bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Evaluation of Hyperpolarizability of l-2-Pyrrolidone-5-carboxylic Acid (l-PCA)
Authors: Kitazawa Manabu , Takahashi Mitsuo , Wada Tatsuo , Sasabe Hiroyuki , Nakano Masayoshi , Yamaguchi Kizashi
Published: July 2006

l-2-Pyrrolidone-5-carboxylic acid (l-PCA) is a novel nonlinear optical material with the optical transparent range down to the UV region. l-PCA molecules are hydrogen-bonded to form the three-dimensional network in a crystal. It has been thought that the network of hydrogen bonds influences on the stability of the crystal structure as well as the second-order optical nonlinearity. We have performed the theoretical evaluation of the contributions of the intermolecular hydrogen bonds to structural stability and second-order nonlinearity in the l-PCA crystals by use of the molecular orbital calculation methods. In the calculation of CNDO/S-SECI (singly excited configuration interaction) method, it is shown that the primary contributor to the molecular hyperpolarizability (β) is an nπ → π* transition in the amide moiety of l-PCA molecule. The calculation of intermolecular interaction energies for l-PCA clusters by the ab initio STO-3G method indicates that the hydrogen bonds in the crystal contribute to the stabilization of the crystal structure by −7.8 to −9.1 kcal mol−1 for one hydrogen-bond formation. Furthermore, it is also confirmed by CNDO/S-CHF (coupled Hartree–Fock) calculation that the hydrogen-bonding interactions induce the enhancement of the βXyz value, a unique β component contributing to the nonlinear optical coefficient (d14). On the basis of the calculated β components, d14 can be estimated to be d14 = 0.30 pm V−1 by the oriented-gas model. This value is in good agreement with the experimental result. Therefore, these results verify that the hydrogen bonds between l-PCA molecules contribute not only to the physical and chemical stability of l-PCA crystals but also to the enhancement of β values. This theoretical estimation shows the effectiveness of the hydrogen bonds in second-order nonlinear optical crystals.
The Electrical and Magnetic Properties of a Novel Two-Dimensional Antiferromagnet Based on BEDT–TTF: θ-(BEDT–TTF)2Cu2(CN)[N(CN)2]2
Authors: Komatsu Tokutaro , Sato Hirohiko , Nakamura Toshikazu , Matsukawa Nozomu , Yamochi Hideki , Saito Gunzi , Kusunoki Masami , Sakaguchi Ken-ichi , Kagoshima Seiichi
Published: July 2006

A crystal-structure analysis and a band calculation, as well as conductivity, thermoelectric power, ESR, and static susceptibility measurements were performed on the new BEDT–TTF salt, θ-(BEDT–TTF)2Cu2(CN)[N(CN)2]2. This salt has a unique polymerized anion comprising infinite Cu–N(CN)2–Cu double helices bridged by disordered CN groups. Although the two-dimensional arrangement of crystallographically equivalent BEDT–TTF+0.5 cations provides a two-dimensional closed Fermi surface within the tight-binding approximation, this salt is semiconductive even at room temperature, probably due to a strong electron correlation in this system. A semiconductor–semiconductor transition has been observed around 220 K. Below 220 K the electronic system is represented as a Mott insulator and a two-dimensional Heisenberg antiferromagnet. Rapid decreases in the ESR line width and spin susceptibility below 50 K indicate the existence of an additional magnetic transition.
Separation of Cadmium Salicylate by Solvent Extraction Using Tris(2-ethylhexyl) Phosphate
Authors: Nambiar Dinesh C , Shinde Vijay M
Published: July 2006

Tris(2-ethylhexyl) phosphate (T2EHP) is used for the extraction of cadmium salicylate. The experimental conditions are established and the probable extractable species is ascertained by log D–log C plots. Microgram amounts of cadmium are determined in the Tris(2-ethylhexyl) phosphate phase with 1-(2-pyridylazo)-2-naphthol as the chromogenic agent. The proposed method is used for the separation of cadmium(II) from zinc(II), mercury(II), lead(II), bismuth(III), antimony(III), and thallium(III) and used for the estimation of cadmium in industrial waste water, kidney stone, cigarettes, and alloy samples.
X-Ray Crystal Structures and Chemical Properties of Heterocyclic Azo Compounds Coupled with m-Alkoxyphenols
Authors: Ishizuki Tomosuke , Murakawa Tomoaki , Yamada Tetsuya , Yuchi Akio , Wada Hiroko , Shiro Motoo
Published: July 2006

X-Ray crystal structures have been determined for two compounds obtained by the coupling reaction of 2-pyridinediazonium salt and m-methoxyphenol, viz., 3-methoxy-4-(2-pyridylazo)phenol (1) and 5-methoxy-2-(2-pyridylazo)phenol (2). The 2-pyridylazo and 2-thiazolylazo compounds having o-methoxy and p-hydroxy groups, such as 1, have lower pKa values and lower affinities for or higher selectivities to metal ions than corresponding o-hydroxy isomers. The resulting bis complexes with metal ions show molar absorptivities greater than 105.
Synthesis of 2′,3′-Didehydro-2′,3′-dideoxy Nucleosides from 2′,2′-Bis(phenylthio) Nucleoside Analogs
Authors: Niihata Shigeo , Kuno Hideyuki , Ebata Takashi , Matsushita Hajime
Published: July 2006

2′,3′-Didehydro-2′,3′-dideoxy nucleosides were synthesized from 2′,2′-bis(phenylthio) nucleoside analogs via five-step reactions. The sulfonyl group of the intermediate was removed by a treatment with sodium amalgam.
Mass-Spectrometric Study on Ion-Molecule Reactions of CF3+ with Nitrogen-Containing Benzene Derivatives, Pyridine, Pyrrole, and Acetonitrile at Near-Thermal Energy
Authors: Tsuji Masaharu , Aizawa Masato , Ujita Hiroki , Nishimura Yukio
Published: July 2006

The gas-phase ion-molecule reactions of CF3+ with nitrogen-containing benzene derivatives (C6H5Y : Y = NH2, NO2, and CN), pyridine, pyrrole, and acetonitrile have been studied at near-thermal energy using an ion-beam apparatus. The major product channels are charge transfer for aniline (71.7 ± 0.5%), O− abstraction for nitrobenzene (91.7 ± 0.5%), electrophilic addition leading to initial adduct ions for benzonitrile (97.5 ± 0.8%), acetonitrile (100%), and pyridine (94.8 ± 0.4%), and electrophilic addition followed by HF elimination for pyrrole (80.0 ± 1.4%). The reaction mechanism is discussed based on product ion distributions and theoretical calculations of the energies of reaction pathways.
Synthetic Photochemistry. LXVII. A Total Synthesis of (±)-Hinesol and (±)-Agarospirol via retro-Benzilic Acid Rearrangement
Authors: Hatsui Toshihide , Wang Jin-Jun , Takeshita Hitoshi
Published: July 2006

