bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syngas reactions XII. The selective preparation of acetaldehyde, alkanols, esters and acetic acid from synthesis gas
Authors: Knifton John F , Lin J J 
Published: December 2004

AbstractSeveral classes of commercially important oxygenates, including acetaldehyde, ethanol, methyl acetate, ethyl acetate and acetic acid as well as C1–C3alcohol/acetate ester mixtures, may each be selectivelygenerated from synthesis gas through the application of novel classes of ruthenium‐containing bimetallic catalysts particularly those of ruthenium and cobalt (RuCo). A particular feature of these versatile catalysts is that all precursors are iodidefree. Products are formed through a combination of carbon monoxide hydrogenation, methanol homologation, methyl acetate homologation and methanol carbonylation reaction sequences.
Evaluation of the activity of some water‐soluble ferrocene and ferricenium compounds against carcinoma of the lung by the human tumor clonogenic assay
Authors: Neuse Eberhard W , Kanzawa Fumihiko 
Published: December 2004

AbstractThe two ferrocene compounds, ferrocenylacetic acid (3) and ferrocylthiomalic acid (4), as well as the ferricenium salts, ferricenium tetrachloroferrate (III) (1) and ferricenium trichloroacetate–trichloroacetic acid solvate (2), were investigated by the in vitro human tumor clonogenic assay for their inhibiting effects, in continuous exposure in a double‐layer medium, on the colony formation of single‐cell suspensions prepared from 30 selected fresh specimens of human adenocarcinoma, squamous cell carcinoma and large‐cell carcinoma of the lung. At the high drug concentration level of 100 μg cm −3, good response ratios were observed for 3 (79%) and 4 (72%), followed by 1 (67%) and 2 (52%). At the low concentration level of 10 μg cm−3 response ratios were below 25% for all compounds, best performance (24%) being shown by 1. In vitro experiments probing the schedule dependencies of the compounds' inhibiting effects against the lung carcinoma cell line PC‐9 were also performed, as were experiments involving the combination of the ferricenium salt 1 and cisplatin, which showed the combination effect to be additive in both one‐hour and continuous‐exposure tests.
Bis(tributyltin) oxide as a wood preservative: Its conversion to tributyltin carboxylates in Pinus sylvestris
Authors: Blunden S J , Hill R. 
Published: December 2004

AbstractTributyltin compounds have been successfully used for many years as wood preservatives, although their chemical nature in timber has not been fully elucidated. This study by 119Sn and 13C NMR spectroscopy has shown that, on impregnation into Pinus sylvestris sapwood, bis(tributyltin) oxide [(Bu3Sn)2O] is rapidly converted to tributyltin carboxylates (Bu3SnOCO·R) via reaction with components of the wood resin. It is further suggested that the formation of these species is a prerequisite for the known disproportionation reaction which occurs in (Bu3Sn)2O‐treated timber.
Electrochemical behaviour of some organotin(IV) compounds by rotating disc voltammetry in non‐aqueous solvents
Authors: Abeed Fathi A , Al‐Allaf Talal A K , Sh Ahmed Kareem 
Published: December 2004

AbstractThe electrochemical behaviour of three series of organotin(IV) compounds having the general formula RySnX4−y (R = Me, nBu or Ph, y = 2 or 3, X = Cl; R = Me or Ph, y = 3, X = NO3, N3, NCS, NCO, OAc or OH) have been examined in the non‐aqueous solvents dimethylformamide and acetonitrile, at rotating disc electrodes of glassy carbon and gold electrodes. The reduction of tin(IV) in the above series gave a single wave and obeyed the Levich plots at both electrodes in the two solvents. The electrode kinetic parameters and halfwave potentials have been determined, and the effect of solvents and substituents on these parameters have been explored.
Surface‐bound organometallic rhodium precursors for 1‐hexene hydrogenation
Authors: Herrero Juana , Blanco Carmen , Esteruelas Miguel A. , Oro Luis A. 
Published: December 2004

