bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of organometallic chemistry for hydrotreatment catalyst development
Authors: Hirschon A S , Wilson R B
Published: January 2005

This paper describes our use of organometallic chemistry to develop enhanced hydrotreatment catalysts. The approach involves (1) identifying the most active catalytic metals, (2) choosing precursors that will be easily activated into these materials under mild conditions, and (3) then increasing the surface area to provide a highly active catalyst. We describe our efforts in studying hydrodenitrogenation (HDN) reactions, including homogeneous reaction chemistry of the CN bond, development of enhanced HDN catalysts for coal liquids, and some applications of organometallic chemistry towards coal liquefaction.
Sulfided heterogeneous, bimetallic Ru/Mo catalysts derived from mixtures of Ru3(CO)12 (or RuCl3) and a molybdenum heteropolyanion: The reactions of ethanol with tetrahydroquinoline
Authors: Koo Sang‐Man , Ryan Dan , Laine Richard M.
Published: January 2005

Efforts have been made to develop Ru/Mo bimetallic catalyst systems for hydrodenitrogenation (HDN) of tetrahydroquinoline (THQ). In the course of these studies, it was discovered that in ethanol, under hydrogen and in the presence of carbon disulfide (CS2), precatalyst solutions containing ruthenium [as Ru3(CO)12 or RuCl3] and molybdenum [as the H3PMo12O40 heteropolyanion (HPA)] decompose to form bimetallic, sulfided particles. Particle diameters run from 0.1 to 5μm depending on the rate of stirring. Catalyst particles with sizes ranging from 0.1 to 1μm can be prepared reproducibly. BET‐measured surface areas for these size particles ranged from 2 to 20m2 g−1. These sulfided particles were found to catalyze, at temperatures of 200–250°C and hydrogen pressures of 200–1000 psig (1.4–6.9 MPa) hydrogen, the N‐ethylation of THQ to form N‐ethyltetrahydroquinoline (N‐Et‐THQ), rather than the formation of propylcyclohexane or propylbenzene, reaction products expected for HDN of THQ. Monometallic heterogeneous catalysts prepared from the individual precatalyst complexes, under identical conditions, show minimal activity for N‐ethylation by comparison with the bimetallic catalyst.

In the absence of hydrogen, the reaction proceeds so that THQ is converted to quinoline, N‐Et‐THQ, N‐C4H9‐THQ and N‐C6H13‐THQ. The latter products appear to arise via acetaldehyde, formed as an intermediate by dehydrogenation of ethanol. Acetaldehyde either condenses with THQ to form N‐Et‐THQ, or self‐condenses (aldol condensation) prior to reaction with THQ, thereby giving higher‐homolog alkylation products.
The use of sulfide cluster‐derived catalysts to understand the promotional effect in hydrotreatment catalysis
Authors: Brenner J R , Carvill B T , Thompson L T
Published: January 2005

Sulfide cluster‐derived ensembles are promising models of the active sites in commercial hydrotreatment catalysts. A series of sulfide clusters were adsorbed intact onto high‐surface‐area γ‐alumina, magnesium oxide and activated carbon supports, then pretreated to produce highly dispersed catalytic ensembles with sizes similar to those of their precursor clusters. The activities of the bimetallic cluster‐derived catalysts were significantly higher than those of the monometallic catalysts. We took this as evidence that direct interactions between molybdenum and the promoter element cause the promotional effect observed in commercial hydrotreatment catalysts. The hydrodesulfurization and hydrodenitrogenation activities correlated with the extent of molybdenum reduction. Our results suggested that the active sites in promoted hydrotreatment catalysts are centered on molecular‐scale ensembles containing molybdenum, sulfur and the promoter element.
Structural study of self‐assembled monolayers of ferrocenylalkanethiols on gold by angleresolved X‐ray photoelectron spectroscopy
Authors: Shogen Satoshi , Kawasaki Masahiro , Kondo Toshihiro , Sato Yukari , Uosaki Kohei
Published: January 2005

An angle‐resolved X‐ray photoelectron spectroscopic study has been performed on structures of self‐assembling systems, viz ferrocenylthiols on a gold (111) crystal. The angular dependence of the intensities of photoemission reveals that ferrocenyl groups are on the outermost layer, separated from the gold substrate by hydrocarbon chains of the thiol groups.
Organotin(IV) derivatives of mercaptosuccinic and thiodiacetic acids
Authors: Sandhu G K , Sharma N
Published: January 2005

Di‐ and tri‐organotin(IV) complexes of general formula R2SnAH, (R3Sn)2AH, R2SnB, (R3Sn)2B (A=dianion of mercaptosuccinic acid; B=dianion of thiodiacetic acid; R=Me, Et, nPr, nBu, nOct in R2Sn and nBu in R3Sn) have been synthesized and characterized by elemental analysis, IR and 1H and 13C NMR spectroscopy. These data support the preferential binding of sulphur over carboxylate by tin(IV) in R2SnAH and (R3Sn)2AH. R2SnAH complexes are assigned pentacoordinated bridged polymeric trigonal bipyramidal geometry whereas (R3Sn)2AH complexes are monomeric with trigonal bipyramidal geometry at tin arising from a bidentate carboxylate group at one tin atom and from weak bonding via Sn←OC at the other tin atom. In R2SnB and (R3Sn)2B, tin(IV) binds to two carboxylate groups in a unidentate and a bidentate manner respectively, resulting in tetracoordinated and pentacoordinated structures. Potential uses of these compounds are discussed.
Diorganotin(IV) complexes of indole 3‐acetic acid
Authors: Sandhu G K , Sharma N
Published: January 2005

