bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaction of 2-(Alkylthiomethyl)phenyllithium with Copper(I) Halides and Structure and Properties of One of the Products—Copper(I) Complexes of 2,2′-Bis(alkylthiomethyl)biphenyl
Authors: Toyota Shinji , Matsuda Yohei , Nagaoka Satoshi , Oki Michinori , Akashi Haruo 
Published: June 2006

Abstract
The title reactions did not afford the corresponding organocopper compound as a stable entity, but rather a dimerized biphenyl compound (2,2′-bis(alkylthiomethyl)biphenyl), its copper(I) halide complex, and alkyl benzyl sulfide. Their yields were influenced by the kind of halides in the copper reagent. The stability and reactivity of the intermediate organocopper compound is discussed on the basis of the ligand-metal interactions. The copper(I) halide complex with the biphenyl which carries two sulfane ligands has a unique polymeric structure in crystals, as evidenced by X-ray analysis, whereas it dissociates into a monomeric form on dissolution in organic solvents. The properties of the complexes were examined by NMR and XPS as well.
Stabilization of Oxo-Metal Bonding by the π-Conjugated System in Dithiolate Ligands: cis-Dioxotungsten(VI) Bis(naphthalenedithiolato) and the Related Complexes as Models for Tungsten Oxidoreductases
Authors: Oku Hiroyuki , Ueyama Norikazu , Nakamura Akira 
Published: June 2006

Abstract
As a model of tungsten oxidoreductase, a dioxotungsten(VI) dithiolato complex, (NEt4)2- [WVIO2(ndt)2]·H2O (1) (ndt = 2,3-naphthalenedithiolato), was synthesized. It has provided the detailed structural dimensions of mutual trans influence between oxo and thiolate. The complex, 1, crystallizes in space group P21/n with a = 7.396(2), b = 17.581(2), c = 28.839(2) Å, β = 95.35(2), and Z = 2, and was refined to R = 2.3%. The short S–C distances of the thiolate trans to the WVI=O groups indicate the presence of the partial double bonding at S–C (thiketone-like) which contributes to the stabilization of the dioxotungsten(VI) species by weakening π-interaction of the WVI–S bonds trans to the WVI=O groups. In the tungstopterin cofactor and the molybdopterin cofactor of the enzyme, the double bonding nature of S–C (thioketone-like) is expected to stabilize the oxo ligand of the tungsten and molybdenum ion.
Voltammetric Study on the Transport of Ions of Various Hydrophobicity Types through Bilayer Lipid Membranes Composed of Various Lipids
Authors: Shirai Osamu , Yoshida Yumi , Matsui Masakazu , Maeda Kohji , Kihara Sorin 
Published: June 2006

Abstract
The ion transport from one aqueous medium, W1, to another, W2, through a bilayer lipid membrane, BLM, was investigated voltammetrically by scanning the applied membrane potential, ΔVW1–W2, and monitoring the membrane current, IW1–W2. The shapes of voltammograms observed with a definite BLM depended on the hydrophobicity and the concentration of the ion added into W1 and/or W2, and can be classified into four types. The transport processes involved in each type of voltammogram were elucidated in the light of knowledge about ion transport processes through liquid membranes and by taking into account the conjugated ion transfers at interfaces of W1/BLM and BLM/W2. The shapes of voltammograms were also transformed when BLMs made of different lipids were employed. The spontaneous condensation of objective ions from W1 and/or W2 to the BLM by the partition with counter ions, which depends on the properties of objective ions, counter ions and lipids composing BLMs, is essential for the ion transport through BLMs.
Macrocyclic Polyazacycloalkane-poly-N-carboxylate Anion as a Receptor for Amino Acid
Authors: Kodama Mutsuo 
Published: June 2006

Abstract
The doubly-protonated 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetracarboxylate anion (H2teta2−), 1,4,7,10,13-pentaazacyclopentadecane-1,4,7,10,13-pentacarboxylate anion (H2pepa3−), and 1,4,7,10,13,16-hexaazacyclooctadecane-1,4,7,10,13,16-hexacarboxylate anion (H2heha4−) have been shown to form stable 1 : 1 ratio complexes with amino acids in aqueous solutions. Their association constants, βL, were determined polarographically. The greater association constants obtained indicate that H2teta2− and H2pepa3− anions selectively interact with an amino acid which has a planar aromatic moiety. The results show the importance of hydrophobic interaction, such as CH–π interaction between the aliphatic CH2 residue of acetate pendant of receptor and the planar aromatic moiety of substrate, amino acid, in holding the protonated macrocyclic polyazacycloalkane-poly-N-polycarboxylate anion and amino acid together. Thus, they act as selective receptors for phenylalanine, tyrosine, tryptophan(e), and their derivatives.
Copper(II) Complexes of 6-Amino-5,7-dioxo-1,4,8,11-tetraazacyclotetradecane
Authors: Kodama Mutsuo 
Published: June 2006

