)–[Fe(CN)6]4−⁄3− system. It was found that k°, αc, and Dapp decrease, depending on the polymer film in which the complex is confined, in the following order: for Dapp and k°, PVPH+>PDMA>CPFP and for αc, PVPH+≈PDMA>CPFP.
On the Reaction of (Vinylimino)phosphoranes. Part 17. Preparation of N-Vinylcarbodiimides and Their [4+2] Cycloaddition with Several Dienophiles to Give Pyridine Ring System
Authors: Nitta Makoto , Soeda Hironobu , Koyama Shinya , Iino Yukio
Published: July 2006

The aza-Wittig reaction of (vinylimino)triphenylphosphorane and its several derivatives was examined to give N-phenyl-N′-vinylcarbodiimide and its derivatives, all of which underwent a [4+2] cycloaddition reaction with electron-rich dienophiles (enamines) and/or electron-deficient dienophiles (activated acetylenes), resulting in the formation of a pyridine ring system. The regioselectivity of the cycloaddition reaction could be rationalized on the basis of a frontier orbital consideration.
Cross-Dehydrocycloaddition of 1,3-Butadiene with Isoprene over MgO and ZrO2
Authors: Suzuka Hiroyasu , Hattori Hideshi
Published: July 2006

A mixture comprising of equal amounts of 1,3-butadiene (BD) and isoprene (IPN) was allowed to react over MgO and ZrO2 at 473 K in order to examine the relation between the product distribution and the reaction mechanisms. Over ZrO2 the most abundant product was 4-ethyltoluene, which was produced by a base-catalyzed Diels–Alder reaction between BD and IPN, followed by double-bond migration and dehydrogenation. In the Diels–Alder reaction, IPN acts as a diene and BD acts as a dienophile. Over MgO, o-xylene was primarily produced by anionic mechanisms. Among the products formed from BD and IPN, 4-ethyltoluene was produced most, though the production of 3-ethyltoluene was considerable. The active sites on ZrO2 were strongly poisoned by both CO2 and NH3. The active sites on MgO were completely poisoned by CO2, and were modified by NH3 in such a way that the reaction mechanisms changed from the anionic mechanisms to those involving the Diels–Alder reaction.
Mixed-Ligand Palladium(II) and Platinum(II) Complexes—Photosensitizers of 1O2 Production and Chemical Quenchers of 1O2
Authors: Kamath Shobha S , Shukla Santwana , Srivastava Tapeshwari S
Published: July 2006

[M(nn)(dhn)] (where M is Pd(II) or Pt(II), nn is 2,2′-bipyridine, 1,10-phenanthroline, 2,2′-biquinoline, or 4,7-diphenyl-1,10-phenanthroline, and dhn is dianion of 2,3-naphthalenediol) photooxidizes the 2,2,6,6-tetramethyl-4-piperidinol in N,N dimethylformamide via 1O2 when irradiated with light of wave-lengths of 420 to 800 nm in presence of molecular oxygen. The presence of 1O2 as an intermediate is confirmed by quenching studies using bis(dibutyldithiocarbamato)nickel(II) and 20% water in DMF. The relative efficiency of 1O2 production sensitized by the above complexes depends on nature of metal, ligand, and geometry of the complexes. However, [Pd(bpy)(dmt)] and [Pd(phen)(dmt)] undergo photooxidation via 1O2 when sensitized by hematoporphyrin IX and its metal derivatives on photolysis under similar conditions. The relative efficiency of 1O2 production depends on the nature of metal in porphyrin.
Spinning Effect on Magic-Angle-Spinning NMR Spectra of Silicone Rubber
Authors: Hayashi Shigenobu , Hayamizu Kikuko
Published: July 2006

High-resolution solid-state 13C, 29Si, and 1H NMR spectra of silicone rubber have been measured using the magic-angle spinning of the sample. The spectra of the three nuclei split into two or three components in the range of the spinning rate between 1.4 and 2.0 kHz. Below 1.4 kHz and above 2.0 kHz, the spectra consist of only one component. Stress caused by the fast spinning is considered to cause conformational changes in the polydimethylsiloxane chains.
Difference in Kinetic Behavior on the Photosensitized Decomposition of the Tris(oxalato)cobaltate(III) Ion by Tris(2,2′-bipyridine)ruthenium(II) and Bis(3,3′-biisoquinoline) (2,2′-bipyridine)ruthenium(II)
Authors: Kato Masako , Ohonishi Yuki , Kimura Masaru
Published: July 2006

The photo-sensitized decomposition of [Co(ox)3]3− (ox=oxalate) was performed using [Ru(bpy)3]2+ (bpy=2,2′-bipyridine) and [Ru(i-biq)2(bpy)]2+ (i-biq=3,3′-biisoquinoline). The dramatic difference in the decomposition behavior appeared between them. In appearance, the decomposition rate obeys first-order with respect to the [Co(ox)3]3− concentration for [Ru(i-biq)2(bpy)]2+ system, whereas zero-order for the [Ru(bpy)3]2+ system. The cause was discussed on the basis of the kinetic analysis.
Fluorogenic Substrate of Pepsin
Authors: Yonezawa Hiroo , Izumiya Nobuo
Published: July 2006

