bluuebunny/crossref_metadata_2025 huggingface dataset:
Conductometric and Spectrophotometric Investigations on Manganese(II) Decanoate in Organic Solvents
Authors: Mehrotra K N , Rawat M K
Published: July 2006

The specific conductance of manganese(II) decanoate in DMF and 1-butanol was measured with a view to determine the critical micelle concentration (CMC), degree of dissociation, and dissociation constant. It was found that the soap behaves as a simple electrolyte and is ionic in nature. The CMC was found to be independent of the dielectric constant of the solvent. The ionic character of manganese(II) decanoate was also confirmed by spectrophotometric measurements.
Alkylation of Phenol by 1-Dodecene and 1-Decanol. A Literature Correction
Authors: Campbell Curt B , Onopchenko Anatoli , Santilli Donald S
Published: July 2006

A recent literature report that 1-dodecene reacts with phenol in the presence of sulfated zirconium oxide (superacid), or 1-dodecanol with phenol in the precsence of H-Mordenite (zeolite), to afford mostly para-substituted alkylphenols has been shown to be incorrect. The product with zirconium is a mixture of ortho/para isomers (≈50–65/50–35), and not the exclusive para isomer as reported. The major product in the case of zeolite catalysis is the o-alkylphenol, with a high degree of end attachment, and not the predominantly claimed para isomers. The selectivity obtained with H-Mordenite during alkylation of phenol differs from the alkylation of alkylbenzenes and anisole, and is best explained on the basis of a surface catalysis phenomenon.
Polytopic Cation Receptors. III. Di- and Triloop Crown Hosts Having Aromatic Junctions. Synthesis, Cation Extraction, and Solid Complex Formation
Authors: Weber Edwin , Skobridis Konstantinos , Ouchi Mikio , Hakushi Tadao , Inoue Yoshihisa
Published: July 2006

A new type of crown compound (1–3) featuring an assembly of two or three individual macrorings with different ring size, rigidity, and donor atoms and having characteristic aromatic junctions is introduced. Syntheses are described and cation binding abilities of the compounds are evaluated by solvent extraction technique and isolation of solid complexes. Due to the number of macrorings and their property, 1–3 are shown to be suitable hosts for the common incorporation of several cations. However, cooperativity of adjacent macrorings in complex formation depending on the used cation is also observed. The constituent bis-crown ethers 4–6 and monocyclic crown ethers 7–10 were examined as comparative compounds for solving the complexation properties of the new hosts.
Thermal Decomposition of Copper(II) Polyamine Complexes
Authors: Ikoma Shuji , Nakasako Shigemori , Yokoi Hiroshi
Published: July 2006

The thermal decomposition of the complexes of copper(II) chloride and sulfate with polyamines has been investigated in detail by thermal analysis, X-ray powder diffraction and ESR spectroscopy. It has been revealed that the chloride complexes decompose to copper metal and carbonaceous product in nitrogen and to copper(I) chloride in air, and the sulfate complexes to copper(I) sulfide and carbonaceous product in nitrogen and to copper(II) oxide in air.
A Novel Method for the Conversion of Halide Anion to the Positive Halogen by Nitrobenzenesulfonyl Peroxide. Application to Oxyhalogenation of Olefin
Authors: Yoshida Masato , Mochizuki Hideki , Suzuki Takashi , Kamigata Nobumasa
Published: July 2006

Bromide and chloride anions could be readily oxidized into positive halogens by treating with p-nitrobenzenesulfonyl peroxide. The positive halogens, thus formed, reacted with olefins to give epihalonium ions, which were trapped by oxygen nucleophiles inter- or intramolecularly to afford oxyhalogenated compounds.
Stereoselective Synthesis of (−)-Trachelanthic Acid and (+)-Viridifloric Acid, Necic Acid Components of Pyrrolizidine Alkaloids from a Common Intermediate
Authors: Niwa Haruki , Ogawa Takeshi , Yamada Kiyoyuki
Published: July 2006

Diastereoselective reduction of a side-chain keto group in (2S,5R)-5-acetyl-2-(t-butyl)-5-isopropyl-1,3-dioxolan-4-one (5) with (i-Bu)2AlH in ether afforded (1′S,2S,5R)-2-(t-butyl)-5-(1′-hydroxyethyl)-5-isopropyl-1,3-dioxolan-4-one (6), while reduction of 5 with LiBH(s-Bu)3 in ether gave the (1′R)-isomer 7 predominantly. (−)-Trachelanthic acid (1) and (+)-viridifloric acid (2) were synthesized upon hydrolysis of 6 and 7, respectively.
The Reaction of Acetals with Silyl Enol Ethers Promoted by the Combination of Tin(II) Chloride and Organic Halide. Novel and Convenient Synthesis of α,β-Unsaturated Ketones
Authors: Oriyama Takeshi , Iwanami Katsuyuki , Miyauchi Yuka , Koga Gen
Published: July 2006

Acetals react with silyl enol ethers to give condensation products in good yield by the action of a reactive halide such as acetyl chloride or methoxymethyl chloride along with a catalytic amount of SnCl2. The procedure employing excessive amount of halide offers a novel and convenient method to synthesize conjugated enones.
Reaction of Methyl Propionate with Methylal over V–Si–P Ternary Oxide Catalysts
Authors: Ai Mamoru
Published: July 2006

The vapor-phase aldol condensation of methyl propionate with formaldehyde was performed using methylal as the source of formaldehyde. The main products were methyl methacrylate and methacrylic acid. The one-pass yield of methyl methacryalte plus methacrylic acid on methylal basis reached 53 mol% at a methyl propionate/methylal molar ratio of 2 over the V–Si–P oxide with an atomic ratio of 1:16: 3.2.
The Addition of 1,3-Diphenylisobenzofuran to Cyclooctatetraene and to Dimethyl Cyclooctatetraene-1,2-dicarboxylate. The Benzene Ring as a Dienophile in an Intramolecular Diels–Alder Reaction
Authors: Saito Katsuhiro , Omura Yoichi , Maekawa Etsuro , Gassman Paul G
Published: July 2006

