bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of six triorganotin(IV) compounds on nitrification and ammonification in soil
Authors: Kuthubutheen A J , Wickneswari R , Kumar Das V G 
Published: January 2005

AbstractThe effects of six triorganotin(IV) compounds and of Thiram on nitrification and ammonification in soil were investigated. Low concentrations of up to 50 μg g−1 of the triorganotin(IV) compounds enhanced nitrate‐nitrogen (NO3−‐N) production in soil. Except for diphenylbutyltin bromide, which inhibited nitrification at 250 μg g−1, the other triorganotin(IV) compounds were inhibitory at concentrations of 100 μg g−1 to less than 250 μg g−1. At 10 μg g−1, only triphenyltin acetate was less inhibitory towards nitrification compared with Thiram. At 250 μg g−1, Thiram exerted a strongly persistent inhibitory effect towards nitrification. The NO3−‐N level recorded 28 days after application was only 0.10 μg g−1 soil. With the triorganotin compounds NO3−‐N levels of 7.05–12.06 μg g−1 soil were recorded 28 days following their application. The deleterious effects of the triorganotin(IV) compounds were less persistent and recovery of nitrification was evident seven days after application. Low concentrations of Thiram and triorganotin(IV) compounds inhibited ammonification, whereas higher concentrations enhanced ammonification. Complete inhibition of ammonification was attained 21–28 days after application of Thiram at 50 μg g−1. On the other hand, with the triorganotin(IV) compounds, except for diphenylbutyltin bromide at 10–50 μg g−1, ammonification persisted at all concentrations 28 days after application.
Laser photochemistry of organometallic compounds related to applications in microelectronics
Authors: Sato Hiroyasu 
Published: January 2005

AbstractPhotochemistry of organometallic compounds achieves a marriage of a rich variety of organometallic chemistry and the full potential of electronically excited states of molecules. The application of lasers as light sources adds a great many new features to these studies, which cannot be attained by other means, because lasers provide light of such a high quality, e.g. a high‐intensity, energetic (i.e. wavelength) purity, a high degree of coherence, and a high spatial and temporal resolution. Laser photochemistry of organometallic compounds, such as laser photochemical vapor deposition (LPCVD), laser ablation, and photochemical dry etching, forms the basis of many important industrial processes which sustain the present‐day microelectronics industries. Lasers are used not only to photodissociate organometallic molecules, but to monitor the reaction steps by probing the starting material, chemical intermediate, or final product by many laser‐based spectroscopic methods. Although it is a very young area of science (the first laser was operated in 1960), this research area is now really ebullient, as a result of strong interest from both the fundamental and the practical sides. Laser photochemistry of organometallic compounds extends a wide and fertile research frontier, full of challenge and novel possibilities. In the present review, the present status of laser (ultraviolet and visible) photochemistry of organometallic compounds related to these industrial applications is briefly reviewed, with special emphasis on the basic studies of the relevant photochemistry and their relationship to photochemical processes on solid surfaces.
Stratification and tributyltin variability in San Diego Bay
Authors: Stang Peter M , Bower David R , Seligman Peter F 
Published: January 2005

AbstractTributyltin (TBT), a biocidal antifoulant in many marine paints, was measured in near‐surface and near‐bottom water over a 25 h period at the entrance to a marina in San Diego Bay, USA. Surface water concentrations varied from 20 to 225 nanograms per liter (ng dm−3) as TBT chloride and bottom water varied from non‐detectable (<1 ng dm−3) to 77 ng dm−3. Surface water concentrations varied, with highest concentrations associated with ebbing tides, and lowest concentrations with flooding tides, indicating that the yacht basin is a source of TBT. Bottom water TBT concentrations were almost always lower than corresponding surface water concentrations. The highest bottom water concentrations were associated with flooding tides and lowest surface water TBT concentrations. Physical water column measurements indicate that vertical stratification developed during ebbing tides and dissipated during flooding tides. This accounted for maximum bottom water and minimum surface water TBT concentrations during flooding tides, due, at least in part, to vertical mixing and dilution during flood tides.
Preparation and properties of triorganostannylmethyl 2,3:5,6‐di‐O‐isopropylidene‐α‐D‐mannofuranosides; pesticidal and fungicidal activities of triphenylstannyl‐carbohydrate derivates
Authors: McDonough Christine R , Taylor Oonah J , Wardell James L 
Published: January 2005

