bluuebunny/crossref_metadata_2025 huggingface dataset:
Conformations and Restricted Rotation about Amide C–N Bonds of 2,2-Dichloro-1′-formyl-3′,4′-dihydrospiro[cyclopropane-1,2′(1′H)-quinoline] and Related Compounds
Authors: Suezawa (née Endo) Hiroko , Hirota Minoru , Sugiura Michiharu , Hamada Yoshiki
Published: July 2006

Conformational preference and rotational barriers of 1′,1′,2,2-tetrachloro-3′-formyl-1′a,7′b-dihydrospiro[cyclopropane-1,2′(3′H)-cyclopropa[c]quinolines] (1) and related N-formyl heterocyclic compounds were determined by 1H- and 13C-NMR spectroscopy. The sp-conformer is usually more preferable in 1 and their rotational barriers about amide C–N bond are within a relatively narrow range from 70.7 to 72.8 kJ mol−1. Infrared carbonyl absorptions of these compounds also support the preferred conformation from the NMR data. The results were discussed from the view point of N–C=O conjugation.
Binuclear Metal Complexes. IL. Synthesis, ESR, and Electrochemical Properties of Strati-bis Copper(II)–Nickel(II) Complexes
Authors: Okawa Hisashi , Kakimoto Miyuki , Izumitani Tatuo , Nakamura Masaaki , Kida Sigeo
Published: July 2006

Strati-bis copper(II)–nickel(II) complexes, CuNi(R-sata) and CuNi(R-sacta) (R=H, 5-Me, 5-Br), have been prepared, where H4(R-sata) and H4(R-sacta) denote 1,2,3,4-tetrakis(R-salicylideneamino)-2,3-dimethylbutane and 1,2-bis(R-salicylideneamino)-1,2-bis(R-salicylideneaminomethyl)cyclohexane, respectively. ESR spectra of the complexes (frozen chloroform solution at liquid nitrogen temperature) showed a tetragonal pattern with a hyperfine coupling constant A⁄⁄ smaller than that of the relevant mononuclear copper(II) complex. Based on cyclic voltammetry and differential pulse polarography, it was shown that the Cu(II)→Cu(I) reduction occurs at a higher potential than that of the mononuclear reference complex. The ESR and electrochemical properties have been interpreted in terms of the stacking of the CuN2O2 and NiN2O2 planes and hence the electron delocalization over the whole molecule through the ligand π-system.
Cathodic Reduction of Ubiquinone-10 Dissolved in Carbon-paste Electrode
Authors: Erabi Tatsuo , Tanaka Masaya
Published: July 2006

Carbon-paste electrodes were prepared with use of ubiquinone-10 dissolved in organic liquids, 1-chloronaphthalene, 1-bromonaphthalene, 1-methylnaphthalene and undecane. Ubiquinone-10 shows a well-defined, pH-dependent cathodic reduction wave in each liquid system and its reduction seems to proceed with two electrons and a proton transfer around neutral pH. The experimental results indicate the wave to be diffusion-controlled, and the apparent diffusion coefficient was additionally calculated in each liquid system.
Alkylation of the Sulfur- and Nitrogen-containing Compounds Analogous to Thiazoline Systems
Authors: Ohara Yoshio , Akiba Kin-ya , Inamoto Naoki
Published: July 2006

N,N-Dimethyl-2-(alkylthio)ethylamines and 3-methylthiazolidines underwent N-methylation both with trimethyloxonium tetrafluoroborate (3a) and with methyl iodide. In the methylation of N,N-dimethyl-o-(methylthio)aniline, the main reaction was S-methylation. On the other hand, in the o-ethylthio derivative, S-methylated product was major with methyl iodide, while N-methylated product was major with 3a. In the N-ethyl or N-benzyl derivative, only S-methylation occurred with both reagents. 3-Methyl-2, 2-diphenyl-2,3-dihydro-benzothiazole gave S-methylated product with 3a, suggesting that S-methylation becomes major when the 2-substituent is bulkier. 4-Methyl-3,4-dmydro-2H-benzo[b][1,4]thiazine was methylated on the nitrogen with 3a, while it gave S-methylated product with methyl iodide. Phenothiazines and 1-dialkylamino-8-(methylthio)naphthalenes gave only S-methylated products. The selective S-methylation in the case of N-methylation was carried out through protonation on the nitrogen atom followed by methylation with 3a. Possibility of intramolecular interaction between sulfonio and amino groups has been discussed based on their NMR data.
Dimeric Copper(II) Acetate Complexes of Thiazoles and Oxazoles
Authors: Tokii Tadashi , Muto Yoneichiro
Published: July 2006

Copper(II) acetate monoadducts, Cu(CH3COO)2·L (L=thiazole, benzothiazole, benzoxazole, 2-methylbenzothiazole, 2-methylbenzoxazole, 2,4-dimethylthiazole, or 2,4,5-trimethylthiazole) were prepared, and they all show antiferromangnetism (−2J=318–344 cm−1) of copper(II) dimer type. The variation in magnetic interaction with the steric nature of the ligand, L, is discussed.
Preparation and Molecular Structure of cis-β,trans(sec-N,P)-{(2-Aminoethyl)dimethylphosphine}(3,7-diazanonane-1,9-diamine)cobalt(III) Bromide Dihydrate
Authors: Ohishi Tomoji , Kashiwabara Kazuo , Ito Haruko , Ito Tasuku , Fujita Junnosuke
Published: July 2006

The reaction of trans-[CoCl2(2,3,2-tet)]+(2,3,2-tet: 3,7-diazanonane-1,9-diamine) with (2-aminoethyl)dimethylphosphine (edmp) afforded only one geometrical isomer of [Co(edmp)(2,3,2-tet)]3+, the structure of which was determined by X-ray analysis to have the cis-β,trans-(sec-N,P) configuration.
Kinetic Study of Aqueous Decompositions of N-(2-Haloethyl)-N′-cyclohexyl-N-nitrosoureas. Effect of Haloethyl Group on the Preference in Decomposition Pathways
Authors: Yoshida Kitaro , Yano Kazuyuki
Published: July 2006

The aqueous decompositions of the title nitrosoureas under various pH conditions were studied kinetically to generalize their hydrolytic mechanisms. The relative decomposition rates of these analogs were in order of the leaving ability of the halogen moiety, which also affected on the preference in their reaction pathways.
Pyridinium-1-thioacylaminides
Authors: Yoshida Hiroshi , Urushibata Kiyomi , Ogata Tsuyoshi
Published: July 2006