The reaction of cyclooctatetraene with 1,3-diphenylisobenzofuran afforded two kinds of 1:1 [2π+4π]-cycloadducts, a cage-type 1:1 cycloadduct and two classes of 1:2 cycloadducts. The cage-type compound was formed from one of the [2π+4π]-cycloadducts via an unprecedented second [2π+4π]-cycloaddition reaction in which the double bond of the benzene moiety acted as a dienophile. A similar reaction with dimethyl cyclooctatetraene-1,2-dicarboxylate gave a 1:1 [2π+4π]-cycloadduct and a 1:2 cycloadduct. No cage-type compound was formed.
A New Enantioselective Approach to the Bicyclo[4.4.0]decane and Bicyclo[4.3.0]nonane Systems
Authors: Asaoka Morio , Nishimura Kuniko , Takei Hisashi
Published: July 2006

Highly diastereoselective routes to cis-fused bicyclo[4.4.0]decane-2,10-diones and bicyclo[4.3.0]nonane-2,9-diones from 5-trimethylsilyl-2-cyclohexen-1-one (1a) and its 3-methyl derivative were established by utilizing an annulation with ω-(alkoxycarbonyl)alkylzinc reagents. Bicyclo[4.4.0]decane-2,8-dione was obtained diastereoselectively by the double Michael reaction of 1a with dienol silyl ether. The diastereoselective Diels–Alder reaction of 1a with cyclopentadiene gave an endo adduct, which can be regarded as a new chiral cyclohexenone synthon, with a high optical purity.
17O NMR Study of Metal Carbonyl Cluster Compounds. IV. The Substituent Effect on the 17O NMR Chemical Shifts for a Series of Tri-Nuclear Metal Carbonyl Cluster Compounds
Authors: Onaka Satoru , Takagi Sigeru , Furuta Hiroyuki , Kato Yoshio , Mizuno Atushi
Published: July 2006

17O NMR spectra have been measured for series of cobalt carbonyl cluster derivatives, RCCo3(CO)9−x(PPh3)x, (RC2R′)Co3−x−yFexMoy(CO)9−yCpy, and R3−xSn[Co(CO)4]x+1. The small 17O-chemical shift differences due to the change of R and/or introduction of PPh3 have been interpreted in terms of the electron buffer action of the Co3 core for RCCo3(CO)9−x(PPh3)x. Good linear correlations between 17O-chemical shifts and CO stretching frequencies have been observed for these derivatives. Some effect of the magnetic anisotropy resulted from the ring current along the metal-triangle on 17O-chemical shifts has been suggested for metal-triangle clusters.
Syntheses and Catalytic Actions of Self-Micelle-Forming Hydrolase Models
Authors: Kawaguchi Kazuo , Ohkatsu Yasukazu , Kusano Tom
Published: July 2006

Hydrolase model catalysts, N-alkyl-Nα-[2-(d-polyhydroxypentyl)-3-acetyl-4-thiazolidinylcarbonyl]-l-histidinamide (acyclic-type catalyst) and N-(N-alkanoyl-l-nistidyl)-β-d-glucosamine (cyclic-type catalyst), which easily form micelles in water by themselves, have been designed and the stereostructural effects of sugar moieties examined on stereoselective hydrolyses of p-nitrophenyl N-benzyloxycarbonyl-l-(or d-)phenylalaninates. An acyclic-type catalyst is l-selective, while a cyclic-type catalyst is l-selective. The stereorecognition of acyclictype catalysts was found to be performed by a sugar moiety, rather than the histidyl type. Comparisons of the activities of three acyclic-type catalysts having different sugar moieties show that a mannose-derived catalyst is the most stereoselective. Judging from kinetic data, it is concluded that the configuration of OH on C-3 of the sugar moiety takes a significant part in the stereorecognition of a catalyst.
Photolysis of Triarylmethylphosphonic Acids and Their Esters
Authors: Shi Min , Okamoto Yoshiki , Takamuku Setsuo
Published: July 2006

Upon UV-irradiation in an alkaline alcohol solution, some triarylmethylphosphonic acids underwent C–P bond cleavage to give triarylmethanes and alkyl dihydrogenphosphates, while, in an acidic or a neutral alcohol solution, they afforded biaryls. Their dimethyl esters gave also biaryls and dimethyl [alkoxy(aryl)methyl]phosphonates, which were derived from the insertion of (dialkoxyphosphinyl)arylcarbenes into the OH bond of the alcohol. The carbene was generated by photo-α,α-elimination of two aryl groups of the phosphonate.
Studies on the Stereoselective Methylation of α-Sulfinyl Carbanions Generated from Three Isomeric Pyridylmethyl p-Tolyl Sulfoxides and Benzyl 2-Pyridyl Sulfoxide
Authors: Furukawa Naomichi , Hosono Eri , Fujihara Hisashi , Ogawa Satoshi
Published: July 2006

A high stereoselectivity in the methylation of 2-pyridylmethyl p-tolyl sulfoxide (2a) with lithium diisopropylamide and iodomethane was observed at low temperature. The chelation of Li+ by both the nitrogen atom in the pyridine ring and the sulfinyl oxygen atom in 2a promotes the stereoselectivity as compared with isomeric sulfoxides.
A Michael Addition and Alkylation Sequence Using Methyl 2-(Trimethylsilyl)propenoate. Stereoselective Synthesis of α-Silyl Esters
Authors: Tanaka Junji , Kanemasa Shuji , Ninomiya Yusuke , Tsuge Otohiko
Published: July 2006

Michael addition of organomagnesiums or -lithiums with methyl 2-(trimethylsilyl)propenoate leads to either 1:1 or 1:2 adduct anions, depending upon the reaction conditions and the reactivity of donor molecules. The adduct anions, both 1:1 and 1:2 types, are quenched with alkyl halides or water in a highly stereoselective manner to produce α-silylated esters. A rigid intramolecular chelation working in the adduct anions is partly responsible for the high selectivity.
Usefulness of the Peptide Segment Separation Method for Asparagine-Rich Protein Syntheses. Synthesis of Malaria Vaccine Analogs Having the Repeated Unit of l-Asparaginyl-l-Alanyl-l-Asparaginyl-l-Prolyl
Authors: Narita Mitsuaki , Takegahara Hitoshi , Ono Seiji , Sato Hisaya
Published: July 2006