AbstractThe synthesis of trioganostannylmethyl 2,3:5,6‐di‐O‐isopropylidene‐α‐D‐mannofuranoside (compound 3, R*OCH2SnR2R′:RR′Me or Ph) from D‐mannose is reported. The compound 3 (RR′Ph) is transmetallated by PhLi to compound 5, R*OCH2Li, Which can be trapped by HgCl2 [as (R*OCH2)2Hg] and by ketones, R3COMe [as compound 7, R*OCH2CR3MeOH]. Two stereoisomers of this compound (7a, R3Ph) were formed in a ratio of 40:60, indicating some asymmetric induction, arising from the chiral R* moiety. Reactions of compound 3, (RR′Ph), with I2, HO2CCF3 and Cl2PtCOD result in Ph–Sn bond cleavage and formation of compound 3 with RPh; R′I, OCOCF3 and Cl respectively. Reactions of compound 3 (RR′Me) with electrophiles can lead to cleavage of either of both types of C–Sn bonds present (e.g. by I2, Br2, Cl2PtCOD or SnCl4) or to attack at the C5–C6 protecting group with release of acetone (e.g. by CF3CO2H, SO2 or CH3COCl). Pesticidal and fungicidal activities of compound 3(RR′Ph) as well as of 1,2:5,6‐di‐O‐isopropylidene‐3‐O(triphenylstannylmethyl)‐α‐D‐glucofuranose (compound 2, RPh) and methyl 4, 6‐O‐benzylidene‐2‐deoxy‐2‐triphenylstannyl‐α‐D‐altropyranoside (compound 1, RPh) are reported.
Assessment of the in vitro broad‐spectrum antiviral activity of some selected antitumor organotin complexes
Authors: Ward Sarah G , Taylor R Craig , Crowe Alan J , Balzarini Jan , De Clercq Erik 
Published: January 2005

AbstractEleven antitumor‐active octahedral organotin complexes of the type R2SnX2L2, where R = methyl, ethyl or phenyl, X = chloride or bromide, and L2 = o‐phenantholine ((phen), 2‐)2‐(pyridyl)‐benzimidazole (PBI) or two dimethylsulfoxides (2DMSO), were examined for their broad‐spectrum in vitro antiviral activity against a number of DNA and RNA viruses. The DNA viruses included in this study were herpes simplex virus type 1 and type 2, a TK–(thymidine kinase deficient) strain of herpes simplex virus type 1, and vaccinia virus. The RNA viruses were vesicular stomatitis virus, Coxsackie virus type B4, Sindbis virus, Semliki forest virus, parainfluenza virus type 3, and human immunodeficiency virus (HIV). Overall, the complexes showed weak antiviral activity and low selectivity. With the exception of (CH3)2SnBr2·PBI and (C6H5)2SnCl2·2DMSO, all of the complexes were active against one or more of the three strains of herpes simplex viruses. On the other hand, only three complexes, (CH3)2SnBr2·PBI, (CH3)2SnBr2·phen, and (C6H5)5SnBr2·PBI, exhibited marginal activity against some of the RNA viruses. None of the complexes was active against vesicular stomatitis or parainfluenza virus. Similarly, there was no inhibitory activity towards HIV‐1‐associated reverse transcriptase or HIV‐1‐induced cytopathogenicity in human T‐lymphocyte MT4 cell cultures at subtoxic concentrations.
The methylation of inorganic tin by humic materials in an aquatic environment
Authors: Shugui Dai , Guolan Huang , Yong Cai 
Published: January 2005

AbstractThis paper presents a study of methylation of inorganic tin (SnCl4·5H2O) by humic materials (humic and fulvic acids) isolated from the sediment of Tianjin Harbor, Tianjin, China, and the effects of pH, salinity, and the concentration of inorganic tin on the production of methyltin were investigated.These humic materials could methylate inorganic tin, and the methyltin product was mainly monomethyltin. Low molecular weight compounds of the humus fraction (i.e. fulvic acid) were more active in the methylation, which could be facilitated by salinity and affected by pH.
A study of the partitioning and sorptive behaviour of butyltins in the aquatic environment
Authors: Dowson P H , Bubb J M , Lester J N 
Published: January 2005

