bluuebunny/crossref_metadata_2025 huggingface dataset:
Equilibrium and EXAFS Studies of Mercury(II) Porphyrin in Aqueous Solution
Authors: Tabata Masaaki , Ozutsumi Kazuhiko
Published: July 2006

Formation of the 2 : 1 mercury(II) porphyrin complex, Hg2(tpps)2− (H2tpps4−: tetrakis(4-sulfonatophenyl)porphyrin), in aqueous solution has been investigated. Equilibrium studies revealed that main chemical species is Hg2(tpps)2− even in a solution of a 1 : 1 molar ratio of Ctpps/CHg and the Hg2(tpps)2− complex is very stable thermodynamically. EXAFS (extended X-ray absorption fine structure) analysis of the Hg2(tpps)2− complex in aqueous solution showed that the Hg–N bond length within the complex is 215(2) pm and the bond length is much shorter than the Hg–O bond length (240 pm) within the hydrated mercury(II) ion. Thus the very strong Hg–N bond is formed upon the complexation of Hg2(tpps)2− and the strong bond formation supports the high stability of the Hg2(tpps)2− complex. Deformation of Hg2(tpps)2− is also discussed in connection with catalytic effect of mercury(II) on metalloporphyrin formation.
X-Ray Diffraction Studies on the Structure of the Tri- and Tetrathiocyanatomanganate(II) Complexes and Solvated Lithium Ion in N,N-Dimethylformamide
Authors: Radnai Tamás , Ishiguro Shin-ichi , Ohtaki Hitoshi
Published: July 2006

The structure of the tri- and tetrathiocyanato-N-manganate(II) complexes in N,N-dimethylformamide (DMF) solution was determined by the solution X-ray diffraction method at 25 °C. The most probable structure of the tri-complex is octahedral with additional three DMF molecules in the first coordination sphere, while the tetra-complex is tetrahedral. The Mn–O and Mn–N bond lengths were determined to be 220 pm in both complexes. The structure of the octahedrally solvated lithium ion [Li(dmf)6]+ with the Li–O bond length of 195 ppm was also determined in an LiSCN solution of DMF.
Growth Process of ZSM-5 Zeolite Film
Authors: Sano Tsuneji , Mizukami Fujio , Takaya Haruo , Mouri Takashi , Watanabe Masami
Published: July 2006

The growth process of a ZSM-5 zeolite film was studied using EDX-SEM, TEM, and EDX-STEM. It became clear that the ZSM-5 zeolite film was formed through a successive accumulation of zeolite crystals of 5 to 10 μm size. It was also found that the crystalline embryos with high Al concentration existed in the vicinity of the inner side of the zeolite film and within the film.
Qualitative Triplet Potential Energy Curves of Arylethylenes along the Double Bond Twisting
Authors: Kikuchi Osamu , Segawa Katsunori , Takahashi Ohgi , Arai Tatsuo , Tokumaru Katsumi
Published: July 2006

The potential energy curves of triplet states of styrene, 2-vinylnaphthalene and 2-vinylanthracene were calculated by the restricted open-shell SCF MNDO methods as a function of the twist angle of the external double bond. It was shown that the shape of the lowest triplet potential energy curve is determined by the relative energies of two triplet states, the “ring-excitation” and “olefin-excitation” states.
1,3-Bis(salicylideneamino)-2-propanol as the Ligand for Manganese(III) Ions
Authors: Mikuriya Masahiro , Yamato Yo , Tokii Tadashi
Published: July 2006

Reaction of 1,3-bis(salicylideneamino)-2-propanol (H3L) with manganese(II) acetate tetrahydrate in the presence of ethylenediamine and sodium thiocyanate give a salen complex [Mn(salen)(NCS)] (H2salen = N,N′-disalicylideneethylenediamine), while that in the presence of water and triethylamine gives a binulear manganese(III) complex [Mn2(L)2(H2O)]·3CH3OH. Both complexes have been characterized by X-ray crystal structure analyses, electronic spectra, and magnetic susceptibilities.
Decomposition of [2.2.2]Cyclophane-1,2-dione Mono- and Bis(tosylhydrazone)s
Authors: Hatta Taizo , Mataka Shuntaro , Tanimoto Satoshi , Tashiro Masashi , Tsuge Otohiko
Published: July 2006

Monotosylhydrazone (2) of [2.2.2]cyclophane-1,2-dione (1) decomposed on silica gel, giving the ring-contracted [2.2.1]cyclophane-17-carboxylic acid (4). The electronic spectrum of 4 showed a red shift of the λmax and a broadening of the peak shape in comparison with that of di-p-tolylacetic acid, due to a through-space π–π interaction. Thermolysis of bis(tosylhydrazone) (3) afforded [2.2.2] cyclophan-1-en-1-yl p-toluenesulfonate (6). An intermediate formation of the corresponding[2.2.2]cyclophan-1-yne is suggested.
Ring-Splitting Reaction of 2,2-Diarylthietane by Electron-Transfer Photosensitization of 9,10-Dicyanoanthracene
Authors: Shima Kensuke , Sazaki Akira , Nakabayashi Kenichi , Yasuda Masahide
Published: July 2006

A 9,10-dicyanoanthracene (DCA)-photosensitized reaction of 3-cyano- or 3-ethoxy-2,2-diarylthietane in acetonitrile gave selectively 2-cyano- or 2-ethoxy-1,1-diarylethene. The ring-splitting reaction proceeds via a one-electron oxidation of the sulfur atom of thietane ring by a photochemical electron transfer to the excited singlet state of DCA.
Crystal Structures of TXC8-TTF (X = Se,Te)
Authors: Nakano Chikako , Wang Ping , Imaeda Kenichi , Maruyama Yusei , Inokuchi Hiroo , Yamochi Hideki , Saito Gunzi
Published: July 2006

The crystal structures of TSeC8–TTF and TTeC8–TTF were determined by X-ray analysis. The molecules in both compounds have chair-like forms and take columnar structures. The distance between the least-squares planes of the central skeleton along the stacking axis in the TSeC8–TTF crystal is nearly equal to that of the TTeC8–TTF crystal. This result is consistent with the fact that the electrical resistivities for both single crystals are of the same order.
Vapor-Phase Beckmann Rearrangement of Cyclohexanone Oxime over an HY Zeolite Catalyst Calcined at High Temperature
Authors: Sato Satoshi , Takematsu Kiyotaka , Sodesawa Toshiaki , Nozaki Fumio
Published: July 2006