AbstractRhodium precursor catalysts supported on palygorskite, montmorillonite and silica were obtained from an organometallic cationic rhodium species and evacuated supports at different temperatures. Based on the different times which precursors took to be active in 1‐hexene hydrogenation, in the liquid phase at atmospheric hydrogen pressure, it has been deduced that the supported rhodium species varies with the support and its dehydration temperature. Activity in this reaction also depended on the support, its dehydration temperature and storage in air. Precursors and catalysts were characterized by X‐ray photoelectron and infrared spectroscopy. Very stable complexes are obtained under humid ambient conditions. With montmorillonite support, activity decreases if rhodium/1‐hexene ratio decreases.
Effect of selenium on arsenic metabolism in Cylindrotheca fusiformis
Authors: Katayama Masayuki , Sugawa‐Katayama Yohko , Benson Andrew A. 
Published: December 2004

AbstractEffects of selenium (Se) on the kinetics of incorporation and excretion of 74As have been studied by use of a marine diatom, Cylindrotheca fusiformis. For the incorporation experiment, the cells were incubated with carrier‐free 74As in a phosphate‐free normal medium, and collected sequentially over 45 h. For the excretion experiment, the cells were transferred to a normal medium and collected sequentially over 95 h. The cell components were fractionated into watersoluble, insoluble and lipid fractions by TLC. 74As was mostly incorporated into the water‐soluble fraction and less than 10% of it into the insoluble and lipid fractions. Within a few hours considerable amounts of 74As were found in those fractios, but after that the rate of accumulation decreased. 74As was excreted into the medium rapidly at the beginning, but the rate of excretion slowed down gradually. In the cells, the amount of As in the insoluble fraction decreased more rapidly than that in the lipid and water‐soluble fractions. The time course changes of 74As in the three fractions showed some oscillation of larger amplitude of variation at first and later approached a constant value. Selenium in the medium showed some effects o the rate of arsenic incorporation as well as on the ratio of the three fractions. In the excretion process, selenium changed the amplitude of the variation and the ratio of 74As in the three fractions at the later times.
Crown ethers in tin chemistry
Authors: Cusack Paul A , Smith Peter J 
Published: December 2004

AbstractThis article comprehensively reviews the literature concerning the adducts formed between crown ethers and organotin(IV), inorganic tin(IV) and inorganic tin(II) species, and it also covers organotin(II) complexes containing alkali metal–crown ether cations. The uses of crown ethers as cocatalysts in organic and organotin synthesis are surveyed and some potential industrial applications of crown ether/tin chemical systems are discussed.
The synergistic effect of polysorbate 80 upon the toxicity of tri‐n‐butyltin chloride
Authors: Sherman Larry R , Kellner Ginny L 
Published: December 2004

AbstractPolysorbate 80 (Tween 80) was used as an emulsifying agent for administering tri‐n‐butyltin chloride (TBTCl) to rats below, at and above the LD50 for the compound. Tween 80 greatly enhanced the toxicity of the organotin compound. The LD50 in the presence of Tween 80 (16% of the emulsion) is less than half of the LD50 when the TBTCl was administered in corn oil.
Synthesis, characterization and catalytic activity of Rh (PPh3)2 (en)Cl complex
Authors: Gokak D T , Kamath B V , Ram R N 
Published: December 2004

AbstractEthylenediamine bis(triphenylphosphine) monochlororhodium has been prepared by the interaction of Wilkinson's catalyst and ethylenediamine in benzene. The complex has been isolated and characterized by conventional and spectroscopic methods. The catalytic activity of the complex was investigated for the hydrogenation of 1‐octene as a model reaction at a hydrogen pressure of 1 atmosphere (101 kPa) using methanol as a solvent. The influence of various factors such as catalyst, substrate concentrations and temperature have been studied. The hydrido complex has been identified as an intermediate product by IR and NMR studies. The experimental data are in accordance with a rate expression of the form:

.
Antifungicidal, antibacterial and antifertility activities of biologically active heterocyclic thiosemicarbazones and their coordination complexes with the dimethylsilicon moiety
Authors: Singh D , Singh R V , Goyal R B 
Published: December 2004