Abstract
A newly synthesized dioxocyclam ligand, 6-amino-5,7-dioxo-1,4,8,11-tetraazacyclotetradecane, reacts with copper(II) ions and forms a stable binuclear yellow complex, [Cu2H−2L]2+, as well as a mononuclear pink complex, [CuH−2L]°, in borate buffer solutions. Their formation equilibria were established by the pH-metric titration and spectrophotometric method. At the dropping mercury electrode the yellow copper(II) binuclear complex gave four reduction steps of equal height in a borate buffer solution, corresponding to the following reduction scheme:
Surfactant Extraction and Determination of Ruthenium(III) as a Thiocyanato Complex
Authors: Tagashira Shoji , Murakami Yoshiko , Nishiyama Miyuki , Harada Nobuko , Sasaki Yoshiaki 
Published: June 2006

Abstract
Ruthenium(III) was reacted to form a complex with thiocyanate, and extracted into the surfactant phase with Zephiramine (Z) by heating. The structure of this ion-pair was estimated to be [RuX2(SCN)2]−·Z+, in which X was a chloride ion, and was observed to cause an increasing absorbance and a blue shift of the spectrum. The determination of ruthenium(III) was investigated by the surfactant extraction-spectrophotometric method using a nonionic surfactant of Triton X-100 as an extraction solvent. The molar absorptivity was equal to 1.16 × 104 dm3 cm−1 mol−1 at 565 nm. Ruthenium(III) could be concentrated from the solution into a surfactant phase having a small volume. The first-order derivative spectroscopic method was used to reduce the interference from other platinum-group elements, such as osmium.
Interconversion between Polymeric Orange and Monomeric Green Forms of a Schiff Base-Oxovanadium(IV) Complex
Authors: Nakajima Kiyohiko , Kojima Masaaki , Azuma Shunryo , Kasahara Ryuichi , Tsuchimoto Masanobu , Kubozono Yoshihiro , Maeda Hironobu , Kashino Setsuo , Ohba Shigeru , Yoshikawa Yuzo , Fujita Junnosuke 
Published: June 2006

Abstract
The orange and green forms of the Schiff base-oxovanadium(IV) complex, [VO{sal-(RR)-stien}]·MeOH (1, green), [VO{sal-(RR)-stien}]·2CHCl3 (2, green), and [VO{sal-(RR)-stien}]·CH3CN (3, orange) (H2{sal-(RR)-stien} = N,N′-disalicylidene-(RR)-1,2-diphenyl-1,2-ethanediamine), have been prepared, and their crystal structures were determined by an X-ray method. The green forms, 1 and 2, contain mononuclear square pyramidal molecules of the complex, while the orange form 3 consists of individual complexes stacked to give an infinite linear ···V=O···V=O··· chain. 1, which crystallizes as monoclinic in space group P21 with Z = 4, has the cell parameters a = 16.684(2), b = 16.923(4), c = 9.249(3) Å, β = 105.76(2)°, and V = 2513(1) Å3. 2, which crystallizes as triclinic in space group P1 with Z = 2, has the cell parameters a = 13.187(3), b = 13.469(3), c = 10.450(3) Å, α = 103.72(2), β = 103.20(3), γ = 63.03(2)°, and V = 1591.2(7) Å3. 3 crystallizes as triclinic in space group P1 with Z = 2. The cell parameters are a = 13.300(3), b = 13.667(4), c = 7.551(1) Å, α = 90.44(2), β = 94.51(2), γ = 97.36(2)°, and V = 1357(1) Å3. The final R indices are R = 0.059 and RW = 0.062 for 1, R = 0.098 and RW = 0.090 for 2, and R = 0.053 and RW = 0.042 for 3. The structural characteristics of these complexes are compared and discussed. 3 shows piezochromism (mechanochromism); its color changes from orange to green upon grinding. 1 and 2 turn orange when heated at 120 °C for a few minutes. The extent of conversion either by grinding or heating was studied by EXAFS (X-ray absorption fine structure) and IR spectroscopy. The orange crystals turn green when exposed to chloroform vapor, and the green crystals turn orange upon exposure to acetonitrile vapor.
Multinuclear NMR Studies on Micellar Formation of Aqueous [Co(N-octyl- or N-dodecylethylenediamine)(3,7-Diazanonane-1,9-diamine)]3+ Solutions
Authors: Iida Masayasu , Yamamoto Mizuho , Fujita Naoko 
Published: June 2006