Alkyl derivatives of indole 3‐acetic acid (IAA) have been prepared and are suitable for investigating steric substituent effects on hormonal activity without major interference from electronic effects. Triorganotin(IV) derivatives of indole 3‐acetic acid and N‐methylindole 3‐acetic acid have been reported to act as insecticidal, fungicidal and bactericidal agents. Me3SnIAA is more active as a biocide than Cy3SnIAA. The activity of these two compounds may be due to the fact that four‐coordinated tin monomers or five‐coordinated tin polymers are often more active than chelated five‐coordinated tin species because these readily undergo hydrolysis to give R3Sn(H2O+)2 species. The ligand affects the rate of formation of the ligand‐free active organotin entity. Biocidal activity is expected from diorganotin(IV) pentacoordinated complexes of indole 3‐acetic acid in the present case due to (i) the activity of pentacoordinated organotin species, (ii) the presence of an—NH moiety in the complexes, which is an active site for binding. The NH moiety may be deprotonated and nitrogen may coordinate with metal ions present in the physiological systems and thus destroy the activity of enzymes.
Comparative study of microwave‐induced plasma atomic emission spectrometry and atomic fluorescence spectrometry as gas‐chromatographic detectors for the determination of methylmercury in biological samples
Authors: Lansens Patrick , Meuleman Carine , Laiño Carmela Casais , Baeyens Willy
Published: January 2005

In order to attain a lower detection limit with the HS GC MIP analytical method (Head‐Space Gas Chromatography with Microwave‐Induced Plasma detection) recently developed for the analysis of methylmercury in biological samples, the quarter‐wave Evenson‐type cavity used until now was replaced by a TM010 Beenakker‐type cavity, which was used with both argon and helium as carrier gas. With an argon plasma, an eightfold increase in detection limit was gained compared with the argon plasma sustained by the Evenson cavity, while only a four‐fold increase was gained with the helium plasma. In a second step of the study, the MIP detector was replaced by an AFS (atomic fluorescence) detector (CVAFS Model‐2, Brooks Rand Ltd, Seattle, USA). With this AFS detector a detection limit of 1 ng methyl mercury per g biological tissue could be reached; i.e. measurements were 40 times more sensitive than those using the Evenson cavity. This detector has some other advantages compared with MIP detection: it is less expensive and easier to manipulate, while the same precision and accuracy are obtained. The use of AFS as detector in the headspace gas chromatographic system is therefore an important improvement for the analysis of methyl‐mercury in biological samples.
From cyclotetrasilazane [(CH3)2SiNH]4 via crystalline silicon nitride imide Si2N2NH to α‐Si3N4
Authors: Schaible Sabine , Riedel Ralf , Werner Elisabeth , Klingebiel Uwe
Published: January 2005

α‐Si3N4 is synthesized by an ammonia thermal synthesis using a cyclic oligosilazane, [(CH3)2SiNH]4, as the starting material. [(CH3)2SiNH]4 reacts in the presence of ammonia at 900°C and 80 MPa pressure to give silicon nitride imide (Si2N2NH). Subsequently, Si2N2NH is converted into α‐Si3N4 by thermal decomposition at 1500°C and 0.1 MPa nitrogen with the simultaneous loss of NH3.
Organotin(IV) complexes of dibasic tridentate Schiff bases containing ONO donor atoms
Authors: Gopinathan S , Degaonkar M P , Hundekar A M , Gopinathan C
Published: January 2005

Organotin(IV) Schiff base complexes of the type (L)SnR2 [where RCH3, C6H5 or CH2CH2CO2 CH3], (LH)Sn(C6H5)3 and (L)SnCl(CH2CH2CO2 CH3) [where LH22‐N‐salicylideneimino‐2‐methyl‐1‐propanol, derived from the condensation of salicylaldehyde and 2‐amino‐2‐methyl‐1‐propanol] have been prepared and characterized on the basis of their elemental analyses, IR, 1H, 13C and 119Sn NMR studies. In these mononuclear complexes the Schiff base acts either as a dianionic tridentate or as a monobasic bidentate moiety by coordinating through an alkoxy group, an azomethine nitrogen and a phenoxide ion to tin. Sulphur dioxide inserts in the tin–methyl/–phenyl bond in the above Schiff base complexes to give tin–O–sulphinates of formulae (L)RSn(SO2R) and (LH)(C6H5)2Sn(SO2C6H5).
2‐HC12CI9: A simple synthesis of PCB‐206
Authors: Humphries R E , Massey A G
Published: January 2005

A one‐pot synthesis is described for polychlorobi‐phenyl number 206. Addition of C6Cl5Li to tetrachlorobenzyne gives 2‐LiC12Cl9, which undergoes Li/H exchange with C6Cl5H to form 2, 2′, 3, 3′, 4, 4′, 5, 5′, 6‐nonachlorobiphenyl
The synthesis of some ferrocenyl tin hydrides
Authors: Imrie Christopher
Published: January 2005

Tin hydrides containing a ferrocenyl (Fc) group have been synthesized. They reduce haloalkanes in good yields and their decomposition products are easily separated from the products by oxidizing the ferrocene compounds to ferrocenium ions.
Speciation of organotin compounds by tandem mass spectrometry
Authors: Lawson G , Ostah N
Published: January 2005

The collison‐induced dissociation of a range of organotin compounds has been examined by tandem (MS–MS) mass spectrometry in order to investigate the potential of the technique for speciation without prior chromatographic separation. Tables of parent–daughte ion relationships are prepared for a group of six closely related compounds. The results obtained are sufficiently characteristic to distinguish between the isolated compounds and to identify the individual components of a simple mixture. This procedure has potential applications for less volatile compounds and for quantitative analysis.
Catalysis of hydrosilylation, part XXII: Polymer‐protected immobilized platinum complex catalysts for gas‐phase hydrosilylation of acetylene
Authors: Marciniec Bogdan , Foltynowicz Zenon , Lewandowski Mariusz
Published: January 2005

A platinum catalyst (hexachloroplatinic acid dissolved in ethanol) was immobilized by anchoring via amine and mercapto groups to silica followed by formation of a polymer layer which protected the catalyst against leaching. These catalysts (A and B) as well as precatalysts (SA‐Pt, SB‐Pt) which were not protected by polymer were tested in the gas‐phase hydrosilylation reaction of acetylene with trichlorosilane.

