bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of Stabilization of ZnO Photoanodes in High pH Solutions
Authors: Kikuchi Eiji , Itoh Kiminori , Katoh Tamihiko , Fujishima Akira 
Published: July 2006

Abstract
Stabilization of ZnO photoanodes was investigated using ZnO thin film electrodes under controlled potential in various pH solutions; the effects of light intensity and agitation were also studied. The photocorrosion of ZnO photoanodes was suppressed at sufficiently cathodic potentials and/or at low light intensity. Agitation of solution also suppressed photocorrosion. On the basis of the experimental results, the mechanism of the stabilization in high pH solutions is discussed and a model is proposed.
Temperature Dependence and Decay Kinetics of the High-Energy Band in DPH Fluorescence
Authors: Yamashita Shoji , Szabo Aurthur G , Cavatorta P 
Published: July 2006

Abstract
The temperature dependence and associated decay kinetics of the high energy band centered at 380 nm in the fluorescence spectrum of 1,6-diphenyl-1,3,5-hexatriene in a nonpolar solvent were investigated. Below 150 K the emission intensity at 380 nm relative to that of a sharp band near 400 nm was very small. Above this temperature the intensity at 380 nm increased with increasing temperature. The fluorescence decay analysis of this band showed two components with decay times of 62 ps and 13.4 ns. The 62 ps component was assigned to the prompt fluorescence of the S2 (1Bu*) state and 13.4 ns component to a delayed type fluorescence from the same state after establishment of a thermal equilibrium with lower S1 (1Ag*) state.
The Addition of the Cyanide Ion to the N-Methyl-3-carbamoylpyridinium Ion in Reversed Micelles
Authors: Goto Ayako , Kishimoto Hiroshi 
Published: July 2006

Abstract
The addition reaction of the cyanide ion to the N-methyl-3-carbamoylpyridinium ion was carried out in reversed micelle systems, and the functions of the electric charge of surfactants and of the entrapped water in the micelle were studied by measuring the rate and equilibrium constants. Reversed micelles formed by hexadecyltrimethylammonium bromide (HTAB), a cationic surfactant, not only enhanced the reaction, but also stabilized the product, 4-cyano-1,4-dihydro-N-methylnicotinamide (P), which is thermodynamically unstable in aqueous media. This was in contrast to sodium 1,2-bis(2-ethylhexyloxycarbonyl)ethanesulfonate (AOT), an anionic surfactant, reversed micelles. In both reversed micelle systems the reaction could be controlled by varying the water content, although neither is favorable for the reaction at a higher water content. From the distribution measurements and spectroscopic studies, it can be suggested that the reaction occurred preferably in the micellar phase, especially in the water pool. Three kinds of effects were proposed for interpreting the enhancement as compared to the reaction in aqueous systems. The first was the local concentration of reaction species in the water pools, and the second was the lower micropolarity of water pools. The third concerned the electric nature of the surfactant and reactant ions.
Limitation of Absorbance Measurement by Using Photoacoustic Method
Authors: Terazima Masahide , Azumi Tohru 
Published: July 2006

Abstract
The solute dependence of the photoacoustic (PA) signal intensity has been examined. The results show that the PA signal intensity depends not only on the released energy, but also on the nature of the solute. This means that the absorbance of an unknown sample cannot be precisely measured by comparing the PA signal intensity with that of a standard solution containing a different solute.
Solvent Extraction of Uni- and Bivalent Metal Picrates with 16-Crown-5 into Benzene
Authors: Takeda Yasuyuki , Kimura Tokutaro , Kudo Yoshihiro , Matsuda Hiroaki , Inoue Yoshihisa , Hakushi Tadao 
Published: July 2006

