bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Formation of a Polypyrrole Film and a Tantalum Oxide Layer by Electrochemical Oxidation
Authors: Park Young-seo , Yamamoto Kimihisa , Takeoka Shinji , Tsuchida Eishun 
Published: July 2006

Abstract
Electropolymerization of pyrrole on tantalum (Ta) electrodes was carried out in Britton-Robinson buffer solutions containing 0.1 M (1 M = 1 mol dm−3) potassium chloride (KCl) under galvanostatic conditions. A polypyrrole (PPy) film and a tantalum oxide (Ta2O5) layer are formed on a Ta electrode by one electrochemical oxidation process. The conditions of this simultaneous formation were investigated in respect with the current density, pyrrole concentration, pH, and total charge. Under certain conditions ([py] = 0.5 M, pH = 1.8, current density = 3.5 mA cm−2, charge 1 C), a 5.6 μm thick PPy film was efficiently formed on a homogeneous 45 nm thick Ta2O5 layer.
Removal of Phosphate from Dilute Phosphate Solution by an Iron Chitosan Complex to Be Used as an Oral Sorbent
Authors: Jing Shi-Bing , Yamaguchi Tatsuaki 
Published: July 2006

Abstract
The long-period administration of aluminum-containing phosphate binders for the treatment of hyperphosphatemia has been shown to carry the risk of aluminum accumulation associated with many bone diseases. An iron chitosan complex prepared by chitosan and iron(II) sulfate was examined as an alternative intestinal phosphate binder. In-vitro experiments have shown that the phosphate-binding capacity of iron chitosan increases with increasing the iron content of iron chitosan, the concentration of phosphate, and the pH of the solution. The phosphate-binding capacity of iron chitosan (iron content 32 mg g−1) was over 30 mg g−1 when 10 mg of iron chitosan was admitted to 10 ml of a phosphate solution of 10 mg dl−1 (pH 7.5) at 37 °C for 6 h. This value is much higher than those of aluminum hydroxide, calcium carbonate, etc., which were practically tried before. No elution of the iron from iron chitosan could be detected under these conditions.
Selective Permeation Properties of Inorganic Ions across a Hydrophobic Membrane
Authors: Igawa Manabu , Nishiura Rie , Mashiyama Noriyuki , Usuda Yoshimi 
Published: July 2006

Abstract
A hydrophobic membrane was prepared from poly(tetrafluoroethylene-co-hexafluoropropylene) by coating method to be a very thin membrane with a high water permeability. The permeation, the diffusion, and the distribution coefficients were measured by time lag method. The permeation coefficient of a salt decreased with the increase of the hydrophilicity of the salt, while hydrophilic salts are permeated readily by the coupling of water flux under a pressure gradient. The characteristic permeation properties of the hydrophobic membrane were caused by the hydrophobic hydration in the pores of the membrane and a hydrophilic ion has a low diffusion coefficient and a high distribution coefficient. The diffusion coefficient of potassium chloride increased with the increases of the temperature or the concentration, while the distribution coefficient had a minimum value at about 55 °C and decreased with the increase of the concentration. Some organics added to the source phase solution affected the hydration structure in the membrane, which changed the permeation properties of salts.
Crystal Structures and Molecular Packing of Tetrakis(alkylthio)tetrathiafulvalene (TTCn–TTF); Part I (n = 3,4,6)
Authors: Nakano Chikako , Mori Takehiko , Imaeda Kenichi , Yasuoka Noritake , Maruyama Yusei , Inokuchi Hiroo , Iwasawa Naoko , Saito Gunzi 
Published: July 2006

Abstract
The crystal structures of tetrakis(alkylthio)tetrathiafulvalene TTCn–TTF (n = 3, 4, 6) were determined by X-ray analysis. The structures of TTCn–TTF drastically changed between n = 3 and 4. The TTC3–TTF molecule has a boat-like shape, like that of TTC1–TTF and TTC2–TTF. On the other hand, the TTC4–TTF and TTC6–TTF molecules have chair-like shapes, like that of TTC5–TTF, and columnar structures with intermolecular effective overlaps between the central π-systems. These results can explain the drastic change in the electrical properties between n = 3 and 4.
Piezoelectric Admittance Measurements of Montmorillonite/Poly(vinyl alcohol) Composite Film-Coated Quartz Crystal Oscillators
Authors: Okajima Takeyoshi , Sakurai Hidetaka , Oyama Noboru , Tokuda Koichi , Ohsaka Takeo 
Published: July 2006