The vapor-phase Beckmann rearrangement of cyclohexanone oxime over an HY zeolite calcined at high temperatures was investigated. Cyclohexanone oxime was rearranged into ε-caprolactam with high conversion at 573 K over an HY zeolite calcined at 873 K. The activity decay was slight, while oxime conversion over an HY zeolite calcined at 773 K steeply decreased during the initial stage of the reaction. The catalytic activity for the rearrangement was not correlated with the physical properties of a fresh catalyst, but with those of a used one, especially regarding their porosity and acidity. It was also found that the produced ε-caprolactam was tightly adsorbed on strong aicd sites, filling the micropores of the zeolite during the initial stages of the reaction, and that a large portion of the catalytic reaction proceeded mainly on weak acid sites located in a region near to the external surface of the zeolite.
The Catalytic Electroreduction of Dioxygen on Iron Protoporphyrin IX Modified Glassy Carbon Electrodes
Authors: Arifuku Fumihiro , Mori Keiko , Muratani Tomomi , Kurihara Hirondo
Published: July 2006

The catalytic electroreduction of dioxygen at iron(III) protoporphyrin IX (hemin) modified glassy carbon electrodes was investigated in an aqueous solution within the pH range 1–13. The reduction potential of dioxygen on a hemin chemically modified electrode was more anodic than that on a hemin adsorbed electrode by a few tens of mV. The results of rotating disk and ring-disk voltammetric measurements indicated that the oxygen molecule is reduced via a one-step reduction accompanying four-electron and four-proton transfer at pH < 11, and via two successive reductions accompanying two-electron transfer and, subsequently, two-electron and four-proton transfer at pH > 12. The quantity of peroxide formation at hemin-adsorbed electrodes decreased with increasing pH, up to 10, and then increased with increasing pH beyond 12. The possible overall mechanisms for the catalytic reduction of dioxygen are described.
The Solvent Extraction and Dissociation of the Ion Pair of Alkali Metal Complex of Monodisperse Poly(oxyethylene) Derivatives with Picrate Ion
Authors: Kikuchi Yoichi , Nojima Yasuhiko , Kita Hiroyuki , Suzuki Toshio , Sawada Kiyoshi
Published: July 2006

The ion pair extraction of the alkali metal ion complex of poly(oxyethylene) monododecyl ethers (DEOn: n = 4, 6, and 8, where n refers to the number of the oxyethylene unit) with picrate ion into 1,2-dichloroethane (1,2-DCE) has been studied by means of a vapor pressure osmometry and a solvent extraction. The extraction equilibria have been interpreted by taking into consideration the ion pair dissociation in 1,2-DCE. Thermodynamic constants of the extraction and the dissociation of the ion pairs have been evaluated from a quantitative analysis of the extraction data. The extractability of the alkali metal ion increases in the order Li+ < Na+ < Cs+ < K+, irrespective of the number of oxyethylene (EO) unit of DEOn. This order was interpreted by the formation constant of the DEOn–alkali metal ion complex in the aqueous phase. The formation constants of the DEOn–alkali metal ion complex both in the aqueous phase and in 1,2-DCE increase with the increase in the number of EO unit. The interionic distance between the cationic complex and picrate ion of the ion pair was estimated from the dissociation constant in 1,2-DCE.
Synthesis of Alkyl Substituted p-Benzoquinones from the Corresponding Phenols Using Molecular Oxygen Catalyzed by Copper(II) Chloride–Amine Hydrochloride Systems
Authors: Shimizu Masao , Watanabe Yoshihito , Orita Hideo , Hayakawa Takashi , Takehira Katsuomi
Published: July 2006

2,4,6-Trimethylphenol was effectively oxidized to trimethyl-p-benzoquinone with molecular oxygen in the presence of a catalytic amount of copper(II) chloride–amines in alcohol at ambient temperature. Various amines could be used as a co-catalyst in the presence of acids, and especially hydroxylamine hydrochloride and acetone oxime coupled with hydrochloric acid showed high activity. 2,6-Dimethyl-p-benzoquinone was also obtained from 2,6-dimethylphenol in good yield in this catalytic oxidation system.
Synthesis of a Polycyclic π-Conjugated System Containing an Azulene Unit by the Flash Vacuum Pyrolytic Method. I. Synthesis and Properties of Cyclopent[a]azulenes
Authors: Kitamori Yoichiro , Yasunami Masafumi , Hioki Takanori , Kikuchi Ikue , Takase Kahei
Published: July 2006

1H- and 3H-cyclopent[a]azulene were synthesized in excellent yields by applying flash vacuum pyrolysis. Their structures were clearly determined. A mixture of 1H- and 3H-cyclopent[a]azulene was completely anionized with methyllithium in THF, but 67% so in ether. Although 1H-cyclopent[a]azulene reacted with dichloroketene to give a [2+2] cycloadduct, 3H-cyclopent[a]azulene reacted with cyclopentadiene to give a [4+2] cycloadduct. These chemical behaviors were predictable according to HMO theory.
Synthesis and Properties of Pheophorbide-Quinone Compounds
Authors: Borovkov Victor V , Gribkov Alexander A , Kozyrev Andrei N , Brandis Alexander S , Ishida Akito , Sakata Yoshiteru
Published: July 2006

New pheophorbide-quinone derivatives with a different kind of quinone moieties were synthesized by mixed anhydride method. The structures of these compounds were confirmed by UV, IR, 1H NMR, fluorescence, and mass spectra. Effective fluorescence quenching of the pheophorbide chromophores in the synthesized molecules was observed depending on the electron-accepting properties of the quinone fragment and spatial disposition of the donor and acceptor. Electron-transfer rate constants were calculated based on fluorescence decay measurements. The role of energetic and conformational changes of pheophorbide-quinones in the electron-transfer processes is discussed.
Synthesis and Some Reactions of Ethyl 2-[2-(Substituted Methyleneamino)anilino]cyclohepta[b]pyrrole-3-carboxylates
Authors: Abe Noritaka , Kakehi Akikazu
Published: July 2006