A mild base-catalyzed retro-benzilic acid rearrangement of a proto-photocycloadduct, formed in highly stereoselective photoaddition of methyl 2,4-dioxopentanoate to 1,5-dimethyl-6-methylene-1-cyclohexene, afforded a spiro[4.5]decenedione derivative. Reductive elimination of the α-dicarbonyl function and C1-homologation furnished (±)-hinesol and (±)-agarospirol.
Preparation of New Nitrogen-Bridged Heterocycles. 39. One-Pot Synthesis of 2H-Pyrano[3,2-a]indolizin-2-one Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Matsubara Ken
Published: July 2006

Various ethyl 2-(3-cyanoallylidene)- or 2-[3-(ethoxycarbonyl)allylidene]-1,2-dihydropyridin-1-ylacetates were prepared from the reactions of 1-(1-ethoxycarbonylalkyl)-2-methylpyridinium halides with activated ethoxymethylidene compounds in the presence of a base. The treatment of these 2-allylidene-1,2-dihydropyridine derivatives with acetic acid at the reflux temperature gave directly the title compounds in low to moderate yields.
Phase-Transfer Nucleophilic Reactions Using Water-Insoluble Alcohols as Organic Solvents
Authors: Ohtani Noritaka , Inoue Yukihiko , Shinoki Noriyuki , Nakayama Katsuhiro
Published: July 2006

Simple nucleophilic substitutions were done under liquid–liquid phase-transfer reaction conditions using water-insoluble alcohols as organic solvents. The reactions proceeded at considerable rates even in the absence of any catalysts, depending on the alcohol, inorganic salt, and the aqueous concentration of the salts. An addition of single- or double-chained onium salts enhanced the reaction rate almost linearly with the amount of the onium salts. The concentrations of inorgainc salts and water in the alcohol phase were analyzed and the relationship between these concentrations and the observed rate constant was discussed. An interfacial reaction mechanism explains the kinetics of this reaction system better than the conventional ion-pair mechanism assumed by most research using hydrocarbon solvents.
Novel Catalyst Systems for Phenol Synthesis by Vapor Phase Oxidation of Benzoic Acid
Authors: Miki Jun , Asanuma Minoru , Tachibana Yakudo , Shikada Tsutomu
Published: July 2006

Nickel, iron, and cobalt oxides showed excellent catalytic activities for the vapor-phase oxidation of benzoic acid to phenol at the reaction temperature of 400 °C. The combination of these metal oxides, catalyst preparation by precipitation followed by calcination at 800 °C, and addition of Na2O to the catalyst about 1% by weight enhanced the conversion of benzoic acid and the selectivity to phenol.

The structure of precipitation catalyst, Fe/Ni atomic ratio on the catalyst surface and formation of sodium benzoate on the catalyst surface play important roles for the optimization of catalyst activity. The novel catalyst systems could throw a new light on a one-step phenol synthesis from toluene. Appreciable one-pass phenol yield was obtained using a binary catalyst system consisting of V2O5–K2SO4–TiO2 and NiO–Fe2O3–Na2O, in which V2O5–K2SO4/TiO2 worked as a catalyst for toluene oxidation to benzoic acid and NiO–Fe2O3–Na2O functioned as a catalyst for benzoic acid to phenol.
Degradation of Azo Dyes by Sodium Hypochlorite 3. Estimation of the Rate Equation for the Degradation of Orange G and Benzopurpurine
Authors: Kanazawa Hitoshi , Onami Tetsuo
Published: July 2006

Degradation of azo dyes, Orange G and Benzopurpurine, by sodium hypochlorite in water was observed by UV spectroscopy. The observed values of the maximum absorbance in the spectra of the reaction mixture fitted well with the polynomials of the fifth degree in reaction time, t. The initial degradation rate of each dye was obtained easily as the differential coefficient of the functions at time 0. The degradation rate (Rd) of both dyes in the initial stage of the reaction was given by the second-order rate equation, Rd = k[Dye][NaOCl], where k is a rate constant. Apparent activation energies and frequency factors of the degradation were estimated as 20.3 kJ mol−1 and 4.59 × 104 dm3 mol−1 s−1, respectively, for Orange G, and 9.56 kJ mol−1 and 5.78 × 103 dm3 mol−1 s−1 for Benzopurpurine.
Design of an Organic Ultramicroelectrode Array. Potential Use of Microstructures of Binary Langmuir–Blodgett Monolayers of Totally π-Conjugated Electroactive and Electroinactive Amphiphiles
Authors: Kunitake Masashi , Nasu Kenji , Narikiyo Yoshitaka , Manabe Osamu , Nakashima Naotoshi
Published: July 2006

Mixed monolayers of totally π-conjugated electroactive compounds, 1-methyl-4-[2-[4-[2-(4-quinolyl)vinyl]phenyl]vinyl]quinolinium perchlorate (1) and 1-methyl-4-[2-[4-[2-(4-pyridyl)vinyl]phenyl]vinyl]pyridinium perchlorate (2) and those of compound 1 and palmitic acid (PA) were formed on a 0.1 M KClO4 aqueous solution. Surface pressure area isotherms and fluorescence microscopic observations suggest that mixtures of compounds 1 and 2 form homogeneous mixed monolayers, but those of 1 and PA are phase-separated in the mixed monolayers. These monolayers were transferred to gold by using the Langmuir–Blodgett technique and then in situ electrochemical characterization was conducted. Cyclic voltammograms of the mixed monolayers of 1-2 and 1-PA on gold indicate rectified transmembrane electron transfer through the monolayer of 1 in the mixed monolayers to hexacyanoferrate(II) in solution. Potential-step chronocoulometric responses have revealed that the monolayer of 1 in the mixed LB monolayer of 1-2 acts as an organic ultramicroelectrode array electrode.
Crystalline-State Reaction of Cobaloxime Complexes. 18. Metastable Intermediate Structure Observed by a New X-Ray Diffractometer for Rapid Data Collection
Authors: Ohashi Yuji , Sakai Yoshii , Sekine Akiko , Arai Yoshifusa , Ohgo Yoshiaki , Kamiya Nobuo , Iwasaki Hitoshi
Published: July 2006