Pyridinium-, 2-methylpyridinium-, and 2,6-dimethylpyridinium-1-thioacylaminides (5–7) were prepared from the corresponding unsubstituted pyridinium-1-aminides and methyl dithiocarboxylates in fairly good yields. The alkylation reaction of 5–7 took place exclusively on the thiocarbonyl sulfur, yielding pyridinium salts in quantitative yields. The NMR spectroscopic studies indicated that E and Z forms existed for these pyridinium salts. The thermal decomposition of 5–7 yielded the corresponding pyridine, nitrile, and sulfur in good yields.
Pseudo-sugars. IX. Synthesis of Three (Hydroxymethyl)cyclohexanepentols
Authors: Ogawa Seiichiro , Nakamura Toshinobu , Chida Noritaka , Suami Tetsuo
Published: July 2006

Three new Dl-(hydroxymethyl)cyclohexanepentols, of which configurations are related to biologically important chiro- and myo-inositols, have been synthesized as hexaacetates from Dl-tri-O-acetyl-(1,3/2,4)-4-benzoyloxymethyl-5-cyclohexene-1,2,3-triol by osmium tetraoxide-oxidation or peroxy acid-oxidation followed by acid hydrolysis, and their structures have been established by 1H NMR spectroscopy.
Studies on 2-Aziridinecarboxylic Acid. X. Simple Stereospecific Synthesis of Optically Active Cystine and threo-3,3′-Dimethylcystine
Authors: Nakajima Kiichiro , Okawa Kenji
Published: July 2006

The reaction of (2S)-Z–Azy–OBzl, (2S,3S)-Z–3-MeAzy–OBzl, and their enantiomers with H2S gave the optically active cysteine and thero-3-methylcysteine derivatives via the stereospecific ring-opening reaction of aziridine, and subsequent oxidation and deblocking procedure gave the titled compounds in good yields.
Lewis Acid Mediated Reaction of Trimethylstyrylsilanes with Thioacetal Derivatives
Authors: Hirao Toshikazu , Kohno Shuichiro , Ohshiro Yoshiki , Agawa Toshio
Published: July 2006

Treatment of trimethylstyrylsilanes with 1-ethoxy-1-(phenylthio)ethane or 2-ethoxy-1,3-dithiolane in the presence of Lewis acid gives the corresponding (E)-allyl sulfide or (E)-2-styryl-1,3-dithiolane, respectively. In both cases, a carbon-oxygen bond of thioacetal derivatives is cleaved selectively.
Preparation and Stereochemistry of Δ-sym-[(2S,2′S)-1,1′-Ethylenedipyrrolidine-2,2′-dicarboxylato]cobalt(III) Complexes with Various Bidentate Ligands
Authors: Okabayashi Minahiro , Okamoto Ken-ichi , Einaga Hisahiko , Hidaka Jinsai
Published: July 2006

Cobalt(III) complexes containing (2S,2′S)-1,1′-ethylenedipyrrolidine-2,2′-dicarboxylate (S,S-epro) and a bidentate ligand were prepared and characterized. The bidentate ligands were ethylenediamine, trimethylenediamine, oxalate, glycinate, (R)- or (S)-alaninate, (R)- or (S)-valinate, (R)- or (S)-prolinate, (R)- or (S)-pipecolate, sarcosinate, or N-ethylglycinate. The S,S-epro ligand coordinates stereoselectively to cobalt(III) ion to take only the Δ-sym configuration. The stereochemistry was discussed on the basis of the electronic absorption, CD, and 1H and 13C NMR spectra. The rate constants of isomerization and the Gibbs’ free energy difference (ca. 0.9 kJ mol−1) between the R(N) and S(N) isomers of the sarcosinato or N-ethylglycinato complex were investigated in relation to the interligand interaction. The thermodynamics and mechanisms of their isomerization process were little influenced by the N-alkyl groups.
The Temperature Dependence of the Ultrasonic Relaxation Process Due to Interaction between Water and Allyl Cellosolve
Authors: Nishikawa Sadakatsu , Yamaguchi Tatsuro
Published: July 2006

Ultrasonic absorption and velocity measurements have been performed in aqueous solutions of Allyl Cellosolve (ethylene glycol monoallyl ether) as functions of the concentration and the temperature. Only a single relaxational absorption has been observed in the frequency range from 15 to 220 MHz and, it has been attributed to the perturbation of the equilibrium expressed as AB\ightleftharpoonsA+B, where A and B are the solute and the solvent molecule respectively. The rate constants at various temperatures have been determined from the concentration dependence of the relaxation frequency, and the thermodynamic parameters associated with the reaction have been calculated. The enthalpy change has also been estimated from the concentration dependence of the maximum excess absorption per wavelength. From these results, it has been concluded that Allyl Cellosolve molecules act as water structure promoters and that the interaction between the solute and the solvent is due to hydrogen bonding. Furthermore, the rate and the thermodynamic properties obtained are compared with those for aqueous solutions of other ethers.
General Relations between Bond Orders and Imaginary Bond-Bond Polarizabilities
Authors: Mizoguchi Noriyuki
Published: July 2006

The imaginary bond-bond polarizability has been studied. Several general relations exist between the bond order and the imaginary bond-bond polarizability and between imaginary bond-bond polarizabilities.
Cyclopropanation of Dimethyl Fumarate and Maleate with gem-Dihalides Catalyzed by Co(0)- or Ni(0)-Complex and Zinc
Authors: Kanai Hiroyoshi , Nishiguchi Yoshimasa , Matsuda Hideki
Published: July 2006

The reaction of bis(acetonitrile)bis(diethyl fumarate)cobalt(0) with dibromomethane gave diethyl trans-1,2-cyclopropanedicarboxylate in a 67% yield based on the cobalt complex. Dimethyl cis-1,2-cyclopropanedicarboxylate was obtained in a 52% yield from the reaction of dimethyl maleate with dibromomethane in the presence of acetonitrilebis(dimethyl maleate)nickel(0) accompanied by the formation of the trans-isomer in a 14% yield. The addition of zinc gave cyclopropanes in over 100% yields based on cobalt or nickel. 3-Methyl- and 3,3-dimethyl-1,2-cyclopropanedicarboxylic acid esters were produced by the reaction of dimethyl fumarate or maleate with 1,1-dibromoethane and 2,2-dibromopropane. The yield in the cobalt catalyst system decreases with an increase of substituents of gem-dibromides, while that in the nickel catalyst system does not vary appreciably. A small amount of dimethyl isopropenylsuccinate was formed as a by-product in the reaction of 2,2-dibromopropane. A mechanism is briefly discussed which involves metallacyclobutane as an intermediate.
Penetration of Lysine Hydrochloride into Lecithin Monolayers from Underlying Aqueous Solutions
Authors: Nakagaki Masayuki , Okamura Emiko
Published: July 2006