We synthesized Schiff bases, ethyl 2-[2-(benzilideneamino)anilino]cyclohepta[b]pyrrole-3-carboxylate (2a) and ethyl 2-[2-(2-butenylideneamino)anilino]cyclohepta[b]pyrrole-3-carboxylate (2b), from ethyl 2-(2-aminoanilino)cyclohepta[b]pyrrole-3-carboxylate (1) in excellent yields by treating 1 with benzaldehyde or 2-butenal in the presence of molecular sieves 4A, respectively. Further, the cyclization and cycloaddition reactions of the Schiff bases were investigated. Treatment of 2a with iron(III) chloride or Pd–C gave ethyl 2-(2-phenylbenzimidazol-1-yl)cyclohepta[b]pyrrole-3-carboxylate and 12H-5,13-dihydrocyclohepta[1′,2′ : 4,5]pyrrolo[2,3-b][1,5]benzodiazepin-12-one (4). A similar treatment of 2b, however, gave ethyl 2-(4-methylqinolin-8-yl)aminocyclohepta[b]pyrrole-3-carboxylate and 4. The reaction of 2a with dimethyl acetylenedicarboxylate (DMAD) gave 15a-ethyl 5,6,7,15-tetramethyl 15,15a-dihydro-14H-pyrrolo[2′,1′ : 1,2]isoquino[3,4-b][1,5]benzodiazepine-5,6,7,15,15a-pentacarboxylate (6) and methyl 4-(3-ethoxycarbonylcyclohepta[b]pyrrol-2-yl)-3-oxo-1,2,3,4-tetrahydroquinoxalin-2-ylideneacetate (7). The reaction of 2b with DMAD, however, gave the 1,4-dihydropyridine derivative as a Diels–Alder adduct, along with 7. The structures of 6 and 7 were confirmed by single-crystal X-ray analyses.
Reaction of Tantalum–Alkyne Complexes with Isocyanates or Acyl Cyanides. Stereoselective Functionalization of Carbon–Carbon Triple Bonds
Authors: Kataoka Yasutaka , Oguchi Yoshiyuki , Yoshizumi Kazuyuki , Miwatashi Seiji , Takai Kazuhiko , Utimoto Kiitiro
Published: July 2006

Treatment of alkynes with low-valent tantalum derived from TiCl5 and zinc produces tantalum-alkyne complexes (not isolated), which react in situ with phenyl isocyanate (or butyl isocyanate) to give (E)-α,β-unsaturated amides stereoselectively. The tantalum–alkyne complexes also react with acyl cyanides in the presence of BF3·OEt2 to give α-cyanohydrins. In both reactions, filtration of the reaction mixture containing the tantalum–alkyne complexes before addition of isocyanates (or acyl cyanides) is indispensable to obtain good yields.
The Selective Separation of Organic Acids through Liquid Membrane Containing Ferrite in the Presence of Alternating Magnetic Field
Authors: Sakai Yasuzo , Konno Emi , Tsuchida Satoru , Takahashi Fujio
Published: July 2006

The selective separation of phenylglyoxylic acid (PGA) from a mixture of PGA and mandelic acid (MA) was carried out by using a liquid membrane containing ferromagnetic powder (LM-FP) in the presence of an alternating magnetic field (A-MF). Ferromagnetic powder, which exhibits a strong coercive property, was added into a mixture of toluene and chloroform (T–C mixture). Many holes of 0.7 mm in diameter were bored in the bottom wall of a Teflon® cylindrical bottle, in which the total hole area occupied 8%. A T–C mixture containing ferromagnetic powder was filled into the holes to prepare LM-FP. Under an exposure of A-MF (200 Oe, 50 Hz) over a 12 h. Fifty four % PGA and 8% MA in the source phase were found to permeate through the LM-FP-containing Sr-ferrite from the source phase of an equimolar mixture of PGA and MA to the receiving phase. The PGA permeation rate through the LM-FP varied over a region between 0.3 and 7.5 times higher than that through a control liquid membrane not containing any ferromagnetic powder in the presence of a magnetic field.
Electron Transport and Redox Chain Reactions in a Mosaic Membrane
Authors: Igawa Manabu , Takabayashi Yasuhiko , Koizumi Toshiaki
Published: July 2006

A circulating current enhances transports of ions and electrons in a mosaic membrane system with ion-exchange membranes and electron-transport membranes. Electron transport is readily coupled to ion transport in a new mosaic membrane with electron-transport regions and ion-exchange regions. Electrons and ions are transported in the same or opposite direction by the driving forces of the redox potential gradient or the concentration gradient. Redox chain reactions are also generated in the mosaic membrane system as the electron flow in biological membranes.
Thermodynamic and NMR Studies on the Complexation of Lanthanoid(III) Ions with o-Phenylenediamine-N,N,N′,N′-tetraacetate in Aqueous Solutions
Authors: Yamamoto Mineko , Nakasuka Noriyuki , Tanaka Motoharu
Published: July 2006

The complex formation of o-phenylenediamine-N,N,N′,N′-tetraacetate (PhDTA, H4L) with trivalent lanthanoid ions (M3+) in aqueous solutions has been studied at a temperature of 25.0 ± 0.2 °C and an ionic strength of 1.0 M in NaClO4 by potentiometry, calorimetry, and 1H and 139La NMR. The formation constant, KML, of 1 : 1 PhDTA complexes increases monotonically with the atomic number of the central metal ions (log KML = 11.39 for La, and 16.26 for Lu), showing the tetrad effect and a linear free energy relationship with the formation constant of CyDTA complexes. The change in entropy increases gradually with increasing atomic number, as is the case for EDTA. The large change in entropy ( ≈ 257–329 J K−1 mol−1) overweighs the endothermicity ( = 5.4–14.6 kJ mol−1) of the complexation. The NMR study indicated that the La–PhDTA complex has four acetate groups with an identical magnetic environment and a lanthanum nucleus with higher electric symmetry in comparison with the corresponding EDTA and CyDTA complexes.
Preparation and Characterization of [Co(tp)2(Men-en)]+ (tp = Tropolonate Ion; Men-en (n = 1−4) = N-Methyl Substituted Ethylenediamine), Inversion and Deuteration at Chiral Nitrogen Centers of [Co(tp)2(Me-en or Me3-en)]+, and Crystal Structures of [Co(tp)2(N,N-Me2-en)]ClO4 and Λ(R)Δ(S)-[Co(tp)2(Me-en)]ClO4
Authors: Kojima Masaaki , Ma Guilin , Miyamoto Toshiro , Ohba Shigeru , Fujita Junnosuke
Published: July 2006