A crystal of [(R)-1,2-bis(methoxycarbonyl)ethyl]bis(dimethylglyoximato)(diphenylmethylphosphine)cobalt(III) changes its cell dimensions with retention of the single crystal form on exposure to visible light. The change is so fast that a new type of diffractometer (IPD-WAS) was developed for rapid data collection. The structures were analyzed at four different stages of the change using the diffractometer, which enabled us to collect the three-dimensional intensity data within 2 h. The cell dimensions of the monoclinic crystal varied from a = 13.678(2), b = 24.880(6), c = 9.391(2) Å, β = 107.99(1)°, and V = 3040(1) Å3 to a = 13.56(1), b = 25.06(1), c = 9.381(6) Å, β = 107.35(6)°, and V = 3044(3) Å3. The space group was changed from P21 to P21/n. The structures at four stages showed that there are two crystallographically independent molecules, A and B, in an asymmetric unit of the crystal before irradiation and that the chiral 1,2-bis(methoxycarbonyl)ethyl (bmce) group of the B molecule is completely inverted to the opposite configuration while the chiral bmce group of the A molecule remains unaltered after irradiation. This brings about an inversion center between the two molecules. The reaction cavity for the B bmce group is significantly greater than that for the A bmce group. At the intermediate stages, the B bmce group takes complicated disordered structures, which indicates that there exists a metastable intermediate structure in the inversion process.
Magnetic Properties and Crystal Structures of Binuclear Copper(II) Complexes with Heterocyclic Thione Donors of 1,3-Bis(hydroxymethyl)-2-imidazolidinethione and 1-Hydroxymethyl-3-methyl-2-imidazolidinethione
Authors: Tokii Tadashi , Nakahara Shinji , Hashimoto Noriyuki , Koikawa Masayuki , Nakashima Michio , Matsushima Hideaki
Published: July 2006

A new series of binuclear copper(II) complexes with 1,3-bis(hydroxymethyl)-2-imidazolidinethione, [Cu(RCOO)(HL1)]2 (where R = CH3 (1), C6H5 (2), 2-CH3C6H4 (3), 4-CH3C6H4 (4), 2-ClC6H4 (5), and 2-BrC6H4 (6)), and with 1-hydroxymethyl-3-methyl-2-imidazolidinethione, [Cu(RCOO)(L2)]2 (where R = CH3 (7), 2-CH3C6H4 (8), and 4-CH3C6H4 (9)), have been prepared. The magnetic susceptibility data of complexes 1—9 conform to the usual dimer equation with the −2J values ranging from 227 to 992 cm−1. Crystal structure analyses of 3, 4, 7, and 9 revealed that two copper atoms are linked by two alkoxo-bridges with separations of 3.015(3)—3.069(3) Å in each complex. The coordination around each copper atom of the complexes is essentially a square planar configuration with one sulfur and two alkoxo-oxygen atoms of HL1 or L2 and one oxygen atom of carboxylates. Each alkoxo-group asymmetrically bridges with the Cu1–O1 bonds (1.90—1.92 Å), which are shorter than the Cu1′–O1 bonds (1.93—1.97 Å). The −2J values for complexes 3, 4, 7, and 9 are much better correlated with the Cu1′–O1 bond distances than with the alkoxo-bridging Cu1–O1–Cu1′ angles.
Magnetic Properties of Some Triangular Trinuclear Complexes of [Ru2M(μ-CH3COO)6(μ3-O)(py)3]n+ with a Diamagnetic Ion M
Authors: Kobayashi Hanako , Uryû Norikiyo , Mogi Iwao , Miyamoto Ryo , Ohba Yasunori , Iwaizumi Masamoto , Sasaki Yoichi , Ohto Akihiro , Ito Tasuku
Published: July 2006

The magnetic susceptibilities and the electron paramagnetic resonances (EPRs) of four complexes: [Ru2M(μ-CH3COO)6(μ3-O)(py)3]n+ (M = Zn(II), Mg(II), and Ru(II): n = 0; and Rh(III): n = 1) salts were observed. These are magnetic dimers of Ru(III). The results were analysed under the assumptions that the strong antiferromagnetic superexchange interaction (J3) is working through μ3-O bridge and that the antiferromagnetic superexchange interaction (J1) through μ-(CH3COO)2–M(dia)–(CH3COO)2 is very weak compared to those of double μ-acetato bridges (J2’s) and of the μ3-O bridge between Ru(III) ions considering the Goodenough–Kanamori rule. The fitting assuming a probability for each path showed the antiferromagnetic interactions through μ3-O were much stronger than that of the symmetric trimer M = Ru(III). J1/k’s were −1.4 — −6.5 K (J1; −97 — −450 m−1), J2/k’s were −40 — −110 K (J2; −2780 — −7640 m−1), and J3/k’s were −500 — −900 K (J3; −34700 — −62500 m−1). Samples of M = Rh(III) and Ru(II) seem to show weak ferromagnetism.
Linear Chain Compounds of Molybdenum(II) Acetate Linked by Pyrazine, 4,4′-Bipyridine, and 1,4-Diazabicyclo[2.2.2]octane
Authors: Handa Makoto , Mikuriya Masahiro , Kotera Takanori , Yamada Kori , Nakao Tadahiro , Matsumoto Hiroki , Kasuga Kuninobu
Published: July 2006

A series of linear-chain complexes of molybdenum(II) acetate linked by bidentate bridging ligands, [Mo2(O2CCH3)4L]n (L = pyrazine (pyz), 4,4′ -bipyridine (4,4′-bpy), and 1,4-diazabicyclo[2.2.2]octane (dabco)), have been prepared, and their crystal structures determined by an X-ray diffraction method. It has been shown that the relatively weak coordinations of the bridging ligands at the axial positions of Mo2(O2CCH3)4 (Mo–N = 2.619 (8)—2.658(6) Å) can effectively control the arrangement of the dimer units to give chain structures with good linearities. No significant interactions between the dimer units have been observed.
Kinetic Study of the Binding of Ca2+ to S-100 Proteins
Authors: Matsuda Sadayuki
Published: July 2006