In order to demonstrate the usefulness of “the peptide segment separation method” for syntheses of Asn-rich proteins, the central area of circumsporozoite protein of human malaria parasite plasmodium falciparum, Boc–(Asn–Ala–Asn–Pro)n–OBzl (n=2, 3, 4, 6, 9, 12, and 18), were prepared by the coupling reactions of H–(Asn–Ala–Asn–Pro)k–OBzl (k=1, 2, 3, 6, 9, and 12) with Boc–(Asn–Ala–Asn–Pro)m–OH (m=1, 3, or 6) using DCC and HOBt as coupling reagents. The peptide chains are separated into peptide segments by the tertiary peptide bonds of Asn–Pro moieties and they are assembled by the sequence of Asn–Ala–Asn separated by a Pro residue. Regardless of the increase in the peptide chain lengths of the amino and carboxyl components, the coupling reactions in DMF or NMP were achieved in high yields. The excellent solubility of the peptides in highly polar solvents was preserved in spite of the tendency for an Asn residue to have a high potential for aggregation through hydrogen bond formed by the side-chain amide group. The purification of the peptide series by recrystallization could be completely achieved and HPLC on a gel filtration column showed all the peptides to be monodisperse.
Synthetic Inorganic Ion-Exchange Materials. LIV. The Amphoteric Behavior of Hydrous Titanium Dioxide Ion Exchangers in Different Preparations
Authors: Sugita Mitsuru , Tsuji Masamichi , Abe Mitsuo
Published: July 2006

Hydrous titanium dioxides in amorphous form (Am-HTDO ) were prepared in a state demineralized as much as possible through different processes. The equiadsorption point (EAP) for anion and cation was determined at an ionic strength of 0.1 with the use of alkali metal chloride solution. The EAP values were strongly affected by the synthetic method, especially hydrolysis pH, and by the kind of probing cations, ranging from 2.7 to 4.5. Chloride ion uptake was not dependent on the kind of coexisting cations. The EAP value of Am-HTDO prepared at pH>13 was appreciably lower than that of Am-HTDO prepared at pH 7–8. The “ion-free” Am-HTDO prepared by using the sol–gel method with Ti[OCH(CH3)3]4 showed approximately the same EAP value as that of Am-HTDO hydrolysed at a similar pH by NaOH solution.
Preparation of Iron and Cobalt Phthalocyanine-1,2:3,4:8,9:10,11:15,16:17,18:22,23:24,25-octakis(N-decyldicarboximide) and Their Catalytic Behavior for Electroreduction of Oxygen
Authors: Kobayashi Nagao , Sudo Keigo , Osa Tetsuo
Published: July 2006

The iron and cobalt phthalocyanines included in the title have been synthesized. Their absorption spectra are unusual compared to other metallophthalocyanines, showing intense hypochromism in the Q band region. The cobalt and iron derivatives show 4-electron reduction capability in the electroreduction of oxygen over the entire range of pH values and in neutral and alkaline pH, respectively, although the potentials are not necessarily positive enough.
Extractive Permeation of Zinc(II) and Cadmium(II) Chloride Complexes through Anion-Exchange Membrane
Authors: Hayashita Takashi , Kurosawa Takahiko , Ohya Shinji , Komatsu Tatsuo , Igawa Manabu
Published: July 2006

Extractive permeation is demonstrated in the permeation of Zn(II) and Cd(II) chloride complexes through an anion-exchange membrane. A selective permeation between Cd(II) and Zn(II) was observed. This selectivity well corresponded to the sorption selectivity with an anion-exchange resin. Under the large concentration gradient of chloride ions across a membrane, Cd(II) chloride complex was selectively enriched in the receiving solution. The concentration ratios between the source and the receiving solution after 40 h reached 5.8 for Cd(II) and 1.2 for Zn(II) when chloride ions of 0.5 mol dm−3 were added to the source solution.
Polarographic Determination of In(III) and Cd(II) in the Presence of Polyethylene Glycol in Hydrochloric Acid
Authors: Kurotu Takuzo
Published: July 2006

The simultaneous determination of In(III) and Cd(II) was investigated by d.c. polarography in the presence of polyethylene glycol (PEG) in 0.1 mol dm−3 hydrochloric acid. The PEG shifts the half-wave potential of Cd(II) from −0.67 to −0.82 V vs. SCE and reduces the wave height. A linear relationship between the wave height for Cd(II) and the concentration was obtained in the presence of various molecular weights of PEG. An increase in the molecular weight of PEG also causes a decrease in the wave height. On the other hand, a reduction wave of In(III) was not observed down to the reduction potential for hydrogen at a certain concentration of PEG. It is, therefore, possible to determine In(III) and Cd(II) separately, since Cd(II) can be determined by multiplying by a calibration factor. In(III) can also be determined by the difference between the merged-wave height for In(III) plus Cd(II) and the wave height for the determined Cd(II).
The Protective Effects of Cyclodextrins against the Oxidation of Methyl Orange by Singlet Oxygen
Authors: Miyajima Koichiro , Komatsu Hiroaki , Inoue Kazuhiro , Handa Tetsurou , Nakagaki Masayuki
Published: July 2006

The degradation of Methyl Orange (MO) by singlet oxygen was inhibited by the addition of α-, β-, and γ-cyclodextrins (CD’s) to an aqueous solution. The protective effect of the CD’s against the MO oxidation decreased in this order; α->γ-\gtrsimβ-CD. From the relation between the rate constant of MO oxidation and the free MO concentration, evaluated by using the formation constants of CD’s with MO, it was found that the MO included by α and γ-CD’s is not decomposed by singlet oxygen, whereas the MO included by β-CD is oxidized by singlet oxygen. The inner cavity of α- or γ-CD well fit for the inclusion of one or two MO molecules respectively, and the access of singlet oxygen to the azo group of the included MO molecule is sterically inhibited. The finding that β-CD has smaller enthalpy and larger entropy changes relevant to the formation of the MO–CD complex than those of α- and γ-CD’s suggested the less tight inclusion of one MO molecule in the cavity of β-CD. Such a loose inclusion of MO by β-CD resulted in the transient exposition of the azo group of the MO molecule to the bulk phase: the attack of the singlet oxygen on the azo group followed.
Bromocresol Green—A Hydrophobic Spectrophotometric Probe for Human Serum Albumin
Authors: Kishore S , Maruthamuthu Meenakshi
Published: July 2006

Bromocresol Green (BCG) has been developed as a new spectrophotometric probe for human serum albumin (HSA). The competing ligands naproxen (NP), 8-anilino-1-naphthalenesulfonate (ANS), and dansylsarcosine (DS) have been found to share common binding sites in HSA and their ability to displace BCG from the first competition site is in the order NP>ANS>DS.
The Syntheses, Crystal and Molecular Structures, and Their Thermal Properties of Tetramethylammonium [Octakis(isothiocyanato)lanthanoidates(III)]·benzene (1/2), [(CH3)4N]5[M(NCS)8]·2C6H6 (M=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy)
Authors: Matsumura Naomi , Takeuchi Toshio , Ouchi Akira
Published: July 2006