Abstract
The aggregation of [Co(R-en)(2,3,2-tet)]X3 (R-en = N-octyl- or N-dodecylethylenediamine, 2,3,2-tet = 3,7-diazanonane-1,9-diamine, and X = Cl or ClO4) in water was investigated by 59Co, 35Cl, 35ClO4, 2H2O, and 1H NMR measurements. NMR parameters, such as the relaxation rates and linewidths for the 59Co and 35Cl nuclei, were appreciably changed by micellar formation. We determined the CMC (critical micelle concentration) values (0.12 mol kg−1 for the octyl complex perchlorate, 0.008 mol kg−1 for the dodecyl perchlorate, and 0.010 mol kg−1 for its chloride) by measuring the NMR relaxations. The obtained CMC values are much larger than those previously reported on these surfactants, and are comparable to those of monovalent surfactants having the same alkyl-chain length. The aggregation of [Co(dod-en)(2,3,2-tet)]X3 (X = Cl or ClO4) in aqueous solution was also measured using vapor-pressure osmometry; the result supports the formation of ion aggregates at the CMCs, which was determined by NMR measurements. The 35Cl NMR measurements indicate that the interaction of the chloride counter ion with the dodecyl complex ion was appreciably larger than that with the dodecyltrimethylammonium ion at concentrations even below CMC. The effect of the trivalent positive charge of the cobalt(III) surfactant on the CMC value may be attenuated by the large size of the head group. A characteristic downfield shift of the 59Co resonance was observed due to the formation of micelles.
Stereoselective Syntheses of α-Glucuronides Using Dehydrative Glycosylation
Authors: Koto Shinkiti , Miura Teruhisa , Hirooka Motoko , Tomaru Aya , Iida Mika , Kanemitsu Masanori , Takenaka Kazuhiro , Masuzawa Shinichi , Miyaji Saeko , Kuroyanagi Naoko , Yagishita Miki , Zen Shonosuke , Yago Kazuo , Tomonaga Fumiya 
Published: June 2006

Abstract
Methyl and benzyl 2,3,4-tri-O-benzyl-d-glucopyranuronates, prepared from d-glucurono-6,3-lactone, afforded selectively the corresponding α-glucopyranosiduronates by the aid of the condensing reagent system composed of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine. Using this method, O-α-d-glucopyranuronosyl-(1→3)-O-α-l-arabinofuranosyl-(1→3)-d-xylopyranose, one of the minimal component units in the structure of plantago-mucilage A from the seeds of Plantago asiatica Linné constituting a Chinese medicine : chegianzi [].
Buffer Catalysis of the Hydrolysis of Phenyl and Methyl Benzenesulfinates. Contrasting Behavior between Acyclic and Cyclic Analogs
Authors: Okuyama Tadashi 
Published: June 2006

Abstract
The hydrolysis of phenyl benzenesulfinate is catalyzed by both acid and base, and is strongly accelerated by the carboxylate and amine base components of the buffer. Carboxylates and amines constitute different groups in the Brønsted plots, falling nearly on two separate lines of β = 1. The carboxylates are about 400-times more effective catalysts than the amines of similar basicity. Solvent deuterium isotope effects on the catalytic constants are small, and the buffer catalysis is considered to be nucleophilic. By contrast, the hydrolysis of the methyl ester was only weakly affected by the buffer, if at all. High efficiencies of oxygen nucleophiles in the catalysis of the hydrolysis of acyclic sulfinates are distinctive compared with the cyclic analogs, and are rationalized by a concerted SN2-like mechanism of the nucleophilic reaction at sulfur.
Formation of 5-Alkoxy-2-aminooxazoles and Their Novel Reactivity: Equilibrium with Nitrile Ylide
Authors: Fukushima Kazuaki , Lu Yue-Qin , Ibata Toshikazu 
Published: June 2006