The effects of trifluoperazine (TFP) and mastoparan (MP) on the rate of Ca2+-release from bovine brain S-100 proteins (s-100a.a′, S-100b) were determined using a stopped-flow method. No remarkable difference was observed in the rate constants for the case of S-100a.a′ and S-100b at pH = 7.14. The addition of MP decreased the rate constants to one fifth, while TFP had little influence.
Preparation and Structure of Sterically Protected Diethynylphosphines and Dibutadiynylphosphines
Authors: Toyota Kozo , Shibata Manabu , Yoshifuji Masaaki
Published: July 2006

Sterically protected diethynyl(2,4,6-tri-t-butylphenyl)phosphines and (2,4,6-tri-t-butylphenyl)bis(4-trimethylsilyl-1,3-butadiynyl)phosphine were prepared and their structures were analyzed by X-ray crystallography. The aromatic rings in these molecules are distorted to boat or more likely envelope forms in the crystals. Large distortion in the –P–C≡C– moieties was also observed.
Synthesis and Dynamic Stereochemistry of Tris(2-methyl-1-azulenyl)methyl Cation and the Corresponding Methane Derivative. Evidence That the Conjugative Effect Largely Contributes to the Transition State of the Ring Flipping
Authors: Ito Shunji , Morita Noboru , Asao Toyonobu
Published: July 2006

The stable carbocation, tris(2-methyl-1-azulenyl)methyl hexafluorophosphate (4·PF6−) was prepared by a hydride-abstraction reaction of the corresponding methane derivative, tris(2-methyl-1-azulenyl)methane (5). The dynamic stereochemistry of 4 and 5 was studied based on the temperature-dependent 1H NMR spectra, which were analyzed by a flip mechanism; the steric effect of the three 2-methyl groups was also investigated by comparing it with that of the 3,3′,3″-trimethyl analogue, tris(3-methyl-1-azulenyl)methyl hexafluorophosphate (1b·PF6−). The threshold rotation mechanism for 4 was a two-ring flip, in contrast to a one-ring flip for 1b, and the activation energies for 4 (78.0 and 73.4 kJ mol−1) were higher than those for 1b due to increased crowding in the transition state for the rotation. Although the activation energies for 5 (49.9 and 43.2 kJ mol−1) were lower than those for 1b, the mechanism for 5 was also a two-ring flip. The mechanism was variable between one- and two-ring flip processes due to a steric effect of the three 2-methyl groups. These results indicate that a conjugative interaction between the central cation and the three azulene rings largely contribute to the transition state of the ring flipping as well as to the ground state.
Direct Construction of the Chroman Structure from 1,3-Diene. Regioselective Protonation of Acyclic Polyene
Authors: Matsui Makoto , Yamamoto Hisashi
Published: July 2006

The regioselective protonation of acyclic polyene was achieved, dependent on the choice of catalyst. The addition of myrcene to trimethylhydroquinone, using boron trifluoride–diethyl ether (1/1), predominantly gave a spiro structure. When (+)-10-camphorsulfonic acid was used as a catalyst, the major compound produced was chroman.
Preparation of Phosphoamino Acid Derivatives with Acid Stable O-Phosphono-Protection for the Boc-Mode Solid-Phase Synthesis of Phosphopeptides
Authors: Wakamiya Tateaki , Saruta Kunio , Yasuoka Jun-ichi , Kusumoto Shoichi
Published: July 2006

Boc-phosphoamino acid derivatives with O-[di(4-nitrobenzyl)- or dicyclohexylphosphono]-protection were prepared for application to the Boc-mode solid-phase synthesis of phosphopeptides. These protecting groups are both stable to TFA, but removable with a combination of trifluoromethanesulfonic acid and methylthiobenzene in TFA. Of these derivatives, Nα-Boc-O-(dicyclohexylphosphono)serine and Nα-Boc-O-(dicyclohexylphosphono)threonine were obtained as crystalline compounds to be favorably utilized as starting materials for solid-phase synthesis using an automated peptide synthesizer. On the other hand, Nα-Boc-O-(dicyclohexylphosphono)tyrosine and all of the O-[di(4-nitrobenzyl)]phosphono derivatives were prepared as crystalline cyclohexylammonium or dicyclohexylammonium salts.
Synthesis of 3-Oxosapriparaquinone, a Diterpene from Salvia prionitis Hance
Authors: Matsumoto Takashi , Takeda Yoshio , Soh Kimiko , Matsumura Hiroyuki , Imai Sachihiko
Published: July 2006

12-Acetoxy-5,10-friedo-4,5-seco-abieta-3,5(10),6,8,11,13-hexaene prepared from (+)-dehydroabietic acid, was converted into a natural rearranged abietane-type diterpene, 3-oxosapriparaquinone, via 12-benzoyloxy-3-hydroxy-5,10-friedo-4,5-seco-abieta-5(10),6,8,12-tetraene-11,14-dione by a series of reactions: hydroboration–oxidation, benzoyl peroxide oxidation, Jones oxidation, and alkaline hydrolysis.
Reaction of Mono-, Di-, and Trichloronitrobenzenes with N-Methyl Substituted Cyclic Tertiary Amines under High Pressure
Authors: Ibata Toshikazu , Shang Muhong , Demura Tetsuo
Published: July 2006

The reactions of mono-, di-, and trichloronitrobenzenes with 1-methylpyrrolidine under high pressure gave products of demethylation and ring-opening through a quaternary pyrrolidinium chloride intermediate formed by the SNAr reaction. On the other hand, the reactions with 1-methylpiperidine and 4-methylmorpholine gave only demethylation products. The selectivities of the reactions of 1-methylpyrrolidine with these chloronitrobenzenes were found to be effected by the neighboring substituent to the pyrrolidinium group.
Synthesis and Structure of 1,4-Dimethoxy and 1,4-Dimethyl-9-(trifluoromethyl)triptycenes
Authors: Toyota Shinji , Watanabe Yoichi , Yoshida Hiroyuki , Oki Michinori
Published: July 2006

As the first example of triptycenes carrying a trifluoromethyl group at the 9-position, the title compounds were synthesized by the Diels–Alder reaction of 9-(trifluoromethyl)anthracene with a substituted benzyne. Rotational barrier of the 9-trifluoromethyl group is more than 25 kcal mol−1 according to the 19F NMR measurements at high temperatures. X-Ray analyses of these compounds reveal that molecules have some unusual bond lengths and angles ascribable to steric interactions between the 1-substituent and the 9-trifluoromethyl group. Comparison of these structural parameters with those of the 9-t-alkyltriptycenes reported previously reveals that the out-of-plane bending of the 1-methoxy group in the latter is unusual. We attribute this anomaly to the presence of the C–H···O hydrogen bond.
Crystal Structures and Hydrogen Bonding in One-Dimensional Chains of 4,5-Dicyanoimidazole and 4,5-Dichloroimidazole
Authors: Nagatomo Shigenori , Takeda Sadamu , Tamura Hatsue , Nakamura Nobuo
Published: July 2006