The catalytic parameters (yield 80%, selectivity 100%) obtained under optimal conditions prove the advantage of catalyst A over 300 h reaction time by the flow method.
Semi‐empirical MNDO study of the structure of some diorganotin (IV) glycylglycinates
Authors: La Manna Gianfranco , Ruisi Giuseppe , Barbieri Renato , Huber Friedo
Published: January 2005

The geometrical structures of some diorganotin glycylglycinates have been obtained using the MNDO semi‐empirical method. A good agreement with the experimental diffractometric data was found.
Seasonality in estuarine sources of methylated arsenic
Authors: Millward G E , Ebdon L , Walton A P
Published: January 2005

The effect of seasonal temperature change on the release of methylated arsenic from macroalgae, phytoplankton and sediment porewaters has been investigated by a series of controlled laboratory experiments. The appearance of dissolved arsenic species in the overlying waters was monitored using a coupled hydride generation/GC AA analytical technique. The liberation of dissolved arsenic species by the macroalgae Ascophyllum nodosum was examined under estuarine conditions at 5 °C and 15 °C. At the lower temperature the release rates were 0.2 μg kg−1 h−1 (wet weight of material) for monomethylarsenic (MMA) and 0.5 μg kg−1 h−1 for dimethylarsenic (DMA), whereas at 15 °C the rates were 0.4 μg kg−1 h−1 and 3.2 μg kg−1h−1, respectively. Incubation experiments were also carried out at 15 °C using the diatom Skeletonema costatum. During the log growth phase, when chlorophyll a concentrations were in the range 1‐5 μg dm−3, the rate of appearance of DMA in the water was ∼3 ng dm−3 h−1. Sediment samples from the freshwater and seawater end‐members of the Tamar Estuary, UK, were incubated under natural conditions at 5 °C and 15 °C. The freshwater sediments released DMA in preference to MMA; the concentrations of both species increased exponentially and reached a steady state in the overlying water after 250 h. Considerably more DMA was produced at 15 °C than at 5 °C, whilst the amount of MMA produced appeared to be insensitive to the temperature increase. In contrast, the seawater sediments always produced more MMA than DMA and the increase in temperature had little effect on the production of either MMA or DMA.

The results of the laboratory experiments were compared with field observations in temperate estuaries, including the Tamar Estuary. The implications of changes of water temperature on the fate of arsenic in estuaries is discussed and modifications to the estuarine arsenic cycle are proposed.
Enhanced detection levels in the GC MS analysis of organometallic compounds, based on pre‐ and post‐acquisition data manipulation
Authors: Lawson G , Ostah N
Published: January 2005

The different modes of data acquisition utilized in GC MS analyses of organometallic compounds are discussed. Comparisons of detection limits for each operating mode are reported and a lower detection limit of ca 5pg organotin compound injected onto the column was determined. Mass spectral data for a range of organotin compounds are presented to facilitate the choice of species suitable for single (selected) ion monitoring (SIM)
The effect of unsaturation on the reaction of aqueous alkyl bromides with brass foil
Authors: Thayer John S
Published: January 2005

Brass (a zinc/copper alloy) foil reacts with mixtures of water and alkyl bromides to give dissolution of zinc and copper. The relative rates of leaching depend on the bromide used: saturated bromides favor dissolution of zinc, whereas unsaturated bromides favor dissolution of copper. This difference is attributed to the formation of π‐complexes between the unsaturated linkages and the copper atoms.
The fate of triorganotin biocides on incorporation into hypalon paint‐based marine antifouling systems:119mSn Mössbauer and 119Sn NMR studies
Authors: Allen D W , Brooks J S , Campbell S J
Published: January 2005

Incorporation of bis(tributyltin) oxide into a Hypalon paint system results in the formation of tributyltin chloride and a second organotin species, the identity of which remains uncertain. Both compounds are appreciably retained by the dried paint matrix, thereby resulting in marked reduction in the release rate of the tributyltin moiety into aqueous systems. In contrast, tributyltin acetate, tributyltin carbonate and bis(triphenyltin) oxide appear to be incorporated into the paint film in a largely unchanged state. In the case of triphenyltin chloride and triphenyltin acetate, evidence of dephenylation to form diphenyl‐ and monophenyl‐tin compounds has been obtained.
Metathesis of silicon‐containing olefins: IX. Synthesis of 1‐(trimethylsilyl)‐1‐alkenes by olefin metathesis
Authors: Foltynowicz Zenon , Pietraszuk Cezary , Marciniec Bogdan
Published: January 2005

1‐(Trimethylsilyl)‐1‐alkenes of general formula CH3(CH2)nCHCHSi(CH3)3, where n = 3–15, have been prepared by a novel method, viz. by an effective cross‐metathesis of vinyltrimethylsilane with 1‐alkenes catalyzed by RuCl2(PPh3)3. Excess of 1‐alkene in the reaction mixture gave 1‐(trimethylsilyl)‐1‐alkenes in good yields of up to 60% (in terms of vinylsilane). The products were identified by NMR spectroscopic (1H, 13C NMR) and GC MS methods.
Ethylation of methylarsenic(III) compounds by sodium tetraethylborate
Authors: Clamagirand Vincent , Marr lain L , Wardell James L
Published: January 2005

The compounds MeAsBr2 and Me2AsBr at concentrations of (1–5) × 10−3 M in acetone solution are ethylated in high yield by NaBEt4 to MeEt2As and Me2EtAs, as shown by 1H NMR spectroscopy. The extents of ethylation of MeAs2+ and Me2As+ (expressed as ions, by convention) in aqueous acid solutions [at concentrations of (5–20) × 10−6 M] were investigated using cold trap/AA and GC AA procedures. The species Me2As+ was ethylated (to give Me2EtAs) in good yield (88%); in contrast, MeAs2+ produced the volatile trialkylarsine, MeEt2As, in poor yield (30%). No volatile trialkylarsine could be obtained on treating inorganic arsenic(III) (As3+) solutions with NaBEt4.
The use of sodium tetraethylborate in the derivatization of octyltin compounds
Authors: Craig Peter J. , Mennie Darren
Published: January 2005