Abstract
The piezoelectric admittance measurements of montmorillonite/poly(vinyl alcohol) (PVA) composite film-coated quartz crystal oscillators were performed in air dried over silica gel, in an atmosphere of moisture with 100% relative humidity at 25 °C and in contact with Na2SO4 aqueous solutions. By use of the electrical equivalent circuit model conventionally proposed for a piezoelectric quartz crystal, the relevant circuit parameters; resistance R, inductance L, and capacitance C were evaluated as a function of the Na2SO4 concentration (0.01–1.0 M (1 M = 1 mol dm−3)). R was almost constant above ca. 0.35 M and increased with decreasing the concentration in the lower concentrations, while L and C were almost independent of the concentration. On the basis of the electrolyte concentration dependence of R, the structural change of the clay/PVA composite film due to swelling with the electrolyte is discussed in comparison with the results for the clay film.
A Magnetic Study of the Iron(III) Complexes of Polyols and Sugars in Aqueous Solution
Authors: Yokoi Hiroshi , Mori Yasuyoshi , Mitani Tsuyoshi , Kawata Satoshi 
Published: July 2006

Abstract
Plots of the effective magnetic moment (μeff) of the iron(III) ion against pH for aqueous iron(III) ion solutions of 1,2-ethanediol, 1,3-propanediol, glycerol, d-glucitol, d-fructose, two oligo-sugars, poly(vinyl alcohol) (PVA), and methyl cellulose at various concentration ratios of polyols or sugars to the iron(III) ion ([iron(III) ion] = 10.0 mM) at room temperature were obtained by the Gouy method. At low concentraion ratios, precipitation resulted at around neutral pH, where the concentration of polymers is expressed in terms of the monomeric residues. The pH range for precipitation became narrower as the ratio increased. However, the precipitates, once formed for the case of the former two diols, remained unchanged at any alkaline pH. During the course of the change in pH from 1 to 13, the μeff value in units of B.M. was initially ca. 6, but steeply decreased at around pH 2, and then leveled off at a constant value of ca. 3.6 in the pH range 3 to 10. It gradually rose to a value of 5–6 beyond pH 10 for the cases of glycerol, d-glucitol, and sugars. This fact, together with the ESR data obtained here, indicates that iron(III) ions exist as usual hydrated ions at pH 1–2, as some cluster like Fe(OH)3 at pH 3–10, and mostly as mononuclear ions coordinated to the alcoholic OH groups at a stronger base pH.
Esterification of Boric Acid with 1,2-Propanediol, 3-Amino-1,2-propanediol, and (±)-3-Dimethylamino-1,2-propanediol as Studied by 11B NMR Spectroscopy
Authors: Oi Takao , Takeda Takuya , Kakihana Hidetake 
Published: July 2006

Abstract
Ester formations of borate ion with 1,2-propanediol, 3-amino-1,2-propanediol, and (±)-3-dimethylamino-1,2-propanediol and stabilities of the formed esters were studied by 11B NMR spectroscopy. For each of the boric acid–diol systems, esters with the 1 : 1 mole ratio of borate ion and diol and with the 1 : 2 mole ratio were formed. In each of the amino–diol–containing systems the 1 : 1 ester was in fact composed of two esters; one from a borate ion and a diol molecule and the other from a borate ion and a protonated diol. Similarly, the 1 : 2 ester consisted of two esters; one from a borate ion and two diol molecules and the other from a borate ion and two protonated diols. The stability constants of the esters formed were calculated based on the peak areas of the signals of the boron species on the 11B NMR spectra. The stability of an ester was strongly correlated with the electronegativity of the anchor moiety of the diol; a higher electronegativity in general yielded a more stable ester.
Bis(1-methylimidazole)iron(II) Complexes of Porphyrins Substituted with Highly Electron-Withdrawing CF3 Groups: Electronic Spectra with Split Q-Bands and MCD Spectra with Unusual Features
Authors: Yoshimura Tetsuhiko , Toi Hiroo , Inaba Shinji , Ogoshi Hisanobu 
Published: July 2006