AbstractThis study was designed to investigate the partitioning and sorptive behaviour of tributyltin(TBT), and its degradation products dibutylitin (DBT) and monobutyltin (MBT), in the aquatic environment. Factorial experiments were undertaken to determine the importance of pH and particulate matter concentration in the sorption of butyltin compounds to solid phases. Results indicate that in freshwaters MBT, and to a lesser extent TBT, will be partitioned towards the particulate phase, whereas DBT exhibits a 50:50 partitioning between particulate and solution phases. In estuarine waters, whilst MBT will almost exclusively sorb on to particulates, TBT will be predominantly in the solid‐phase fractions but 10–30% may remain in solution. DBT, in contrast, is solubilized in estuarine waters. A more detailed investigation of TBT sorption and particulate matter concentration was undertaken using adsorption isotherms on different sediment types. The results from batch isotherm tests plotted according to the Freundlich adsorption model revealed that TBT adsorption varied with sediment type, increasing in the order sandy‐silt < silty‐sand < silty‐clay. TBT sorption was found to be reversible, indicating that contaminated sediments may release TBT to overlying waters following sediment distrubance. Interstitial water partitioning studies indicate that TBT predominates in the particulate phase with partition coefficients for TBT higher than for DBT and MBT. The TBT partition coefficient in interstitial waters appears to be related to total organic carbon loadings.
Antimicorbial effects of newly synthesized organotin(IV) and organolead(IV) derivatives
Authors: Kumari Anita , Tandon J P , Singh R V 
Published: January 2005

AbstractTriorganotin(IV) and triorganolead(IV) derivatives of the types Me3Sn(SCZ) and Ph3Pb(SCZ) (where SCZ− is the anion of a semicarbanzone ligand) have been synthesized by substitution reactions of trimethyltin chloride and triphenyl‐lead chloride with semicarbazones derived from heterocyclic ketones. The resulting complexes have been characterized by elemental analyses, molecualr weight determinations and conductivity measurements. The mode of bonding has been established on the basis of infrared and 1H, 13C and 119Sn NMR spectroscopic studies. Some respresentative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria; the results of these investigations have been reported in the present paper.
Polygermoxanes suitable for biochemical purposes. Part I. Digermoxanes (low‐viscosity oils)
Authors: Duverneuil Gilles , Mazerolles Pierre , Perrier Elisabeth 
Published: January 2005

AbstractIn order to replace silicones in some of their biomedical applications, e.g. syringe lubrication, implants ets., a series of digermoxanes (R1R2R3Ge)2O (R = n–alkyl, aryl) were synthesized. These compounds are thermally stable oils; their viscosities, depending on the nature of substituents, lie in the range 1–72 cPo (mPa s) at 20°C.
The association between selenium and humic substances in forested ecosystems—laboratory evidence
Authors: Gustafsson Jon Petter , Johnsson Lars 
Published: January 2005

AbstractIn the soils and aquatic systems of coniferous forests, selenium is usually associated with humic substances. To clarify further some of the mechanisms involved, labelled and unlabelled selenite were added to two forest floors and to a brownwater lake. Sequential extraction procedures and chromatographic methods were used to evaluate the resulting association between selenium and humic substances. It was observed that the forest floors fixed most of the added selenite by means of microbial reductive incorporation and that selenium was preferentially incorporated into lowmolecular‐weight fractions of the humic substances. By contrast, selenium reduction was much slower in the brown‐water lake and instead, inorganic complexation of selenite to metal–humic complexes was important during the experiment, provided that the concentrations of competing ligands were low.
Simplified sample preparation for GC speciation analysis of organotin in marine biomaterials
Authors: Ceulemans M. , Witte C. , Łobiński R. , Adams F. C. 
Published: January 2005

AbstractTwo simple sample preparation methods for the speciation analysis of triphenyltin and butyltin compounds in marine biotissues, using tetramethylammonium hydroxide (TMAH) solubilization and enzymic hydrolysis, have been developed and compared with conventional acid digestion. Derivatization was carried out in situ using sodium tetraethylborate (NaBEt4) without prior separation of the analytes from the tissue matrix. Separation and detection was performed using capillary gas chromatography (GC) coupled to microwave‐induced plasma atomic emission spectrometry (MIP AE) allowing detection limits of 2 ng g−1 (as tin) to be reached. The accuracy of the presented methods was demonstrated by the analysis of a fish reference material (NIES No. 11). the necessity for sample clean‐up is discussed and examples of the analysis of mussel tissue are shown.
Synthesis and radiopharmacological study of new metallated thiazolidines and dithioacetals of N‐allyl‐substituted cysteamine and methylcysteamine
Authors: Rima G. , Satge J. , Sentenac‐Roumanou H. , Fatome M. , Laval J. D. , Lion C. , Alazard O. , Chabertier P. 
Published: January 2005