The surface pressure of the monolayers of dimyristoyl phosphatidylcholine (DMPC) on lysine mono- and dihydrochloride solutions was measured and the amount of positively charged lysine which had penetrated into a DMPC monolayer was calculated by successive approximation. The amount of penetration was smaller for lysine monohydrochloride than for the dihydrochloride. Moreover, both were smaller than that of uncharged lysine because mono- and dihydrochloride are more hydrophilic than uncharged lysine. The average area per molecule in the monolayer consisting of lysine and DMPC, A23, was obtained. In the case of charged lysine, A23 increased with the mole fraction of lysine in a monolayer, X2, in contrast it decreased with X2 in the case of uncharged lysine. The partial molecular area of positively charged lysine was considerably larger than that of uncharged lysine. This indicates that the remarkable expansion of a monolayer is caused by the penetration of positively charged lysine because of electrostatic repulsion in the monolayer. The effect of sodium chloride on the adsorption of lysine was also investigated, but the amount adsorbed was independent of the presence of 0.5 mol dm−3 sodium chloride.
NMR Studies of Picolyl-type Carbanions. VI. Anions Produced by Reactions of Methyl-substituted Quinolines and Isoquinolines with Butyllithium
Authors: Konishi Kazuyori , Takahashi Kensuke
Published: July 2006

The 13C and 1H NMR spectra have been observed for the title anions with lithium as a counter ion in polar solvents. Two kinds of anions are formed by lithium-proton exchange and addition of butyllithium. The charge distributions in the anions are discussed in terms of the σ-included ω-HMO method. The former anions can be regarded as picolyl-type carbanions, but the latter ones are ionic species having two of three basic characteristics on picolyl-type carbanions.
Mössbauer Spectroscopic Study of FeCl3-doped Polyacetylene
Authors: Sakai Hiroshi , Maeda Yutaka , Kobayashi Taka-aki , Shirakawa Hideki
Published: July 2006

Mössbauer spectra of FeCl3-doped polyacetylenes [CH(FeCl3)y]x (y=0.074, 0.087, and 0.13), which exhibit high electrical conductivities of ≈800, ≈800, and ≈100 S/cm at room temperature, have been measured at the temperatures of 290, 196, 78, and 5 K, respectively. The spectra consist of a superposition of two quadrupole-split doublets, described as doublet (A) and doublet (B), at 290, 196, and 78 K. At 5 K the doublet (A) splits into six lines arising from the magnetic hyperfine interaction, whereas the doublet (B) still remains paramagnetic. The doublet (B) increases remarkably in the Mössbauer absorption with decreasing temperature and is predominant. The values of the isomer shift, the quadrupole splitting, and the internal magnetic field, indicate that the iron compounds corresponding to the doublet (A) and (B) are FeCl2·nH2O (n=1 and/or 2) and FeCl4−, respectively. These results established that the mechanism of the FeCl3-doping process in polyacetylene is as follows:

2FeCl3+e−→FeCl4−+FeCl2,

FeCl2+nH2O→FeCl2·nH2O(n=1 and/or 2).
The Crystal Structure of Bis(2,2′-bipyridine)-catena-μ-tetrafluoroborato-copper(II) Tetrafluoroborate
Authors: Nakai Hisayoshi
Published: July 2006

The crystal structure of the title compound was determined by means of the X-ray diffraction technique. The crystal is triclinic, space group P\barl, a=11.288(8), b=15.186(17), c=7.368(4) Å, α=74.93(3), β=78.23(3), γ=65.92(3)°, and Z=2. The structure was solved by the heavy-atom method and refined by the least-squares method to R=0.068 for 3678 non-zero reflections. The crystal is composed of BF4− ions and polymeric chains of [Cu(BF4)(bpy)2+] in which a tetrafluoroborate ion bridges two adjacent copper atoms through its two fluorine atoms. The coordination polyhedron around the copper atom is a tetragonally distorted octahedron; the four nitrogen atoms of bipyridine molecules in the equatorial plane are arranged in a flattened tetrahedral manner (average Cu–N=1.99 Å) and the two axial Cu–F distances are 2.566(6) and 2.662(4) Å. In both bipyridine molecules, the two pyridine rings are twisted slightly from each other; the interplanar angle is 3.1° in one bipyridine ligand and 10.2° in the other.
Noncovalent Interactions in Metal Complexes. VI. Bonding Interaction between Chelate π-System and Menthyl Group in Copper(II), Nickel(II), and Palladium(II) Complexes of 1-l-Menthyloxy-3-benzoylacetone
Authors: Nakamura Michio , Okawa Hisashi , Kida Sigeo
Published: July 2006

Metal complexes, M(l-moba)2(H2O)n (M=Cu(II), n=0; Ni(II), n=2; Pd(II), n=0) and M(bpy)(l-moba)ClO4 (M=Cu(II), Pd(II)), where H(l-moba) denotes 1-l-menthyloxy-3-benzoylacetone, have been synthesized and characterized by means of elemental analyses, NMR spectra, electronic spectra, and circular dichroism spectra. In the NMR spectra of H(l-moba), Pd(l-moba)2, and Pd(bpy)(l-moba)ClO4, the methylene protons adjacent to the l-menthyloxy group were observed as AB quartet. The chloroform solutions of Cu(l-moba)2 and Cu(bpy)(l-moba)ClO4 showed a positive CD band at 15500 and 16200 cm−1, respectively. The chloroform solution of Ni(l-moba)2(H2O)2 also showed a weak, positive CD band near 16000 cm−1. When pyridine or t-butylamine was added to the chloroform solution of Cu(l-moba)2, a negative CD appeared around 17000 cm−1 attributable to the five-coordinate species Cu(l-moba)2B. On the other hand, with adding an amine to the chloroform solution of Ni(l-moba)2(H2O)2, the 16000 cm−1 CD band decreased its intensity and finally disappeared. Similar trend was observed when alcohol, DMSO, or DMF was added to the chloroform solution of Ni(l-moba)2(H2O)2. NMR and CD spectral results have been rationalized by assuming that the l-menthyl group interacts with the chelate ring of l-moba− and this interaction gives rise to a chirality around the metal ion.
Studies on the β-Turn of Peptides. III. Syntheses and Conformational Properties of N-(2,4-Dinitrophenyl)tetrapeptide p-Nitroanilides Related to β-Turn Preferring Sequences in Proteins
Authors: Sato Kazuki , Nagai Ukon , Higashijima Tsutomu
Published: July 2006