The titled series of isomorphous complexes, the first octakis(isothiocyanato) complexes of lanthanoids, were obtained. Their crystals are tetragonal, space group P4nc, Z=2. The cell dimensions of the praseodymium complex, for example, are a=15.871(7), c=11.543(6) Å, U=2908(3) Å3, and Dm=1.29(3), Dx=1.29 g cm−3, μ(MoKα)=11.60 cm−1, with a final R value of 0.069. The metal atom is octa-coordinated by eight isothiocyanate ions in an intermediate geometry between cube and square-antiprism. The benzene included in the praseodymium complex crystals was retained up to 174°C (DTA), and was not removed even after being heated for 12 h at 110°C. In cases of the other isomorphous members, the benzene was removed at lower temperatures, respectively. The isomorphous fluorobenzene adduct was obtained only for the lanthanum complex.
Convenient Synthesis of 3-Acyl- and 3-Alkyl-1,2-naphthoquinones
Authors: Takuwa Akio , Kai Ryoji
Published: July 2006

3-Acyl-1,2-naphthalenediols prepared by the photoinduced addition reaction of 1,2-naphthoquinone with alkanals were oxidized with Fremy’s salt to give 3-acyl-1,2-naphthoquinones in good yields. The diols were reduced with amalgamated zinc, followed by oxidation to afford 3-alkyl-1,2-naphthoquinones in moderate yields.
Stereochemistry in the Conversion of Phenyldiazomethane into Stilbenes and Spirooxetanes Caused by Tetrahalogenated 1,4-Benzoquinones. Effects of Halogen Substituents
Authors: Oshima Takumi , Nagai Toshikazu
Published: July 2006

Reaction of phenyldiazomethane (1) with tetrafluoro-1,4-benzoquinone (2a) gave isomeric mixtures of stilbenes (3, cis/trans=4.7) and spirooxetanes (4a, cis/trans=1.1) via zwitterion intermediates. Similarly, tetrabromo-1,4-benzoquinone (2c) provided 3 and spirooxetane (4c); however, the cis/trans ratio of 3 dropped to 2.3 and 4c was solely the trans isomer. On the other hand, reaction with tetraiodo-1,4-benzoquinone (2d) afforded no spirooxetane and gave a further reduced isomer ratio of 3 of 1.9.
A Facile, Practical Synthesis of 2-(6-Methoxy-2-naphthyl)propenoic Acid
Authors: Hiyama Tamejiro , Wakasa Noriko , Ueda Tomoko , Kusumoto Tetsuo
Published: July 2006

A facile and practical method for the synthesis of 2-(6-methoxy-2-naphthyl)propenoic acid, a precursor of anti-inflammatory agent naproxen, is described. The method involves (1) Pd-catalyzed ethynylation of 2-bromo-6-methoxynaphthalene, (2) regioselective addition of HX to the triple bond, and (3) Pd-catalyzed carbonylation of the resulting vinyl halide followed by (4) alkaline hydrolysis.
Analysis of Solvent Effects on the Rate of the Cope Rearrangement: Evidence for Its Hydrogen-Bond-Insusceptible Nature
Authors: Mitsuhashi Tsutomu , Yamamoto Gaku
Published: July 2006

The kinetic study was made by 1H NMR for the Cope rearrangement of 4,4-dicyano-5-ethyl-1,5-heptadiene in a variety of solvents at 90°C, which revealed that the reaction is affected by solvent polarity to some extent but is insusceptible to hydrogen bonding with protic solvents, in agreement with our prediction as to solvation of the dipolar transition state for [3,3]sigmatropic reactions.
Heat Capacities and Phase Transitions of Crystalline 1,3,5-Trichloro-2,4,6-trimethylbenzene
Authors: Fujiwara Takahiro , Atake Tooru , Chihara Hideaki
Published: July 2006

Heat capacities were measured of 1,3,5-trichloro-2,4,6-trimethylbenzene by adiabatic calorimetry from 3 to 327 K covering the three stable solid phases, II, III, and IV. The phase transitions, III–II and IV–III, are of first order and accompanied by a hysteresis effect. The IV–III transition occurs at 163.5 K when the crystal cooled slowly from Phase II, whereas the heat capacity anomaly splits into two at 158.7 and 163.5 K if the crystal was cooled rapidly. From the time dependence of Raman spectra at low frequencies, kinetics of transition II–III was studied; it is best explained by diffusionless nucleation mechanism. The thermal hysteresis can be rationalized by assuming the existence of a metastable phase IV′.
Crystal Growth of Transition Metal Fluorides
Authors: Ohtori Norikazu , Yoshikawa Yuzo , Sasaki Ken-ichi , Moriwaki Hisaki , Yokoyama Haruhiko
Published: July 2006

Kinetics of crystal growth of transition-metal fluorides, MF2(M=ZnII and PbII) has been studied by the use of both constant composition and conventional methods. The effective orders in an empirical reaction-rate function of supersaturation were 1.71 (2.0) for ZnF2·4H2O and 0.88 (1.2) for PbF2 (The values in the parentheses are from the conventional method). These findings suggest that the crystals of zinc fluoride grow by a spiral growth (surface reaction) mechanism and lead fluoride by a bulk diffusion controlled mechanism.
X-Ray Crystal Structures of Nickel Complexes with 2-Methyl-8-quinolinol, Ni(mq)2(H2O)2 and Na3Ni3H6(mq)15·H2O
Authors: Yuchi Akio , Shiro Motoo , Murakami Hiroshi , Wada Hiroko , Nakagawa Genkichi
Published: July 2006