Abstract
The Rh2(OAc)4-catalyzed reactions of diazoacetates with diisopropylcyanamide gave 5-alkoxy-2-aminooxazoles. Their isolation was achieved by introduction of a bulky alkoxy group at 5-position. The 5-alkoxy-2-aminooxazole reacted with methanol to give a 1 : 1-adduct in a quantitative yield. The kinetic study indicates that this reaction proceeds in a stepwise mechanism including an equilibrium of the 5-alkoxy-2-aminooxazole with a nitrile ylide intermediate.
The Roles of 2- and 3-Axial Methoxy Groups in Determining the Stereochemistry of the Complex Metal Hydride Reduction of Cyclohexanones: Examination of the Cieplak Model
Authors: Senda Yasuhisa , Sakurai Hiroshi , Nakano Shigeru , Itoh Hiroki 
Published: June 2006

Abstract
The 2- and 3-axially substituted methoxy groups in cyclohexanones exhibit steric hindrance similar to that of the methyl group in LiAlH4 and NaBH4 reductions. The chelate complex formation between the zinc ion and the two oxygens in the molecule was suggested in the zinc borohydride reduction. The relative reactivities of cyclohexanones in which the 2-axial position is substituted by the methyl or the methoxy group in the LiAlH4 reduction strongly support Cieplak’s proposal, which focuses on the importance of the stabilization of the transition state by anti-periplanar allylic bonds.
Reactivity of trans-[M(CO)(DMF)(Ph2PCH2CH2PPh2)2] (M = Mo, W) toward Terminal Alkynes: Synthesis of Alkynylhydrido and Vinylidene Complexes
Authors: Nakamura Goh , Harada Yuji , Mizobe Yasushi , Hidai Masanobu 
Published: June 2006

Abstract
Treatment of trans-[Mo(CO)(DMF)(dppe)2] (1a; dppe = Ph2PCH2CH2PPh2) with HC≡CCOOMe in benzene at room temperature or at reflux afforded an alkynylhydrido complex [Mo(C≡CCOOMe)H(CO)(dppe)2] (4a), whereas the reactions of 1a with arylacetylenes HC≡CR in benzene at reflux resulted in the formation of vinylidene complexes cis-[Mo(=C=CHR)(CO)(dppe)2] (R = Ph (6a) or 4-MeC6H4). The W analogue trans-[W(CO)(DMF)(dppe)2] (1b) gave only alkynylhydrido complexes [W(C≡CR)H(CO)(dppe)2] (R = COOMe (4b) or Ph) by treatment with either HC≡CCOOMe or HC≡CPh. From the Mo vinylidene complex 6a was obtained an alkylidyne complex cis-[Mo(≡CCH2Ph)(CO)(dppe)2][BF4] (9a) upon treatment with aqueous HBF4, whereas the reactions of Mo and W alkynylhydrido complexes 4 with HBF4·Et2O also resulted in the formation of the alkylidyne complexes cis-[M(≡CCH2COOMe)(CO)(dppe)2][BF4] (10). The vinylidene complexes cis-[M(=C=CHCOOMe)(CO)(dppe)2] (11) were readily derived from 10 by the reactions with NaOMe; these were not accessible from direct treatment of 1 with HC≡CCOOMe. The detailed structures of 4a, 4b, 9a, and 11b (M = W) have been established by single-crystal X-ray analyses.
Synthesis of Cysteine-Containing Polypeptide Using a Peptide Thioester Containing a Cys(Acm) Residue
Authors: Kawakami Toru , Kogure Shuji , Aimoto Saburo 
Published: June 2006

Abstract
A method was developed for the preparation of a cysteine-containing polypeptide, using a Cys(Acm)-containing peptide thioester obtained by a Boc solid-phase method. To demonstrate the utility of the developed method, human adrenomedullin consisting of 52 amino acid residues was synthesized. A peptide thioester, Boc–[Cys(Acm)16]–adrenomedullin(1—19)-SCH2CH2CO-β-Ala–NH2, and [Cys(Acm)21, Lys(Boc)25,36,38,46]-adrenomedullin(20—52) were prepared by conventional solid-phase methods. These peptide segments were condensed in the presence of silver ions, an additive, and a base. When HOBt or HOOBt was used as an additive, the segment coupling proceeded with negligible decomposition of Acm groups to give the desired product. A method for the removal of S-Acm groups from cysteine residues under basic conditions in the presence of silver ions and water, is also described.
Reaction Mechanism of NO Reduction by CH4over Rare Earth Oxides in Oxidizing Atmosphere
Authors: Otsuka Kiyoshi , Zhang Qinghong , Yamanaka Ichiro , Tono Hiromi , Hatano Masaharu , Kinoshita Hiroo 
Published: June 2006