AbstractSynthetic, structural and biological aspects of trigonal‐bipyramidal, Me2Si(NS)Cl and octahedral, Me2Si(NS)2 types of organosilicon (IV) complexes of heterocyclic thiosemicarbazones (NSH) have been described. The complexes were characterized by elemental analysis, molecular weight determination, conductance measurements and electronic, infrared, 1H and 13C NMR spectral studies. Some ligands and their corresponding dimethylsilicon (IV) complexes have been tested for their effects on several pathogenic fungi and bacteria. Two representative complexes have also been found to act as sterilizing agents by reducing the production of sperm in male mice.
Sedimentary siloxanes: A depositional history
Authors: Pellenbarg Robert E , Carhart Homer W 
Published: December 2004

AbstractA Puget Sound sediment core has been quantitatively analyzed for organic silicon content, as derived from post‐1945 release of poly(organo)‐siloxanes (silicones). The sedimentary silicone data record and preserve at depth, a smeared event horizon, or first appearance of silicone in the sediment column. Core samples older than 50 years showed no detectable silicone as measured by a new procedure utilizing inductively coupled plasma (ICP) emission spectroscopy after solvent extraction to collect the silicone from gram‐sized sediment core samples.
Research on tributyltin in Australian estuaries
Authors: Batley Graeme E , Scammell Marcus S 
Published: December 2004

AbstractTributyltin (TBT) from marine antifouling paints has been shown to have a major impact on the oyster industry in eastern Australia. Current research projects are examining the impact of TBT on Australian estuaries, assessing the response of sensitive biota to recently imposed bans and determining whether a continuing use of TBT on large vessels is an environmental concern.
Speciation for analysis of organotin compounds by GC AA and GC MS after ethylation by sodium tetraethylborate
Authors: Ashby J R , Craig P J 
Published: December 2004

AbstractA range of organotin compounds has been ethylated using the reagent sodium tetraethylborate in a simple one‐step procedure. Analysis of the volatile, fully alkylated derivatives has been achieved by GC AA with confirmation of the identity of the resulting ethylated derivatives by GC MS. Conditions for the GC AA and GC MS analysis of the organometallic ethyl derivatives are given.
Active sites, nature and mechanism of carbon dioxide—propylene oxide copolymerization and cyclization reactions employing organozinc—oxygen catalysts
Authors: Kuran Witold 
Published: December 2004

AbstractReaction of carbon dioxide with propylene oxide in the presence of catalysts with condensed zinc species (;derived from diethylzinc and dihydric phenols, e.g. catechol o C6H4(;OH)2 and saligenin 0 HOC6H4CH2OH) yields poly(;propylene carbonate) as well as propylene carbonate. The above reaction in the presence of catalysts with noncondensed zinc species (;derived from diethylzinc and phenol) yields propylene carbonate as the main product, but in relatively low yield. The mechanism of the linear and cyclic carbonate formation is discussed in terms of the nature of the catalyst's active sites for both types.
Synthesis, characterization and in vitro antitumour activity of di‐n‐butyltin(;iv) derivatives of some aromatic carboxylic acids, including aspirin
Authors: Meriem Abdelkader , Willem Rudolph , Biesemans Monique , Mahieu Bernard , de Vos Dick , Lelieveld Peter , Gielen Marcel 
Published: December 2004

AbstractEleven di‐n‐butyltin(;IV) derivatives of the type (;a) (;C4H9)2(;XYC6H3COO)2Sn or (;b) {[(;C4H9)2(;XYC6‐H3COO)Sn]2O}2 (;X, Y = H, 2‐OH, compound 1a; H, 2‐OCH3, compounds 2a and 2b; H, 2‐OCOCH3, 3a; 2‐OH, 3‐OCH3, 4a; 2‐OH, 3‐CH3, 5a; H, 3‐OCH3, 6a and 6b; H, 3‐N(;CH3)2, 7a; H, 2‐(;CF3), 5‐(;CF3), 8a and 3‐OCH3, 4‐OH, 9a) have been prepared and characterized by 1H, 13C and 119Sn NMR, Mössbauer and mass spectroscopy. The in vitro antitumour activity of these compounds against MCF‐7 human tumour cells was higher than that of cis‐platin, but only three compounds, 4a, 8a and 9a, scored better than cis‐platin against the WiDr cell line.
Syntheses and electrochemical behaviour of novel dmit or dmio (dithiolato) cobalt(iii) complexes with a η5‐cyclopentadienyl or η5‐pentamethylcyclopentadienyl ring
Authors: Ushijima Hirobumi , Sudoh Susumu , Kajitani Masatsugu , Shimizu Kunio , Akiyama Takeo , Sugimori Akira 
Published: December 2004