A series of complexes of the type [Co(tp)2(R1R2NCH2CH2NR3R4)]+ (tp = tropolonate ion; R1–R4 = H or CH3) were prepared and characterized by physicochemical methods. The rates of OH−-catalyzed deuteration (H → D, kD) and inversion (epimerization, kep) at the chiral amine nitrogen centers of [Co(tp)2(Me-en or Me3-en)]+ (Me-en = N-methylethylenediamine, Me3-en = N,N,N′-trimethylethylenediamine) in aqueous solutions were measured at 34.0 °C. The kD and kep values are, respectively, ca. 10 and ca. 103 times as large as those of [Co(acac)2(Me-en or Me3-en)]+ (acac = 2,4-pentanedionate ion). The reduction (Co3+/Co2+) half-wave potential increases from −0.31 (vs. SCE) for [Co(tp)2(en)]+ (en = ethylenediamine) to −0.09 V for [Co(tp)2(Me4-en)]+ (Me4-en = N,N,N′,N′-tetramethylethylenediamine) in spite of the expected electron-donating effect of the methyl groups, and the results were ascribed to the steric effect of –N(CH3)2. This interpretation was supported by the X-ray analysis of [Co(tp)2(N,N-Me2-en)]ClO4 (N,N-Me2-en = N,N-dimethylethylenediamine) in which the Co–N(tertiary amine) bond length (2.022(4) Å) is longer than the Co–N(primary amine) one (1.930(3) Å). The crystal data and R value are: Monoclinic, C2/c, a = 16.558(3), b = 13.541(2), c = 19.125(3) Å, β = 102.62(1)°, V = 4184(1) Å3, Z = 8, R = 0.044 for 2009 observed unique reflections. The crystal structure of Λ(R)Δ(S)-[Co(tp)2(Me-en)]ClO4 was also determined. The crystal data and R value are: Monoclinic, P21/a, a = 11.608(5), b = 22.754(9), c = 7.936(6) Å, β = 106.02(7)°, V = 2015(2) Å3, Z = 4, R = 0.084 for 1057 reflections.
Slab Optical Waveguide with Octadecylsilane Coated Surface for Absorption Detector of Flow Analysis
Authors: Tsunoda Kin-ichi , Itabashi Hiromitsu , Akaiwa Hideo
Published: July 2006

A K+ doped glass slab optical waveguide (SOWG) was coated with octadecylsilane (ODS) to separate and concentrate analytes onto the SOWG with hydrophobic interaction between analytes and ODS. As an absorption detector of flow analysis, the ODS–SOWG detector was almost insensitive to a blue dye (bromothymol blue) which is not adsorbed to the surface of the SOWG. On the other hand, it was highly sensitive to another blue dye of coomassie brilliant blue G-25O (CBB) which is firmly adsorbed onto the SOWG surface.
X-Ray Structure, Ligand Substitution, and Other Properties of Trinuclear Ruthenium Complex, [Ru3(μ3-O)(μ-C6H5COO)6(py)3](PF6) (py = pyridine), and X-Ray Structure of Dinuclear Ruthenium Complex, [Ru2(μ-C6H5COO)4Cl]
Authors: Abe Masaaki , Sasaki Yoichi , Yamaguchi Tadashi , Ito Tasuku
Published: July 2006

Crystal structure of an oxo-benzoate-bridged trinuclear ruthenium complex, [Ru3(μ3-O)(μ-C6H5COO)6(py)3](PF6) (py = pyridine) (1), was determined for the first time for the complexes with a Ru3(III,III,III)(μ3-O) core. The complex crystallizes in hexagonal space group P63 with a = 13.619(6), c = 19.204(9) Å, V = 3085(3) Å3, and Z = 2. The Ru···Ru distance of 3.350(2) Å is similar to those of the trinuclear complexes of other metal ions, [MIII3(μ3-O)(μ-RCOO)6(L)3]+ (L = neutral unidentate ligand). The complex in 0.1 M (n-C4H9)4NPF6-acetonitrile at 20 °C shows four reversible one-electron processes at E1⁄2 = +1.58, +0.71, −0.26, and −1.54 V vs. Ag/Ag+ (0.1 M AgClO4). It undergoes pyridine-d5 exchange with the first-order rate constant, 4.9 × 10−6 s−1 at 60 °C ([1] = 4.7 mM, [py-d5] = 387 mM). Small modification of the synthetic procedure of the trinuclear complex leads to the precipitation of the crystals of well-known type of dimeric ruthenium (II,III) complex, [Ru2(μ-C6H5COO)4Cl], which crystallizes in monoclinic space group C2/c with a = 21.668(10), b = 10.741(8), c = 12.797(5) Å, β = 110.22(4)°, V = 2795(3) Å3, and Z = 4. The crystal contains infinite zig-zag chain of ···Cl–Ru–Ru–Cl···along c-axis with Ru–Ru–Cl of 175.5(1)°, Ru–Cl–Ru of 118.1(1)°, and the Ru–Ru distance of 2.290(1) Å.
Luminol Chemiluminescence-Delay Method for Determination of Copper(II)
Authors: Kamidate Tamio , Ishikawa Atsushi , Watanabe Hiroto
Published: July 2006

The copper(II)-catalyzed oxidation of cysteamine with oxygen was carried out in a basic medium involving luminol. After preferential oxidation of cysteamine to disulfide, a Cu(II)-catalyzed luminol chemiluminescence (CL) reaction was subsequently commenced with hydrogen peroxide accumulated during the oxidation of cysteamine. Thus, a delay time from reaction initiation to a sharp flash of CL was observed. This delayed CL of luminol was applied to the determination of copper(II) by measuring the delay time or CL intensities. The delay time and the CL intensity at maximum light emission were linearly correlated with the Cu(II) concentration over the range from the detection limit of 3.0 × 10−6 to 2.0 × 10−5 M. The relative standard deviation of the CL intensity and the delay time in five successive experiments was 3.0% at 1.0 × 10−5 M of Cu(II). The tolerance limits of Fe(III), Ni(II), and Zn(II) in the present method were 20- to 100-times higher than those in the conventional luminol CL method.
Correlation between the ortho-Positronium Pick-off Annihilation Lifetime and the Free Volume in Molecular Liquids and Polymers
Authors: Kobayashi Yoshinori , Haraya Kenji , Kamiya Yoshinori , Hattori Shigeru
Published: July 2006

A good correlation between the ortho-positronium (o-Ps) pick-off annihilation lifetime and the free volume, computed as the difference between the specific volume at room temperature and that at 0 K, is reported for molecular liquids and polymers. Bondi’s group contribution approach was employed for estimating the specific volume at 0 K. The o-Ps lifetimes in molecular solids, such as phenanthrene deviate considerably from the correlation. It is suggested that a bubble may be formed around Ps in liquids and polymers, but not in the low-molecular-weight crystalline solids. A correlation is presented between the diffusion coefficients of Ar and the lifetimes of o-Ps in both liquids and polymers.
On the Sorption of d-Metal Ions on Mixed Phosphates of the 4-th Group Elements
Authors: Bortun Anatoly Ivanovich , Budovitskaya Tatjana Antonovna , Strelko Vladimir Vasiljevich
Published: July 2006