The crystal structure of 4,5-dicyanoimidazole ((CN)2Imd) was determined by an X-ray diffraction at room temperature; monoclinic, P21/a, a = 7.259(2), b = 7.529(1), c = 10.0972(9) Å, β = 102.74(1)°, V = 538.2(2) Å3, Z = 4, R = 0.043, and Rw=0.066 for 1090 observed reflections. Crystal structure of 4,5-dichloroimidazole (Cl2Imd) was redetermined; tetragonal, P41212, a = 6.843(4), c = 24.236(7) Å, V = 1134(1) Å3, Z = 8, R = 0.043, and Rw = 0.058 for 427 observed reflections. Molecules in Cl2Imd and in (CN)2Imd are linked by intermolecular N–H···N hydrogen bonds to form one-dimensional chains. The hydrogen bonds in Cl2Imd are formed between the ring nitrogen atoms, while those in (CN)2Imd are between the ring and the cyano nitrogens. The hydrogen bond distance (3.051(2) Å) of N···N in (CN)2Imd is long, compared with that (2.800(6) Å) in Cl2Imd. The weak hydrogen bond in (CN)2Imd was also indicated by IR and 15N CP/MAS NMR spectra.
Fluorescence Properties of Pyrylium and Thiopyrylium Salts
Authors: Parret Sylvie , Morlet-Savary Fabrice , Fouassier Jean-Pierre , Inomata Kiyoshi , Matsumoto Takeo , Heisel Francine
Published: July 2006

Due to their very substantial fluorescence emission, pyrylium and thiopyrylium salts are widely used as laser dyes and photosensitizers. This paper deals with the fluorescence properties (quantum yields and wavelengths of the fluorescence maxima as well as the lifetimes of the singlet excited states) of eight pyrylium and ten thiopyrylium salts, with special emphasis on the effect of α and γ substitutions of the heterocycle.
Diffusion Process of a Liquid Crystal Probed by the Transient Grating Method
Authors: Ohta Kaoru , Terazima Masahide , Hirota Noboru
Published: July 2006

Translational diffusion of MBBA (N-(4-methoxybenzylidene)-4-n-butylaniline) in the nematic and isotropic phases is investigated by the transient grating (TG) method. The origin of the TG signal due to the population grating is attributed to the spatial variation of the order parameter and, as a result, the time dependence of the signal reflects the diffusion of the cis form of MBBA, not of the trans form. In the nematic phase, the diffusion constant parallel to the director orientation, D||, is always larger than the perpendicular one, D⊥. The obtained values are 2.2—2.5 times larger than previously reported ones measured by using a photosensitive probe molecule in the liquid crystal. The anomaly previously reported near the nematic–isotropic phase transition temperature is not observed, and the diffusion constant in the isotropic phase is close to the average value of the both components, 1/3(D + 2D⊥). The experimental values are also compared with the ones calculated from two theoretical expressions by Franklin, and Chu and Moroi.
Highly Sensitive and Low Loss Ion-Exchanged Glass Optical Waveguides Constructed by the Successive Doping of K+ and Ag+ Ions
Authors: Chen Xiao-Min , Itoh Kiminori , Murabayashi Masayuki
Published: July 2006

A K+ ion-exchanged glass optical waveguide (OWG) was combined with an Ag+ ion-exchanged glass OWG on one substrate by tapered velocity coupling to obtain a low loss and highly sensitive ion-exchanged OWG system. The relative sensitivity of the Ag+-doped region was more than 1000 times per unit length (the reference here being spectroscopic measurements with normal incidence of monitoring light). The attenuation of the guided light was 3—5 dB cm−1 at the highly sensitive part. Stability against heat and against UV-irradiation were investigated also.
Stereoselective Formation and Characterization of S-Bridged Dinuclear Λ- and Δ-[Co{Co(didentate-N,S)3}(d-pen-N,O,S)]-Type Complexes (didentate = 2-Aminoethanethiolate, l-Cysteinate, and d-Penicillaminate (d-pen))
Authors: Yonemura Toshiaki , Nakahira Sayuri , Ama Tomoharu , Kawaguchi Hiroshi , Yasui Takaji , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

Novel S-bridged dinuclear cobalt(III) complexes having different absolute configurations in [Co(didentate-N,S)3] moieties, Λ- and Δ-[Co{Co(didentate-N,S)3}(d-pen-N,O,S)]+ or 2− (didentate = 2-aminoethanethiolate (aet), l-cysteinate (l-cys), and d-penicillaminate (d-pen)), were prepared stereospecifically. The dinuclearizing reaction of ΔLll-fac(S)-[Co(l-cys-N,S)3]3− with [CoCl(NH3)5]2+ and d-penicillaminate proceeded with configurational retention in the [Co(l-cys-N,S)3] moiety, while the reaction using the Co(II) ion instead of [CoCl(NH3)5]2+ was accompanied by a configurational inversion in the [Co(l-cys-N,S)3] moiety. The occurrence of the configurational inversion was related to the intramolecular N–H···O hydrogen bonds between two ligands in the formation process of the dinuclear complexes. The newly prepared dinuclear complexes were characterized on the basis of their electronic absorption, CD, 13C NMR, and IR spectral data. Electrochemical measurements of [Co{Co(didentate-N,S)3}(d-pen-N,O,S)]+ or 2− gave two redox waves at ca. −0.61 V and −0.85 to −1.04 V (vs. Ag/AgCl). The former wave corresponds to the Co(III)/Co(II) redox of the [Co(S)3(d-pen-N,O,S)] moiety, and the latter one to that of the [Co(didentate-N,S)3] moiety.
Highly Acidic Extractant, 4-Benzoyl-3-phenyl-5-isoxazolone: The Synergistic Extraction of Alkaline Earth and Alkali Metals Combined with Trioctylphosphine Oxide or Bis(diphenylphosphinyl)methane
Authors: Le Quyen T H , Umetani Shigeo , Sasaki Takayuki , Tomita Takeshi , Matsui Masakazu
Published: July 2006