Abstract
Rare earth oxides have been examined as catalysts for the catalytic reduction of NO by CH4 in the presence of oxygen. Among the rare earth oxides examined, Sc2O3 and Sm2O3 were found to be active for this reaction. For the Sm2O3 catalyst, ZrO2 was the most effective support. The mechanism of the reaction was studied over the Sm2O3/ZrO2. Kinetic studies indicated that CH4 oxidation is initiated by O2, and NO can react only with CH3 radicals formed from the reaction of CH4 with O2. Ab-initio MO calculations also suggested that CH3 radical is a more favorable reducing species for selective reduction of NO than CH4. It is thus proposed that NO is reduced into N2 by the CH3 radical formed from the activation of methane by oxygen.
Raman Spectroscopy as a Useful Probe of Mechanisms of Deterioration of Metal Oxide Materials due to Laser Irradiation
Authors: Sato Hiroyasu , Nishio Satoru , Kato Shinobu , Marumo Kenji , Matsuzaki Akiyoshi , Yoshida Ryo 
Published: June 2006

Abstract
Raman spectroscopy provides a very useful means to study mechanisms of deterioration of metal oxide materials due to laser irradiation. Excimer laser irradiation (308 nm) induced transition of anatase of TiO2 to rutile, while it did not cause substantial changes for rutile or HfO2. The deterioration mechanism is essentially a thermal one, as supported by the morphological changes monitored by SEM measurements.
Micellar Rate Effects on Alkaline Hydrolysis of Hydroxamic Acids
Authors: Ghosh Kallol Kumar , Roy Supriya 
Published: June 2006

Abstract
The kinetics of alkaline hydrolysis of N-phenylbenzohydroxamic acid and its para-substituted derivatives (X–C6H4–CO–N(OH)C6H5; X = H, CH3, OCH3, NO2, F) have been investigated in the presence and absence of cationic (ethyl hexadecyl)dimethylammonium bromide) and anionic (sodium-1-dodecanesulfonate and lithium dodecyl sulfate) surfactants at 55 °C in 5% (v/v) dioxane–water medium. A catalytic effect was found with cationic surfactants and an inhibitory effect in the presence of anionic surfactants was observed. The rate-surfactant profiles can be analyzed in terms of pseudo-phase and Piszkiewicz models.
Effects of Metal Cations on the Dynamic Characteristics of a Phospholipid Thin Film at an Air/Water Interface
Authors: Makino Masakazu , Kamiya Mamoru , Ishii Toshio , Yoshikawa Kenichi 
Published: June 2006

Abstract
We measured the time-dependent surface pressure of a dioleoylphosphatidylcholine film at an air/water interface. Our results indicate that: (i) the surface pressure of the thin film traces a closed hysteresis loop accompanied by repetitive cycles of compression and expansion, and (ii) the area of the hysteresis loop markedly increases in the presence of sodium ions. We propose a kinetic model for this phenomenon which includes cooperative aggregation/dissociation at the air/water interface. The experimental findings have been successfully reproduced with the aid of a computer simulation based on this theoretical model.
Photocatalysis of H3PW12O40 for 4-Chlorophenol Decomposition in Aqueous Media
Authors: Einaga Hisahiro , Misono Makoto 
Published: June 2006

Abstract
Photocatalytic properties of PW12O403− (abbreviated as PW123−) for the 4-chlorophenol (4-CP) decomposition was investigated by using a 300 W Xe lamp at 35 °C in aqueous media. The rate of the 4-CP decomposition was not influenced by pH in the range from 1.0 to 2.0, where PW123− is stable. In the dark, no reaction proceeded. When the photolysis was carried out under O2 atmosphere, 4-CP was decomposed and the catalyst remained in the oxidized form. In the deaerated solution, PW123− was reduced to PW12O404− (PW124−) by irradiation, the amount of PW124− formed during irradiation being approximately identical with the amount of 4-CP concurrently consumed. When the irradiation was stopped and O2 was introduced, PW124− was oxidized rapidly to PW123− and a small amount of 4-CP decomposed.
Based on these facts we deduced that the reaction consists of the following three steps: (1) photoexcitation of PW123−, (2) one-electron reduction of the excited PW123− to PW124− with simultaneous oxidation of 4-CP, and (3) reoxidation of PW124− to the original form by O2. 4-CP is also decomposed in the last step, although the amount is much smaller than that in step (2). The dependency of the reaction rates on the concentration of substrate was explained by Langmuir (or Michaelis Menten) type kinetics, indicating that the complex formation between PW123− and 4-CP is the indispensable step of the photocatalytic decomposition.
Anomalous Magnetic Quenching of ortho-Positronium in Solutions of Nitrobenzene and 1,3-Dimethyl-2-nitrobenzene
Authors: Kobayashi Yoshinori , Hirata Kouichi 
Published: June 2006