AbstractFour novel cobalt(III) complexes with a cyclopentadienyl or pentamethylcyclopentadienyl ring and dmit or dmio ligands were synthesized, and their electrochemical behaviour was investigated. All these complexes exhibited three one‐electron transfer steps: one reduction and two oxidation steps. In addition, a novel organosulphur compound was afforded by electrochemical oxidation of dmit cobalt complex. Thus, these complexes may have considerable synthetic potential as precursors for electron reservoirs and organosulphur compounds.
Dissociative photoionization of Al2(Ch3)6 and Al2(Ch3)3Cl3 in the range 40–100 eV
Authors: Nagaoka Shin‐Ichi , Koyano Inosuke , Imamura Takashi , Masuoka Toshio 
Published: December 2004

AbstractDissociation processes of the organoaluminum compounds Al2(CH3)6 and Al2(CH3)3Cl3 have been studied in the range of valence and Al:2p core‐level ionization by means of photoelectron–photoion and photoion–photoion coincidence techniques. The double‐ionization threshold and the Al:2p core‐ionization threshold of Al2(CH3)6 are estimated to be about 30 and 80 eV1 eV = 96.4853 kJ mol−1.
respectively. The relative yields of the H+Al+ and H+CHm,+ (m′ = 0–3) ion pairs are enhanced around the Al:2p core‐ionization threshold of Al2(CH3)6. The photoion–photoion coincidence intensities of Al2(CH3)3Cl3 are negligibly small throughout the energy range studied. The ratio of the relative yield of AlC2H6+ to that of Al+ increases smoothly through the Al:2p core‐ionization and/or excitation region of Al2(CH3)3Cl3. The variation of the fragmentation pattern with photon energy is discussed in conjunction with the relevant electronic states.
Hydrogermylation of phenylacetylene catalyzed by onium chlorometallates
Authors: Lukevics E , Barabanov D I , Ignatovich L M 
Published: December 2004

AbstractTriethylbenzylammonium chlorometallates [Et3NCH2Ph][MCln]m− (M = Pt, Pd, Rh, Ir, Fe, Co, Cu, m = 1–3, n = 3–6), polymer‐anchored ionic metal complexes [℗—CH2PBu3][MCln]n− and some other chlorometallates and complexes of platinum, rhodium, ruthenium and osmium were studied as catalysts in the hydrogermylation of phenylacetylene with triethylgermane. All the complexes containing platinum, palladium and rhodium were found to be effective catalysts. The cis/trans ratio of the products obtained is determined by the metal atom involved and decreases in the following order: Ir > Rh ≫ Pd > Pt.
Conversion of arsenobetaine by intestinal bacteria of a mollusc Liolophura japonica chitons
Authors: Hanaoka Ken'Ichi , Motoya Tomoko , Tagawa Shoji , Kaise Toshikazu 
Published: December 2004

AbstractThe intestinal micro‐organisms of Liolophura japonica chitons converted arsenobetaine [(CH3)3As+CH2COO−] to trimethylarsine oxide [(CH3)3AsO] and dimethylarsinic acid [(CH3)2AsOOH] in the arsenobetaine‐containing 1/5 ZoBell 2216E medium under aerobic conditions, no conversion being observed in an inorganic salt medium. This conversion pattern of arsenobetaine → trimethylarsine oxide ← dimethylarsinic acid was comparable with that shown by the microorganisms associated with marine macroalgae. On the other hand, no conversion was observed in either medium under anaerobic conditions.
Facile esterification promoted by the triphenylstibine oxide‐phosphorus sulfide (Ph3SbO/P4S10) system
Authors: Nomura Ryôcki , Miyazaki Shin‐Ichiro , Nakano Takahiro , Matsuda Haruo 
Published: December 2004