To confirm the general applicability of CD spectra of N-(2,4-dinitrophenyl(Dnp))tetrapeptide p-nitroanilides (pNA’s) to the analysis of β-turn preference of the tetrapeptide sequences, Dnp-pNA derivatives of some tetrapeptides related to β-turn preferring sequences in proteins were synthesized and subjected to CD and 1H NMR measurements. CD spectra of Dnp–Gly–l-Pro–l-Asn–Gly–pNA (5a) were just the mirror image of those of gramicidin S-model peptide, Dnp–Gly–d-Ala–l-Pro–Gly–pNA (6). This suggested that 5a strongly preferred the β-turn and the type of turn was different from that of 6. The relative intensities of Cotton effects of the tetrapeptide with the general structure Dnp–Gly–l-Pro–Y–Gly–pNA (Y=l-Asn, Gly, l-Ala, or l-Gln) roughly agreed with the bend potentials of the amino acid residues at the third position of β-turns in proteins reported by Chou and Fasman. The effects of changing the amino acid residues at the second position of β-turn were also examined.
The Claisen Rearrangement of the Lithium Enolate of 1-(2-Thienyl)alkyl Alkanoate and the Birch Reduction of the Resulting 2-(3-Thienyl)alkanoic Acid
Authors: Sado Mitsuo , Abe Hideaki , Inuzuka Nobuki , Shirai Kozo , Kumamoto Takanobu
Published: July 2006

It was found that the Claisen rearrangement of the lithium enolate of 1-(2-thienyl)alkyl alkanoate in refluxing THF resulted in the formation of 2-(3-thienyl)alkanoic acid (2). Similarly, when the lithium enolate of 4-(2-thienyl)-4-butanolide was stirred at room temperature in the presence of hexamethylphosphoric triamide, 5,6-dihydro-4H-cyclopenta[b]thiophene-4-carboxylic acid was obtained. Further, it was found that the Birch reduction of 2 and subsequent alkylation with benzyl bromide gave a regioselective ring-opening product, 4-benzylthio-3-ethyl-3-alkenoic acid, in a good yield. The Birch reduction of 2-thienylacetic acid, followed by alkylation with benzyl bromide, also gave (Z)-3-benzylthio-3-hexenoic acid as the main product.
Stereoselective Intramolecular Diels-Alder Reactions of α,β-Unsaturated Amides Using Internal Coordination of Metal Salts
Authors: Takebayashi Toyonori , Iwasawa Nobuharu , Mukaiyama Teruaki , Hata Tadashi
Published: July 2006

The intramolecular Diels-Alder reactions between acyclic dienes and α,β-unsaturated amides utilizing the internal coordination of the metal salts have been studied in detail. When the magnesium salts of N-(trans, trans-2,4-alkadienyl)-N-(2-hydroxyphenyl)acrylamide derivatives are employed, the intramolecular Diels-Alder reactions are remarkably accelerated and the corresponding cycloadducts are obtained in high yields with isomeric ratios (exo-adducts: endo-adducts) of about 3 : 2. And the same reactions of N(trans, trans-2,4-alkadienyl)-N-(2-hydroxyphenyl)-1-cyclopentenecarboxamide afford predominantly (60 : 40 to 85 : 15 selectivity) trans-fused cycloadducts (exo-adducts) in good yields.
Photoaddition Reaction of 1,4-Dibromo-2,5-piperazinedione with Cyclohexene
Authors: Itoh Kuniaki
Published: July 2006

The photo-induced addition reaction of 1,4-dibromo-2,5-piperazinedione (1) with cyclohexene in acetonitrile gave 1 : 1-adducts[1-(2-bromocyclohexyl)-2,5-piperazinediones] and 1 : 2-adducts[1,4-bis(2-bromocyclohexyl)-2,5-piperazinediones] besides 3-bromocyclohexene, 1,2-dibromocyclohexane, and a solvent-incorporated product, trans-2-acetylamino-2-bromocyclohexane. Stereochemistry of the adducts was elucidated and mechanism of the addition reaction was discussed.
Zeeman Effect on 81Br NQR in Phosphorus Tribromide–Boron Tribromide
Authors: Terao Hiromitsu , Fukura Masanori , Okuda Tsutomu , Negita Hisao
Published: July 2006

The Zeeman effect on 81Br NQR in a single crystal of PBr3·BBr3 was studied at room temperature. The crystal has an orthorhombic symmetry. The bond angles have been found to be 111.2±0.1° and 111.5±0.1° for Br–B–Br, and 107.0±0.1° and 109.1±0.3° for Br–P–Br. The Br atoms of BBr3 group have relatively large values of η, 0.151±0.004 and 0.120±0.007, while the Br atoms of PBr3 group have small values, 0.025±0.005 and 0.020±0.004. The large η values of Br atoms of BBr3 group are ascribed to the π bonding existing in the B–Br bonds.
Raman Spectra of Compounds under Inversion Motions. III. N-Methylpyrrolidine
Authors: Fukushima Kunio , Sasaki Hisayo
Published: July 2006

Raman spectra of N-methylpyrrolidine were measured in various states and a normal vibration calculation was carried out on its conformers. Results of the measurement and calculation indicate that the Raman band of the inversion vibrational mode is caused to shift remarkably by the formation of hydrogen bond to the nitrogen atom. This phenomenon, along with the enthalpy of hydrogen bond formation obtained from measurements at various temperatures, suggests that the conformer predominant in pure liquid corresponds to one minimum in the potential for the inversion motion, which has a low potential barrier and high anharmonicity.
Crystal Structures of Mixed Ligand Copper(II) Complexes Containing l-Amino Acids. III. Aqua(l-histidinato)(l-serinato)copper(II) Trihydrate
Authors: Sasada Yoshio , Takenaka Akio , Furuya Toshio
Published: July 2006

The copper(II) complex containing l-histidine and l-serine crystallizes from an aqueous solution. Crystals of aqua(l-histidinato)(l-serinato)copper(II) trihydrate are monoclinic, space group P21, a=11.046(2), b=7.315(1), c=9.737(1) Å, β=101.34(2)° and Z=2. A square-planar coordination around copper consists of α-amino nitrogen and δ-nitrogen atoms in histidine and α-amino nitrogen and α-carboxyl oxygen atoms in serine, the two amino groups being in cis position. The fifth coordination site is occupied by a water molecule, and the carboxyl oxygen atom of serine in the adjacent complex makes a weak bond with copper to complete a distorted octahedron. The chelating scheme and overall crystal structure are the same as those of (l-alaninato)aqua(l-histidinato)copper(II) trihydrate (1). Crystallization water molecules are situated on the fixed positions in the void space surrounded by the columns of the complexes, but the hydroxyl group of serine takes two sites randomly. The common chelating scheme in the present crystal and 1 is in correspondence with the observation that serine and alanine are of moderate cooperativity with histidine in forming the ternary complexes.
Structure of the Electrical Double Layer at the Interface between Nitrobenzene Solution of Tetrabutylammonium Tetraphenylborate and Aqueous Solution of Lithium Chloride
Authors: Kakiuchi Takashi , Senda Mitsugi
Published: July 2006