Mixed titanium–zirconium, tin–zirconium, and tin–titanium phosphates containing different amounts of the 4-th group elements were synthesized and their ion-exchange properties towards Cu2+, Co2+, Ni2+, and Cr3+ ions were studied. The values of the equilibrium costants of the ion-exchange reactions of the d-metal sorptions from acetate and chloride solutions were calculated. It was found that the sorbents affinity to the transitional metal ions greatly depended on their chemical composition; enriching of tin-containing samples with Zr and, especially, with Ti increases the affinity to Co2+ ions; enrichment of titanium-zirconium containing ionites with Zr increases their affinity to Cu2+ ions, etc. It is suggested that the observed changes in the selectivity of the inorganic ion-exchangers are connected with the possibility of creating in their structure adsorption centers with different geometrical parameters depending on the dimensions of the 4-th group elements.
Kinetics and Mechanism of Substitution of Aqua-Ligands from cis-Diaquobis-[2-(m-tolylazo)pyridine]ruthenium(II) Complex by 1,10-Phenanthroline in Aqueous Medium
Authors: Mahanti Bibekananda , De Gauri Sankar
Published: July 2006

The kinetics of substitution of aqua-ligands from above title complex by 1,10-phenanthroline in aqueous medium has bean studied spectrophotometrically at different temperatures (40–55 °C). The following rate law has been established for the reaction systems at pH 5.6.

where L and tap represent 1,10-phenanthroline and 2-(m-tolylazo)pyridine respectively, k1 is the water dissociation rate constant of [Ru(tap)2(H2O)2]2+ (i.e. complex 1), k−1 is the aquation rate constant, and k2 is the ligand capturing rate constant of the penta coordinated intermediate, [Ru(tap)2(H2O)]2+. Ionic strength has a very little effect on the rate constants. The rate increases with the increase in pH in the range of 4.5 to 6.0. Activation parameters (ΔH≠ and ΔS≠) were also calculated. Experimental results are consistent with a dissociative mechanism. The solvent effect study was used to verify the mechanistic conclusion.
Microdetermination of Rhenium with Sodium Pentacyanonitrosylferrate(III) and Thiocyanate
Authors: Wahi Anu , Kakkar Lajpat Rai
Published: July 2006

A highly simple and sensitive method for the microdetermination of perrhenate ion was developed which is based on the formation of a mixed ligand complex with thiocyanate and pentacyanonitrosylferrate(III) (nitroprusside) in the presence of tin(II) chloride as reductant. The dark yellowish-brown species thus obtained was quantitatively extractable into 3-methyl-1-butanol whose absorption was measured at 410 nm. A large number of transition elements including Pt-metals do not cause any interference in the method and the results obtained are quite reproducible with a standard deviation of 0.002. The method obeys Beer’s law in the range of 0.91–2.57 ppm of Re with molar absorptivity and Sandell’s sensitivity of 3.86 × 104 dm3 mol−1 cm−1 and 0.0048 μg-Re cm−2, respectively. The method handles satisfactorily the analysis of a wide variety of samples. Rhenium, thiocyanate and nitroprusside in the extracted species were found to be in a respective ratio of 2 : 3 : 1.
Study of Photochemical Reactions of Decamethylcyclopentagermane
Authors: Mochida Kunio , Tokura Satoshi
Published: July 2006

The photolysis of decamethylcyclopentagermane (1) in cyclohexane at room temperature proceeds readily along with the generation of dimethylgermylene to give octamethylcyclotetragermane. Photochemically generated dimethylgermylene reacts with 2,3-dimethylbuta-1,3-diene or carbon tetrachloride to give 1,1,3,4-tetramethyl-1-germa-3-cyclopentene or chlorodimethyl(trichloromethyl)germane, respectively. The transient absorption of 1 in cyclohexane at 490 nm, obtained by laser flash photolysis, is due to dimethylgermylene at 293 K. The reaction rates of dimethylgermylene with some trapping agents are examined. In 3-methylpentane, dimethylgermylene also shows an absorption band at 506 nm at 77 K. The photo-generated dimethylgermylene appears to be in the singlet ground state.
High-Pressure Effect on the Radical Reduction of Spin Probes in Human Erythrocytes
Authors: Yamaguchi Takeo , Takata Masaki , Kimoto Eiji
Published: July 2006

The radical reduction of spin probes in human erythrocytes was studied using neutral radicals such as 2,2,6,6-tetramethyl-1-piperidinyloxyl (Tempo) and 2,2,6,6-tetramethyl-4-hydroxy-l-piperidinyloxyl (Tempol), and anion radical, 2,2,6,6-tetramethyl-4-phosphoryl-1-piperidinyloxyl (Tempo phosphate). On the basis of the differences in the reduction rate of spin probes in intact erythrocytes, 4,4′-diisothiocyanatostilbene-2,2′-disulfonate-treated erythrocytes, and hemolysate, it was found that Tempo and Tempol permeate the lipid bilayer, while Tempo phosphate is transported by a band 3 protein. Under high presssure, the reaction of nitroxide radicals with reductants in cytosol was accelerated and the transport of the anion radical by the band 3 protein was suppressed.
Studies in Vilsmeier–Haack Reaction. IX. Synthesis and Application of Novel Heterocyclo-Substituted Furo[2,3-c:5,4-c′]dipyrazole Derivatives
Authors: Awad Ibrahim M A
Published: July 2006

The Vilsmeier-Haack reaction on 4,4′-bi-4H-pyrazole-5,5′(1H, 1H′)-dione brought about the formation of one methyl group, chloro substitution of a carbonyl group in the 5-position, and the cyclization of the 5-chloro-3-(2-amino-1-formylethenyl)derivative in one step to give the corresponding furo[2,3-c:5,4-c′]dipyrazole (3). Treatment of 3 with some secondary heterocyclic amines gave the aminomethylene derivatives 6–8. Interaction of 3 with hydroxylamine hydrochloride, hydrazine hydrate and phenylhydrazine afforded the corresponding isoxazolyl and pyrazolyl derivatives 9–11 which have been screened in vitro for antibacterial and antifungal activities.
Silver(I) Oxide Catalyzed Oxidation of o-Allyl- and o-(1-Propenyl)phenols
Authors: Iyer Meera R , Trivedi Girish K
Published: July 2006