Fluorogenic substrates of pepsin; Dns–Ala–Phe–Trp–Val–Leu–OCH2Py and Dns–Phe–Trp–Val–Leu-OCH2Py were synthesized by a solution method. Incubation of pepsin with Dns–Ala–Phe–Trp–Val–Leu–OCH2Py resulted in specific cleavage at the Phe–Trp bond and the time-dependent increase in fluorescence intensity at 345 nm paralleling the extent of substrate hydrolysis. The optimum pH of the substrate was 3.0 and the Km and kcat values were 8.0×10−5 M and 0.10 s−1, respectively. The linearity of the plot of fluorescence intensity vs. enzyme concentration was satisfactory in the range of 50 nM to 500 nM of pepsin at a substrate concentration of 50 μM. Because of its simplicity and rapidity, this method is useful for the measurement of pepsin action. In contrast, Dns–Phe–Trp–Val–Leu–OCH2Py was not cleaved by pepsin.
Reinvestigation of the Phosphazo Method and Synthesis of N-(t-Butoxycarbonyl)-l-arginine p-Nitroanilide and a Chromogenic Enzyme Substrate for the Factor Xa
Authors: Oyamada Hidekazu , Saito Takashi , Inaba Shinsaku , Ueki Masaaki
Published: July 2006

Reaction conditions for the phosphazo method were reinvestigated in order to apply this method to the synthesis of p-nitroanilide(pNA)s of t-butoxycarbonyl(Boc)-and benzyloxycarbonyl(Z)-amino acids.
Palladium Catalyzed Reaction of Silacyclobutanes with Acetylenes
Authors: Takeyama Yoshihiro , Nozaki Kyoko , Matsumoto Kozo , Oshima Koichiro , Utimoto Kiitiro
Published: July 2006

Whereas the reaction of 1,1-dimethyl-1-silacyclobutane (1a) with dimethyl acetylenedicarboxylate in the presence of Pd catalyst provides dimethyl 1,1-dimethyl-1-sila-2-cyclohexene-2,3-dicarboxylate almost exclusively, the reaction of 1a with phenylacetylene affords allyldimethylstyrylsilane as a major product. The reaction of silacyclobutane with phenylallene provided three isomeric products.
Enantio- and Diastereo-Selective Synthesis of (+)-Grandisol
Authors: Narasaka Koichi , Kusama Hiroyuki , Hayashi Yujiro
Published: July 2006

(+)-Grandisol, an insect pheromone having cyclobutane skeleton, is synthesized enantio- and diastereo-selectively. The key steps in the synthesis are the asymmetric [2+2] cycloaddition reaction catalyzed by a chiral titanium reagent and the diastereoselective conjugate addition reaction by the combined use of Me2CuLi and trimethylsilyl trifluoromethanesulfonate.
An Useful Synthetic Method for 3-Substituted δ-Lactones. Synthesis of (±)-Secocrispiolide
Authors: Kato Michiharu , Ouchi Akihiko , Yoshikoshi Akira
Published: July 2006

2-Phenylthio-2-penten-5-olide (1) acted as a reactive Michael acceptor toward some typical carbon neucleophiles to give 3-substituted 2-phenylthio-5-pentanolides (2) which were convertible both to 3-substituted 5-pentanolides by reductive desulfurization and to 3-substituted 2-penten-5-olides by sulfenic acid syn elimination of the sulfoxides 4 derived from 2. The Pummerer rearrangement of 4 provided 3-substituted 2-phenylthio-2-penten-5-olides and/or 2-hydroxy-2-penten-5-olides. (±)-Secocrispiolide was synthesized via the adduct obtained by the Michael reaction of 1 with the Grignard reagent prepared from 2,6-dimethylbenzyl bromide and magnesium.
Crystal and Molecular Structure of [2-(2-Benzoxazolyl)phenolatotetrachloroplatinum]·[2-(2-Benzoxazolyl)phenol]·Ethanol, [PtCl4-(C13H8O2N)]·(C13H9O2N)·C2H5OH: Possibly a Stable New Pentavalent Platinum Complex
Authors: Furuhashi Akiko , Ono Isao , Ouchi Akira , Yamasaki Akira
Published: July 2006

The crystal and the molecular structures of the title complex were determined by means of the single-crystal X-ray diffraction method. The crystal of PtC28H23O5N2Cl4, F. W. 804.40, (black-violet in color) is monoclinic, with the space group of P21⁄a, a=18.293(4), b=9.682(2), c=15.797(3) Å, β=96.55(2)°, U=2779.6(9) Å3, Z=4, Dm=1.90, Dx=1.92 g cm−3, and μ (Mo Kα)=57.37 cm−1. The platinum atom is in a hexa-coordinated octahedral geometry, where one 2-(2-benzoxazolyl)phenolate (bxp−) ion is chelated with its N and phenolato O atoms. The bxp− ligand as well as the free Hbxp molecule are both approximately planar, and their planes are approximately in parallel: They are arranged alternately and are laid roughly along the a-axis. Although the overlappling areas of the neighboring rings are only 23 and 13% respectively of the whole ring area, the interplane distances are 3.42 and 3.49 Å.
Local Structure, Tg, and IR Transparency of Potassium Titanate Glasses and the Local Structure of Calcium Titanate Ceramics
Authors: Nishida Tetsuaki , Yamaguchi Yasuharu , Yamada Miho , Takashima Yoshimasa
Published: July 2006

The Mössbauer spectrum of xK2O·(95−x)TiO2·5Fe2O3 glasses (x=35–60), consisting of a paramagnetic doublet peak due to tetrahedral Fe3+, suggests that the Fe3+ is substituted for the tetrahedral Ti4+. The isomer shift (δ=0.20–0.23 mm s−1) and the quadrupole splitting (Δ=0.72–0.81 mm s−1) decrease linearly with the increasing K2O content. The glass transition temperature (Tg) decreases similarly as the Δ does, supporting the “Tg−Δ rule” discovered by Nishida et al., i.e., the Tg of oxide glasses is expressed by Tg=aΔ+b. (The slope “a” is 680 °C mm−1 s.) The IR absorption spectra show two peaks at 880 and 640 cm−1 corresponding to the Ti(Fe)O4 and TiO6 units, respectively. The relative absorption intensity of the Ti(Fe)O4 units becomes higher when the K2O content increases. The potassium titanate glasses (plate) show IR transparency, having the transmission edge of 5.4 μm. The Mössbauer spectrum of xCaO·(95−x)TiO2·5Fe2O3 ceramics (x=5–50) consists of two doublet peaks due to Fe3+ and Fe2+. Both the δ and Δ of the Fe3+ are constant irrespective of the CaO content, whereas the fraction (relative absorption area) of the Fe3+ decreases linearly from 94 to 75% when the CaO content is increased from 5 to 50 mol%.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. XVIII. Factors Affecting the Rates of Dissociation of N–B Bond in the Coordinated Form of 9-[2-(Dialkylaminomethyl) phenyl]-9-borabicyclo[3.3.1] nonanes
Authors: Toyota Shinji , Oki Michinori
Published: July 2006