Octyltin trichloride (OctSnCl3) and dioctyltin dichloride (Oct2SnCl2) have been reacted with sodium tetraethylborate (NaBEt4) to yield the volatile tetraalkyltin derivatives OctSnEt3 and Oct2SnEt2. Single and mixed solutions of the octyltin chlorides have been derivatized, separated and quantified using interfaced GC AA and GC MS methodology.
Crystal structure and in vitro antitumour activity of dibutylbis(5‐chloro‐2‐hydroxybenzoato)tin(IV)
Authors: Gielen Marcel , Bouâclam Mohammed , Mahieu Bernard , Tiekink Edward R. T.
Published: January 2005

The crystal structure of the title compound, [nBu2Sn(5‐Cl‐2‐OH‐C6H3CO2)2], shows that in the monomeric species the six‐coordinate Sn atom exists in a skew trapezoidal bipyramidal geometry in which the four O donor atoms, derived from two asymmetrically chelating carboxylate ligands, define the basal plane and the n‐butyl substituents lie over the weaker SnO interactions defining a CSnC angle of 147.6(2)°. An unusual feature of the structure is the presence of both intra‐ and inter‐molecular hydrogen bonding contacts which serve to stabilize the structure. The in vitro antitumour activity of this compound against mammary and colon carcinoma cell lines is also reported.
Effects of GaAs and Ga2O3 on magnetometric behavior of iron oxide particles in rabbit lungs
Authors: Aizawa Yoshiharu , Takata Tsutomu , Karube Hitomi , Nakamura Ken , Kotani Makoto
Published: January 2005

Intratracheal instillation of a GaAs suspension has been histopathologically shown to induce a diffuse pulmonary response. In the present study, magnetometry was used to evaluate the effects of intratracheally instilled GaAs and Ga2O3 on the behavior of externally magnetized iron oxide (Fe3O4) particles instilled in rabbit lung. Magnetometric evaluation of the effects of GaAs in rabbits dosed with 30 mg or 300 mg per animal showed a significantly decreased relaxation of iron oxide particles at 1, 3, 7, 14, 21 and 28 days following instillation compared with the controls. On the other hand, in the rabbits exposed to Ga2O3, significantly reduced decay constants were observed only on the first and third days following instillation.

Relaxation indicates a rapid decrease of remanent magnetic field following magnetization of the lungs due to random rotation of phagocytosed iron oxide particles in macrophages.

Clearance of the iron oxide particles was measured by serial determinations of the remanent magnetic field at the end of magnetization estimated from relaxation curves. Clearance was significantly impaired at 14, 21 and 28 days after instillation in rabbits exposed to both doses of GaAs. Slightly delayed clearance was also observed in rabbits exposed to Ga2O3.

Histological examination of lungs instilled with GaAs indicated active phagocytosis of GaAs and iron oxide particles by pulmonary macrophages, as well as pneumonocytes hyperplasia with marked thickening of the alveolar walls. Minimal histological changes with retention of iron oxide particles were found in the lungs exposed to Ga2O3.
Different acute effects of oral and intratracheal administration of disodium arsenate and gallium arsenide on heme synthesis in rats
Authors: Kondo Masao , Ichikawa Isamu
Published: January 2005

The acute influences of arsenic compounds on the metabolism of porphyrins and heme in various organs of rats after oral or intratracheal administration of disodium arsenate (Na2HAsO4) and gallium arsenide (GaAs) were examined and compared.

For the oral administration experiments, 21 or 84 mg of Na2HAsO4, or 2 or 4 g of GaAs, per cm3 saline per kg body weight of each animal was administered to Jcl: Wistar male rats and the organs were removed after exsanguination from the vein of the right axilla under anesthesia with ether, 16 h after administration. In the case of intratracheal administration, rats given 8.2 or 16.4 mg of Na2HAsO4, or 0.2 or 0.4 g GaAs per cm3 saline per kg body weight were examined under the same experimental conditions as for the administration route.

Increase in the body weight of rats was suppressed after intratracheal administration of the two arsenic compounds. In these rats the hematocrit value increased significantly. These changes were not shown by the orally administered rats. Elevation in δ‐aminolevulinate synthase (ALA‐S, EC 2.3.1.37) activity in erythroblasts by Na2HAsO4 was much higher after intratracheal administration than after oral administration. Suppression in the activities of δ‐aminolevulinate dehydratase (ALA‐D, EC 4.2.1.24) and porphobilinogen deaminase (PBG‐D, EC 4.3.1.8) in peripheral erythrocytes by Na2HAsO4 and GaAs were stronger by intratracheal administration than by the oral route. Influences of GaAs on the activity of PBG‐D in rat liver were shown to be more effective by oral administration than by the intratracheal route. Oral administration of Na2HAsO4 and GaAs had a stronger suppression effect on the activities of ALA‐D and PBG‐D in rat kidney.

It seems from these results that the different extents of the influence of arsenic compounds might depend on the routes of intake.
Effects of various elements on arsenic accumulation of the alga Dunaliella salina
Authors: Yamaoka Yukiho , Takimura Osamu , Fuse Hiroyuki
Published: January 2005

The effect of 23 various elements (nitrogen, manganese, magnesium, molybdenum, zinc, selenium, gallium, nickel, cobalt, lithium, strontium, vanadium, tin, antimony, bismuth, cadmium, chromium, lead, iron, silver, copper, potassium and calcium) in water on growth and arsenic accumulation in Dunaliella saline was investigated. The order of growth inhibition of D. salina by these elements was Ag>Cd>Co>Ni>Cu>Zn>Fe>Sb>Ga>Cr>Bi>Sr>Mn>Sn>Se>Pb>V>Ca, Mg, Mo, K, Li.