Two Ni(II) complexes with 2-methyl-8-quinolinol (Hmq) were prepared and their structures determined by single-crystal X-ray diffraction techniques. In Ni(mq)2(H2O)2, which is orthorhombic, space group Pccn, Z=8 the geometry is trans(O,O), cis(N,N), and cis(H2O,H2O), and the octahedron is appreciably distorted. In Na3Ni3H6(mq)15·H2O, which is monoclinic, space group P21⁄c, Z=4, three binuclear units Ni(1)–Na(1), Ni(2)–Na(2), and Ni(3)–Na(3), are involved. All the Ni atoms are surrounded by three ligands in a mer configuration. The Na(1) and Na(2) atoms are five-coordinated with two ligands and an O atom bridging Na and Ni atoms within a dimer. The Na(3) atom has, together with the ligands, a coordinated water which is hydrogen-bonded to the O atom coordinating to the Ni(3) atom. These dimeric units are infinitely linked by intermolecular hydrogen bonds. Compared to the corresponding complexes of 8-quinolinol derivatives without 2-methyl substituent, the Ni–N is elongated by 0.06–0.12 Å, whereas the Ni–O is shortened by 0.01–0.05 Å. An increase in the bond angle (7–11 deg) between a N atom of a ligand and the donor atom (Y) which occupies the trans position to the O atom of the same ligand, reduces the steric interaction between the methyl group and Y in Hmq complexes. Shorter contacts between ligands in Hmq complexes than those in Hq complexes lead to their lower stabilities and, thus, the lower extractabilities.
Substituent Effects on 15N and 17O NMR Chemical Shifts in 4′-Substituted trans-NNO-Azoxybenzenes
Authors: Sawada Masami , Takai Yoshio , Tanaka Takanori , Hanafusa Terukiyo , Okubo Masao , Tsuno Yuho
Published: July 2006

15N and 17O NMR spectra have been measured for a series of 4′-substituted trans-NNO-azoxybenzenes (AZOXY) and the obtained substituent chemical shift (SCS) values have been analyzed by means of the LSFE equation. Both the resonance and the polar contribution of substituents are important in determining the 15N(β) SCS and the adjacent terminal 17O SCS in the –Nα=Nβ(O)– function of the AZOXY set. The resonance contributions of the AZOXY sets differ from those of the corresponding PYNO sets in view of a depressed pi-acceptor resonance contribution. That is, the resonance susceptibility ratio in the LSFE equation, ρπ+⁄ρπ−, varies from 1.4 (PYNO) to 2–4 (AZOXY) for both 15N and 17O SCS. The results are compared with the 13C SCS of the corresponding positions in the relevant aromatic side-chain systems, and characterized in terms of repulsive pi-acceptor interaction between the substituents and the side-chain pi-electron systems. The importance of such dual resonance susceptibility has been shown for understanding characteristic features of the 15N and the adjacent 17O SCS.
Asymmetric Trasformation of Symmetrical Epoxides to Allylic Alcohols by Lithium (S)-2-(N,N-Disubstituted aminomethyl)pyrrolidide
Authors: Asami Masatoshi
Published: July 2006

Enantioselective deprotonation of symmetrical epoxides was studied by using chiral lithium amide, prepared from (S)-2-(N,N-disubstituted aminomethyl)pyrrolidine and butyllithium. Chiral allylic alcohols were obtained with moderate to high enantiomeric excesses (ee’s) (41–92% ee) from several cyclic and acyclic epoxides employing lithium (S)-2-(1-pyrrolidinylmethyl)pyrrolidide in tetrahydrofuran (THF) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).
The IR Photochemistry of Organic Compounds. IV. The Infrared Multiple-Photon Decomposition of Cyclic Ethers Induced by a TEA CO2 Laser
Authors: Majima Tetsuro , Ishii Tadahiro , Arai Shigeyoshi
Published: July 2006

The mechanism of the infrared multiple-photon decomposition (IRMPD) of saturated cyclic ethers (1–7) has been systematically studied on the basis of product analysis, particularly with the aim of finding a suitable cyclic ether for oxygen-isotope separation. The main products are H2CO, CO, H2, and lower hydrocarbons. Acetaldehyde is additionally formed in the IRMPD of 1 and 3–6, while acetone is produced only in the IRMPD of 3b. The initial process is the homolytic cleavage of the C–O bond to yield the corresponding biradical with a high internal energy. The biradical decomposes sequentially of through secondary IRMPD to yield the primary products with high internal energies. The decomposition of the biradicals proceeds mainly via β-fission, but also partly via γ-fission. Some of the primary products further decompose sequentially or through secondary IRMPD into stable products. Several radical intermediates are trapped with Br2. The product distributions are clearly dependent on the irradiation parameters. This dependence and the branching ratio are discussed in terms of sequential decomposition, the collisional effect, and the internal energy of the transient species. On the basis of the experimental results, it is suggested that, among cyclic ethers, the best starting ether in the oxygen-isotope separation by a TEA CO2 laser is tetrahydropyran (4).
Studies on the Formation of Magnetite Colloidal Dispersions in the Presence of Poly(vinyl alcohol)
Authors: Yokoi Hiroshi , Yagishita Kazuhiro , Nakanishi Yoichiro
Published: July 2006

The formation of magnetite in aqueous solutions containing Fe3+ and Fe2+ ions in 2:1–1:2 ratio and poly(vinyl alcohol) at room temperature has been studied by magnetic susceptibility and optical absorption measurements. It has been found that the yield reaches a maximum after allowing the solutions at pH 10.5 to stand in a sealed state for 24 h. Transmission electron micrographs for their cast films have revealed that colloidal particles with diameters of 40–100 Å form either chain-like or cluster-like agglomerates. The particles have been identified as magnetite crystals by electron diffraction analysis and by direct observation of the crystal lattice structures.
The Independence of the Counter-Ion Density and the Electric Field from Polyelectrolyte Model Configurations on the Model Surfaces
Authors: Kaneko Tetsuo
Published: July 2006

The polyelectrolyte models of two different configurations are used in order to show that the counter-ion density and the electric field on the surface of a polyelectrolyte model can not be strongly sensitive to the configuration of the model. These models are a layer and a cylinder in which charged groups are packed. Counter-ion densities and electric fields, which appear in water on the surfaces of the layer and the cylinder because of ionic dissociation, are estimated on the basis of the Poisson–Boltzmann equation. Their estimations show that both the counter-ion density and the electric field on the surface of the cylinder are approximately equal to those on the surface of the layer.
Time-Resolved Dissociation of Ionized Propanoic Acid
Authors: Arakawa Ryuichi
Published: July 2006

The appearance energies of C3H5O2+, C3H5O+, C3H4O+, C3H3O+, CHO2+, and C2H5+ from propanoic acid were obtained. The kinetic shifts were observed for the formation of C3H5O2+, C3H5O+, and C3H4O+. The dissociation of ionized propanoic acid is metastable for the loss of a hydrogen atom and water. The results of the metastable-ion-intensity ratios, collisional activation mass spectra and kinetic-energy releases indicate that the propanoic acid ion isomerizes to a more stable enol tautomer prior to dissociation.
X-Ray Structural Studies of Green and Brown Crystals of trans-[CoCl2(N48)]X (N48=1,4,7,10-Tetraazacyclopentadecane, X=NO3−, BF4−, and ClO4−)
Authors: Tsuchimoto Masanobu , Takazawa Hiroyuki , Kita Masakazu , Nonoyama Matsuo , Ohba Shigeru , Saito Yoshihiko , Fujita Junnosuke
Published: July 2006