The oxidation behavior of o-alkenylphenols towards a one-electron transfer agent, silver(I) oxide, was studied. Oxidation of an o-(1-alkenyl)phenol yields a dimeric product via the intermediacy of a quinonemethide radical. However, in the case of an o-(2-alkenyl)phenol where the γ-carbon bears substituents, a 2H-chromene is the product. During the course of this study, carpanone, a naturally-occurring lignan, was synthesized.
Time-Resolved ESR Studies on Photosensitized Reaction of Maleic Anhydride in Alcohols: CIDEP Memory Transfer in Spin-Adduct Formation
Authors: Ohara Keishi , Murai Hisao , Kuwata Keiji
Published: July 2006

A triplet photosensitization reaction of maleic anhydride with alcohols and the subsequent secondary reaction were studied by a time-resolved ESR method. The hydrogen abstraction reaction of the C=C bond site of maleic anhydride in the excited triplet state was examined and discussed as the primary step. The adduct radical formed in the secondary reaction between maleic anhydride and alcohol radicals showed a characteristic E/A-shaped hyperfine line(s). This phenomenon can be explained by the CIDEP “memory transfer” of the multiplet (E/A) spin polarization of the alcohol radicals to the adduct radical. The spin-lattice relaxation times of the excited triplet state of xanthone as the sensitizer in 2-propanol and cyclohexanol were also estimated.
A Time-Resolved EPR Study on the Photochemical α-Cleavage of Benzoin and Related Molecules
Authors: Mukai Masahiro , Yamauchi Seigo , Hirota Noboru , Koyanagi Motohiko , Futami Hiroshi
Published: July 2006

The photochemical α-cleavage reactions of benzoin, benzoin methyl ether (BME) and deoxybenzoin (DOB) in methylcyclohexane and benzene have been studied by means of the time-resolved EPR technique. Strong emissive CIDEP spectra of the radicals produced by the α-cleavage reactions are observed in benzoin and BME. From the analysis of the hyperfine splittings they are assigned as benzoyl and α-hydroxybenzyl radicals in the case of benzoin and benzoyl and α-methoxybenzyl radicals in BME. It is clearly shown that the cleavage reaction takes place in the T1(nπ*) states of these carbonyls and the triplet mechanism (TM) is mainly responsible for the CIDEP spectra. From the time profile of the CIDEP signals it is also shown that the produced radicals react almost exclusively with each other. In the case of DOB, the α-cleavage is found to be much less efficient and a hydrogen abstraction reaction is more dominant at room temperature. It is concluded that the cleavage rate constant (kc) is in the order, kc (BME) > kc (benzoin) >> kc (DOB).
Band Assignment of Anomalously Strong Absorption Band of 2,6-Diaminopyridine by Interaction with Acetic Acid
Authors: Inuzuka Kozo , Fujimoto Akira
Published: July 2006

Upon the addition of acetic acid to 2,6-diaminopyridine in isooctane, a new anomalously strong band appears near 340 nm over 2 × 10−3 mol dm−3. The corresponding band was, on the basis of the results of a molecular orbital calculation and spectroscopic experiment, assigned to the π–π* absorption band of (E)-6-amino-2(1H)-pyridinimine (tautomer) formed through the hydrogen-bond formation of 2,6-diaminopyridine with two acetic acid molecules.
Surface-Enhanced Raman Spectra of Isomeric Picolines Adsorbed on Silver Sols
Authors: Sarkar Uttam Kumar , Chakrabarti Subhasis , Misra Tridibendra Narayan
Published: July 2006

Raman spectra of 2-, 3-, and 4-methylpyridines (MePys) are obtained in the bulk phase, in aqueous solution and in the adsorbed state on silver sol. Addition of the MePys to Ag-sol results in aggregation of the Ag-particles showing characteristic charge transfer (CT) bands. Significant surface enhancement of Raman bands is observed. Both the estimated enhancement factor and the absorption maximum of CT band are in inverse parallel relationship with the electron density of the N atom as reflected by the Hammett σ value of the substituent. It is inferred that the charge transfer interaction between the absorbates and the metal particles contributes to the enhancement mechanism. SER spectra of MePys adsorbed on Ag-sol are compared with the reported spectra of these molecules adsorbed on Ag-electrode and the difference in the surface structure is discussed. Some new bands appear in the SER spectra and some vibrational modes show SERS selectivity. These experimental observations provide information about the orientation of the molecules on the metal surface.
Relation between the Vibrational Wavepacket Propagation Formalism and the Time-Correlation Function Formalism for Absorption and Raman Scattering
Authors: Lee Soo-Y
Published: July 2006

By a proper choice of the system Hamiltonian and the dipole or polarizability operators, we show that the widely used wavepacket propagation formalism for optical absorption presented by Heller (J. Chem. Phys., 68, 2066 (1978)) and vibrational Raman scattering by Lee and Heller (J. Chem. Phys., 71, 4777 (1979)) can be derived from the dipole and polarizability correlation function formalisms, respectively, presented by Gordon (Adv. Magn. Reson., 3, 1 (1968)). Gordon focused on processes in the ground electronic state, whereas Heller et al. dealt with optical processs involving excited electronic states. The cases of an isolated molecule and of a molecule in a bath where only pure electronic dephasing occurs are both considered in this paper.
Motions of Methylammonium Ions in (CH3NH3)3Sb2I9 Crystals Studied by 1H NMR
Authors: Koziol Piotr , Furukawa Yoshihiro , Nakamura Daiyu , Jakubas Ryszard
Published: July 2006

The molecular motions and phase transitions at 147 and 111 K in solid tris(methylammonium) nonaiododiantimonate(III), (CH3NH3)3Sb2I9, were investigated by measuring the temperature dependences of the proton spin-lattice relaxation times (T1 and T1ρ) in the static and rotating frames and the second moment (M2) of 1H NMR absorption above 90 K. In room-temperature phase I, it was revealed that the cations underego a rapid overall rotation. The cations in low-temperature phases II and III were shown to have almost fixed orientations in the crystals, but performed a rapid C3 reorientation about the C–N bond axis.
Mercury(63P1)-Photosensitized Decomposition of Tetramethyllead
Authors: Yamamoto Shunzo , Inoue Satomi , Sueishi Yoshimi , Nishimura Norio
Published: July 2006