AbstractVarious esters are conveniently prepared by direct esterification of the corresponding carboxylic acids with alcohols catalyzed by a triphenylstibine oxide–phosphorus(V) sulfide combined system (Ph3SbO/P4S10) under mild conditions (25–80 °C).
Speciation of butyltin compounds by on‐line HPLC‐ETAA of tropolone complexes in environmental samples
Authors: Astruc A , Astruc M , Pinel R , Potin‐Gautier M 
Published: December 2004

AbstractTropolone (Trop) forms in solution stable complexes with monobutyltin (MBT Trop2) and dibutyltin (DBT Trop). This property has been used to develop a separation procedure of butyltin compounds by liquid chromatography on cyanopropyl‐bonded silica columns with a solution of tropolone in toluene as eluent.Tin‐specific detection by on‐line ETAA allowed the development of a simple procedure suitable for the determination of tributyltin and dibutyltin in water and sediment samples.
Synthesis and spectroscopic characterization of dimethyl‐, di‐n‐butyl‐, di‐t‐butyl‐and diphenyl‐tin(iv) derivatives of dipeptides: Crystal and molecular structure of di‐n‐butyltin(iv) glycylvalinate
Authors: Mundus‐Glowacki Brigitte , Huber Friedo , Preut Hans , Ruisi Giuseppe , Barbieri Renato 
Published: December 2004

AbstractThe dipeptide complexes R2SnL listed below have been synthesized: (a) Me2SnL; H2L = glycylalanine (H2GlyAla), glycylvaline (H2GlyVal), glycylmethionine (H2GlyMet), glycyltryptophan (H2GlyTrp), glycyltyrosine (H2GlyTyr); (b) nBu2SnL; H2L = H2GlyAla, H2GlyVal; (c) nBu2SnL.H2O; H2L = glycylglycine (H2GlyGly), H2GlyAla; (d) tBu2SnL; H2L = H2GlyAla, H2GlyVal; (e) tBu2SnGlyGly. H2O; (f) Ph2SnL; H2L = H2GlyAla, H2GlyVal, H2GlyTyr, H2GlyTrp; (g) Ph2Sn(HGlyVal)2. The crystal and molecular structures of nBu2SnGl Val have been determined by single‐crystal X‐ray diffraction. The polyhedron around tin is a distorted trigonal bipyramid, analogous to that of Et2SnGlyTyr (see Vornefeld et al., Appl. Organomet. Chem., 1992, 6: 75). According to infrared and 119Sn (ΔE parameters) Mössbauer spectroscopic data the R2SnL derivatives can be classified by their solid‐state structure into two types which are distinguished by the nature of the axial carboxylate [(i) monodentate, as in nBu2SnGlyVal; (ii) bidentate]. Bonding in R2SnL.H2O and Ph2Sn(HGlyVal)2 has been discussed on the basis of vibrational data. Rationalization of the 119Sn Mössbauer parameters has been attempted by ‘literal’ point‐charge model, calculations of ΔE in the structural context described above. According to 13C NMR spectra, compounds Me2SnL are undissociated in methanol solutions, whilst dissociation is inferred for aqueous solutions, probably concerning the carboxyl and amino groups only. Five‐coordination in methanol and aqueous solutions has been assumed for Me2Snl from 119Sn NMR chemical shifts. Values of coupling constants |2J(119Sn, 1H)|, determined from 1H NMR spectra, gave estimates of CSnC angles in Me2SnL in the range 128–136° in methanol and aqueous solutions, which correspond to values from 119Sn Mössbauer ΔE parameters (129.6–133.8°). The structural relationship of R2SnL molecules in the solid state and in solution phase has been discussed.
Confusion between dimethyl selenenyl sulfide and dimethyl selenone released by bacteria
Authors: Chasteen Thomas G 
Published: December 2004