Crystal structures of green (X=NO3−(1), BF4−(2)) and brown (X=BF4−(3) and ClO4−(4)) salts of trans-[CoCl2(N48)]X (N48=1,4,7,10-tetraazacyclopentadecane) were determined by an X-ray diffraction method. The complex cation is a RSSR(SRRS) isomer for the four chiral nitrogen atoms and has approximate C2 symmetry. Green crystals 1 and 2 are monoclinic and have the chiral space group P21, comprising one antipode of the complex ion by spontaneous resolution, whereas brown crystals 3 and 4 are orthorhombic and a racemate. The eight-membered chelate ring formed by the N48 ligand and the Co atom takes a distorted boat–boat (BB) form in 1 and 2, whereas the conformation is disordered in 3 and 4 with BB (40%) and distorted twist–boat-chair (TBC; 60%) forms at room temperature. At 113 K, the eight-membered chelate ring in 4 takes exclusively the TBC form. The crystal data are as follows: [CoCl2(C11H26N4)]X, monoclinic NO3 salt, 1, P21, a=9.672(3), b=12.285(5), c=7.051(2) Å, β=94.70(3)°, V=835.0(5) Å3, Z=2, T=300(1) K, final R=0.037 for 2381 reflections. Monoclinic BF4 salt, 2, 2, P21, a=9.857(2), b=12.694(2), c=7.065(1) Å, β=94.34(2)°, V=881.5(2) Å3, Z=2, T=300(1) K, final R=0.031 for 1880 reflections. Orthorhombic BF4 salt, 3, Pcab, a=12.816(1), b=22.359(2), c=12.388(1) Å, V=3549.8(5) Å3, Z=8, T=300(1) K, final R=0.095 for 2086 reflections. Orthorhombic ClO4 salt at 300(1) K, 4a, Pcab, a=12.829(1), b=22.376(2), c=12.425(1) Å, V=3566.7(6) Å3, Z=8, final R=0.070 for 1764 reflections; orthorhombic ClO4 salt at 113(2) K, 4b, a=12.630(2), b=22.276(5), c=12.354(2) Å, V=3475.7(11) Å3, final R=0.109 for 2215 reflections.
Preparation and Some Properties of [CoIIorIII{RhIII(aet or l-cys-N,S)3}2]-Type S-Bridged Trinuclear Complexes
Authors: Konno Takumi , Aizawa Sen-ichi , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

The reactions of fac-[Rh(aet)3] (aet=2-aminoethanethiolate) or ΔLLL-fac-[Rh(l-cys-N,S)3]3− (l-cys=l-cysteinate) with [CoCl(NH3)5]2+ produced [CoIII{RhIII(aet or l-cys-N,S)3}2]3+or3−, while the reactions with Co2+ formed [CoII{RhIII(aet or l-cys-N,S)3}2]2+or4− which were oxidized to give [CoIII{RhIII (aet or l-cys-N,S)3}2]3+or3−. These complexes were optically resolved or separated by fractional crystallization or column chromatography, and characterized from their absorption, CD and 13C NMR spectra. The reactions of fac-ΔLLL-[Rh(l-cys-N,S)3]3− with [CoCl(NH3)5]2+ or Co2+ at room temperature proceeded with retention of the starting ΔLLL configuration to give the ΔLLLΔLLL isomer, while the reaction with Co2+ at high temperature (ca. 95 °C) was accompanied by inversion to form the ΔLLLΛLLL, ΛLLLΛLLL, and ΔLLLΔLLL isomers. Cyclic voltammetric measurements of [CoIII {RhIII(aet or l-cys-N,S)3}2]3+or3− in water showed a quasi-reversible redox couple corresponding to the central Co(III)/(II) at ca. −0.3 V vs. Ag/AgCl. Their absorption and CD spectra and cyclic voltammograms are discussed in comparison with those of the corresponding [CoIII{CoIII (aet or l-cys-N,S)3}2]3+or3−.
A Facile Preparation of O-Alkyl Selenocarboxylates and Selenoamides via Se-Alkynyl Selenocarboxylates
Authors: Ishihara Hideharu , Yoshimi Michinari , Hara Nobuhiko , Ando Hiroyuki , Kato Shinzi
Published: July 2006

Se-Alkynyl selenocarboxylates (1) were found to readily react with alcohols and amines to give O-alkyl selenocarboxylates (4) and selenoamides (6) in moderate to good yields, respectively. The formation mechanisms of 4 and 6 via selenoketene and ammonium alkyneselenolate, respectively, are proposed.
Substituent Effects. 22. The Solvolysis of α-t-Butylbenzyl Tosylates
Authors: Tsuji Yutaka , Fujio Mizue , Tsuno Yuho
Published: July 2006

The rates of solvolysis of α-t-butylbenzyl tosylates were determined in 80% aqueous acetone (80A) and 80% aqueous ethanol (80E) for an extended series of substituents. The substituent effect can be linearly correlated in terms of the Yukawa–Tsuno LArSR relationship, with a ρ value of −5.542 and an r value of 1.093 in 80A, and −5.650 and 1.106 in 80E, respectively. The large negative ρ and exalted r values suggest the operation of the kc mechanism in this solvolysis without nucleophilic solvent assistance and methyl participation. From a comparison of the substituent effects, the exalted r value of 1.15 observed in the solvolysis of α-methylbenzyl chlorides can be attributed to the enhanced resonance demand characteristic of secondary benzylic system rather than to a correlational artifact arising from nonlinearity due to SN1–SN2 mechanistic change. The solvolysis of this system can be utilized as an appropriate reference system for the accurate estimation of σ+ constants in various solvents.
Selective and Active Transport of In3+ through N-Nitroso-N-p-octadecylphenylhydroxylamine Ammonium Salt Impregnated Membrane
Authors: Okushita Hiroshi , Shimidzu Takeo
Published: July 2006