Mercury(63P1)-photosensitized decomposition of tetramethyllead was investigated at 393 K and at pressures from 260 to 6700 Pa. Ethane and methane were detected as gaseous products. From the pressure dependences of the yields of ethane and methane, and from the effects of O2 and H2 on the yield of ethane, it was deduced that the main initial reactions involve Pb–C bond cleavage.
Thermodynamic Studies on the Complexation of Alkaline-Earth Metal Ions with o-Phenylenediamine-N,N,N′,N′-tetraacetate in Aqueous Solutions
Authors: Nakasuka Noriyuki , Sawaragi (née Kunimatsu) Mihoko , Matsumura Kazunori , Tanaka Motoharu
Published: July 2006

Potentiometric and calorimetric studies were carried out for the complexation of o-phenylenediamine-N,N,N′,N′-tetraacetate (PhDTA, L4−) with alkaline-earth metal ions (M2+) in aqueous solutions at 25.0 °C and 1.0 M (NaClO4). The formation constants (log KML) obtained are 6.48 (Be), 6,481 (Mg), 8.27 (Ca), 5.47 (Sr), and 3.99 (Ba), respectively. The changes in enthalpy (/kJ mol−1) are 45.5 (Be), 34.3 (Mg), −14.0 (Ca), 2.7 (Sr), and 2.5 (Ba), respectively.
Cyclization of N-Terminal Fragments of Elcatonin
Authors: Inoue Takashi , Kishida Satoshi , Ohsaki Masutaka , Kimura Hitoshi
Published: July 2006

It was proved that the cyclization yields on N-terminal fragments of elcatonin were dependent on cyclic positions of the corresponding linear peptides.
Preparation of Aromatic Iodoacetyl Derivatives by Direct Iodination with a Potassium Iodide–Potassium Iodate–Sulfuric Acid System
Authors: Okamoto Tsuyoshi , Kakinami Takaaki , Nishimura Tetsuo , Hermawan Irwan- , Kajigaeshi Shoji
Published: July 2006

The reaction of aromatic acetyl derivatives with potassium iodide and potassium iodate in acetic acid in the presence of sulfuric acid at room temperature gave iodoacethyl derivatives in good yields.
Allylation of Carbonyl Compounds with Catalytic Amount of Indium
Authors: Araki Shuki , Jin Shun-Ji , Idou Yoshiyuki , Butsugan Yasuo
Published: July 2006

Allylation of aldehyde and ketone, and prenylation of 2-chlorobenzoquinone were achieved by using a combination of a catalytic amount of indium(III) chloride and metallic aluminium or zinc.
Metallic Nickel-Catalyzed Reduction of Aryl Halides with Zinc Powder and Ethanol
Authors: Sakai Mutsuji , Lee Ming-San , Yamaguchi Kôji , Kawai Yasuyuki , Sasaki Ken , Sakakibara Yasumasa
Published: July 2006

Aryl halides were exclusively reduced in ethanol to give the corresponding arenes in the presence of zinc powder and a catalytic amount of metallic nickel under nitrogen. The reduction was accelerated by adding excess zinc powder to the catalyst system. A probable reaction pathway is presented.
Catalytic Acid Fluoride Synthesis via Carbonylation of Organic Bromides in the Presence Potassium Fluoride
Authors: Okano Tamon , Harada Nobuyuki , Kiji Jitsuo
Published: July 2006

Various aryl bromides were carbonylated under an atmospheric pressure of carbon monoxide in DMF in the presence of potassium fluoride to give aroyl fluorides in excellent yields. The carbonylation was promoted by the addition of phase transfer catalysts, but the contamination with water reduced the selectivity.
A Facile Synthesis of Sulfoxides by Oxidation of Sulfides with Sodium Bromite in an Aprotic Solvent in the Presence of Clay Minerals
Authors: Hirano Masao , Kudo Hiroyuki , Morimoto Takashi
Published: July 2006

The title oxidation has been performed in dichloromethane in the presence of “wet”-montmorillonite and -kaolin. The substrates studied include dialkyl, alkyl aryl, diaryl, and cyclic sulfides, which give the corresponding sulfoxides in good yields under neutral and mild conditions.
The Isomerism of the (Ethylenediamine-N,N′-dipropionato)(ethylenediamine)cobalt(III) Ion and Its Stereoselective Isomerization Reaction
Authors: Kawaguchi Hiroshi , Maruyama Noboru , Ama Tomoharu , Yasui Takaji
Published: July 2006

Three isomers (one α and two β) of [Co(eddp)(en)]+ were prepared and optically resolved. The stereochemistry was studied on the basis of absorption, CD, and 13C NMR spectral data. Two β isomers, β(e-1) and β(e-2), were conformational diastereomers arising from a difference of the chirality around one of the asymmetric N atoms in a coordinated eddp ligand. The β(e-1) β(e-2) change was an inversion reaction at the asymmetric sec-N atom in the in-plane β-alaninate ring of the coordinated eddp, and the rate was slow. The α β(e-1) or β(e-2) change (coordination-site exchange reaction) was stereoselective and could be explained by the Co–O bond rupture mechanism proposed for Co(III)–edda complexes.
Intercalation and Bilayer Formation of Phospholipids in γ-Type Layered Transition Metal Phosphates
Authors: Kanzaki Yasushi , Abe Mitsuo
Published: July 2006

Intercalation of natural phospholipids, phosphatidylethanolamine (PEA) and phosphatidylcholine (PC), into inorganic layered compounds was examined in ethanol and chloroform solutions. γ-Type titanium(IV) phosphate and zirconium(IV) phosphate were selected as host layered compounds. They are strong solid acids and also known as inorganic ion exchangers. The intercalation of PEA was propagated in chloroform solution in the presence of n-alkylamine forming a bilayers of PEA–alkylamine mixture. The direct reaction of PEA with γ-phosphates was not successful. On the other hand PC reacted directly with the layered compounds either in the chloroform or in the ethanol solution of PC and successfully formed bilayers.
Comparison of 2,4-Hexadienoic with 1-Hexanoic Acids as Extractant for Copper(II)
Authors: Yamada Hiromichi , Kato Chizuko , Mizuta Masateru
Published: July 2006

2,4-Hexadienoic and 1-hexanoic acids have been evaluated as extractant for copper(II). The extraction was carried out using benzene and 1-octanol as solvent at 25 °C and aqueous ionic strength of 0.1 mol dm−3 (NaClO4). The stoichiometry of the extracted species and their extraction constants were determined by graphical method. The extraction of copper(II) with 2,4-hexadienoic acid has been found to proceed through a mechanism different from that with 1-hexanoic acid. 2,4-Hexadienoic acid has been proved to be similar in the extraction behavior for copper(II) to benzoic acid. While, 1-hexanoic acid as extractant for copper(II) has been demonstrated to resemble decanoic acid.
Selective Ion Transport in Acetonitrile Across the Ionophore-Immobilized Polymer Membranes Used as the Sensor of the Ion-Selective Electrodes
Authors: Nakamura Toshio , Ueda Takahiro , Fujimori Kunihide
Published: July 2006