Abstract
The bis(1-methylimidazole)iron(II) complexes of porphyrins substituted with one, two, or four CF3 groups at pyrrole β-positions of a porphyrin have been studied by electronic absorption and magnetic circular dichroism (MCD) spectroscopies. The splittings of Q-bands observed in the electronic spectra of the complexes may arise from asymmetrical electronic effects of the highly electron-withdrawing CF3 group on the porphyrin periphery. The ratio of absorption intensity (ε(α)/(ε(β)) decreased with an increase of the number of CF3 group, suggesting the decrease of a splitting in HOMOs. The MCD spectra of the bis(1-methylimidazole)iron(II) porphyrin complexes were markedly sensitive to the porphyrin peripheral substituents. The MCD spectra in Soret region successively changed in shape with the number of CF3 group on porphyrin periphery and consequently were apparently inverted in sign, which can be explained by the shift of maximal wavelength accompanied by a change in intensity.
AlCl3–N,N-Dimethylaniline: A Novel Benzyl and Allyl Ether Cleavage Reagent
Authors: Akiyama Takahiko , Hirofuji Hajimu , Ozaki Shoichiro 
Published: July 2006

Abstract
A combination system of AlCl3–N,N-dimethylaniline was found to cleave benzyl ethers readily to give parent alcohols in excellent yields. The system also cleaved allyl as well as methyl ethers. Numerous functional groups such as benzoyloxy, phenylthio, and olefinic double bond were not affected. Comparisons of AlCl3–N,N-dimethylaniline and AlCl3–anisole were described.
Thermotropic Liquid Crystals Based on Chito-Oligosaccharides. 1. Synthesis of Chitobiose Octaalkanoates and Chitotriose Undecaalkanoates and Their Thermal Properties
Authors: Sugiura Makoto , Minoda Masahiko , Watanabe Junji , Fukuda Takeshi , Miyamoto Takeaki 
Published: July 2006

Abstract
This paper deals with the preparation of two series of chito-oligosaccharide derivatives, chitobiose octaalkanoates, and chitotriose undecaalkanoates, in which the amino- and hydroxyl groups were blocked with alkyl pendants of differing lengths via an ester linkage. By differential scanning calorimetry(DSC) and optical microscopic observations, these compounds were found to exhibit an enantiotropic mesophase at temperatures ranging from ca. 50 °C to ca. 200 °C. The texture of the mesophases were similar to those of the discotic columnar liquid crystals formed by the cellobiose and cellotriose equivalents. However, the amido group in the chito-derivatives seems to stabilize the mesophase to an appreciable extent, bringing about higher temperatures and a longer temperature span of the mesophase than those of the cello-equivalents.
Photosensitized Oxygenation of Olefins with Zinc Tetraphenylporphine-1,4-Diazabicyclo[2.2.2]octane Complex
Authors: Sakuragi Masako , Ichimura Kunihiro , Sakuragi Hirochika 
Published: July 2006

Abstract
In the presence of a proper amount of amines such as 1,4-diazabicyclo[2.2.2]octane (DABCO) and piperidine, zinc tetraphenylporphine (ZnTPP) works as a not only apparently more effective but also more photoresistant sensitizer for singlet-oxygen oxygenation of olefins than in the absence of the amines. This is ascribed to the facts that ZnTPP forms a 1 : 1 complex with DABCO, and that DABCO coodinated to ZnTPP has no ability to quench singlet oxygen, as revealed by detection of singlet oxygen phosphorescence and product distributions in oxygenation of d-limonene, 1,2-dimethylcyclohexene, and 1-phenylcyclobutene.
Energy- and Electron-Transfer Pathways in the Triplet-Sensitized Photolysis of N-(1-Naphthoyl)-O-(p-toluoyl)-N-phenylhydroxylamine with Substituted Benzophenones
Authors: Sakurai Tadamitsu , Utsumi Kazuo , Ohkita Akira , Nakamura Makoto , Inoue Hiroyasu 
Published: July 2006