Arsenic accumulation in D. salina was unaffected by an increase in calcium and chromium. Also, the arsenic content in D. salina decreased at a potassium concentration of 100 mg dm−3, and was also reduced by the addition of cadmium and nitrogen; however, it was increased by the addition of lithium at 100 mg dm−3, tin, gallium, bismuth, strontium, vanadium, iron and manganese at 10 mg md−3, lead, antimony, zinc, copper cobalt and nickel at 1 mg dm−3, selenium at 0.1 mg dm−3, and silver at 0.005 mg dm−3, respectively. These results imply that arsenic accumulation by D. salina depends upon biological activity and physical adsorption.
Comparisons of survival time estimates for niigata prefecture (japan) residents exposed to ingested arsenic
Authors: Tsuda Toshihide , Yamamoto Eiji , Babazono Akira , Mino Yoshio , Kishi Yoshiki , Kurumatani Norio , Ogawa Takanori , Aoyama Hideyasu
Published: January 2005

Survival analysis was used to analyze follow‐up data on an arsenic‐poisoned area, identified in 1959, in order to assess the effect of arsenic on survival time. The subjects were 443 residents of Namiki‐cho, Nakajo‐machi, Niigata Prefecture, Japan, who ingested well water contaminated with arsenic between 1955 and 1959. Their exposure to arsenic was only by ingestion of well water. We observed this historical cohort from October 1959 to February 1992. Survival time was calculated in two ways: from 1959 (the end of exposure) until death or until 1992 (the termination of follow‐up); or from birth until death or until 1992. The entire cohort was divided into two groups according to the arsenic concentration measured in the wells in 1959. Different survival curves of the two were drawn using the Kaplan–Meier method. The lifetime survival curves indicate that the lifetimes of arsenic‐exposed residents were significantly shorter than that of the low‐dose exposure group or of unexposed residents. From the differences in the estimated lifetime survival curves, the effect of arsenic on the mortality of the residents can be inferred.
Altered protein synthesis in rat kidney cells exposed to semiconductor materials
Authors: Aoki Yasunobu , Lipsky Michael M. , Fowler Bruce A.
Published: January 2005

It is thought that the extensive industrial use of arsenic, gallium and indium, which have applications as the materials for III–V semiconductors, will increase human exposure to these compounds in the near future. We have undertaken the development of new biological indicators for assessing exposure to these elements. Element‐specific alterations in protein synthesis patterns were expected to occur following exposure to arsenic compounds. We examined alterations in protein synthesis in primary cultures of rat kidney proximal tubule epithelial cells by sodium arsenite, gallium chloride and indium chloride, utilizing two‐dimensional gel electrophoresis. After incubation with the chemicals for 20 h, newly synthesized proteins were labeled with [35S]methionine. A protein with a molecular weight (Mr) of 30 000 was markedly induced on exposure to 10 μM arsenite or 300 μM gallium chloride, and synthesis of proteins with Mr values of 85 000, 71 000, 65 000, 51 000, 38 000 and 28 000 were also increased by exposure to arsenite and gallium chloride. No significant changes were observed upon exposure to indium. Some of these increased proteins could be heat‐shock proteins.
Effects of hijiki feeding on arsenic distribution in rats administered large doses of arsenate
Authors: Katayama Masayuki , Sugawa‐Katayama Yohko , Otsuki Kazuko
Published: January 2005

Male rats fed a diet of 5% Hijiki seaweed or 5% cellulose for two weeks were administered large doses of sodium arsenate (Na2HAsO4) 7mg As kg−1 of body weight, during two days. At 48 h following the last arsenic administration, selected organs were isolated and homogenized. Femur and feces were lyophilized; portions of them were irradiated with thermal neutrons in a research nuclear reactor and their arsenic concentrations were determined from the induced gamma radiation from 76As. The greatest concentration of arsenic was detected in blood cells. A greater arsenic level was found in urine from the Hijiki diet group than in that of the cellulose diet group. The percentage distribution of arsenic in various organs indicated that the arsenic concentrated in blood cells 48 h after the arsenate administration, in comparison with the value 24 h after the arsenate administration [M. Katayama et al., Appl. Organomet. Chem. 6 389 (1992)]. The Hijiki diet accelerated arsenic accumulation in blood cells and the femur more than the cellulose diet, and arsenic levels in other organs (liver, heart, lung and kidney) of the Hijiki diet group decreased faster than those from the cellulose diet group.
Pulmonary toxicity of indium arsenide and arsenic selenide following repeated intratracheal instillations to the lungs of hamsters
Authors: Tanaka Akiyo , Hisanaga Akira , Hirata Miyuki , Omura Minoru , Inoue Naohide , Ishinishi Noburu
Published: January 2005

Chronic toxicity of indium arsenide (InAs) and arsenic selenide (As2Se3) was studied in male Syrian golden hamsters which received InAs or As2Se3 particles, each containing a total dose of 7.5 mg of arsenic, by intratracheal instillations once a week for 15 weeks. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During their total lifespan, the cumulative body weight gain of the hamsters in the InAs group was suppressed significantly compared with that in the control group, but not in the As2Se3 group when compared with that in the control group. However, the survival rate for the InAs group was significantly higher compared with the control group, but not for the As2Se3 group when compared with the control group. During the animals' total lifespan, one lung adenoma was seen in the 27 hamsters in the InAs group and one lung adenoma in the 23 hamsters in the control group. No tumors of the lung were observed in the As2Se3 group. Malignant tumors outside the lung appeared in four hamsters in the InAs group and in two in the As2Se3 group. No non‐lung malignant tumours were seen in the control group. Total tumor incidence rates were 25.9% (7/27) in the InAs group, 10.3% (3/29) in the As2Se3 group and 8.7% (2/23) in the control group. There were therefore no significant differences in tumor incidence between the InAs or the As2Se3 group, and the control group.