Abstract
Distribution constant (KD,L) of 16-crown-5 (16C5) and overall extraction equilibrium constants (Kex) of uni- and bivalent metal picrates with 16C5 were determined between benzene and water at 25 °C. The Kex values were analyzed by four fundamental equilibria, extraction constant of picric acid, KD,L formation constant in water and ion-pair extraction constant (Kex,ip) with a picrate ion of the 16C5–metal ion complex. The Kex value of 16C5 for the uni- and bivalent metal ions decreases in the order Ag+&gt;Na+&gt;Tl+&gt;K+&gt;Rb+&gt;Cs+&gt;Li+ and Pb2+&gt;Ba2+≥Sr2+&gt;Ca2+, respectively. Size-fit relationship holds for extraction-selectivity of 16C5 toward alkali metal ions, but it does not hold for that toward alkaline earth metal ions. Factors influencing extractability and extraction-selectivity of 16C5 for metal ions were discussed from the viewpoint of molecular grounds. Kex,ip value of 16C5 varies with a cation of the same charge held in the cavity. Kex,ip values of 16C5–metal picrate complexes were compared with those of 15-crown-5–metal picrate complexes. Various effects on ion-pair extractability of a 16C5–metal ion complex with a picrate anion were explained.
A Structural Study of a Series of Bis(2,3-alkanedione dioximato)nickel(II) Complexes in the Crystal and the Liquid States by X-Ray Absorption Spectroscopy
Authors: Yamashita Seiichi , Yanase Yoshio , Yamaguchi Toshio , Wakita Hisanobu 
Published: July 2006

Abstract
The structures of a series of bis(2,3-alkanedione dioximato)nickel(II) complexes, [Ni(R,R′-dioxH)2], with dioxH=C(=NOH)–C(=NO), R and R′=H(A), R=CH3 and R′=H(B), CH3(C), C2H5(D), n-C3H7(E), n-C4H9(F), n-C5H11(G), n-C6H13(H), or n-C10H21(I), were investigated in crystals, pyridine solution, and melt (160 °C) by means of extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES), magnetic susceptibility, and UV/visible spectra. The magnetic susceptibility of complexes C, F, and H in crystals revealed a diamagnetic character. The electronic spectra of crystalline samples E, F, and H changed with the alkyl substituents of the glyoximato ligands, while the corresponding spectra in a pyridine solution were very similar to each other, independent of the glyoximato ligands. The EXAFS data showed that the average Ni–N distance within nickel(II) glyoximato complexes is 1.85–1.88 Å, practically independent of the alkyl substituents of the glyoximato ligands. The XANES spectra were found to correlate with the molecular packing structures of nickel(II) glyoximato complexes in crystals, pyridine solutions, and melt.
A New Synthesis of 3-Hydroxy-2,5-dialkyl-1,4-benzoquinone from 3-Halo-3,6-dialkyl-1,2-cyclohexanedione Using Iodine–Copper(II) Acetate
Authors: Horiuchi C Akira , Suzuki Yasuto 
Published: July 2006

Abstract
The reaction of 3-iodo-3,6-dialkyl-1,2-cyclohexanedione (2) with iodine–copper(II) acetate in acetic acid–water (5:1) at 80 °C gave the respective 3-hydroxy-2,5-dialkyl-1,4-benzoquinone in 38–80% yields. On the other hand, the reaction of 2 with copper(II) acetate in acetic acid–water (10:1) under refluxing afforded the respective 3,3′-dihydroxy 2,2′,5,5′-tetraalkyl-4,4′-diphenoquinone (5) in 41–85% yields. In the case of 3-bromo-3,6-dialkyl derivative (3) with copper(II) acetate, the diphenoquinone derivatives and 3-hydroxy-2,5-dialkyl-1,4-benzoquinone were obtained.
Synthetic Photochemistry. LI. Structure Elucidation of the Pyrolysates Formed by “Retro-Benzilic Acid Rearrangement” of the Proto-Photocycloadducts of Methyl 2,4-Dioxopentanoate-Olefins
Authors: Hatsui Toshihide , Nojima Chitoshi , Takeshita Hitoshi 
Published: July 2006

Abstract
Pyrolysates obtained from the proto-photoadducts of methyl 2,4-dioxopentanoate with olefins were shown to be 3-acetyl-1,2-cyclopentanedione derivatives. One-pot formation of polyfunctionalized cyclopentane derivatives via a photocycloaddition has no precedence. Intentional preparation of the ring system was also achieved by a diethyl azodicarboxylate–triphenylphosphine treatment of the proto-adducts.
Syntheses and Some Reactions of Trimethylsilylated Dinitrogen Complexes of Tungsten and Molybdenum
Authors: Komori Keiko , Sugiura Seiya , Mizobe Yasushi , Yamada Masaki , Hidai Masanobu 
Published: July 2006