Abstract
The magnetic quenching of ortho-positronium (o-Ps) has been studied for various solutions of nitrobenzene and 1,3-dimethyl-2-nitrobenzene. Static magnetic fields were applied to the solutions and the average o-Ps lifetimes were measured as a function of the field strength up to 1 T. Anomalous magnetic quenching, similar to that observed for nitrobenzene in hexane, was found for solutions of nitrobenzene in isopentane, pentane, diethyl ether and heptane as well as 1,3-dimethyl-2-nitrobenzene in dodecane and toluene. It is suggested that o-Ps detached from a weakly bound complex between positronium (Ps) and the nitrocompound may be responsible for the anomalous effect.
Electrochemical Behavior of Electrodes Modified with π-Conjugated Polymers in 0.5 M H2SO4 (aq) and 1 M KOH (aq) Electrolytes
Authors: Yamamoto Takakazu , Matsuzaki Takehiro , Minetomo Akiyuki , Kawazu Yoichi , Ohashi Osamu 
Published: June 2006

Abstract
Plantinum electrodes modified with 10 kinds of π-conjugated polymers have been prepared. These polymers include poly(pyridine-2,5-diyl) PPy, poly(2,2′-bipyridine-5,5′-diyl) PBpy, poly(3-octylthiophene-2,5-diyl) P3OcTh, and poly(6-hexylpyridine-2,5-diyl) P6HexPy. Films of PPy and PBpy behave as good H+-transporting materials in 0.5 M H2SO4 (aq). Plots of log i vs. V for electrodes modified with the polymers give linear lines in a current density region of 10−5.5—10−2 A cm−2. The slope of the line, β = dV/d(log i), depends on the kind of the polymer. Hydrophilic PPy and PBpy give a β value of 3.2 × 10−2 V, while hydrophobic P3OcTh and P6HexPy with long alkyl chains give a larger β value of 4.5 × 10−2 V. Diffusion coefficients of H+ in films of PPy, PBpy, and poly(quinoline-2,6-diyl) P(2,6-Q) are estimated to be larger than 10−7 cm2 s−1 from limiting currents at room temperature. The i–V curve of a P(2,6-Q)-modified Pt electrode shows a strong pH-dependence reflecting a chemical change of the polymer with pH. The PPy-, PBpy-, and P3OcTh-modified Pt electrodes exhibit acceleration effects for evolution of O2 from 1 M KOH (aq).
Chain Compounds of Rhodium(II) Trifluoroacetate Linked by p-Quinone [Rh2(O2CCF3)4(p-Q)]n, p-Q = 1,4-Benzoquinone, 1,4-Naphthoquinone, and 2,3-Dimethyl-1,4-benzoquinone
Authors: Handa Makoto , Mikuriya Masahiro , Sato Yuka , Kotera Takanori , Nukada Ryoji , Yoshioka Daisuke , Kasuga Kuninobu 
Published: June 2006

Abstract
A series of chain complexes of rhodium(II) trifluoroacetate, [Rh2(O2CCF3)4(p-Q)]n (p-Q = 1,4-benzoquinone (1,4-bq), 1,4-naphthoquinone (1,4-nq), and 2,3-dimethyl-1,4-benzoquinone (2,3-dmbq)) have been prepared. The chain structures were confirmed by the X-ray structure analyses. The carbonyl oxygens of the p-quinones are coordinated to the Rh2 centers with the distances of 2.248(5) (for p-Q = 1,4-bq), 2.248(3) (for p-Q = 1,4-nq), and 2.247(9) Å (for p-Q = 2,3-dmbq), respectively. The bridging mode of the p-quinone was discussed in relation to the substituent effect of CF3 group on the carboxylate.