AbstractDimethyl selenone [(CH3)2SeO2] has been reported in the literature as a metabolite released by bacteria in contact with selenium metal or selenium salts. In this study, mass spectral, chromatographic, and boiling‐point data are presented that show that dimethyl selenone has been confused with dimethyl selenenyl sulfide (CH3SeSCH3). In addition, the headspaces above monocultures of selenium‐resistant bacteria were examined using gas chromatography followed by fluorine‐induced chemiluminescence detection. A number of alkyl sulfur and selenium species were detected, along with dimethyl selenenyl sulfide. A pathway from oxidized selenium salts to reduced methylated selenides and dimethyl selenenyl sulfide is also presented.
Kinetics of substitution at ternary titanium(IV)–cyclopentadienyl, pyronato or pyridinato–halide or alkoxide complexes
Authors: Burgess John , Parsons Simon A 
Published: December 2004

AbstractRate laws and kinetic parameters are reported for substitution at titanium(IV) complexes Ti(LL)2X2, where LLH=cyclopentadiene, the 4‐pyrone ethylmaltol, several 4‐pyridinones, and related ligands, and X=halide or alkoxide, in acetonitrile solution at 298.2 K. Reactivities are discussed in terms of the nature of the leaving group, the entering group and the non‐leaving ligand LL−. Activation volumes of −15 and −12 cm3 mol−1 have been determined for thiocyanate attack at Ti(cp)2Cl2 and Ti(etmalt)2Cl2 respectively. Substitution mechanisms are discussed in the light of the kinetic parameters obtained.
Linus Carl Pauling ‐ 28. 2. 1901 ‐ 17.8. 1994
Authors: Jaenicke Lothar 
Published: December 2004

AbstractDas Jahr 1939 steht, wie in der Geschichte der Menschheit, auch in der der Chemie wie eine Zeitenwende: Während von Berlin aus in der Welt die Lichter ausgelöscht wurden, erschien in New York ein Buch von mäßigem Umfang: Linus Pauling: „The Nature of the Chemical Bond and the Structure of Molecules and Crystals ‐ An Introduction to Modern Structural Chemistry”︁. Man kann seit diesem fokussierenden Genieblitz tatsächlich die Chemie in ihren weitesten Ausstrahlungen als Zeit vor (B. P.) und nach Pauling (A. P.) zählen, denn dieses Buch hatte einen ungeheuren Einfluß auf alles, das chemisch ist ‐ und das ist alles Tote und Lebende, weil es durch chemische Bindungen in Form und im Raum gehalten wird. Und es ist nicht ein Zufallsstreich, sondern das Ergebnis einer phänomenalen Zusammenschau und einer, durch Gespür für das, was die Natur zusammenhält, zielvoll gelenkten, von Intuition beflügelten und seismorgraphisch alle Anregungen aufnehmenden, ungeheuer optimistischen geistigen und experimentellen Arbeit eines Mannes, der zugleich die Phantasie hatte, die neuen Vorstellungen auf viele in den Kulissen stehende Fragen anzuwenden, so daß wir heute reflexmäßig die Vorgänge in uns und um uns herum als Yin/Yang(Paß)‐Kommunikation zwischen Atomen, Molekülen und höher strukturierten Verbänden, Organisationen interpretieren.
The pigeon retina: Quantitative aspects of the optic nerve and ganglion cell layer
Authors: Binggeli Richard L. , Paule W. J. 
Published: December 2004

AbstractStudies of electron micrographs of pigeon optic nerve showed numerous unmyelinated fibers (29% of total) and more than twice as many total fibers as previously reported. The 2.4 million axons had a mean diameter below 1 μ, close to the limit of resolution of light microscopy. This probably accounts for the large discrepancy between light and electron microscopic counts. Studies of retinal whole mounts showed an irregular distribution of cells in the ganglion cell layer including a minor posterior fovea and an area of increased density in the posterior‐superior quadrant. Sample counts produced an estimate of over 4.8 million cell bodies in this layer. Cytological investigation indicated that over 85% of these cells were neuronal. The considerable excess of neuron cell bodies over axons in thought to be explained by the presence of large numbers of amacrine cells, cells which do not project axons into the optic nerve.