Abstract
Quantum-yield and thermodynamic analyses of the triplet-sensitized photolysis of the title hydroxylamine (NT, 1) with 4,4′-bis(dimethylamino)benzophenone (BAB), 4-dimethylaminobenzophenone (DAB), 4,4′-dimethoxybenzophenone (DMB), and 3,3′-bis(trifluoromethyl)benzophenone (BFB) suggest that the BAB- and DAB-sensitized reactions proceed by a preferential electron-transfer pathway within a triplet-exciplex intermediate, formed between the triplet-state sensitizer and the ground-state NT, to give N-phenyl-1-naphthalenecarboxamide (2) and p-toluic acid (3). On the other hand, the energy-transfer pathway in this exciplex intermediate, eventually forming 2 and 3, as well as toluene (4), predominates for reactions sensitized with DMB and BFB having fewer electron-donating substituents than does the dimethylamino group of BAB and DAB. The finding that benzil, both excited singlet and triplet states of which lie below those of NT, brings about a sensitized photolysis to afford the same fragmentation products, provides strong evidence for the existence of a triplet-exciplex intermediate. In addition, evidence concerning the operation of an electron-transfer mechanism in our sensitized photolysis comes from an observation that the photolysis of NT sensitized with N,N,N′,N′-tetramethylbenzidine, the excited state of which is one of the most powerful one-electron reductants, gives the same product distribution as does that obtained by the BAB- and DAB-sensitized reactions.
Perfluoroalkylation of Olefins by Electrooxidation of Perfluoroalkanoic Acids: Relations between Product-Selectivity and Current Density and Structures of Olefins
Authors: Uneyama Kenji , Watanabe Shunsuke , Tokunaga Yukio , Kitagawa Kouichi , Sato Yasuhiro 
Published: July 2006

Abstract
Electrooxidation of perfluoroalkanoic acids RfCO2H (Rf = CF3, C3F7, C7F15 together with CHF2, CH2F) in the presence of electron-deficient olefins (methyl acrylate, methyl methacrylate, acrylamide, and acrylonitrile) provided perfluoroalkylated products. The electrolysis was conducted in MeCN–H2O (7 : 1) using platinum electrodes in an undivided cell. Dimerization of methyl acrylate accompanying perfluoroalkylation, occurs in 40–50% yield under 20 mA cm−2 current density. 1,2-Addition of trifluoromethyl or difluoromethyl radicals to carbon-carbon double bond predominates in acrylamide under the high current density (100–200 mA cm−2). On the other hand, 1,2-addition of trifluoromethyl and acetamido groups and 1,2-addition of trifluoromethyl and hydroxyl groups occur in the low current density ( &lt; 5 mA cm−2) electrolysis of methyl methacrylate.
Magnetic Properties of Cobalt(II) and Nickel(II) Benzoate Adducts with Quinoline Analogues
Authors: Emori Shuji , Shima Chiemi 
Published: July 2006

Abstract
Various cobalt(II) and nickel(II) 3-substituted benzoate adducts with quinoline, 4-methylquinoline, and quinoxaline were prepared. They were then characterized by means of magnetic susceptibility and IR spectroscopy. The variation in their magnetic moments is discussed in terms of the basicities of the benzoate ligands as well as the coordinate-bond lengths between the benzoate oxygen and metal atoms. For the nickel(II) compounds, the formation of weak nickel(II)–nickel(II) bonding is suggested.
Synthesis and Magnetisms of Oxamido– and Oxamato-Bridged Binuclear Nickel(II)-Copper(II) Complexes
Authors: Ohba Masaaki , Shiozuka Michito , Matsumoto Naohide , Okawa Hisashi 
Published: July 2006

Abstract
Oxamido- and oxamato-bridged binuclear nickel(II)–copper(II) complexes [CuL1Ni(Me6[14]aneN4)](ClO4)2·H2O (1), [CuL2Ni(Me6[14]aneN4)]ClO4 (2), and [CuL3Ni(Me6[14]aneN4)]ClO4 (3) have been synthesized and characterized, where Me6[14]aneN4 = rac-(5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, H2L1 = N,N′-bis(2-pyridylmethyl)oxamide, H3L2 = N-methyl-N′-(4-methyl-6-oxo-3-azahept-4-enyl)oxamide, H3L3 = N-(4-methyl-6-oxo-3-azahept-4-enyl)oxamic acid. The cryomagnetic susceptibilities (4.2–300 K) were well reproduced by the equation derived from H = −2JSNi·SCu (SNi = 1, SCu = 1⁄2) with the J values −78.2 cm−1, −64.5 cm−1, and −72.8 cm−1 for (1), (2), and (3), respectively.
Synthesis of Water-Soluble Lanthanide Porphyrin Sandwich Complexes: Bis(tetrapyridylporphyrinato) Cerium(IV), [Ce(tpyp)2], and Bis(tetramethylpyridylporphyrinato) Cerium(IV), [Ce(tmpyp)2]
Authors: Jiang Jianzhuang , Machida Ken-ichi , Adachi Gin-ya 
Published: July 2006