NMR spectra of the title compounds reveal that they exist in the intramolecularly N–B coordinated form. The NMR signals exhibited dynamic behaviors accompanied with the dissociation of the N–B bond and total line shape analyses of the exchanging nuclei afforded kinetic parameters for the topomerization. Entropies of activation are large and positive, typical for the dissociation of coordination bonds. Examination with the multiple probes shows that the nitrogen inversion requires additional energy after the N–B bond dissociation. The barrier for the topomerization is affected by N-alkyl groups due to their F-strain. The barrier height is reduced in nonpolar solvents and not influenced by nucleophilicity of solvents. These solvent effects are discussed in connection with polarity of the N–B bond and steric hindrance of the boron atom.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. XIX. Sulfur Inversion in 9-[2-(Ethylthiomethyl)phenyl]-9-borabicyclo[3.3.1]nonane Proceeds via Dissociative Mechanism
Authors: Toyota Shinji , Oki Michinori
Published: July 2006

Kinetic parameters for sulfur inversion in the title compound were determined by the dynamic NMR method in CD2CL2 as follows: ΔH≠ 14.2±0.1 kcal mol−1, ΔS≠ 11.3±0.3 cal mol−1 K−1, ΔG233≠ 11.6 kcal mol−1. The large and positive entropy of activation suggests that the inversion takes place through dissociative mechanisms. Comparison of the rate constants obtained with multiple probes shows that the rotation about the Cph–B bond requires further energy after the dissociation of the S–B bond. The solvent effect on the sulfur inversion is small but distinct; the more polar a solvent, the higher the barrier to the inversion. Dynamic behaviors of a related compound are also discussed.
Nucleophilic Ring-Opening of Chlorooxiranes: A New Synthesis of α-Hydroxy α′-Substituted Ketones from Carbonyl Compounds and 1-Chloroalkyl p-Tolyl Sulfoxides
Authors: Satoh Tsuyoshi , Ogura Asako , Ikeda Youko , Yamakawa Koji
Published: July 2006

The addition of 1-chloroalkyl p-tolyl sulfoxides to carbonyl compounds gave adducts which were then converted to chlorooxiranes in two steps with good overall yields. The treatment of the chlorooxiranes with various nucleophiles gave α-hygroxy α′-substituted ketones or α-hydroxy ketones in good yields.
Nucleophilic Substitution Reactions between Diphosphonate and Orthophosphate Characterized by High-Performance Liquid Chromatography and 31P NMR Spectroscopy
Authors: Yoza Norimasa , Okamatsu Miki , Tokushige Noriko , Miyajima Tohru , Baba Yoshinobu
Published: July 2006

Inorganic diphosphonate with phosphorus of an oxidation number +3 was found to react with orthophosphate (oxidation number +5) at 50 °C to give phosphonylated compounds; dimeric isohypophosphate (oxidation numbers +3 and +5) and a novel trimeric compound (oxidation numbers +3 and +5). Orthophosphate ion is considered to act as a ligand with two or three nucleophilic sites that were phosphonylated stepwise by diphosphonate. Kinetic processes of the nucleophilic reactions were monitored by HPLC and 31P NMR. Two products, the dimer having one P–H bond and the trimer with two P–H bonds, were well-resolved by HPLC and their yields, based on orthophosphate applied, were 85% (dimer) and 3% (trimer) when a mixed solution of 0.5 M diphosphonate and 0.1 M orthophosphate was incubated at 50 °C for 21 h. A complicated 31P NMR spectrum that indicated a large coupling constant(JPH=650 Hz) and grew with incubation time is reasonably assigned to the unsymmetrical isohypophosphate composed of both a phosphate group and a phosphonate group. Apparent formation constants of the dimer and trimer were evaluated.
Intramolecular Energy Transfer in Covalently Linked Polypyridine Ruthenium(II)/Osmium(II) Binuclear Complexes. Ru(II)(bpy)2Mebpy– (CH2)n–MebpyOs(II)(bpy)2 (n=2, 3, 5, and 7)
Authors: Furue Masaoki , Yoshidzumi Toshiyuki , Kinoshita Shuichi , Kushida Takashi , Nozakura Shun-ichi , Kamachi Mikiharu
Published: July 2006

A novel series of polymethylene-linked heterobinuclear complexes of polypyridine ruthenium(II)/osmium(II) complex Ru(II)(bpy)2Mebpy–(CH2)n–MebpyOs(II)(bpy)2(bpy=2,2′-bipyridine and n=2, 3, 5, and 7), 1, was prepared. The photophysical behavior was examined in various solvents. The emission spectra of 1 (excitation wavelength: 455nm) showed a nearly complete quenching of RuII→π*(bpy) metal-to-ligand charge transfer (MLCT) emission and the enhancement of OsII→π*(bpy) MLCT emission. The luminescence lifetime measurements by a time-correlated single photon-counting method provided evidence that intramolecular energy transfer is a significant pathway for the observed emission quenching. The rate constants of the intramolecular energy transfer in ethanol are 5.3×108, 3.3×108, 1.3×108, and 1.0×108s−1 for 1(n=2, 3, 5, and 7), respectively. They were found to be proportional to the inverse sixth power on the center-to-center distance of the two complexes. The mechanism is discussed in terms of the Förster (a dipole-dipole interaction) mechanism.
Methanol Synthesis from CO2 and H2 over CuO–ZnO Catalysts Combined with Metal Oxides under 13 atm Pressure
Authors: Xu Zheng , Qian Zaihu , Mao Liqun , Tanabe Kozo , Hattori Hideshi
Published: July 2006