Abstract
A series of new trimethylsilyldiazenido complexes [MX(NNSiMe3)(L)4] (M=Mo: X=I; M=W: X=CF3SO3; L=PMe2Ph or 1/2 dpe; dpe=Ph2PCH2CH2PPh2) and trimethylsilylhydrazido(2−) complexes [MX2(NNHSiMe3)(PMe2Ph)3] (M=Mo: X=I or Br; M=W: X=CF3SO3) and [MX(NNHSiMe3)(dpe)2]X (M=Mo: X=I; M=W: X=CF3SO3) were prepared by treatment of dinitrogen complexes cis-[M(N2)2(PMe2Ph)4] or trans-[M(N2)2(dpe)2] with Me3SiX in benzene. The trimethylsilyl groups on the terminal nitrogen atoms were easily replaced by hydrogen by the reaction with MeOH or H2O, affording, for example, diazenido and hydrazido(2−) complexes such as [WI(NNH)(dpe)2] and [WI2(NNH2)(PMe2Ph)3] from [WI(NNSiMe3)(dpe)2] and mer-[WI2(NNHSiMe3)(PMe2Ph)3], respectively. When reduced with excess Na in THF under N2, complexes trans-[MI(NNSiMe3)(PMe2Ph)4] (M=Mo or W) and mer-[WI2(NNHSiMe3)(PMe2Ph)3] gave (Me3Si)2NH and NH3 in substantial yields, accompanied by the regeneration of the parent dinitrogen complexes. Additional amount of NH3 was obtained by the hydrolysis of the evaporated reaction mixture residue.
Effect of α-Cyclodextrin on the Electrochemistry of (Ferrocenylmethyl)dodecyldimethylammonium Bromide at a Glassy Carbon Electrode
Authors: Opallo Marcin , Kobayashi Nagao , Osa Tetsuo , Yamada Hiroshi , Onodera Shinji 
Published: July 2006

Abstract
The influence of α-cyclodextrin (α-CD) on the electrochemistry of (ferrocenylmethyl)dodecyldimethylammonium bromide (I) was studied with a glassy carbon (GC) electrode. α-CD increases the apparent diffusion coefficient of I. This unusual effect is explained in terms of disruptive effect of α-CD on I’s aggregates. α-CD also influences, to some extent, I’s adsorption onto GC electrode when adsorbed from its micromolar aqueous solution.
Dielectric Properties of Dehydrated Ca1Na10-A and Na12-A Zeolites
Authors: Ohgushi Tatsuo , Nonaka Kenji , Yoshida Hiroyuki , Takaishi Tetsuo 
Published: July 2006

Abstract
Dielectric properties of completely dehydrated Ca1Na10-A and Na12-A zeolites were studied. The properties of Ca1Na10-A bore close parallels to those of Na11-ZK4 having almost the same cation distribution as Ca1Na10-A. The properties of Na12-A were markedly different from those of Ca1Na10-A and the unusual behavior of the zeolite were attributed to a larger mobility of Na+ ion on the 4-ring site.
Absence of the Enhanced Methanation Activity of Ni/TiO2 in the SMSI State as Examined with Pulse Surface Reaction Rate Analysis
Authors: Mori Toshiaki , Suzuki Kenzi , Saito Masahiro , Hattori Tadashi , Murakami Yuichi 
Published: July 2006

Abstract
From rate measurements with pulse surface reaction rate analysis, it was found that the methanation activity of Ni/TiO2 was the same both in the SMSI and in the normal states.
Evaluation of Oxidation of Vegetable Oils by Pyrolytic Sulfurization Gas Chromatography
Authors: Kawai Itsuro , Hara Tadashi 
Published: July 2006

Abstract
Oxygen determination by pyrolytic sulfurization gas chromatography was applied to observe the degree of oxidation of vegetable oils. Oxidation deterioration of vegetable oil and the effect of antioxidants were evaluated.
Preparation and Characterization of Triethylenetetramine Cobalt(III) Complexes with 1,2-Ethanedithiolate or 1,2-Ethanedisulfinate
Authors: Konno Takumi , Umehara Hideki , Okamoto Ken-ichi , Hidaka Jinsai 
Published: July 2006