Selective and active transport of In3+ was studied through a polypropylene membrane impregnated with N-nitroso-N-p-octadecylphenylhydroxylamine ammonium salt (3). In3+ is selectively concentrated from In3+–Zn2+, In3+–Al3+ and In3+–Zn2+–Al3+ mixtures by an antiport mechanism as a counter flow of H+, respectively. The selective transport of In3+ was found to be attributed to the chelating affinity between 3 and In3+. As a model experiment of the practical use, the separation of In3+ from the solution of containing 10–100 folds of Zn2+ was investigated. The present membrane selectively separates In3+, the separation factor is 200–250. It is suggested that the present membrane system is useful for separation of indium from the ore containing indium such as the zincblende.
Oxidation of Cycloalkanols to the Corresponding Cycloalkanones with Chlorine in the Presence of Nitroxide Radical as a Mediator
Authors: Yamaguchi Masao , Takata Toshikazu , Endo Takeshi
Published: July 2006

A method for the oxidation of cyclic alcohols to the corresponding cyclic ketones with 2,2,6,6-tetramethyl-1-piperidinyloxyl (a mediator) and chlorine is described. This oxidation involves an oxoaminium salt, formed from the nitroxide radical and chlorine, which oxidizes cyclic alcohols to give the corresponding ketones in good yields.
51V NMR Chemical Shift and Anisotropy in Solid Metavanadates
Authors: Hayashi Shigenobu , Hayamizu Kikuko
Published: July 2006

51V NMR spectra of alkali and ammonium metavanadates have been measured with and without magic angle spinning (MAS) of the sample at a high static magnetic field (9.40T). The isotropic chemical shifts have been determined accurately from the MAS spectra, while the principal values of the shift tensor have been estimated from the static spectra. Correlations between the NMR parameters and structural factors have been briefly discussed.
Statistical Thermodynamic Study of Polar Organic Liquids
Authors: Kawai Satoshi , Arakawa Kiyoshi
Published: July 2006

A statistical thermodynamic study of polar organic liquids has been worked out on the basis of the liquid model as an assembly of particles immersed in a uniform background potential, which was proposed in the preceding paper (Bull. Chem. Soc. Jpn., 63, 307 (1990). The liquid model is regarded as a kind of mean field approximation. Calculations of thermodynamic functions of eight polar liquids (acetone, 2-butanone, dimethyl sulfoxide, chlorobenzene, bromobenzene, benzonitrile, nitrobenzene, and aniline) have been performed. The results show that the theory is effectively applicable to four polar liquids (acetone, 2-butanone, dimethyl sulfoxide, and nitrobenzene) as well as to nonpolar ones. However, for other four liquids (chlorobenzene, bromobenzene, benzonitrile, and aniline) some deviations of calculated values from experimental data have been found, which are supposed to occur from some restriction of free rotation of molecules in these liquids. Detailed considerations have been given on this subject.
Electrostatic and Hydrophobic Interactions in the Ion Associations between Tripositive Complex Ions and Sulfonate Anions
Authors: Iida Masayasu , Iwaki Masayo , Matsuno Yumi , Yokoyama Haruhiko
Published: July 2006

The ion associations of [Co(NH3)6]3+, [Cr(en)3]3+(en=ethylenediamine), lel3-[Cr(R-chxn)3]3+  lel3=lel,lel,lel-, and chxn=trans-1,2-cyclohexanediamine), [Co(bpy)3]3+ (bpy=2,2′-bipyridine), [Co(phen)3]3+(phen=1,10-phenanthroline), and [Cr(phen)3]3+ with Cl−, SO42−, CH3SO3−, C6H5SO3−, (CH2SO3)22−, and m-C6H4(SO3)22− were investigated at 25°C by means of conductivity measurements of aqueous mixed electrolyte solutions with a stoichiometrically constant ionic strength of 0.01 mol dm−3. The ion-association constants thus obtained were compared with each other and also with those estimated by the use of electrostatic theories of ion association. Some specific interactions besides such usual electrostatic ones were found to play important roles in the ion associations of SO42− with [Co(NH3)6]3+ and [Cr(en)3]3+, in those of C6H5SO3− and m-C6H4(SO3)22− with [Co(phen)3]3+, [Cr(phen)3]3+, and [Co(bpy)3]3+, and in those of SO42−, C6H5SO3−, and m-C6H4(SO3)22− with lel3-[Cr(R-chxn)3]3+. The specific interactions existing in the first group were presumed to be short-range electrostatic ones, such as hydrogen-bonding, and in the second group, the so-called hydrophobic ones. The complex ion, lel3-[Cr(R-chxn)3]3+, seemed to have both interactions, depending on the counter anions.
Belousov–Zhabotinskii Reaction with 2,3-Diones
Authors: Tsukada Masao , Inamoto Naoki
Published: July 2006

2,3-Butanedione and 2,3-pentanedione have been found to generate chemical oscillations in 2,3-dione/BrO3−/Ce4+/H2SO4 system. The concentration range within which the oscillatory behavior can be observed for each reactant is reported.
Mixture Dependences of OH(2Σ) Produced in the Oxidations of C2H2 and C2H6 in Shock Waves
Authors: Koike Tohru
Published: July 2006

The OH(2Σ) emissions from shock-heated mixtures of C2H2/O2, C2H2/C2H6/O2, and C2H6/O2 diluted in Ar were observed and the mixture dependences of the emissions were obtained. OH(2Σ) production, depending on the test gas mixture, could be in accordance with the view-point that the two oxidations of C2H2 and C2H6 progress by influencing each other.
Mass Spectral Study of Ionized-Hydroxyacetone Dissociation
Authors: Arakawa Ryuichi
Published: July 2006

The ionization and appearance energies of hydroxyacetone (CH3COCH2OH) were obtained. The metastable dissociation of ionized hydroxyacetone involves the loss of a hydrogen atom and CHO. The results of the metastable-ion intensity and collisional activation indicate that the hydroxyacetone ion does not isomerize to the enol tautomers prior to dissociation.
Hexaammineruthenium Complex as Two-Electron Catalyst for Oxygen Evolution by Homogeneous and Heterogeneous Water Oxidation
Authors: Ramaraj Ramasamy , Kaneko Masao , Kira Akira
Published: July 2006

The [Ru(NH3)6]3+ complex is shown to be a two-electron catalyst for homogeneous as well as heterogeneous water oxidation to evolve dioxygen. The oxygen evolution is proposed to proceed by two molecules of the complex through a peroxo-bridged intermediate involving higher oxidation state [Ruv(NH3)6]5+.
Photoinduced Alkylation Reaction of Benzo[f]indole-4,9-dione with Arylalkenes
Authors: Nakagawa Katsuhiko
Published: July 2006