The synthesis of methanol from CO2 and H2 in a flow reactor was studied over CuO–ZnO catalysts combined with ZrO2, MgO, Al2O3, or Cr2O3 under a presssure of 13 atm. CuO–ZnO–Al2O3, CuO–ZnO–ZrO2, and CuO–ZnO–MgO showed higher activity and higher selectivity for methanol than did CuO–ZnO. The selectivity for methanol formation became higher as the reaction temperature was lower, or any of the H2/CO2 ratio, the pressure and the space velocity were higher. On the basis of analyses by XRD, XPS, and ultraviolet diffused reflectance spectroscopy, the active centers of CuO–ZnO–ZrO2 seem to be a Cu+–ZnO species stabilized by ZrO2.
Support Effect of Re Catalyst on Methanol Synthesis from CO2 and H2 under a Pressure of 5 atm
Authors: Xu Zheng , Qian Zaihu , Tanabe Kozo , Hattori Hideshi
Published: July 2006

Methanol synthesis by the reaction of CO2 with H2 over Re supported on ZrO2, CeO2, La2O3, and Al2O3 was studied under a pressure of 5 atm by the use of a flow reactor. Methanol was formed over Re/CeO2, Re/ZrO2, and Re/La2O3, but not over Re/Al2O3 and ZrO2 alone. On the basis of XPS analysis, the active state of Re was suggested to be Re0 for Re/ZrO2 and Re/CeO2. For Re/Al2O3, Re was incompletely reduced, resulting in no formation of methanol. Methanol synthesis was inferred to proceed via CO in the case of Re/ZrO2, and via the reaction of CO2 with surface OH in the case of Re/CeO2 by FT-IR analysis.
UV and DSC Analyses of Suspensions of Mixtures of Phosphatidylcholine and a Fatty Acid Having a Diene Group
Authors: Hasegawa Etsuo , Hatashita Masanori , Kimura Noboru , Tsuchida Eishun
Published: July 2006

The aqueous suspensions of the mixtures of a phosphatidylcholine (1,2-Bis[(2E,4E)-2,4-octadecadienoyl]-sn-glycero-3-phosphocholine (1b) and 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (1a)) with a fatty acid ((2E,4E)-2,4-octadecadienoic acid and octadecanoic acid), having a diene chromophore were analyzed by DSC and UV measurements. The phase transition was dependent on the composition of the lipid mixtures. The UV spectral change of the diene chromophore of a fatty acid for the 1a mixtures corresponded well with the phase transition determined by DSC analyses, but not for the 1b mixtures.
Terminal Polar Substituent Effect on the Liquid Crystalline Properties of a Series of 4-Octyloxy-N-(4-substituted benzylidene)anilines
Authors: Miyajima Seiichi , Enomoto Takehiko , Kusanagi Tomohiro , Chiba Takehiko
Published: July 2006

Mesomorphic properties are studied on the title compounds where substituents are F, Cl, Br, I, NO2, and CN. Besides the known mesophases, nematic and smectic Ad, in CN and NO2 homologues, stable smectic A and B phases were observed in either of the Cl and Br derivatives. Metastable nematic and smectic A phases were found in F derivative. The effects of terminal polar substituents, stabilization of the smectic A phase by moderately polar substituents, and of the nematic phase by strongly polar substituents, were confirmed.
Synthesis and Characterization of Six-Membered Cyclometallated Complexes of 2-Bezylpyridine with Rhodium(III)
Authors: Hiraki Katsuma , Onishi Masayoshi , Kishino Hiroko
Published: July 2006

2-Benzylpyridine (Hpiph) is metallated with RhCl3·3H2O to give [{Rh(piph)Cl2(Hpiph)}2]·H2O [piph=2-(2-picolyl)phenyl] in which piph is coordinated at phenyl-1-C and picolyl-N atoms. This complex reacts with tertiary phosphines (PR3) such as PEt3, PEt2Ph, and PPh3 to yield [Rh(piph)Cl2(PR3)2].
Catalytic Behavior of Rhodium(I) Complexes in Hydrogermylation and Hydrosilylation of Phenylacetylene
Authors: Wada Fumio , Abe Seiji , Yonemaru Norio , Kikukawa Kiyoshi , Matsuda Tsutomu
Published: July 2006

Rhodium complexes, Rh(L)(C2H4)2 {L=(CH3C=O)2CH (acac), and (CF3C=O)2CH (hfa)}, catalyze hydrogermylation and hydrosilylation of phenylacetylene with Bu3GeH and R3SiH (R=Bu, Et), respectively, to produce Ph(R3M)C=CH2 (M=Ge, Si) selectively. Other rhodium complexes, that is, [RhCl(C2H4)2]2, Rh2Cl2(cod)2, Rh(tmhd)(C2H4)2 {tmhd=(t-BuC=O)2CH}, and Rh(dbm)(C2H4)2 {dbm=(PhC=O)2CH}, also catalyze these reactions, but with less regioselectivity.
Aggregates in Langmuir–Blodgett Films of Spiropyrans Having Hydroxyl or Hydroxymethyl Group
Authors: Miyata Akio , Unuma Yutaka , Higashigaki Yoshiyuki
Published: July 2006