Electrocapillary curves at the polarized interface between a nitrobenzene solution of tetrabutylammonium tetraphenylborate (TBATPB) and an aqueous solution of lithium chloride at various concentrations of TBATPB and LiCl have been measured by the drop time method using a dropping electrolyte solution electrode at 25 °C. The relative surface excesses of tetrabutylammonium and tetraphenylborate ions in the nitrobenzene phase and of lithium and chloride ions in the aqueous phase were well described by the Gouy-Chapman theory of diffuse layers for both sides of the interface. A model of the electrical double layer for the nitrobenzene–water interface is presented, in which an ion-free inner layer consisting of laminated monolayers of water and nitrobenzene is sandwiched by the two diffuse layers on each side of the interface. The potential difference across the inner layer, which was estimated to be ca. 20 mV at the potential of zero charge, was found to be dependent on the surface charge density and to be nearly independent of the electrolyte concentration.
A Photoelectron Spectroscopic Estimation of the Concentrations of Simple Hydrogen-bonded Dimers Produced in the Temperature-controlled Supersonic Nozzle Beam
Authors: Tomoda Shinji , Kimura Katsumi
Published: July 2006

A photoelectron spectroscopic method is proposed to estimate the ratio of number densities between the monomer and the dimer produced in the supersonic jet. Approximate monomer-dimer ratios have been estimated for water, methanol and formic acid by assuming that the photoionization cross sections of the monomer and dimer are equal to each other. The results show reasonable agreement under similar conditions to those available from mass spectrometric analyses of fragmentation patterns. A simple temperature-controlled supersonic nozzle beam source is described here, which enables us to produce hydrogen-bonded dimers in measurable amounts.
An Interpretation of the Asymmetric Induction Observed in Rhodium–Bis(dibenzophosphole) Complex Catalyzed Hydroformylation According to an X-Ray Molecular Structure Analysis of an Iridium–(2R,3R)-2,3-O-Isopropylidene-1,4-bis(5H-dibenzophosphol-5-yl)-2,3-butanediol Complex
Authors: Hayashi Teruyuki , Tanaka Masato , Ogata Ikuei , Kodama Teruyuki , Takahashi Tamotsu , Uchida Yasuzo , Uchida Tokiko
Published: July 2006

An X-ray molecular structure analysis of [(2R, 3R)-2,3-O-isopropylidene-1,4-bis(5H-dibenzophosphol-5-yl)-2,3-butanediol((−)-DIPHOL)](1,5-cyclooctadiene)chloroiridium(I) was carried out. The complex takes a distorted trigonal bipyramidal structure, and the chelate ring of (−)-DIPHOL makes a chair form, which decreases the distances of atoms in the chelate ring from the P–Ir–P coordination plane. Thus, the chiral coordination structure of DIPHOL becomes remarkably different from that of DIOP. Through a comparison of the results of X-ray analyses, the results obtained in asymmetric hydroformylation (predominant absolute configuration and optical yield of products) catalyzed by the rhodium-complexes were explained on the basis of some well-grounded assumptions.
Synthesis of Potential Antineoplastic Anthracenedione Derivatives. II. 1,2-Dihydroxy Derivatives
Authors: Nakamura Katsumi , Asai Tomoyuki , Hara Tamio , Minorikawa Naoki , Suami Tetsuo
Published: July 2006

In continuation of the preceding paper in this series, four derivatives of 1,2-dihydroxy-5,8-bis[2-(2-hydroxyethylamino)ethylamino]-9,10-anthracenedione: a positional isomer of mitoxantrone have been prepared to establish a relationship between the position of the hydroxyl groups on the A ring and antineoplastic activity against experimental leukemia L1210 in mice. Two compounds were found to be fairly active.
Effects of Additives on Photo-methoxylation of Methyl 2-Pyridinecarboxylate in Acidic Methanolic Solutions. Promotion by 4-Substituted Pyridines
Authors: Sugimori Akira , Ogishima Teruo , Miyazawa Yoshiyuki , Hasegawa Ryo , Suzuki Yoko
Published: July 2006

The rate of photo-methoxylation of methyl 2-pyridinecarboxylate(1) in acidic methanol is accelerated by 4-substituted pyridines and their analogs, 4,4′-bipyridine and pyrazine. The photo-methoxylation of 1 is not promoted by triplet sensitizers, electron donors, or electron acceptors. Detailed analyses on the 1–4-pyridinecarbonitrile(3) system including wavelength dependence lead to a mechanism for the promotion via an excited complex formed from an excited 1 and 3 in the ground state.
NAD(P)+–NAD(P)H Model. 43. Formation of 1,4-Dihydronicotinamide in the Reaction of Pyridinium Salt and Glyceraldehyde
Authors: Ohno Atsuyoshi , Ushida Satoshi , Oka Shinzaburo
Published: July 2006

It has been found that N-substituted 1,4-dihydronicotinamides are produced by the reaction of N-substituted 3-carbamoylpyridinium salts with glyceraldehyde and its analogous compounds. A mechanism of the reaction is suggested.
Manufacture of Pure Titanium(IV) Oxide by the Chloride Process. II. Selective Extraction of Titanium(IV) and Iron(III) from Hydrochloric Acid Leach Liquor of Ilmenite Ore by Tributyl Phosphate
Authors: Narita Eiichi , Takeuchi Hitoshi , Ichikawa Hitoshi , Odagawa Takao , Okabe Taijiro
Published: July 2006

The selective recoveries of titanium(IV) and iron(III) from the synthetic hydrochloric acid leach liquor of ilmenite, i.e., 1.8–11 M (1 M=1 mol dm−3) hydrochloric acid solutions containing 0.25–0.57 M titanium(IV) and 0.27–0.29 M iron(III), or each single metal ion, were investigated by solvent extraction with benzene solutions of various tributyl phosphate (TBP) concentrations under the volume ratio (Org/Aq) of unit at 25 °C. Iron(III) was extracted into the TBP phase over a wide concentration range of hydrochloric acid studied, and the extraction was considerably accelerated by the salting-out effect of the coexisting titanium(IV). Since no extraction of titanium(IV) was observed at hydrochloric acid concentrations lower than 6 M, iron(III) could be recovered selectively from 3–6 M hydrochloric acid solutions under the conditions of the molar ratio [TBP]org/[Fe(III)]init aq≤3.0. On the other hand, titanium(IV) in the residual aqueous phase was also extracted as TiCl4·3TBP at a concentration range of chloride ion higher than 7 M. The coextractions of other metal ions and free hydrochloric acid could be prevented by controlling the TBP concentration in the organic phase as [TBP]org/[Ti(IV)]init aq≤3.5. The problem in applying the solvent extraction technique to actual leach liquor is discussed, as well as the recovery of free hydrochloric acid from the residual leach liquor.
On the Interaction of CrO2Cl2 Vapor with the Surface of γ-Al2O3 and the Formation of a Chromium Oxide Covering
Authors: Damyanov Damyan , Vlaev Lubomir
Published: July 2006