Photoreaction of 1-alkyl-2-methyl-1H-benz[f]indole-4,9-diones (indolequinones) with arylalkenes in benzene gave 3-alkylated products. Irradiation of 1-allyl substituted indolequinone in benzene gave 1,3-hydrogen shift product in the presence or absence of arylalkenes. The fluorescence of 1,2-dimethyl-1H-benz[f]indole-4,9-dione exhibits a large bathochromic shift in polar solvents, indicating polar charge-transfer character for its S1-state.
The Effects of Aromatic Compounds on the Hydrogen-Transfer Reaction to Coal Model Compounds
Authors: Chiba Koji , Tagaya Hideyuki , Suzuki Toru , Sato Shimio
Published: July 2006

A hydrogen-transfer reaction from a hydrogen molecule to benzophenone in 1-methylnaphthalene without a donor was accelerated in the presence of anthracene. Phenanthrene and pyrene were detrimental to the reaction. Dibenzyl ether conversion was also accelerated by the addition of anthracene, pyrene, and fluorene. Conversions of coal model compounds in 1-methylnaphthalene under a hydrogen atmosphere correlated well with conversions in tetralin under a nitrogen atmosphere.
New Synthesis and Diels–Alder Reactions of 2-Aminomethyl-1,3-butadienes and Related 1,3-Dienes
Authors: Hosomi Akira , Masunari Toshiyuki , Tominaga Yoshinori , Hojo Makoto
Published: July 2006

2-Aminomethyl-1,3-butadienes and 2,3-bis(aminomethyl)-1,3-butadienes, readily prepared by the Grignard cross-coupling reaction of 2-bromo-2-aminopropene and vinylic bromides, are good Diels–Alder dienes toward various activated dienophiles to afford aminomethyl-substituted cyclohexenes.
Optical Resolution by Replacing Crystallization of Ammonium Salts of N-Acetyl-Dl-2-aminobutanoic Acid, N-Acetyl-Dl-norvaline, and N-Acetyl-Dl-norleucine
Authors: Shiraiwa Tadashi , Yamauchi Masahiro , Yamauchi Takatoshi , Yamane Takao , Nagata Makoto , Kurokawa Hidemoto
Published: July 2006

Ammonium salts of N-acetyl-Dl-2-aminobutanoic acid, N-acetyl-Dl-norvaline (Dl-AcNva·AM salt), and N-acetyl-Dl-norleucine were optically resolved by replacing crystallization in the presence of the ammonium salt of N-acetyl-l-alanine to give their salts with l-configuration. The optical resolution of the Dl-AcNva·AM salt, espcially, gave the optically pure l-AcNva4·AM salt by purification in 80% yield based on the half amount of the Dl-salt used as the starting material.
Reactions of Benzocyclopropene with Sulfonyl Isocyanates and Nitrones: Cycloadditions through C–C σ-Bond Rupture of Three-Membered Ring
Authors: Kagabu Shinzo , Saito Katsuhiro , Watanabe Hiroyuki , Takahashi Kensuke , Wada Katsuaki
Published: July 2006

Alkane- and arenesulfonyl isocyanates were added to benzocyclopropene across the C–C σ-bond of the three-membered ring, giving 2-sulfonyl-1-isoindolinones. The reaction with C,N-diphenylnitrone afforded a similar cyclization product, 3,4-dihydro-3,4-diphenyl-1H-2,3-benzoxazine. These reactions are considered to proceed through zwitterionic intermediates formed by the fission of the C–C σ-bond of the three-membered ring by the electrophiles.
Oxidation of Cycloalkanes in a Radiofrequency Plasma
Authors: Tezuka Meguru , Yajima Tatsuhiko
Published: July 2006

Cyclopentane, cyclohexane, cycloheptane, and cyclooctane were reacted in a radiofrequency plasma containing oxygen to give mixtures of the corresponding cycloalkanones and cycloalkanols. Tetralin was also oxidized to 1-tetralone and 1-tetralol. Based on the effects of reaction variables on the oxidation rate, the reaction scheme involving the autoxidation of cycloalkyl radicals was proposed.
Vinyl Polymers Bearing Pyrrole Ring: I. Syntheses of Pyrroles Having 3-Substituent Bearing Vinyl Group
Authors: Kamogawa Hiroyoshi , Nakata Takuharu , Ohori Shin , Komatsu Sei
Published: July 2006

Pyrroles having 3-substituent bearing the vinyl group with an ester or amide spacer were synthesized starting with 1-(phenylsulfonyl)pyrrole. Homopolymerization of the vinyl monomers thus synthesized provided cross-linked insoluble polymers, but their copolymers with 1-vinyl-2-pyrrolidone were soluble in common solvents.
The Photosensitized Oxygenation of Furanoeremophilanes. III. The Transformations to the Skeletally Isomeric Lactones from Furanofukinol
Authors: Naya Keizo , Shimizu Mitsuaki , Nishio Hideki , Takeda Motonori , Oka Shogo , Hirota Keiji
Published: July 2006

Pairs of the skeletal isomers of eremophilane-type lactones were synthesized from furanofukinol via photosensitized oxygenation, followed by lactone cleavage and reformation. Their stereochemistry has been clarified so as to be consistent with a classification method outlined in our earlier papers.
Syntheses and Properties of N-Fluoropyridinium Salts
Authors: Umemoto Teruo , Harasawa Kikuko , Tomizawa Ginjiro , Kawada Kosuke , Tomita Kyoichi
Published: July 2006

Various stable N-fluoropyridinium salts with a non- or weakly nucleophilic counter anion such as TfO−, FSO3−, BF4−, SbF6−, ClO4−, CH3SO3− etc., or with an electron-donating or -withdrawing substituent(s) on the pyridine ring were synthesized and their properties investigated. N-Fluoropyridinium-2-sulfonates, N-fluoroquinolinium triflate, and highly hindered N-fluoro-2,6-di-t-butylpyridinium salts were also synthesized. They were synthesized by counter anion displacement reactions of unstable pyridine-F2 compounds, fluorination of salts of pyridines with protonic acids or silyl esters with F2, and/ or fluorination of Lewis acid complexes of pyridines. The scope of each method was examined in detail. Each of the N-fluoropyridinium salts was assigned as the first stable 1 : 1 salt structure of the pyridine nucleus and halogen atom on the basis of the spectral and elemental analyses. The stability depended on the nucleophilicity or basicity of the counter anions and electronic nature or position of the ring substituents. These results and NMR analyses clearly showed the unstable pyridine-F2 compounds to have N-fluoropyridinium fluoride salt structure. Some N-fluoropyridinium triflates were hydrolyzed and the products were examined, suggesting a unique hydrolysis mechanism.