Abstract
A reaction of tris(acetylacetonato) cerium(III), [Ce(acac)3], with tetrapyridylporphyrinato dilithium, Li2tpyp, produces a water-soluble sandwich complex bis(tetrapyridylporphyrinato) cerium(IV), [Ce(tpyp)2], in appreciable yield, which is followed by the same water-soluble sandwich complex bis(tetramethylpyridylporphyrinato) cerium(IV), [Ce(tmpyp)2], formed by methylation of the tpyp ligand in [Ce(tpyp)2].
Thermal Behavior and Mass Spectra Aspects of 1,3,5-Triazine Derivatives Based on Isocyanuric Acid
Authors: Shimasaki Choichiro , Nakayama Hiroaki , Iwaki Akiko , Tsukurimichi Eiichi , Yoshimura Toshiaki , Hasegawa Kiyoshi 
Published: July 2006

Abstract
Eleven 1,3,5-triazine derivatives were investigated by the use of a thermal-analysis techniques. These compounds showed a remarkable difference in pyrolytic behavior and decomposed thermally by a cleavage of the triazine ring and the liberation of water, isocyanic acid, and carbondioxide. The pyrolysis products were separated and identified by a gas chromatograph coupled to a mass spectrometer. All of the obtained information led to the proposal of a thermal degradation mechanism for the triazine derivatives, which is presented here. The main pyrolysis and fragmentation by electron impact mechanisms were classified into four categories, respectively.
Molecular Structures of Dimeric Reduction Products of Pulegone
Authors: Kikuchi Mitsuko 
Published: July 2006

Abstract
The molecular structures of “isobishydropulegone” and “Harries–Roeder ketol,” isomers of “bishydropulegone,” which are dimeric reduction products of pulegone, were determined as being (1S, 3′aR, 4R, 6′R, 7′aS)-7′a-hydroxy-2′,2′,3′,3′,4,6′-hexamethylspiro[cyclohexane-1,1′-octahydroinden]-2-one and (1R, 3′aS, 4R, 6′R, 7′aS)-7′a-hydroxy-2′,2′,3′,3′,4,6′-hexamethylspiro[cyclohexane-1,1′-octahydroinden]-2-one respectively by the analysis of the two-dimentional NMR spectra.
Stereoselective Decomposition of Pyrazolines Containing Trifluoromethyl Groups
Authors: Nishida Masakazu , Hayakawa Yoshio , Matsui Masaki , Shibata Katsuyoshi , Muramatsu Hiroshige 
Published: July 2006

Abstract
The reaction of (Z)- and (E)-6,6,6-trifluoro-4-trifluoromethyl-4-hexen-3-ones (1) with diazomethane afforded the corresponding cis- and trans-pyrazolines (2), respectively. Photochemical and thermal decompositions of the r-3, t-4-bis(trifluoromethyl)pyrazoline gave selectively r-1, t-2-bis(trifluoromethyl)-1-propionylcyclopropane (3) and 3,4-bis(trifluoromethyl)-2-ethyl-4,5-dihydrofuran (4). On the other hand, those transformations of the r-3,c-4-isomer of the pyrazoline gave a mixture of the r-1,c-2-isomer of 3, 4, and 4,5-bis(trifluoromethyl)-5-hexen-3-one (5).
Novel Synthesis of 2-Phosphinoylphospholane 1-Oxide Derivatives
Authors: Miyamoto Yasushi , Yamashita Mitsuji , Oshikawa Tatsuo 
Published: July 2006

Abstract
Reactions of 2-phospholene 1-oxides with N-bromoacetamide in aqueous organic solvent produced 2-bromo-3-hydroxyphospholane 1-oxides, which reacted with sodium salts of dialkyl phosphonates to afford novel 2-phosphinoylphospholane 1-oxide derivatives. A 4-phosphin-oyl-2-phospholene derivative was also prepared.
Oxidative Chlorination of 1,10-Phenanthroline and Its Derivatives by Phosphorus Pentachloride in Phosphoryl Chloride
Authors: Yamada Masaki , Nakamura Yoshio , Hasegawa Tadashi , Itoh Akinobu , Kuroda Shigeyasu , Shimao Ichiro 
Published: July 2006

Abstract
Some of aromatic hydrogens of 1,10-phenanthroline and its derivative, 1,10-propano-bridged 1,10-phenanthroline-2,9(1H,10H)-dione, were oxidatively substituted by chlorine atoms with excess amount of phosphorus pentachloride in phosphoryl chloride to give the polychlorinated products.
Topological Indices of Unbranched Catacondensed Benzenoid Hydrocarbons
Authors: Hosoya Haruo , Gutman Ivan , Nikolic Jasmina 
Published: July 2006