The synergistic extraction of alkaline earth (Mg2+, Ca2+, Sr2+, and Ba2+) and alkali metals (Li+ and Na+) with a highly acidic extractant, 4-benzoyl-3-phenyl-5-isoxazolone (HPBI), combined with a synergist, trioctylphosphine oxide (TOPO) or bis(diphenylphosphinyl)methane (BDPPM), has been examined. The results were compared with those of the analogous extractants, 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone (HPMBP) and 3-methyl-1-phenyl-4-trifluoroacetyl-5-pyrazolone (HPMTFP) which are also highly acidic extractants derived from heterocyclic compounds. Owing to the strong acidity of HPBI (pKa = 1.23), alkaline earths were extracted quantitatively from a very low pH region. Especially, alkaline earths were readily extracted at pH 2—3 with the bidentate phosphine oxide, BDPPM, as a synergist. The extraction of Li+ and Na+ with HPBI and TOPO was inferior to that with HPMBP and HPMTFP, though their acidity is weaker. In contrast to the excellent extractability of HPBI, its separation was poor. The extractability and separability are discussed in terms of the molecular structure, particularly the distance of the two donating oxygens.
Synthesis and Characterization of Highly Pure Form of Sodium Salt of Anionic, Thiomalatogold(I) Complex with Antiarthritic Activity. Analogs of Anionic, Thiomalatosilver(I) Complex with Antimicrobial Activity
Authors: Nomiya Kenji , Yokoyama Hiroshi , Nagano Hitomi , Oda Munehiro , Sakuma Sadatoshi
Published: July 2006

Sodium salt of anionic Au(I) complex with a trianion of thiomalic acid tma3− (H3tma = HOOCCH(SH)CH2COOH), known as an effective antiarthritic drug, was prepared in highly pure form by one-step synthesis from NaAuCl4 and tma3− in aqueous solution. The reaction consisted of a reduction of Au(III) by tma3− and the following complexation of Au(I) with tma3− ligand. The disulfide species of tma3− formed by this reduction was removed by passing through an anion-exchange resin column and the contaminating NaCl by passing through a gel filtration column. The tma–Au(I) complex was also prepared by another reaction based on ligand exchange of the intermediate complex AuCl(thiodiglycol) with tma3−. It was purified using the anion-exchange resin and gel filtration columns. The target compound, finally isolated in 30% yield in highly pure form, has been characterized by complete elemental analyses, TG/DTA, FT-IR, 1H and 13C NMR spectroscopies, and molecular weight was determined in aqueous solution by molmass measurement based on the cryoscopic method combined with dissociation degree determination based on the [Na+] measurement in equilibrium state using a Na+-ion selective electrode. This Au(I) complex was an oligomer with a formula of {Na2[Au(tma)]·1.75H2O}n (n = 3—10; MW = 1260—4220). This polymerization degree, low in comparison with previously proposed data, was determined in the neutral aqueous solution without any other electrolytes under the concentration range CNa = 0.914—182.9 mmol dm−3. The tma–Au(I) complex exists in an oligomeric form both in the solid and in aqueous solution. The properties of the oligomeric tma–Au(I) complex were compared with those of the previously reported complex and a commercially available sample, and also with those of the recently prepared, oligomeric tma–Ag(I) complex with antimicrobial activity.
Spectrophotometric Determination of Zirconium with 5,7-Diiodo-8-hydroxyquinoline
Authors: Nijhawan Monica , Chauhan Rakam Singh , Kakkar Lajpat Rai
Published: July 2006

5,7-Diiodo-8-hydroxyquinoline (diiodo-oxine) has been used as an analytical reagent for the spectrophotometric determination of zirconium with which it forms a yellow colored complex (1 : 2) in dilute hydrochloric acid solution. The complex is extractable into chloroform from 0.1—0.2 mol dm−3 HCl showing an absorption maximum at 417.5—421 nm with a molar absorptivity of 1.87 × 104 dm3 mol−1 cm−1 and Sandell sensitivity equal to 4.8 × 10−3 μgZr cm−2. Beer’s law holds good in the range 0—5 μgZr cm−3, with a standard deviation ±0.006 and relative mean error ±0.36%. The method is simple, selective and sensitive.
Complexes of 15,15′-Trimethylenebis(1,4,7,10,13-pentaazacyclohexadecane-14,16-dione) with Bivalent Metal Ions. Complexation Equilibria in an Aqueous Solution
Authors: Kodama Mutsuo
Published: July 2006

With polarographic and potentiometric methods, the complexation equilibria of 15,15′-trimethylenebis(1,4,7,10,13-pentaazacyclohexadecane-14,16-dione) [abbreviated to bis(dioxo[16]aneN5)] with Cu2+, Cd2+, Hg2+, and Pb2+ ions were investigated systematically. It was found that bis(dioxo[16]aneN5) reacts with Cu2+ ion affording a 2 : 1 ratio binuclear complex, designated Cu2L4+ or [Cu2H−4L]°, but in the reactions with Cd2+, Hg2+, and Pb2+ ions it forms 1 : 1 ratio complexes, ML2+. Comparison of formation constants for the complexes of the latter bivalent metal ions with those of the parent 1,4,7,10,13-pentaazacyclohexadecane-14,16-dione [abbreviated to dioxo[16]aneN5] showed that the attachment of the second dioxo[16]aneN5 moiety always enhances the complexation ability of the dioxo[16]aneN5 ligand considerably, suggesting the formation of sandwich-type complexes, where the metal(II) ion is located between the two cyclic pentaamine moieties.
Successive Chemical Reactions Accompanying a One-Electron Oxidation of a {MNO}6-Type Nitrosyl Complex, Pentachloro(nitrosyl)ruthenate(2−), and a Characterization of the Product Species
Authors: Ooyama Dai , Nagao Noriharu , Howell F Scott , Mukaida Masao , Nagao Hirotaka , Tanaka Koji
Published: July 2006