The optical properties of monomolecular layers at an air–water interface and also of Langmuir–Blodgett (LB) films of several photochromic spiropyrans with a single hydrophobic long chain and either a hydroxyl or a hydroxymethyl group have been investigated. Changes in the optical spectra of these films were induced by either UV irradiation or heating. UV-visible, and IR absorption spectra showed that spiropyran SP145 formed J-aggregates and SP147 formed H-aggregates. The half-decay period of the J-aggregate to the spiropyran (SP) form was longer than that of the colored monomeric photomerocyanine (PMC) to the SP form. It was concluded that hydrogen bonding between neighboring colored PMC molecules via hydroxyl, hydroxymethyl, and nitro groups stabilizes the aggregate state.
Shock Tube Studies of the H2–O2–CO Reaction by Atomic Resonance Absorption Spectroscopy
Authors: Koike Tohru
Published: July 2006

The atomic resonance absorptions of O- and H-atoms in the reaction of shock-heated H2/O2/CO/Ar(1/1/1/97 and 0.2/1/1/97.8) mixtures were observed over a relatively low temperature range from 1000 to 1400 K. The induction times, determined from the absorptions, were investigated by means of computer modeling which included a sensitivity test. The rate constant for the important initiation reaction, CO+O2=CO2+O, was evaluated to be k13=1013.1±0.6exp (−196.9±14.9kJ⁄RT) cm3 mol−1 s−1, which may supplement the lack of reported rate constants in the low-temperature region.
Formations of OH(X2II, A2Σ+) in the Reaction of NH(3Σ−) with NO in Incident Shock Waves
Authors: Yokoyama Keiichi , Sakane Yasuo , Fueno Takayuki
Published: July 2006

Gaseous mixtures of HNCO and NO diluted in Ar were heated by incident shock waves to about 3500 K to investigate the bimolecular reaction of NH(3Σ−) with NO. Ultraviolet emissions from the excited NH(A3II) and OH(A2Σ+) were monitored to determine the rate constants for the ground-state reaction NH(3Σ−)+NO→N2+OH(X2II). The branching ratio defined as the rate constant for the formation of OH relative to that for the NH(3Σ−) decay was found to be 0.32±0.07 at the shock-wave temperature adopted. An intense spike of chemiluminescence due to OH(A2Σ+→X2II) was observed, a finding which indicates a possible participation of the channel NH(3Σ−)+NO→N2+OH(A2Σ+) at high temperatures.
Titanium(III) Chloride Mediated Reduction of 1-Nitro-2-phenylethenes
Authors: Sera Akira , Fukumoto Shoji , Tamura Masako , Takabatake Kiyoshi , Yamada Hiroaki , Itoh Kuniaki
Published: July 2006

The reaction of 1-nitro-2-phenylethenes (β-nitrostyrenes) with aqueous titanium(III) chloride afforded substituted pyrroles in addition to the expected reduction products, oximes and carbonyl compounds. 2-Substituted 1-nitro-2-phenylethenes yielded divinylamine derivatives instead of pyrroles. The reaction mechanism has been rationalized by taking account of the electron transfer from titanium(III) species to the nitro olefins, followed by protonation, dimerization, cyclization, and/or hydrolysis.
Complex Formation of Gelatin and Chondroitin Sulfate and the Effects on H+ Ion Binding
Authors: Yonese Masakatsu , Yano Mikio , Kishimoto Hiroshi
Published: July 2006

Soluble and insoluble complex formations of gelatin and chondroitin 6-sulfate (Chs-C) were studied by measuring their viscosities and transmittances; the effects of complex formations on H+ ion binding were studied by pH titrations. Soluble complexes were formed electrostatically with low ionic strengths; the compositions of the complexes varied with pH from those of solutions. The weight fraction of Chs-C of the saturated soluble complex was found to be 0.294 at pH=5.1. The composition of the insoluble complexes increased in the fraction of Chs-C with decreasing pH. The compositions were found to agree with the theoretical predictions obtained from the condition of electroneutrality. Furthermore, from pH titrations of mixed solutions comprising gelatin and Chs-C, the apparent dissociation constants, pKa of the carboxylic groups of both polymers were obtained. They were found to increase due to soluble complex formation; soluble complex formation depresses the dissociation of H+ ions due to a shielding of the positively charged amino groups of gelatin.
Electronic Spectra of Phenanthrolinediones, Phenanthrolinones, Bipyridinediones, and Amino-Substituted Phenanthrolines
Authors: Yamada Masaki , Kimura Miki , Nishizawa Mineyasu , Kuroda Shigeyasu , Shimao Ichiro
Published: July 2006

The electronic spectra of three types of 1,10-phenanthroline derivatives having different π-conjugated systems, phenanthrolinedione, phenanthrolinone, and the parent phenanthroline, showed characteristic patterns easily distinguished from each other. Analogous spectral patterns were noted in amino-substituted 1,10-phenanthrolines, and the protonated structures of these compounds were characterized on the basis of such spectral features.
Palladium-Catalyzed Vinylation of Haloazulenes and Halotropolones with Olefins. Utility of the Heck Reaction in the Conjugated Carbon Chain Preparation
Authors: Horino Hiroshi , Asao Toyonobu , Inoue Naoto
Published: July 2006