Abstract
The topological indices σ (recently proposed by Merrifield and Simmons) and Z (put forward by one of the present authors, Bull. Chem. Soc. Jpn., 44, 2332 (1971)) of unbranched catacondensed benzenoid hydrocarbons are examined and their dependence on molecular structure is established. Approximate formulas are deduced, enabling an easy and accurate calculation of σ and Z.
ENDOR Study of the Cation Radicals of Vitamin E Derivatives. Relation between Antioxidant Activity and Molecular Structure
Authors: Mukai Kazuo , Uemoto Yuichi , Fukuhara Masami , Nagaoka Shin-ichi , Ishizu Kazuhiko 
Published: July 2006

Abstract
An ENDOR study of vitamin E derivatives was carried out. The molecular structures of the cation radicals of models for vitamin E derivatives were determined by means of ENDOR. The relation between the antioxidant activity and the molecular structure of vitamin E was discussed.
The Intramolecular Structure of Oxonium Ion in Concentrated Aqueous Deuterochloric Acid Solutions
Authors: Kameda Yasuo , Uemura Osamu 
Published: July 2006

Abstract
Time-of-flight (TOP) neutron diffraction experiments have been carried out for pure liquid D2O and concentrated aqueous deuterochloric acid solutions (DCl)x(D2O)1−x (x = 0.10, 0.23). The errors due to the inelasticity effect on the molecular structure in the solution were markedly reduced by the TOF measurement at the small scattering angle (2θ=44°). From the least square fit of the theoretical intramolecular interference function to the observed one, the internuclear distances, rOD and rDD, and the root mean square displacements, lOD and lDD, in both D3O+ and D2O molecules were determined as follows; rOD = 1.04(4) Å, rDD = 1.63(5) Å, lOD = 0.07(2) Å and lDD = 0.12(6) Å for D3O+, and rOD = 0.983(5) Å, rDD = 1.55(4) Å, lOD = 0.067(8) Å, and lDD = 0.12(4) Å for D2O. The bond angle ∠DOD in D3O+ was also calculated to be 103°. The trigonal pyramidal structure of oxonium ion in the liquid phase has been lead through this investigation.
Preparation and Characterization of Cobalt(III) Complexes Containing 1,1′-Bis(diphenylphosphino)ferrocene (dppf) or 1,1′-Bis(dimethylphosphino)ferrocene (dmpf) as a Bidentate Ligand, and Molecular Structures of [Co(acac)2(dmpf)]B(C6H5)4 and [Co(dtc)2(dmpf)]B(C6H5)4 (acac = 2,4-pentanedionate ion, dtc = dimethyldithiocarbamate ion)
Authors: Adachi Masahiro , Kita Masakazu , Kashiwabara Kazuo , Fujita Junnosuke , Iitaka Naoyuki , Kurachi Saeko , Ohba Shigeru , Jin Dou-man 
Published: July 2006

Abstract
Four new complexes, [Co(acac or dtc)2(dppf or dmpf)]X (X = BF4, B(C6H5)4) have been prepared and characterized by absorption and 1H NMR spectra, and electrochemical measurements. The [Co(acac)2(dppf)]+ complex exhibits the first d-d band at much lower energy than that of [Co(acac)2(dppe)]+ (dppe = 1,2-bis(diphenylphosphino)ethane), while the other complexes give the bands at similar energies to those of the corresponding diphosphine complexes. The structures of two dmpf complexes have been determined by the X-ray diffraction method. Crystal data are: [Co(acac)2(dmpf)]B(C6H5)4 (1), monoclinic, P21/a, a = 20.366(4), b = 13.513(2), c = 16.860(2) Å, β = 108.09(2)°, V = 4411(1) Å3, Z = 4, R = 0.041 for 5774 reflections. [Co(dtc)2(dmpf)]B(C6H5)4 (2), monoclinic, C2/c, a = 33.573(7), b = 10.148(1), c = 31.039(6) Å, β = 123.13(1)°, V = 8856(2) Å3, Z = 8, R = 0.044 for 6323 reflections. In these complexes dmpf functions as a bidentate chelate ligand with the Co–P bond distances of 2.250(1)–2.257(2) Å and the P–Co–P chelate angles are 101.09(4)° in 1 and 102.3(1)° in 2. The trans influence of the phosphino donor group is observed on the Co–O (ca. 0.04 Å) and Co–S (ca. 0.03 Å) bond distances.