Regarding histopathological findings in the lung, incidence rates of proteinosis‐like lesions, pneumonia, metaplastic ossification and emphysema were seen only in the InAs group, and alveolar or bronchiolar cell hyperplasia observed in both the InAs and the As2Se3 groups were at significantly higher rates than those in the control group.

From these results, it was concluded that InAs and As2Se3 particles could induce pulmonary toxicity when instilled intratracheally into hamsters. A great deal of attention should be paid to the toxicity of both InAs and As2Se3, even though in this study the adverse health effects of As2Se3 appeared to be less than those of InAs.
Biomethylation and biotransformation of arsenic in a freshwater food chain: Green alga (chlorella vulgaris)→shrimp (neocaridina denticulata)→killifish (oryzias iatipes)
Authors: Kuroiwa Takayoshi , Ohki Akira , Naka Kensuke , Maeda Shigeru
Published: January 2005

Tolerance, bioaccumulation, biotransformation and excretion of arsenic compounds by the fresh–water shrimp (Neocaridina denticulata) and the killifish (Oryzias latipes) (collected from the natural environment) were investigated. Tolerances (LC50) of the shrimp against disodium arsenate [abbreviated as As(V)], methylarsonic acid (MAA), dimethylarsinic acid (DMAA), and arsenobetaine (AB) were 1.5, 10, 40, and 150μg As ml−1, respectively.

N. denticulata accumulated arsenic from an aqueous phase containing 1 μg As ml−1 of As(V), 10 μg As ml−1 of MAA, 30 μg As ml−1 of DMAA or 150 μg As ml−1 of AB, and biotransformed and excreted part of these species. Both methylation and demethylation of the arsenicals were observed in vivo. When living N. denticulata accumulating arsenic was transferred into an arsenic–free medium, a part of the accumulated arsenic was excreted. The concentration of methylated arsenicals relative to total arsenic was higher in the excrement than in the organism.

Total arsenic accumulation in each species via food in the food chain

Green algae (Chlorella vulgaris)

→ shrimp (N. denticulata)

→ killifish (O. latipes)

decreased by one order of magnitude or more, and the concentration of methylated arsenic relative to total arsenic accumulated increased successively with elevation in the trophic level. Only trace amounts of monomethylarsenic species were detected in the shrimp and fish tested. Dimethylarsenic species in alga and shrimp, and trimethylarsenic species in killifish, were the predominant methylated arsenic species, respectively.
Novel polymers containing carbon–anchored organotin groups
Authors: Seyferth Dietmar , Craig Masterman T.
Published: January 2005

Three polymers containing Bu2SnX (X=OAc or Cl) groups linked to the polymer through a C–Sn bond have been prepared by hydrostannation (via Bu2Sn HCl) of the following CH=CH2h‐containing polymers: (1) a polybutadiene containing approx. 70% of 1,2 CH=CH2 units; (2) poly(allyl methacrylate); (3) poly(tetraethylene glycol monoallyl ether methacrylate). The first and third were tested for activity against a number of marine organisms and found to be inactive. Presumably this observed biological inactivity arises from the fact that R3Sn(H2O) ions are not released into the aqueous medium.
Methylation of inorganic tin by decaying spartina alterniflora in estuarine water and by estuarine water
Authors: Falke Anne M. , Weber James H.
Published: January 2005

Methyltin compounds (MeSn) which do not originate from man–made pollution are common in estuaries and particularly in salt marshes containing the marsh grass Spartina alterniflora. This study reports the results of experiments in which estuarine water containing S. alterniflora leaves is spiked with inorganic tin, and estuarine water alone is spiked with inorganic tin and MeSn. When decaying leaves are present, inorganic tin concentrations in the water decrease and there is a 10‐fold increase in inorganic tin concentration in the leaves. This biosorption follows pseudo–first–order kinetics. MeSn3+ and Me2Sn2+ occur occasionally in the water. The Me2Sn2+ concentration decreases with time and the Me3Sn2+ concentration increases with time in S. alterniflora leaves. The results of estuarine water amended with inorganic tin and MeSn in the absence of leaves are quite different. The overall inorganic tin concentration decreases significantly during the experiment, the MeSn3+ concentration is approximately constant, and concentrations of Me2Sn2+ and Me3Sn+ increase. This means that net methylation of inorganic tin has occurred. We conclude that decaying S. alterniflora is likely to be important in the cycling of tin in salt marshes.
Laser photodissociation of trimethylaluminum and trimethylindium on a quartz substrate: Laser–induced fluorescence study
Authors: Sato Akihiko , Kasatani Kazuo , Sato Hiroyasu
Published: January 2005

Laser photodissociation of trimethylaluminum and trimethylindium at 248 nm on a quartz substrate was studied by detecting aluminum and indium atoms appearing as reaction intermediates by laser–induced fluorescence. Photodissociation occurred predominantly in the adsorbed state in the experimental conditions. Kinetic energy distributions of the atoms were measured and were simulated by Maxwell–Boltzmann distributions in order to discuss photodissociation mechanisms.
(η5‐Pentamethylcyclopentadienyl)trimethyltitanium as a precursor for the syndiospecific polymerization of styrene
Authors: Kucht Homa , Kucht Andreas , Rausch Marvin D. , Chien James C. W.
Published: January 2005

An equimolar mixture of Cp*Ti(CH3)3 (2) and Ph3C+[B(C6F5)4]− (1) forms a highly active and syndioselective catalyst for the polymerization of styrene, producing 96% syndiotactic polystyrene (PS) at an activity of 0.91 × 107 g PS (mol Ti)−1 (mol styrene)−1 h−1. Both activity and syndioselectivity can be increased using tri–isobutylaluminum (TIBA) to scavenge the system. ESR measurements indicate that the polymerization proceeds via titanium(IV) intermediates. Catalysts derived from 2/methylaluminoxane (MAO) as well as Cp*TiCl3/MAO also function as syndioselective styrene polymerization catalysts, but are less active than the ‘cationic’; system derived from 1 and 2.
Synthesis and characterization of diorganotin(IV) derivatives of 2‐mercaptopyridine and crystal structure of diphenyl pyridine‐2‐thiolatochlorotin(IV)
Authors: Schmiedgen Ralf , Huber Friedo , Preut Hans , Ruisi Giuseppe , Barbieri Renato
Published: January 2005

Diorganotin(IV) derivatives of 2‐mercaptopyridine (HSPy), R2Sn(SPy)2, R2SnCl(SPy) (R = Me, iPr, nBu, tBu, Cy, Ph) and Cy2SnBr(SPy), were obtained from R2SnX2 (X = Cl, Br) and NaSPy.