The reactions of 3-iodotropolone with styrenes (styrene, p-methoxystyrene, and 2-vinylpyridine), methyl acrylate, and allylic compounds (methyl 3-butenoate, 3-butenenitrile, 1-allyl-3,4-dimethoxybenzene, and 1-allyl-3,4-methylenedioxybenzene) were carried out, according to the modified Heck’s procedure, to give 3-styryl-, 3-(2-carboxyvinyl)-, and 3-(3-substituted 1-propenyl)tropolones, respectively. Similarly, 4-bromo- or 5-bromotropolone was made to react with these olefins to yield 4-styryltropolone or the corresponding 5-(2-substituted vinyl)- and 5-(3-substituted 1-propenyl)tropolones. Substitution of 2-chlorotropone by styrenes produced 2-styryltropones. Extension of the vinylation to 2-amino-6-bromoazulenes, ethyl 3-bromo-1-azulenecarboxylate, and diethyl 2-chloro-1,3-azulenedicarboxylate resulted in a similar substitution.
Syntheses, Crystal Structures, and Antitumor Activities of Dinuclear Platinum(II) Complexes, Di-μ-sulfoacetato-bis[(diamine)platinum(II)] Trihydrate
Authors: Miyamoto T Ken , Ichida Hikaru
Published: July 2006

A series of new dinuclear platinum(II) complexes have been prepared from the reaction of [PtL2(OH)2] with sulfoacetic acid: [PtL2(slac)]2·3H2O, where slac=sulfoacetate dianion; L2=1,2-diaminocyclohexane (1a–1c) or 1,2-diaminoethane (2) and L=isopropylamine (3) or ammine (4). They have di-μ-carboxylato bridged dinuclear zwitterionic structures in crystals. Among them, complexes (1a–1c) show significant antitumor activities against mice ieukemia L1210.
Raman Phonon Spectroscopic Study of Phase Transition in 4-Cyanopyridine Crystal
Authors: Chakrabarti Subhasis , Misra Tridibendra Marayan , Sarma Mahesh Kumar , Medhi Kanak Chandra
Published: July 2006

Raman phonon spectroscopy in the 10–170 cm−1 range has been used to study phase transition in 4-cyanopyridine crystal. At 77 K, ten distinct phonon modes and an internal mode are observed whereas at 300 K the spectrum shows only six phonon bands and an internal mode. The temperature dependence of spectral pattern and phonon band width suggest that the crystal goes through a phase transition around 120 K. Experimental result suggests that the phase transition is discontinuous with a small structural change.
Crystalline 1 : 1 Inclusion Complexes between a Roof-Shaped Diamide Host and Methanol or Propionic Acid. Crystal Structures and Modes of Interaction
Authors: Csöregh Ingeborg , Finge Stephan , Weber Edwin
Published: July 2006

The crystal structures of two inclusion complexes between anti-N-N′-di-t-butyl-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxamide host and methanol [a=11.8893(4), b=18.0943(7), c=12.6322(4) Å, β=108.47(3)°, P21⁄c, Z=4] or propionic acid [a=11.4580(8), b=11.7614(9), c=12.4675(8) Å, α=95.37(3), β=109.70(3), γ=113.26(3)°, P\bar1, Z=2] as guests have been studied by X-ray diffraction. Closed loops of different sizes, formed via hydrogen-bond interactions between host and guest or between the hosts only, characterize both structures. The crystals with the propionic acid guest consist of hydrogen-bonded host : guest associates with 2 : 2 stoichiometry, while the methanol inclusion gives rise to infinite hydrogen-bonded chains.
Molecular Structure and Carbonylation of Ethyl(benzenethiolato)-palladium(II) Complex, trans-PdEt(SPh)(PMe3)2
Authors: Osakada Kohtaro , Ozawa Youichi , Yamamoto Akio
Published: July 2006

X-Ray crystallography of ethylpalladium thiolato complex, trans-PdEt(SPh)(PMe3)2, shows the detailed features of the Pd–C and Pd–S bonding. Reaction of the complex with CO at 5 atm gives S-phenyl thiopropionate. The NMR spectrum of the reaction mixture under 1 atm of CO shows the presence of trans-Pd(COEt)(SPh)(PMe3)2 formed through CO insertion into the Pd–C bond.
Urea Sensitive Field Effect Transistors Based on Dithio Group-Containing Langmuir–Blodgett Membranes
Authors: Lee Shouryu , Anzai Jun-ichi , Osa Tetsuo
Published: July 2006

2-(Octadecyldithio)pyridine (1) and 5-(octadecyldithio)-2-nitrobenzoic acid (2) were synthesized in order to prepare Langmuir–Blodgett (LB) membranes which possess reactive dithio groups on the surface for further modification with enzymes. The monolayer membrane, composed of 1 or 2, was deposited successfully on an ion-sensitive field effect transistor, and the membrane surface was modified with urease covalently by a thiol–disulfide exchange reaction. The LB membrane-based sensor 2 showed a better potentiometric response to urea than that of the membrane-based sensor 1. The results are discussed on the basis of the reactivity of the dithio groups to urease at the membrane surface.
Thermally Irreversible Photochromic Systems. Photoreaction of Diarylethene Derivatives with Imidazo[1,2-a]pyridine Rings
Authors: Nakayama Yasuhide , Hayashi Koichiro , Irie Masahiro
Published: July 2006

A non-symmetrical diarylethene with imidazo[1,2-a]pyridine ring on one end and thiophene ring on the other end, 1,2-dicyano-1-(2-methylimidazo[1,2-a]pyridin-3-y1)-2-(2,4,5-trimetyl-3-thieny1)ethene 2Z underwent a hexatriene-cyclohexadiene type reversible ring-closure reaction by photoirradiation, while an only Z–E isomerization was observed for a symmetrical diarylenthene with two imidazo[1,2-a]pyridine rings, 1,2-dicyano-1,2-bis(2-methylimidazo[1,2-a]pyridin-3-yl)ethene 1Z. The ring-closure reaction was not discerned. The photogenerated closed-ring form 2C had the absorption band at 535 nm, which is 23 nm longer wavelengths than that of the corresponding dithienylethene, and kept the absorption intensity constant for more than 24 h at 80 °C. The quantum yield close to unity was observed for the photochemical ring-opening reaction of 2C with 546 nm light.
Partition Coefficient of 21H,23H-Porphine and Its Metal(II) Complexes between Heptane and Nonaqueous Polar Solvents
Authors: Wakui Yoshito , Imura Hisanori , Suzuki Nobuo
Published: July 2006