Abstract
Triethylenetetramine (trien) cobalt(III) complexes with 1,2-ethanedithiolate (edt) or 1,2-ethanedisulfinate (edsi) were prepared and characterized by absorption, CD, and 13C NMR spectra. Each of the two complexes gave three possible geometrical isomers (cis-α, cis-β-RR,SS, and cis-β-RS,SR) which were separated and optically resolved by fractional crystallization and/or column chromatography.
Preparation of Bicyclic Crown Ethers Containing Amide Groups: Coordination of the Oxygen Atoms of the Amide Groups
Authors: Kumagai Takeshi , Akabori Sadatoshi 
Published: July 2006

Abstract
9,12,23,26,31,36-Hexaoxa-1,6,15,20-tetraaza-3,4: 17,18-dibenzotricyclo[18.8.5.56,15]octatriaconta-3,17-diene-2, 5,16,19-tetraone (7a) was obtained by the reaction of phthaloyl dichloride with 1,4,10-trioxa-7,13-diazacyclopentadecane in 38% yield, and related compounds were prepared by a similar method. Compound 7a showed high extraction abilities toward alkali, alkaline earth, and other metal cations (Ag+, Tl+, and Pb2+), especially lithium and sodium cations.
Asymmetric Alkylation of β-Keto Esters with Alkylsulfonium Salts Containing a Sugar Group
Authors: Umemura Kazuyuki , Matsuyama Haruo , Kobayashi Michio , Kamigata Nobumasa 
Published: July 2006

Abstract
The asymmetric alkylation of 2-methoxycarbonyl-1-indanone (2) and ethyl 2-methylacetoacetate (5) with an alkylsulfonium salt containing a sugar group were investigated. (S)-Ethyl 2-allyl-2-methylacetoacetate (6b) was obtained with up to 25% optical purity on alkylation of the enolate ion of 5 using the allyl(p-tolyl)sulfonio d-glucoside derivative (1h).
Reaction of Methyl 2,3,5,6,11,11b-Hexahydro-3-oxo-1H-indolizino[8,7-b]indole-5-carboxylate and Its Derivatives with N-Bromosuccinimide
Authors: Irikawa Hajime , Mutoh Susumu , Uehara Masahiro , Okumura Yasuaki 
Published: July 2006

Abstract
Methyl 2,3,5,6,11,11b-Hexahydro-3-oxo-1H-indolizino[8,7-b]indole-5-carboxylate was converted into the tetrahydro, dihydro, and dehydro esters using N-bromosuccinimide. On treatment with acetic acid, the 6a-bromo indolenine derivative bearing a substituent on C-11b gave a mixture of 8- and 9-bromo compounds by migration of the bromine to the benzene ring, while the corresponding 6a-chloro derivative afforded the oxindole.
A Synthetic Route to (±)-Humulone
Authors: Obara Heitaro , Onodera Jun-ichi , Machida Yoshihisa , Yada Shuji 
Published: July 2006

Abstract
The synthesis of (±)-humulone was achieved by the prenylation of 2,3,4,6-tetrahydroxyisovalerophenone with 1-bromo-3-methyl-2-butene.
An Improved Synthetic Method of (S)-2-Alkoxypropanals from Ethyl (S)-Lactate
Authors: Kobayashi Yuko , Takase Mitsuru , Ito Yoshio , Terashima Shiro 
Published: July 2006

Abstract
The title synthetic method which undergoes without racemization, was explored employing sequential amidolysis with a secondary amine, alkylation with an alkyl halide under basic conditions, and reduction with sodium bis(methoxyethoxy)aluminium hydride.
A Novel Use of the Ionic Hydrosilation in the Synthesis of Carbapenem Key Intermediate
Authors: Kobayashi Yuko , Ito Yoshio , Terashima Shiro 
Published: July 2006

Abstract
The ionic hydrosilation of the 3-acetyl-2-azetidinone derivative in the presence of boron trifluoride etherate was found to effect highly stereoselective reduction of the acetyl group (at most, 17:1), giving rise to the desired 3-[(R)-1-hydroxyethyl]-2-azetidinone derivative as a major product. Simultaneous reductive removal of the bis(p-methoxyphenyl)methyl group was also observed depending upon the reaction conditions.
A Facile Preparation of 7-(Substituted amino)-6H-pyrrolo[3,4-d]pyrimidine Derivatives
Authors: Noguchi Michihiko , Kiriki Yasutoshi , Kajigaeshi Shoji 
Published: July 2006