Ph2SnCl(SPy) crystals, as determined by singlecrystal X–ray diffraction, are monoclinic in the space group P21/n. Tin forms with the bidentate SPy ligand a four–membered chelate ring with a short NSnS bite angle of 64.8(1)° leading to a heavily distorted trigonal–bipyramidal environment about tin. Apical Cl–Sn–N angle = 156.1(1)° equatorial C–Sn–C angle = 121.9(2)°. From 119Sn Mössbauer and IR data, analogous structures are inferred for the other solid compounds R2SnX(SPy), and distorted octahedral molecular structures for the solid compounds R2Sn(SPy)2 with R in the trans position, and sulfur atoms and nitrogen–donor atoms each in cis positions. According to IR and 1H, 13C and 119Sn NMR data, the solid–state molecular structures are retained in chloroform solution.
Organosilicon polymers with alternating σ‐ and π‐conjugated systems
Authors: Yuan Chien–Hua , West Robert
Published: January 2005

A series of organosilicon polymers containing polysilane and diethynylaryl units along the polymer backbone were synthesized and examined with respect to their optical absorptions. The results indicate that delocalization takes place through the σ–π conjugated system. Lengthening of π‐conjugation leads to lower excitation energies while nearly identical UV–vis spectra are observed with increased Si–Si chain length. Introducing a thiophene unit into the π‐system instead of a benzene unit leads to a bathochromic shift reflecting greater σ–π delocalization. The polymers undergo photodegradation, probably via cleavage of the Si–Si bonds, and thermal crosslinking by reaction at the C≡C triple bonds. When doped with iodine, these polymers become semiconducting with conductivity of the order of 10−4 S cm−1.
Synthesis, NMR spectra and chromatographic properties of five trimethylarsonioribosides
Authors: Francesconi Kevin A. , Edmonds John S. , Stick Robert V.
Published: January 2005

Five trimethylarsonioribosides were prepared from naturally occurring and synthetic dimethylarsinylribosides (arsenosugars) by reducing them with 2,3‐dimercaptopropanol and quaternizing the resultant arsine with methyl iodide. The trimethylarsonioribosides prepared in this manner were the four novel compounds methyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside (as the iodide), (2′R)‐2′, 3′‐dihydroxypropyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside (as the formate), 3′‐[(2″, 3″ ‐dihydroxypropyl)hydroxyphosphinyloxy] ‐ 2′ ‐hydroxypropyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside and 3‐(5′‐deoxy‐5′‐trimethylarsonio‐β‐D‐ribosyloxy)‐(2S)‐2‐hydro xypropanesulfonate, and the known (2′S)‐2′‐hydroxy‐3′‐(sulfooxy)propyl 5‐deoxy‐5‐trimethylarsonio‐β‐D‐riboside. They were synthesized to serve as standards for chromatographic analyses of arsenic compounds in marine samples and for investigations into the biotransformation of arsenic in marine organisms. NMR spectral and chromatographic data for the five trimethylarsonioribosides are presented and compared with those of their dimethylarsinyl analogues.
Working Methods Paper: Certification of methylmercury compounds concentration in marine sediment reference material, IAEA‐356
Authors: Horvat M. , Mandić V. , Liang L. , Bloom N. S. , Padberg S. , Lee Y.‐H. , Hintelmann H. , Benoit J.
Published: January 2005

An intercomparison exercise was organized between seven laboratories using various isolation procedures (extraction, distillation, ion‐exchange and alkaline digestion) and detection systems (CV AAS, cold vapour atomic absorption spectroscopy; CV AFS, cold vapour atomic fluorescence spectroscopy; GC, ECD, gas chromatography electron capture detector and HPLC with CV AFS detection) for determination of methylmercury compounds in sediment sample. All certification criteria were fulfilled and therefore the value for total concentration of methylmercury compounds was certified to be 5.46 ng g−1, with a 95% confidence interval from 4.07–5.84 ng g−1. The acceptable range, calculated as two times the confidence interval of the mean is therefore from 4.68–6.23 ng g−1. This is the first sediment reference material ever to be certified for concentration of methylmercury compounds. Comparison of the data obtained by various methodologies has shown that the most critical step is the isolation of methylmercury compounds from binding sites. Acid leaching only cannot release methylmercury compounds quantitatively. Total release of methylmercury compounds could only be achieved by alkaline digestion or distillation. This simple intercomparison exercise has shown that since large numbers of laboratories world‐wide are performing methylmercury compound analyses using various improved and specific separation methods and sensitive detection systems, certification of methylmercury compounds in different biological and environmental samples should not be a problem in the future.
Use of a chromium tricarbonyl complex in a diels–alder reaction: Improved preparation of angularly trifluoromethyl‐substituted tetrahydrophenanthrone
Authors: Bonnet‐Delpon Danièle , Lequeux Thierry , Gruselle Michel , Malezieux Bernard
Published: January 2005

The tricarbonyl complex prepared from 1‐trifluoromethyldihydronaphthalene and Cr(CO)3(NH3)3 undergoes Diels–Alder cycloaddition under high‐pressure conditions (15 kbar) to give after decomplexation by natural light and deprotection, the tetrahydrophenanthrone product in 65% yield. This new methodology allows the activation of unreactive styrenes in Diels–Alder cycloaddition.
Speciation of organolead compounds in air by GC–MS–SIM
Authors: Nerín Cristina , Pons Begoña
Published: January 2005

A procedure for trapping tetraalkyl‐lead (TAL) compounds in air is described. The system consists of a solid cartridge containing a mixture (65:35, w/w) in series of Porapak and Tenax. A contaminated atmosphere with a known concentration of TAL was generated in the laboratory. This atmosphere was trapped in the solid cartridge. After passing synthetic air through the system, the cartridge was extracted with hexane in an ultrasonic bath. The organic extract was concentrated under nitrogen current and the compounds were analyzed by GC–MS–SIM.