Samples of γ-Al2O3 containing different amounts of residual hydroxyl groups were obtained by thermal treatment. The possibility of interaction of the surface hydroxyl groups of γ-Al2O3 with chromyl chloride vapor was studied by IR spectroscopy. The hydrogen chloride evolved as a result of the reaction interacts with both strained Al–O–Al bridges and the surface OH groups. Different types of OH groups show different reactivities with respect to the interaction with CrO2Cl2. Bands at 3780 and 3700 cm−1 are due to OH groups which have a much higher reactivity than the OH groups responsible for bands at 3744 and 3733 cm−1. Not all of the OH groups participate in the surface reaction. Decrease in their surface density results in increase in the reactivity. Modification of the γ-Al2O3 surface is achieved by reaction cycles consisting of treatment with CrO2Cl2 vapor and hydrolysis of the compounds obtained by water vapor. As a result, an increase in the chromium oxide amount on the surface of γ-Al2O3 is observed. This is ascribed to the “secondary” OH groups formed after the hydrolysis.
Kinetics of Gas Phase Addition Reactions of Trichlorosilyl Radicals. VI. Orientation of Additions to 2-Pentenes
Authors: Dohmaru Takaaki , Nagata Yoshio
Published: July 2006

Addition reactions of ·SiCl3 radicals to cis- and trans-2-pentene have been studied in the gas phase between 30 and 136 °C. The ratio of the rate of formation of 2- with 3-trichlorosilylpentane, R2⁄R3, was found to vary with temperature or with HSiCl3 concentrations (1.47–17.6 μmol cm−3). This variation was successfully interpreted by the decomposition of an adduct radical, CH3CH(SiCl3)\dotCHCH2CH3.
Graph-theoretical Formula for Ring Currents Induced in a Polycyclic Conjugated System
Authors: Aihara Jun-ichi , Horikawa Tsuyoshi
Published: July 2006

A graph-theoretical formula was derived for ring currents induced in a polycyclic conjugated system by a uniform magnetic field. Two advantages of this formula are that ring currents can be evaluated by inspecting a geometry of a conjugated system, and that they can be attributed to the individual π-electron rings.
The Consecutive Determination of Serum Ammonia and Leucine Amino Peptidase with an Ammonia Gas-sensing Electrode
Authors: Hato Masakatsu , Shimura Yukio , Akiyama Tomiko , Nakayama Hiroko
Published: July 2006

A simple method for the consecutive determination of serum ammonia and the activity of leucine amino peptidase (LAP) with an ammonia gas-sensing electrode is described. The values determined by the present method agree with those determined by conventional methods within 6%.
Potassium-selectivities of Bis(benzo-15-crown-5) Derivatives Obtained from Cyclohexanedicarboxylic Acids
Authors: Kimura Keiichi , Ishikawa Atsuo , Tamura Hiroshi , Shono Toshiyuki
Published: July 2006

Several bis(benzo-15-crown-5) derivatives containing a cyclohexane or benzene ring in the bridge chain were synthesized as neutral carriers of coated-wire potassium-selective electrodes. The bis(benzocrown ether) derivative obtained from cis-1,2-cyclohexanedicarboxylic acid was found to be outstandingly potassium-selective.
Enthalpies of Transfer of Monovalent Ions from Water to Water–Acetonitrile Mixtures
Authors: Miyaji Kiyoshi , Morinaga Kenichi
Published: July 2006

Ionic enthalpies of transfer from water to water–acetonitrile mixtures were estimated for Na+, K+, Rb+, Cs+, Ag+, Tl+, Me4N+, Et4N+, n-Pr4N+, n-Bu4N+, Ph4As+, Ph4B−, Cl−, Br−, I−, NCS−, NO3−, ClO4−, and picrate ion on the basis of the assumption ΔHt°(Ph4As+)=ΔHt°(Ph4B−).
Electrocatalytic Reaction of Fe2+⁄3+ Aqua Ions by [Mo(CN)8]4−⁄3− Complexes
Authors: Sato Keiichi , Ohsaka Takeo , Matsuda Hiroaki , Oyama Noboru
Published: July 2006

The catalysis of the oxidation of Fe2+ aquaion by [Mo(CN)8]3− ion, which is formed on an electrode surface, and that of the reduction of Fe3+ aqua ion by [Mo(CN)8]4− ion were examined by means of hydrodynamic voltammetry at a rotating disk pyrolytic graphite electrode The rate constants of the electron transfer cross-reaction of the Fe2+/[Mo(CN)8]3− and Fe3+/[Mo(CN)8]4− systems were estimated to be (7.0±0.5)×106 and (6.6±0.5)×106 cm3 mol−1 s−1, respectively.
Polarographic Study of Mixed Ligand (o-Mercaptobenzoate–Citrate) Complexes of Cadmium(II), Lead(II), and Thallium(I)
Authors: Gupta Keval C , Sharma Kalpana K
Published: July 2006

The mixed ligand complex formation of o-mercaptobenzoic acid and citric acid with Cd(II), Pb(II), and Tl(I) in aqueous KNO3 (μ=1.0 mol dm−3) solutions containing Triton X-100 (0.001%) has been investigated by polarography. It was shown that only one mixed ligand entity MAiXj is formed, where i is two for Cd (II) and one for Tl(I) j is one for all complexes and A and X are the o-mercaptobenzoate and citrate ligands respectively. The stability constants have been evaluated.
Photochemical Reaction of S-Alkyl 3-Oxobutanethioate
Authors: Hasegawa Tadashi , Shimizu Toshio , Iwasaki Kazuhiko , Oguchi Sh\={o}shichi
Published: July 2006

Irradiation of S-alkyl 3-oxobutanethioate (1) in benzene or ethanol yielded the disulfide 2. Irradiation of S-alkyl α-bromothioacetate also gave the disulfide 2. The photochemical reaction of the 3-oxobutanethioate 1 involves the Norrish Type I reaction followed by rapid fragmentation of the radical ·CH2COSR to the thiyl radical 5.
Cyclization Reaction of Bis(tributylstannylated) α-Ketols with Heterocumulenes. Preparation of O,O-Vinylene Imino- and Thiocarbonates
Authors: Sakai Shizuyoshi , Murata Masashi , Wada Nobuto , Fujinami Tatsuo
Published: July 2006