A one-electron oxidation species of the title complex, [Ru(NO)Cl5]−({RuNO}5-type nitrosyl complex), converted into cis-[Ru(NO)Cl4(CH3CN)]−({RuNO}6-type nitrosyl complex) at low temperature (5 °C) in the dark. The product species could be isolated and characterized. An X-ray structure determination showed a remarkably short N–O bond distance of the Ru–NO moiety: l(N–O) = 0.998 Å, l(Ru–N) = 1.787(5) Å, ∠Ru–N–O = 175.1(6)°. Under room light at 25 °C, the complex underwent a facile nitrosyl photoelimination to give trans-[RuCl4(CH3CN)2]−, the structure of which was also established. During the course of the reactions, two other unidentified species were confirmed to exist by cyclic voltammetry.
Synthesis of 1,3-Dioxane-Bridged Pyropheophorbide-Diimide and Pyropheophorbide Dimer and Their Intramolecular Electron and Energy Transfer
Authors: Osuka Atsuhiro , Marumo Shinji , Wada Yukihisa , Yamazaki Iwao , Yamazaki Tomoko , Shirakawa Yoshihiro , Nishimura Yoshinobu
Published: July 2006

1,3-Dioxane-bridged pyropheophorbide–diimide dyads and pyropheophorbide dimer were synthesized by simple acid-catalyzed reactions of methyl pyropheophorbide d with diimide-substituted diols and with pentaerythritol, respectively. 1,3-Dioxane-bridged bacteriopyropheophorbide–diimide was similarly prepared from bacteriopyropheophorbide a. Intramolecular electron-transfer and energy-transfer reactions in these models have been studied by picosecond fluorescence measurements.
Effect of Hexacyanoferrate(III) on Mycobacterium smegmatis 7Fe Ferredoxin: Further Evidence for Formation of a 6Fe(2 × [3Fe–4S]) Ferredoxin
Authors: Imai Takeo , Kamata Kazuya , Saito Hiroshi , Urushiyama Akio
Published: July 2006

Addition of potassium hexacyanoferrate(III) to Mycobacterium smegmatis 7Fe ferredoxin resulted in the formation of a new 6Fe(2 × [3Fe–4S]) ferredoxin, which was verified by the iron content and resonance Raman spectra of the highly purified preparation. The results suggest that the 4Fe cluster in the native ferredoxin was converted into a 3Fe cluster. The new 3Fe cluster produced was found to be similar in structure to the native 3Fe cluster as judged by the Raman spectra. The produced 6Fe(2 × [3Fe–4S]) ferredoxin was further degraded into apoferredoxin upon application of additional hexacyanoferrate(III).
Electronic Effects of Substituents on Indole Nitrogen on the Photochromic Properties of Indolylfulgides
Authors: Uchida Soichi , Yokoyama Yasushi , Kiji Jitsuo , Okano Tamon , Kitamura Hitoshi
Published: July 2006

The attempt to synthesize N-p-tolylsulfonylindolylfulgide by Stobbe condensation was unsuccessful because hydrolysis of the Stobbe-condensation product eliminated the sulfonyl moiety to give, after several steps, the N-unsubstituted fulgide. Pd(II)-catalyzed carbonylation of 2-butyne-1,4-diol derivative bearing the N-p-tolylsulfonylindole, however, afforded the desired N-p-tolylsulfonylindolylfulgide. A comparison of absorption spectroscopic and photochromic properties of these fulgides with those of the known N-methylindolylfulgide gave the following results. The electron-withdrawing substituent on nitrogen (i) shortened the absorption maximum of the colored form, (ii) suppressed thermal E–Z isomerization, and (iii) enlarged quantum yields of photochromic reactions.
Alkyl Radical Substitution on Disulfide in the Presence of Cobalt(II) Complexes
Authors: Tada Masaru , Sugano Kiyohiko , Yoshihara Takao
Published: July 2006

Photolysis of methyl(L)cobaloxime (L = trans ligand) (1) or methyl(L)-O,O′-bis(difluoroboryl)cobaloxime (2) in the presence of bis(4-chlorophenyl) disulfide gave 4-chlorophenyl methyl sulfide together with 4-chlorophenylthio(L)cobaloxime (5) or 4-chlorophenylthio(L)-O,O′-bis(difluoroboryl)cobaloxime (6). Similar photolysis in the presence of 2,2,6,6-tetramethyl-1-piperidyloxyl (TEMPO) gives 1-methoxy-2,2,6,6-tetramethylpiperidine. The reactivity of the cobaloximes 1 and 2 to the disulfide and TEMPO increases when the cobaloximes have a trans ligand (L) of larger steric requirement and low pka, or when the equatorial ligand is an electronegative O-(difluoroboryl)dimethylglyoxime. Two probable mechanisms are proposed for the reaction. The first is a direct radical substitution on the disulfide with a methyl radical, and the second involves the initial interaction between the disulfide and the (L)cobaloxime radical to afford arylthio(L)cobaloxime (5 or 6) and an arylthio radical. The latter radical reacts with methyl(L)cobaloxime to give aryl methyl sulfide.
Chemically Induced Dynamic Electron Polarization Studies of Photochemical Reactions: Acetone in 2-Propanol and Triethylamine
Authors: Hirota Noboru , Tominaga Keisuke , Yamauchi Seigo
Published: July 2006

The results of Chemically Induced Dynamic Electron Polarization (CIDEP) studies of acetone in 2-propanol and triethylamine are reviewed to show how CIDEP studies can reveal interesting details of the initial processes of photochemical reactions. After a brief description of various mechanisms that give rise to CIDEP, the following topics are discussed: a) spectral pattern and the main reacting state, b) CIDEP mechanisms and the temperature and frequency dependences of the spectra, c) direct EPR observation of the radical pair spectra in solution, d) time-developments of the CIDEP signals and spin and reaction dynamics of the initial processes of photochemical reactions, e) quantitative analyses of the magnitudes of CIDEP in terms of a stochastic Liouville equation, and f) some related applications. An overview of the remaining problems and the future outlook is also presented.
The Effects of CO2-Conditioning of Polymers on Positron Annihilation and Gas Permeation Properties
Authors: Tanaka Kazuhiro , Ito Masamichi , Kita Hidetoshi , Okamoto Ken-ichi , Ito Yasuo
Published: July 2006

The effects of CO2-conditioning, i.e. exposing a polymer film to high pressure CO2 and degassing it in vacuo, on positron annihilation and gas permeation properties of polyimides and polyethylene were investigated. Both lifetime and intensity of ortho-positronium (o-Ps) (τ3 and I3, respectively) increased for polyimides by the CO2-conditioning. The size distribution of free space holes, which was evaluated from annihilation rate distribution of o-Ps, became broader and shifted to larger size. Permeability, diffusion, and solubility coefficients of gases for polyimides increased by the CO2-conditioning. The increases in diffusion coefficient are attributed to increases in volume fraction of free space holes, VF. The increases in τ3 and in I3 were much larger than those expected from the increases in VF. This may be explained by a model based on an interplay between electron affinity and size of free space holes for Ps formation. In the CO2-conditioned films, permeability and diffusion coefficients, VF, and I3 gradually decreased with lapse of time but after five months they were still larger than those in the as-cast films, whereas τ3 remained almost constant. No effect of the CO2-conditioning was observed for polyethylene.
Experimental Study of Amorphous Silica Crystallization in Na2CO3–NaHCO3 Solutions as a Source of Chert Formation in Lake Magadi
Authors: Muraishi Haruto
Published: July 2006