Abstract
6-Phenyl-7-(substituted amino)-6H-pyrrolo[3,4-d]pyrimidine-2,4(1H,3H)-diones 3 were obtained by the reaction of 5-formyl-1,3-dimethyl-6-[(substituted amino)methyl]-2,4(1H,3H)-pyrimidinediones (1) with aniline (2a).
A Facile Halogenative Cyclization of 4-(2-Benzothiazolyldithio)azetidinones (Kamiya’s Disulfide) into 2β-(Halomethyl)penams in a Two Layer System
Authors: Tanaka Hideo , Tanaka Motoaki , Yamada Sho-zo , Nakai Akira , Ohbayashi Hisashi , Terada Tadafumi , Torii Sigeru 
Published: July 2006

Abstract
Chlorinative cyclization of 4-(2-benzothiazolyldithio)azetidinones into 2β-(chloromethyl)penams has been successfully performed by treatment with aqueous sodium nitrite in a two-layer solution comprising aqueous hydrochloric acid and dichloromethane layers. Similarly, the corresponding 2β-(bromomethyl)penams can be obtained by use of aqueous hydrobromic acid in place of aqueous hydrochloric acid.
Efficient Reduction of 2-Haloacetophenone Derivatives to the Corresponding Halohydrins by 9,10-Dihydro-10-methylacridine in the Presence of Titanium Tetrachloride, Comparison with the Reduction in the Presence of Perchloric Acid
Authors: Mochizuki Seiji , Fukuzumi Shunichi , Tanaka Toshio 
Published: July 2006

Abstract
2-Haloacetophenone derivatives are reduced by an acid-stable NADH model compound, 9,10-dihydro-10-methylacridine, in the presence of HClO4 in acetonitrile at 335 K to yield 10-methylacridinium ion and the parent acetophenone derivatives as well as halohydrins, while the reduction of 2-haloacetophenone derivatives in the presence of TiCl4 in dichloromethane undergoes much more readily even at 298 K to yield the corresponding halohydrins selectively.
Conductimetric Studies of Ionic Association of Tetraalkylammonium Halides and Tetraphenylborate in N,N-Dimethylformamide–Methyl Ethyl Ketone Mixtures at 25 °C
Authors: Islam Nurul , Zaidi S B A , Ansari Aijaz Ahmad 
Published: July 2006

Abstract
The molar conductivities of Et4NBr, n-Pr4NBr, n-Bu4NBr, and n-Bu4NBPh4 have been measured in N,N-dimethylformamide–methyl ethyl ketone (DMF–MEK) mixtures (34.5≥D≥20.10) over the maximum concentration range (2×D3×10−7 mol dm−3) along with the densities and viscosities of the solvent mixtures at 25 °C. The conductance data have been analyzed by using the Fuoss-1978 (F78) conductance equation and the results compared with those obtained from the Justice (J) and the Fuoss-Onsager-Skinner (FOS) equations. The molar conductivities at infinite dilution (Λ0), the thermodynamic association constant (KA) and the distance or the ion-size parameter (R or a°) are evaluated from these data. A better fit of the parameters was provided by the F78 equation which yielded KA and R values. The Λ0 and the KA values are found to increase with decrease in the dielectric constant of the medium and in a given solvent mixture they follow the order Et4NBr&gt;n-Pr4NBr&gt;n-Bu4NBr&gt;n-Bu4NBPh4.
The Complexation Equilibria of Mercury(II) Ions with Macromonocyclic 16-Membered Dioxopentamine, 18-Membered Dioxohexamine, and Their Related Compounds
Authors: Kodama Mutsuo , Kimura Eiichi 
Published: July 2006

Abstract
We have investigated the equilibria of complexation reactions of mercury(II) ions with 16-membered macrocyclic dioxopentamine (dioxo[16]aneN5), 18-membered macrocyclic dioxohexamine (dioxo[18]aneN6), and their related compounds by employing a polarographic method and pH-metric titration. Dioxo[16]aneN5, dioxo[18]aneN6, and other dioxo ligands except dioxotetramines were found to form solely 1 : 1 ratio mercury(II) complexes designated as HgH–1L+ with displacement of one amide proton, while the macrocyclic 16-membered monooxopentamine(monooxo[16]aneN5) forms HgL2+ in addition to HgH–1L+. The substitution of amine nitrogen of dioxo[16]aneN5 by the sulfur donor unexpectedly gave no increase in the stability of mercury(II) complex of dioxo ligand, HgH–1L+.
Syntheses and Structures of Indolo[6,7-g]indoles, a New Heteroaromatic System
Authors: Nagawa Yoshinobu , Goto Midori , Honda Koichi , Nakanishi Hiroshi 
Published: July 2006