Aromatic α-ketols reacted with diethylaminotributylstannane at 60 °C to afford a mixture of (Z)- and (E)-1,2-bis(tributylstannyloxy)-1,2-diarylethenes, which were allowed to react with organic isothiocyanates and carbon disulfide to give substituted O,O-vinylene imino- and thiocarbonates, respectively. Aliphatic α-ketol, 3-hydroxy-2-butanone, was treated by the aminostannane, followed by the reaction with carbon disulfide to form (E)-1,2-bis(tributylstannylthio)-2-butene.
The Thermal Reactions of Allyl-substituted Germyl Radicals
Authors: Mochida Kunio , Miyagawa Isoo
Published: July 2006

The allyldibutylgermyl and dibutyl(2-methylallyl)germyl radicals in benzene at 80 °C afforded diallyldibutylgermane and dibutylgermane, and dibutylbis(2-methylallyl)germane and dibutylgermane, respectively. The mechanism of these reactions is discussed.
Reactions of 2,4-Azetidinedione with Nucleophilic Reagents
Authors: Maruyama Kazuhiro , Arita Yoshihiro
Published: July 2006

The reaction of 2,4-azetidinedione with a variety of nucleophiles was compared with that of N-methylsuccinimide. 2,4-Azetidinedione gave ring-cleaved addition products, while N-methylsuccinimide afforded simply addition products to the carbonyl group.
Substituent Effects on the Dissociation Constants of 1-Aryl-5-hydroxy-2-hydroxymethyl-4-pyridones
Authors: Imafuku Kimiaki , Takahashi Kumio , Matsumura Hisashi
Published: July 2006

Six new 1-aryl-5-hydroxy-2-hydroxymethyl-4-pyridones were synthesized and their dissociation constants were measured. Hammett analysis of pKa values for proton gain and proton loss gave the following equations: pK1=2.74–0.34σ and pK2=8.80–0.36σ, respectively.
Reduction of Organic Halides with Diethyl Phosphonate and Triethylamine
Authors: Hirao Toshikazu , Kohno Shuichiro , Ohshiro Yoshiki , Agawa Toshio
Published: July 2006

Reduction of organic halides [gem-bromochlorocyclopropanes, 1,1,1-trichloromethane derivatives, 1,1-dibromo-2-benzyloxyethylene, methyl α-bromocinnamate, α,p-dibromoacetophenone, and (1,2-dibromoethyl)benzene] with diethyl phosphonate and triethylamine is surveyed.
A Practical Synthesis of Olivetol
Authors: Anand Ramesh Chander , Ranjan Harish
Published: July 2006

A simple and practical synthesis of olivetol has been described in 55% overall yield from α-resorcylic acid.
The Molecular Structure of Trimethylamine–Boron Triiodide as Studied by Gas Electron Diffraction
Authors: Iijima Kinya , Shibata Shuzo
Published: July 2006

The molecular structure of trimethylamine–boron triiodide (CH3)3N·BI3 has been determined from gas electron-diffraction data. The molecular parameter values and their uncertainties are rg(B–I)=2.245±0.004 Å, rg(N–B)=1.663±0.013 Å, rg(C–N)=1.497±0.005 Å, rg(C–H)=1.103±0.010 Å, ∠IBI=108.6±0.4°, and ∠CNC=106.0±0.8°. The potential barrier around the N–B bond has also been estimated to be about 3.5 kcal mol−1 (1 cal=4.184J).
The Cation-Cation Interactions in Aqueous Mixed Electrolyte Solutions of Quaternary Phosphonium Chlorides
Authors: Takaizumi Katsuko , Wakabayashi Toshiki
Published: July 2006

Density measurements were carried out at six temperatures between 1 and 55 °C for three series of aqueous mixed electrolyte solutions, each of which contained (n-Bu)4PCl and Ph4PCl with the mole ratios, 3:1, 1:1, and 1:3, respectively. The mixed solutions are assumed to be the model solutions of the phosphonium chlorides, (n-Bu)4−n PhnPCl(n=1,2, and 3), with respect to the pair-wise interactions between the cations, for which a model has been proposed in a previous paper. The volume B-coefficients(Bv) determined for the model salts are in good agreement with those for the corresponding pure salts and those reproduced by the equation derived from the model. The results indicate that the phenyl groups affect weakly the butyl cospheres in both the intermolecular processes and intramolecular processes and that among the ion-ion interactions the cation-cation interactions are the main factor for determining the Bv′s. These can be decomposed into three parts, arising from the butyl-butyl, phenyl-phenyl, and butyl-phenyl interactions.
Magnetic Susceptibility and ESR Studies of Highly Conductive CuL(TCNQ)2 Incorporating 2,2′-Bipyridine or Ethylenediamine as Ligand
Authors: Seto Tomoyoshi , Inoue Motomichi , Inoue Michiko B , Nakamura Daiyu
Published: July 2006

Electron spin resonance spectra were recorded on highly conducting CuL(TCNQ)2 (L: 2,2′-bipyridine or ethylenediamine) at different temperatures. The observed g values increased with decreasing temperature. On the basis of the g shift and the static susceptibility observed, a local magnetic susceptibility contributed from Cu and that from TCNQ, were evaluated individually. The local Cu susceptibility is of the Curie type. The Curie constant indicates that each Cu atom carries 0.05 umpaired electron on the average in Cu(bpy)(TCNQ)2 and 0.07 in Cu(en)(TCNQ)2: the average oxidation number of copper is equal to 1.05 in the former and 1.07 in the latter. The local susceptibility of TCNQ can be interpreted by a narrow band model in which the susceptibility is given by the sum of the Curie term and a temperature-independent paramagnetic term.This suggests that the TCNQ arrays have inherently metallic nature.
Charge-transfer Interaction of a Series of Trifluoromethylated Benzenes in the Ground and Excited States
Authors: Yamaguchi Yuji , Nogami Takashi , Mikawa Hiroshi , Kumadaki Itsumaro , Kobayashi Yoshiro
Published: July 2006