A conductometric study was carried out concerning the selective ion transport of alkali and alkaline earth metal ions, mainly in acetonitrile (AN), across a membrane of polyacrylamide (PAA) coupled to such ionophores as tetraethylene glycol monododecyl ether, hexaethylene glycol monododecyl ether, dibenzo-18-crown-6, and cryptand222B. A sintered glass filter membrane was impregnated with PAA-ionophores and the conductivity of the solution of one side of the membrane was measured in order to monitor the ion transport across the membrane from the opposite side. Alkali and alkaline earth metal ions could pass across the ionophore-free PAA membrane, but the ions were entrapped in the PAA-ionophore membranes. Tetraethylammonium and perchlorate ions, however, could pass across both the PAA and the PAA-ionophore membranes. The entrapped ions could pass across the PAA-ionophore membranes if a complexing reagent was added to the solution on one side of the membrane by forming complexes with the reagent. The limiting equivalent conductivities and the ion association constants of (Li-12C4)+ClO4−, (Li-Cryp22)+ClO4−, (K-DB18C6)+ClO4−, (K-Cryp222)+ClO4−, (Mg-12C4)2+2ClO4−, (Ba-DB18C6)2+2ClO4−, (Ba-Cryp22)2+2ClO4−, and (Ba-Cryp222)2+2ClO4− were determined. The limiting equivalent conductivities were used to compare the relative conductivity values among different species obtained the conductometric measurements of ion transport across the membrane.
Synthesis and Characterization of trans-[CoCl2(N4x)]+ (N4x = 1,4,7,10-Tetraazacycloheptadecane, -cyclooctadecane, -cyclononadecane, -cycloicosane, -cyclohenicosane, and -cyclodocosane)
Authors: Tsuchimoto Masanobu , Fujita Junnosuke
Published: July 2006

New macrocyclic ligands, 1,4,7,10-tetraazacyclooctadecane (N411), -cyclononadecane (N412), -cycloicosane (N413), -cyclohenicosane (N414), and -cyclodocosane (N415), and the Co(III) complexes, trans-[CoCl2(N4x)]+ (x = 10−15) were prepared and characterized. While two isomers, one has an RSSR(SRRS) and the other an RSSS(SRRR) configuration for the four chiral nitrogen atoms, were obtained for the N4x (x = 12−15) complexes, only the RSSR(SRRS) isomer was isolated for the N410 and N411 complexes. The ligand field strength of N4x (Δ(N)) decreases largely from x = 6 to 9 or 10, and then shows an increasing tendency with the increasing ring members. The reduction potential for the Co(III)/Co(II) couple (E1⁄2) becomes less negative with the increasing ring members, and the ΔEp(= Epa − Epc) values are very large for the N48–N411 complexes. The variations of these observed values with the number of ring members indicate that medium-sized chelate rings are unstable compared with other sized ones.
Magnetic Properties of Oxygen Centered Trinuclear Ruthenium(III) and Rhodium(III) Complexes
Authors: Kobayashi Hanako , Uryû Norikiyo , Tokiwa Ayako , Yamaguchi Tadashi , Sasaki Yoichi , Ito Tasuku
Published: July 2006

The magnetic susceptibility and ESR of triangular trinuclear coordination compounds, [Ru3(μ3-O)(μ-CH3COO)6(py)3]+ and [Ru3(μ3-O)(μ-CH3COO)6(py)3]+ salts of powders, were measured in the region between liquid-He temperature and room temperature. Ru(III) ions are in the low spin state and Rh(III) ions are diamagnetic. The experimental results were analyzed using a localized model with antiferromagnetic exchange interactions, while taking the molecular orbital moment Zeeman effect into consideration. A weak magnetic interaction through the μ-CH3COO bridges is discussed. The averaged g-factor of the Ru salt was about 2.26, and the best-fit antiferromagnetic exchange interaction was about J = −69.5 cm−1.
The Biogenetic-Type Cyclization of the Unsaturated Monocyclic Alcohol with Formic Acid; Facile Synthesis of the Tricarbocyclic Alcohol, (+)-2-Epi-allo-cedrol
Authors: Naemura Koichiro , Hasegawa Tomoyuki , Miyabe Hajime , Chikamatsu Hiroaki
Published: July 2006

The biogenetic-type cyclization of (+)-(3S)-2-(3-hydroxy-3-methyl-4-pentenyl)-1-methyl-3-(1-methylethenyl)cyclopentene, prepared from d-limonene, with formic acid gave stereo and regiospecifically the formates of the tricyclic compounds of the allo-cedrol skeleton, hydrolysis of which gave the unsaturated alcohols, (+)-(1S,5R,7R,8S)-2,6,6,7-tetramethyltricyclo[5.2.2.01,5]undec-2-en-8-ol (27) and (+)-(1S,5R,7R,8R-2,6,6,7-tetramethyltricyclo[5.2.2.01,5]undec-2-en-8-ol. Hydrogenation of 27 gave (+)-(1R,2S,5R,7R,8S)-2,6,6,7-tetramethyltricyclo[5.2.2.01,5]undecan-8-ol, (+)-2-epi-allo-cedrol.
Behaviors of α-Fluorocarbenoids Derived from the Nucleophilic Desulfinylation of α-Chloro-α-fluoroalkyl Sulfoxides
Authors: Uno Hidemitsu , Sakamoto Katsuji , Semba Fumihiko , Suzuki Hitomi
Published: July 2006

2-Aryl-1-chloro-1-fluoroethyl sulfoxides underwent nucleophilic desulfinylation with PhMgBr to give (Z)-fluorostyrene derivatives in a very stereoselective manner (> 33 : 1) via an α-fluorocarbene species. When treated with 3 equiv of PhLi in the presence of N,N,N′,N′-tetramethylethylenediamine, they similarly formed fluorostyrenes as a stereoisomeric mixture (E : Z = 2 : 1), but with 1 equiv of PhLi 2-aryl-1-chloro-1-fluoroethanes were the major product. On the other hand, no formation of a fluoroalkene was observed in the desulfinylation of 1-chloro-1-fluoro-4-phenylbutyl sulfoxide with the nucleophiles. In the latter reaction, oxidation and/or phenylation of the intermediate carbene were the main pathways.