Amorphous silica was treated with Na2CO3–NaHCO3 and Na2CO3–NaHCO3–NaCl solutions, which are related to the alkaline brine in Lake Magadi in East Africa; its transformation was followed as a function of time under various temperatures (100—160 °C) and pHs (8—12). The reaction occurred in steps. Three kinds of sodium silicates (magadiite, kenyaite, and SiO2-X2) appeared as intermediate phases in solutions with various pH, and finally converted into quartz. The rate of formation of naturally occurring silicates and quartz (chert) was roughly estimated by extrapolating the basis of the data on the temperature dependence of the conversion rate. From those crystallization observations, the preparation conditions for obtaining well-crystallized silicates were determined, and kenyaite was synthesized, which has note yet been obtained as a highly crystallized compound.
Long-Life Excited States of CdS Photocatalytic Particles
Authors: Nakabayashi Seiichiro , Yanagida Masatoshi , Uosaki Kohei
Published: July 2006

The CdS particles are irradiated by the green light from an Ar laser. The irradiation produces the electron-hole pairs and other excited states in the particle. The lifetime of the excited state is ca. 10 μs, which is extremely long compared with the recombination time of the electron and hole pairs. This long-life state forms an optical absorption band in the excitation-modulated transmission spectra. The relationship between the spectral intensity and the strength of the excitation light suggests that this absorption band is caused by the photoionization of the intervalence states and the change in the electrostatic field in the CdS particles.
Highly Twisted Ethylene Dianion Dilithium Stabilized by Phenyl and Silyl Groups
Authors: Sekiguchi Akira , Ichinohe Masaaki , Nakanishi Tetsuo , Kabuto Chizuko , Sakurai Hideki
Published: July 2006

Phenyl- and silyl-substituted ethylene dianion dilithiums, [1-phenyl-1,2,2-tris(trimethylsilyl)ethylene]{bis[(dimethoxyethane)lithium(I)]} (2) and [1,1-diphenyl-2,2-bis(trimethylsilyl)ethylene][tris(tetrahydrofuran)dilithium(I)] (4), were prepared and characterized by X-ray crystallography as well as NMR spectra. The crystal structures of 2 and 4 revealed interesting structural features. One of the lithium cations was located near to the two central carbon atoms, ipso and ortho carbons of the phenyl ring, while the other one was found above the benzene ring. The central C–C bond is twisted by ca. 90° for 2 and ca. 70° for 4.
Dual Nature of (Phenylseleno)cobaloxime in the Reaction with 2-Propynyl Derivatives
Authors: Tada Masaru , Nagasaka Ritsuko
Published: July 2006

Photolysis or thermolysis of (phenylseleno)cobaloxime gives a pair of radicals: phenylseleno radical and cobaloxime radical, which are considered to be equilibrated with the ion pair by a single electron transfer. The radical addition on the acetylenic moiety takes place when the 2-propynyl derivatives have weak leaving groups (OH, OPh, OAc). On the other hand, the ionic substitution with phenylseleno anion takes place on bromides and tosylates.
Enantioselective Aerobic Oxidation of Sulfides Catalyzed by Optically Active β-Oxo Aldiminatomanganese(III) Complexes
Authors: Nagata Takushi , Imagawa Kiyomi , Yamada Tohru , Mukaiyama Teruaki
Published: July 2006

Enantioselective aerobic oxidation of sulfides into optically active sulfoxides was achieved by using pivalaldehyde in the presence of a catalytic amount of optically active β-oxo aldiminatomanganese(III) complexes. An acylperoxomanganese complex, formed from the original manganese complex, molecular oxygen, and pivalaldehyde, was supposed to be a key intermediate in the present oxidation. The crystal structure of chloro-{N,N′-bis[3-oxo-2-(2,4,6-trimethylbenzoyl)butylidene]-(1S,2S)-1,2-diphenylethylenediaminato}manganese(III) was determined by X-ray diffraction methods, which suggested that the bulkiness of the substituents in β-oxo aldimine ligand had played an important role in controlling the approach of sulfides to the manganese complex. Kinetic resolution took place during the subsequent oxidation process of sulfoxide into the corresponding sulfone, and the optical purity of the remaining sulfoxide increased.
Uricase Model Reactions of Polylysine–Cu(II) Complexes
Authors: Tokimitsu Yoshirou , Ise Norio , Tanaka Naoki , Kunugi Shigeru
Published: July 2006

Oxidation of uric acid was catalyzed by Cu(II) complexes of polylysines. The presence of the polylysine as the second ligand (in addition to the first ligand; the substrate) showed an enhancement of the intrinsic catalytic activity of Cu(II) ions. Accounting for the apparent substrate inhibition phenomenon, due to the absorbance interference by the intermediate, approximate Km value for the model systems were determined to be around 30—40 μM, which are better than that of the free Cu(II) system, 60—80 μM, and comparable or even better than the Km values for some enzymatic reactions. From the CD spectrum the conformation of the polymer ligands is known to influence the catalytic activity. A preference of partly ordered structure is implied.
The Optical and Photoelectrochemical Properties of Electrodeposited CdS and SnS Thin Films
Authors: Adachi Atsushi , Kudo Akihiko , Sakata Tadayoshi
Published: July 2006

An electrodeposition technique was employed to synthesize CdS and SnS thin films. The optical and photoelectrochemical properties of these films were studied. Red emission peaks of as-deposited CdS thin films were observed around 650—700 nm at 77 K. Anodic photocurrents were observed for the CdS thin films used as semiconductor electrodes. Lowering current densities for the deposition increased both the photoluminescence intensity and the photocurrents. SnS thin films were prepared by a pulsed electrodeposition technique. The films had a large absorption coefficient of 105 cm−1 order. Stirring the electrolyte solution had a drastic effect on the film growth. This suggests that the diffusion of elemental sulfur which reacts with electrochemically formed Sn is the rate determining step of the SnS formation.