Each step of the process was studied independently. Losses of volatile compounds in the evaporation step, the storage of the cartridge over 45 days before the extraction step and the break‐through volumes have been established in order to achieve optimization of the whole process. The analytical conditions of the final quantification include a linear range between 1.32 pg and 50.10 ng for Et4Pb, and 5.30 pg and 51.40 ng for Me4Pb. The detection limits are 0.66 pg, 3.40 pg, 1.07 pg, 1.05 pg and 2.60 pg for Et4Pb, Et3MePb, Et2Me2Pb, EtMe3Pb and Me4Pb, respectively.
The performance of an analytical method for determination of tbt during a six‐year monitoring programme
Authors: Waldock M. J. , Waite M. E.
Published: January 2005

Tributyltin (TBT) concentrations have been measured in UK waters, shellfish and sediments during the period 1986–1992. The methodology was based on conversion of alkyltin compounds to hydrides following extraction, and then measurement by gas chromatography with flame photometric detection. The collection of a large set of data to assess changes in environmental concentrations of organotins required use of good analytical quality control procedures at a time when no reference materials were available. An analytical quality control (AQC) system based on in‐house quality control materials was devised and the performance of the method independently assessed by periodic participation in intercalibration exercises with other expert laboratories.
Biotransformation of butyltin compounds using pure strains of microorganisms
Authors: Errécalde Olivier , Astruc Michel , Maury Georges , Pinel Raoul
Published: January 2005

The debutylation of tributyltin chloride by several strains of fungi, yeasts and bacteria is described. Under standard conditions and with low initial concentration of substrate, significant biotic degradation of tributyltin (6–32%) was detected after five days at 28°C. Dibutyltin and monobutyltin were formed in all cases, with higher yields of the latter. Two microorganisms catalysed the transformation of monobutyltin to dimethyltin and trimethytin whereas all microorganisms were able to methylate inorganic tin(IV) to trimethyltin. Our results suggest that tributyltin biodegradation by microorganisms is generally possible, provided sufficiently low concentrations of substrate are used.
Acid extraction treatment of sediment samples for organotin speciation; occurrence of butyltin and phenyltin compounds on the cadiz coast, south‐west spain
Authors: Gomez‐ariza J. L. , Beltrán R. , Morales E. , Giraldez I. , Ruiz‐benitez M.
Published: January 2005

A method is described for leaching of nanogram amounts of mono‐, di and tri‐butyltin compounds and mono‐, di‐ and tri‐phenyltin compounds from sediments. The procedure is based on soaking the sediments in a water–hydrogen bromide mixture (2:3) with magnetic stirring for 1 h followed by extraction with 0.02% (w/v) tropolone solution in pentane for 2 h. Organotins are determined by GF FPD after clean‐up through a Florisil column and derivatization by Grignard pentylation. The method has been applied to the study of water and sediments in different areas of south‐west Spain. Predominant species are butyltins, especially tributyltin (TBT), which has high values in waters and sediments of Puerto de Santa Maria and Cadiz Bay, as well as in sediments of the Sancti Petri Channel, which suggests a harmful action on biota. A direct relation has been found beween organotin levels and distance of potential focus determined by boating activities. In addition, the relative occurrence of dibutyltin (DBT) and monobutyltin (MBT) together with TBT has been noted, possibly as a result of a degractation process, and the influence of grain size of sediment and presence of organic matter on organotin accumulation has been studied.
Interlaboratory programme for the quality control of trimethyllead determination in the environment
Authors: Quevauviller Ph. , Wang Y. , Turnbull A. B. , Dirkx W. M. R. , Harrison R. M. , Adams F. C.
Published: January 2005

Determinations of the trimethyllead moiety in environmental samples are carried out by a number of laboratories in Europe. To verify the quality of such determinations, the Measurements and Testing Programme (formerly BCR) of the European Commission organised an interlaboratory exercise which allowed discussion and comparison of the different techniques used so far in lead speciation analyses. In addition, this first step enabled a study of the feasibility of the preparation of candidate reference materials (CRMs) for the determination of the trimethyllead moiety in simulated rainwater to be carried out. The solutions used in this study were carefully prepared and their homogeneity and stability verified. This paper describes the organisation and the results of the intercomparison and discusses the further development of the project.
A new family of heavy transition metal coordination compounds and its application, I. Design, synthesis and characterization of volatile organohafnium precursors
Authors: Grafov Andrei V. , Mazurenko Eugene A. , Battiston Giovanni A. , Zanella Pierino , Tisato Francesco , Braga Franco , Traldi Pietro
Published: January 2005

The first three representatives of a new family of volatile organohafnium compounds suitable as metallo‐organic chemical vapour deposition precursors were synthesized. A combination of cyclopentadienyl and alkoxo‐ligands with a bicyclo[2.2.1]heptanc framework was used. Volatility at relatively low temperatures for hafnium compounds was found and the precursors were characterized by elemental analysis and spectroscopic methods (IR, 1H and 13C NMR, mass spectrometry and mass‐analysed ion kinetic energy spectroscopy). The outlook for use in hafnium functional materials synthesis was derived from the fragmentation data.