Abstract
Photolysis of 1,1′-(1,8-naphthylene)-bis(1H-1,2,3-triazole)s (1) in methanol has given new heteroaromatic system compounds, indolo[6,7-g]indoles (2). The spectral properties of these compounds were studied in comparison with those of the corresponding benz[g]indoles (4) obtained from the similar photolysis of 1-(1-naphthyl)-1H-1,2,3-triazoles (3). The 1H NMR and IR spectra of 2 and 4 suggest the existence of a strong intramolecular hydrogen bonding in 2. The X-ray crystallographic analysis of tetraethyl 1H, 10H-indolo[6,7-g]indole-2,3,8,9-tetracarboxy late, 2a, indicates that the molecule has almost twofold rotational symmetry, and the framework is distorted due to the steric overcrowding.
Lipid-Protein Interaction in Mixed Monolayers from Phospholipids and Proteins
Authors: Mita Tomoyoshi 
Published: July 2006

Abstract
The thermotropic behavior of different proteins with phospholipids in monolayers was investigated by measuring the surface pressure and the surface viscosity. When phospholipids, such as dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC), were mixed with the hydrophobic proteins, such as hemoglobin and β-casein, below their phase transition temperatures (Tc), a considerable expansion of monolayers was observed. On the other hand, when phospholipids were mixed with the hydrophilic proteins, such as bovine serum albumin (BSA) and lysozyme below Tc, no expansion was observed. When DMPC was mixed with different proteins at Tc or above, all mixtures formed slightly deviated monolayers from ideal mixing, independent of a variety of proteins. This type of behavior suggests that the hydrophobic proteins perturb the structure of boundary lipids near the protein molecule below Tc, while the hydrophobic proteins do not perturb the phospholipid structure below Tc because of their low hydrophobicities. At Tc or above the membrane properties are independent of a variety of proteins, because all lipid hydrocarbon chains cause a disordering, even without proteins. In addition, when DPPC was mixed with a hydrophobic protein, such as hemoglobin, the fluidity of monolayer increased significantly.
High-Pressure Aminolysis of Lactones to Hydroxy Amides
Authors: Matsumoto Kiyoshi , Hashimoto Shiro , Uchida Takane , Okamoto Tadashi , Otani Shinichi 
Published: July 2006

Abstract
The preparation of hydroxy amides from a wide variety of lactones and amines has been achieved at 9 kbar and 30 or 65 °C. The yields of hydroxy amides were moderate to excellent. Some limitations were encountered in the reaction of 6-hexanolide; for example, diethylamine gave only a 15% yield of the corresponding amide at 8 kbar and 60 °C. 4-Pentanolide did react with extremely unreactive amines such as 4-nitroaniline and diphenylamine, and the product was a mixture of the hydroxy amide and 3-aminobutyric acid.
The Ullmann Condensation Reaction of Haloanthraquinone Derivatives with Amines in Aprotic Solvents. VI. The Combination of Cu(I) and Hydroxo or Alkoxo Cu(II) as Effective Catalyst System
Authors: Arai Sadao , Hashimoto Yoshio , Yamagishi Takamichi , Hida Mitsuhiko 
Published: July 2006

Abstract
The reaction rate of the Ullmann condensation reaction of haloanthraquinone with ethylenediamine (EN) by copper(I) halide catalyst decreased along with the formation of inactive Cu(II) species [Cu(EN)2X2] by one-electron transfer from Cu(I) to haloanthraquinone. However, the combination of Cu(I) and Cu(II) salts, having an OH, OCH3, or OCOR group, enhanced the reaction rate in the following order: CuCl&lt;CuCl–CuCl(OCH3)&lt;CuCl–Cu(OCH3)2&lt;CuCl–Cu(OH)2. In condensation using Cu(OR)2 or CuCl(OCH3) alone, the Cu(II) species was reduced to Cu(I) to form an active catalyst system [Cu(I)+Cu(II)]. On the other hand, CuBr2 or CuCl2 was not reduced and was ineffective for the reaction. These were confirmed by ESR measurements and the presence of a dehalogenation product. Mixed valence species bridged by the alkoxo or hydroxo group was proposed as an active species.