The partition coefficients of 21H,23H-porphine (H2por) and its copper(II) (Cu(por)) and zinc(II) (Zn(por)) complexes were determined in nonaqueous two-phase systems. A linear free-energy relationship was observed between the partition coefficients of H2por and Cu(por). The partition coefficient of Zn(por) was suppressed by coordination bonding with the polar solvent molecules.
Classification of Phenothiazine Complexes by Structure and Electronic Properties
Authors: Kozawa Kozo , Hoshizaki Taketoshi , Uchida Tokiko
Published: July 2006

Donor-acceptor complexes were prepared, and their structures and electronic properties were observed. Donors were phenothiazine and its four derivatives, and acceptors were metallic chlorides (Lewis acids), iodine, and two π-type acceptors. By the absorption edge of diffuse reflection spectra (λE) and crystal structure, the complexes were classified into four groups. Groups I, II, and III correspond to the complexes with Lewis acids or iodine, and group IV consists of complexes with π-type acceptors. The summarized characteristics of each group are as follows. Group I: λE≤950 nm, complete charge transfer, insulator, and alternate arrangement of cations and anions. Group II: 1200 nm≤λE≤1700 nm, complete charge transfer, semiconductive behavior, and oligomeric or columnar arrangement of cation radicals. Group III: λE>2500 nm, partial charge transfer, metallic conductor or semiconductor with small activation energy, and columnar arrangement. Group IV: λE≥1700 nm, and semiconductive behavior. Based on these classifications, we have proposed a mechanism for controlling the aggregate manner of cation radicals.
Synthetic Photochemistry. LVI. Photorearrangement of Dimethyl 2-Oxohomobarrelene-6,7-dicarboxylates
Authors: Mori Akira , Nukii Yasuhiro , Endo Akihiro , Takeshita Hitoshi
Published: July 2006

The direct irradiation of dimethyl 2-oxohomobarrelene-6,7-dicarboxylates in chloroform gave indanone derivatives. A benzophenone-sensitized reaction gave a new tricyclic compound, dimethyl 5-oxotricyclo[4.3.0.02,9]nona-3,7-diene-1,2-dicarboxylate, the formation of which was quenched by isoprene.
Synthesis of Benzo[1,2:4,5]dicycloheptene-1,9-dione via 6,7,12,13- Tetrahydro-7,12-methano-3H-cycloheptacyclodecene-3,14-dione and Its Protonation Behavior
Authors: Kato Masahiko , Mitsuda Masaru , Shibuya Takuji , Furuichi Kimiaki
Published: July 2006

6,7,12,13-Tetrahydro-7,12-methano-3H-cycloheptacyclodecene-3,14-dione has been synthesized starting from the [4+6]-cycloaddition product of the reaction of 3,4-bis(methylene)-7,7-dibromobicyclo-[4.1.0]heptane with tropone. The adducts were transformed to their epoxides, which were treated with trifluoroacetic acid to give the 3,14-dione. This was transformed to benzo[1,2:4,5]dicycloheptene-1,9-dione, bis(tropono)benzene, by two different methods: (1) by heating it with trichloroacetic acid and DDQ in toluene or (2) through bromination followed by heating in DMF. The 1,9-dione is protonated in coned sulfuric acid to give bis(hydroxytropylium) dication, while it is protonated mainly (>80%) on the C-9 carbonyl oxygen and less (<40%) on the C-1 carbonyl oxygen in deuteriochloroform containing trifluoroacetic acid.
Synthesis of Optically Active Substituted Cyclohexenones from Carbohydrates by Catalytic Ferrier Rearrangement
Authors: Chida Noritaka , Ohtsuka Masami , Ogura Katsuyuki , Ogawa Seiichiro
Published: July 2006

Conversion of hex-5-enopyranosides into substituted cyclohexanones (Ferrier rearrangement) was found to proceed efficiently with a catalytic amount of various mercury(II) salts at room temperature in a neutral solvent system. Among the mercury(II) salts tested, mercury(II) trifluoroacetate showed the highest activity. Four optically active cyclohexenones were prepared from hex-5-enopyranosides utilizing this method.
Benzophenone-Sensitized Photolysis of N,N-Dibenzyl-O-acylhydroxylamines. Mechanism of the Imine-Forming Radical Elimination Reaction
Authors: Sakurai Tadamitsu , Mizuno Hisashi , Kubota Tsuneari , Inoue Hiroyasu
Published: July 2006

Title hydroxylamines (1) undergo benzophenone-sensitized photolysis to give N-benzylidenebenzylamine (2), p-substituted benzoic acids (3), and monosubstituted benzenes (4) derived from decarboxylation of p-substituted benzoyloxyl radicals. Analysis of the linear Stern–Volmer plots, both for the sensitized photolysis of 1 and for the phosphorescence quenching of benzophenone by 1, demonstrates the participation of triplet 1 in this photolysis. The logarithm of the ratio (kr⁄kd), where kt is the rate constant for homolytic cleavage of the N–O bond in triplet 1 and kd is that for its deactivation, used as a measure of the triplet-state reactivities of 1, exhibited a good Hammett-type relationship against the substituent constant (σ) with a slope (ρ) of −0.75. This indicates the exclusive occurrence of homolysis of the N–O bond in the first excited triplet state of 1. Thus the decomposition of 1 activated by triplet benzophenone is classified as an imine-forming radical elimination. The results of deuterium isotope and micellar effects on the sensitized photolysis suggest that the “out-of-cage” products 4 are obtained by decarboxylation and subsequent hydrogen abstraction of p-substituted benzoyloxyl radicals which escaped from the triplet cage in competition with spin inversion to the singlet cage. In this singlet cage, hydrogen abstraction giving 2 and 3 and recombination affording the starting 1 were found to take place exclusively.
Discrimination of Rotational Isomers of Jet-Cooled Acetophenone Derivatives as Studied by Sensitized Phosphorescence Excitation Spectroscopy
Authors: Yamamoto Seiji , Hashimoto Nobuhisa , Ito Mitsuo
Published: July 2006