Charge-transfer interaction of a series of trifluoromethylated benzenes with several donor molecules was investigated by measuring electronic absorption and fluorescence spectra. Half-wave reduction potentials of acceptors were determined by cyclic voltammetry. Charge-transfer absorption bands were observed for several systems. Thermal one-electron transfer reactions were observed for solutions of hexakis(trifluoromethyl)benzene and several aromatic amines even in nonpolar solvents. Charge-transfer fluorescence was observed for solutions of hexakis(trifluoromethyl)benzene or tetrakis(trifluoromethyl)benzene and weak donor molecules such as benzene, toluene, or p-xylene.
Synthesis of Biphenyloferrocenophanes
Authors: Shimizu Iwao , Kamei Yoshio , Tezuka Takeshi , Izumi Taeko , Kasahara Akira
Published: July 2006

Some ferrocenophanes, in which the two cyclopentadienyl rings are linked by biphenyl rings, have been synthesized via intramolecular reductive coupling of the corresponding formyl compounds with a low-valent titanium reagent. The structures of these cyclophane compounds were determined by IR, NMR, and UV spectra analyses. Transannular π-electronic interactions between the two biphenyl rings were examined on the basis of electronic spectra.
The Physicochemical Properties of Aqueous Solutions of Sodium Alkanesulfonates. Apparent Molar Volumes, Viscosity B Coefficients, Heats of Solution, and Surface Tensions
Authors: Tamaki Kunio , Ohara Y\={o}ko , Inabe Masahiro , Mori Tetsushi , Numata Fumio
Published: July 2006

The apparent molar volumes, viscosity B coefficients, heats of solution, and surface activity of sodium alkanesulfonates (RSO3Na, methyl to hexyl) in water were measured. The limiting apparent molar volumes at 25 °C increase with the number of carbon atoms in the alkyl chain; the increment per methylene group is about 16 cm3mol−1. The viscosity B coefficients of MeSO3Na and EtSO3Na increase with the temperature, while those of n-BuSO3Na decrease with an increase in the temperature. The changes in heat capacity for dissolution in water, ΔCpo, as calculated from the heats of solution at 15, 25, and 35 °C, were negative for MeSO3Na and EtSO3Na, while the ΔCpo values for n-PrSO3Na and higher homologs were positive. MeSO3Na raises the surface tension of water, while EtSO3Na and higher homologs reduce it. The structural changes in the solvent water upon the dissolution of sodium alkanesulfonates are discussed in comparison with those of sodium alkyl sulfates previously reported.
Spectrophotometric Determination of Palladium and Bismuth(III) with Semimethylxylenol Blue
Authors: Ueda Joichi , Kadowaki Kyoko
Published: July 2006

Procedures are described for the spectrophotometric determination of palladium and bismuth(III) with Semimethylxylenol Blue (SMXB). SMXB reacts with palladium and bismuth(III) to form reddish-violet 1:1 complexes. The optimum pH ranges for the color development are pH 1.0–1.7 for palladium and pH 1.0–1.4 for bismuth(III). The absorption maxima of the colored solutions lie at 565–568 nm and at 568–570 nm, respectively. Beer’s law is obeyed over the range of 0.4–3.2 μg cm−3 of palladium and 0.4–4.0 μg cm−3 of bismuth(III), and the sensitivities of the determinations are 4.0×10−3 μg Pd cm−2 and 6.1×103 μg Bi cm−2 for 0.001 of absorbance. For the palladium determination, gallium, tin(IV), bismuth(III), scandium, zirconium, and iron(III) interfere, but tin(IV), scandium, zirconium, and iron(III) can be masked by the addition of fluoride. For the bismuth(III) determination, gallium, tin(IV), scandium, zirconium, and iron(III) interfere, but the effect of iron(III) is eliminated by the addition of l-ascorbic acid, and tin(IV) and scandium can be masked by fluoride. A consecutive determination of palladium and bismuth(III) by the difference of the rates of color developments for their complexes was also studied.
Partial Molal Volumes and Volume Changes for Complex Formation of [M(phen)3]Cl2 in Aqueous Solutions
Authors: Yoshitani Kouzou , Yamamoto Manabu , Yamamoto Yuroku
Published: July 2006

The partial molal volumes, \barV°, of [M(phen)3]Cl2 (M=Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)) and 1,10-phenanthroline were determined from density measurements at 25 °C. From the values for \barV° of [M(phen)3]2+, M2+ and phen the volume changes for complex formation of [M(phen)3]2+, Δ\barV°, were caluculated. Values for \barV° of [M(phen)3]Cl2 varied from 445.1 cm3 mol−1 for [Fe(phen)3]Cl2 to 458.1 cm3 mol−1 for [Zn(phen)3]Cl2 and were in the order, [Fe(phen)3]2+<[Co(phen)3]2+>[Ni(phen)3]2+<[Cu(phen)3]2+<[Zn(phen)3]2+. The Δ\barV° of [Fe(phen)3]2+ was significantly small, 4.7 cm3 mol−1. While those of other metal chelate ions were similar values, ca. 20 cm3 mol−1. The smaller Δ\barV° of [Fe(phen)3]2+ is considered to be due to the spin change from the high-spin aqua ion, [Fe(OH2)6]2+, to the low-spin complex ion, [Fe(phen)3]2+.
Kinetics and Mechanisms of Anation and Exchange Reactions in Pentakis(N,N-dimethylformamide)dioxouranium(VI) Ion in Nonaqueous Media
Authors: Doine Hideo , Ikeda Yasuhisa , Tomiyasu Hiroshi , Fukutomi Hiroshi
Published: July 2006

The exchange reaction of N,N-dimethylformamide (dmf) in [UO2 (dmf)5]2+ ion and the anation reactions by SCN− and N3− have been studied by the NMR method in CD2Cl2 and the stopped-flow method in DMF, respectively. For the dmf exchange reaction, rate=(kd+kIKos[DMF])[UO2(dmf)52+]/(1+Kos[DMF]), where kd, kI, and Kos are (1.30±0.21)×102 s−1, (2.94±0.07)×103 s−1, and 1.59±0.11 mol−1 kg at −50 °C, respectively. For the anation reactions by SCN− and N3−, the pseudo-first-order rate constant (kobsd) is expressed by kobsd={k−1+(k1+k−1)Kos[X]}⁄(1+Kos[X]) (X=SCN− and [UO2(dmf)5]2+ for the anation reactions by SCN− and N3−, respectively). The values of k1, k−1, and Kos at 25 °C are 1.95×102 s−1, 4.27×102 s−1, 1.48×102 M−1 (1 M=1 mol dm−3), and 1.64×103 s−1, 3.72×102 s−1, 1.80×102 M−1 for SCN− and N3−, anation reactions, respectively. These results suggest that the substitution reaction in [UO2(dmf)5]2+ ion proceeds through the associative interchange mechanism. The difference of reactivities for SCN− and N3− toward [UO2(dmf)5]2+ ion seems to be related to the pKa values for acids, HSCN and HN3.