The S1(n,π*)←S0 and T(n,π*)←S0 sensitized phosphorescence excitation spectra of jet-cooled o- and m-substituted (fluoro- and methyl-) acetophenones have been measured. The two rotational isomers (O-cis and O-trans isomers) of each molecule arising from the orientation of the acetyl group with respect to o- or m-substituent have been discriminated. The energy difference in the 0–0 transition between the two isomers is less than 100 cm−1 for m-substituted acetophenone but more than 300 cm−1 for o-substituted acetophenone. The characteristic energy difference can be explained from the fact that the electronic excitation is localized on the C=O group.
Isotope Effects on the Reorientational Motion of Hydrated H2O Molecules in Alkali Metal Bromide Dilute Aqueous Solutions Studied by NMR Spectroscopy
Authors: Shimizu Akio , Taniguchi Yoshihiro
Published: July 2006

The spin-lattice relaxation times of 1H and 17O nuclei of hydrated H2O molecules in alkali metal bromide (LiBr, NaBr, KBr, and CsBr) dilute aqueous solutions in the concentration range from 0.2 to 1.0 mol kg−1 at 25 °C were measured by NMR spectroscopy. The reorientational correlation times for the intramolecular 1H–1H (τHH+) and 1H–17O (τOH+) axes, as well as the perpendicular axis (17O nuclei, τ17O+) to the molecular plane of a hydrated H2O molecule were determied. The two reorientational correlation times (τHH+ and τOH+) of pure H2O and hydrated H2O molecules in Li+, Na+, K+, and Cs+ ions were equal, respectively. Comparing previous data for hydrated D2O molecules with that calculated by using correction values (rHH, rOH, and quadrupolar constant) for H2O molecules, the ratios of τD+(D2O)/τOH(H2O) and τ17O+(D2O)/τ17O+(H2O) were found to be of the same order as η(D2O)/η(H2O), except for the τ17O+(D2O)/τ17O+(H2O) value for the Li+ ion.
Synthesis of Optically Active Polyamides Having Axially Dissymmetric 1,1′-Binaphthalene-2,2′-dicarboxylic Acid Component and Their Optical Resolution Ability as Chiral Adsorbent for HPLC
Authors: Tamai Yasufumi , Matsuzaka Yutaka , Ôi Shuichi , Miyano Sotaro
Published: July 2006

Optically active polyamides 4a–4c were synthesized from the polycondensation of axially dissymmetric 1,1′-binaphthalene-2,2′-dicarbonyl dichloride (2) with 1,4-benzenediamine, 1,6-hexanediamine, and 1,10-decanediamine, respectively. CD spectra of the polyamides 4a–4c are essentially the same as those of the corresponding model diamides 6a–6c prepared from 2 and benzenamine, 1-hexanamine, and 1-decanamine, respectively. This similarity indicates that the conformation of the 1,1′-binaphthalene-2,2′-dicarboxamide moieties of the polyamides 4a–4c in solution state are rather similar to those of the corresponding model diamides 6a–6c. Several axially chiral biaryl compounds and 3,5-dinitrophenylcarbamates (3,5-DNPCs) derived from 1-aryl-1-alkanols were resolved by HPLC equipped with the columns packed the chiral stationary phases (CSPs) prepared from 4a–4c adsorbed on spherical silica gel. A main control factor for the chiral discrimination seems to be the hydrogen bonding between the amide groups of the CSPs and the hydrogen-bonding sites of the atropisomeric biaryls. The donor–acceptor interaction between the binaphthalene moiety of the CSPs and the 3,5-dinitrobenzene moiety of the 3,5-DNPCs may also be important for the chiral discrimination of the 3,5-DNPCs.
Optical Properties of CdS Microcrystallite-Doped Al2O3 Thin Films Prepared by Rf-Sputtering
Authors: Tanahashi Ichiro , Yoshida Masaru , Mitsuyu Tsuneo
Published: July 2006

Al2O3 thin films containing CdS microcrystallites were successfully prepared by an rf-magnetron sputtering technique. Photoluminescence spectra of films exhibited blue band-edge emission at a higher energy than that of bulk CdS. The spectral change seems to arise from a zero-dimensional confinement of electrons and holes in CdS microcrystallites.
Synthesis and X-Ray Crystal Structure of the Dicopper(I) Complex of 2-(Diphenylphosphino)pyridine (Ph2Ppy). [Cu2(μ-Ph2Ppy)2(CH3CN)2](PF6)2
Authors: Maekawa Masahiko , Munakata Megumu , Kitagawa Susumu , Yonezawa Teijiro
Published: July 2006

The dicopper(I) complex with 2-(diphenylphosphino)pyridine (Ph2Ppy), [Cu2(μ-Ph2Ppy)2(CH3CN)2](PF6)2 has been prepared. The crystal structure has been determined crystallographically: Space group P\bar1, a=10,807(6), b=11.756(8), c=8.606(7) Å, α=90.36(6), β=95.98(5), γ=92.90(5)°, Z=1, R=0.067. The two copper atoms are bridged by two Ph2Ppy molecules in a head-to-tail arrangement, resulting in a rare staggered conformation of the eight-membered ring CU2P2N2C2, whose factor is concerned with the coordination numbers of the central metal atoms. 1H NMR studies show that the ligand of a CH3CN in the titled compound undergoes dissociation in acetone solution.