AbstractNew germa‐ and silathiazolidines or germa‐ and siladithioacetals with N‐allyl‐substituted cysteamine and methylcysteamine ligands have been synthesized and their pharmacological properties (toxicity, radioprotective activity) have been studied. A notable decrease in the toxicity and a rather large increase in the radioprotective activity of these new organometallic derivatives compared to N‐allyl‐substituted cysteamine and methylcysteamine were observed.
The hydrodechlorination of chloroaromatic and unsaturated chloroaliphatic compounds using a nickel boride reagent
Authors: Yale M. , Keen C. , Bell N. A. , Drew P. K. P. , Cooke M. 
Published: January 2005

AbstractA nickel boride reagent, prepared in situ by the reaction of nickel chloride with sodium borohydride, has been used to hydrodechlorinate and hydrogenate chloroaromatic compounds. The same reagent can also dechlorinate chloro‐olefinic compounds but chloroalkanes do not react. The reactions can be sustained by addition of hydrogen gas and the ratio of the aromatic to aliphatic hydrocarbons produced can be varied by addition of sodium hydroxide to the reaction mixture and by the duration of the reaction. The reactivity of polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), chlorobenzene and tetrachloroethylene have been studied. Capillary gas chromatography was used to follow the course of reactions and gas chromatography‐mass spectroscopy (GC–MS) was used for product identification.
Arsenobetaine and other arsenic species in mushrooms
Authors: Byrne A. R. , Šlejkovec Z. , Stijve T. , Fay L. , Gössler W. , Gailer J. , Lrgolic K. J. 
Published: January 2005

AbstractArsenic species in arsenic accumulating mush‐ rooms (Sarcosphaera coronaria, Laccaria amethystina, Sarcodon imbricatum, Entoloma lividum, Agaricus haemorrhoidaius, Agaricus placomyces, Lycoperdon perlatum) were determined. HPLC/ICP MS and ion‐exchange chromatogra‐ phy–instrumental neutron activation analysis (NAA) combinations were used. The remarkable accumulator Sarcosphaera coronaria (up to 2000 mg As kg−1 dry wt) contained only methylarsonic acid, Entoloma lividum only arsenite and arsenate. In Laccaria amethystina dimethylarsinic acid was the major arsenic compound. Sarcodon imbricatum and the two Agaricus sp. were found to contain arsenobetaine as the major arsenic species, a form which had previously been found only in marine biota. Its identification was confirmed by electron impact MS.
Synthesis and characterization of 7‐(CH3)3N‐4‐ {2,4‐(NO2)2C6H3S}‐nido‐7‐CB10H11 and its Biodistribution in C57B16 Mice Bearing B16 Melanoma
Authors: Morris John H. , Peters Gavin S. , Koldaeva Elena , Spryshkova Raisa , Borisov Gergy 
Published: January 2005

Abstract7‐(CH3)3N‐4‐{2,4‐(NO2)2C6H3S}‐nido‐7‐CB10H11 has been synthesized through a Friedel‐Crafts substitution reaction on 7‐(CH3)3N‐nido‐7‐ CB10H12. A biodistribution study in mice with implanted B16 melanoma indicates that the compound locates in neoplastic tissue at concentrations which suggest that its use in 10B neutron capture therapy may be feasible.
On the reactions of molybdenum and tungsten carbonyls with trimethyl‐ and triethyl‐aluminium
Authors: Pasynkiewicz S. , Jankowski J. 
Published: January 2005

AbstractReactions of hexacarbonylmolybdenum, hexacarbonyltungsten and arene complexes of tricarbonylmolybdenum and tricarbonyltungsten with trimethyl‐ and triethyl‐aluminium have been studied. It has been found, based on IR and NMR spectra, that trialkylaluminium does not form complexes with hexacarbonyls of molybdenum and tungsten. Arene (mesitylene, toluene and benzene) complexes of tricarbonylmolybdenum form 1 : 1 complexes with triethylaluminium, and arene complexes of tricarbonyltungsten form complexes with trimethyl‐ and triethyl‐aluminium. Regardless of the molar ratios of reactants (arene)M(CO)3/AlEt3, only one of the three CO groups bonded to molybdenum or tungsten forms a complex with AlEt3. Fast exchange between free and complexed trialkylaluminium and an exchange of trialkylaluminium between all three carbonyl groups have been observed in benzene, toluene and decalin solutions. In the 1H NMR spectra of the products of the reactions of (mesitylene)Mo(CO)3 with AIEt3 and AIMe3, signals at –9 to –14ppm (characteristic for molybdenum hydrides) were present. It confirmed an alkylation of molybdenum followed by β‐ or α‐hydrogen elimination with the formation of the corresponding molybdenum hydrides, the actual catalyst of aromatic hydrocarbon hydrogenation.
Metabolism of arsenic compounds by the blue mussel mytilus edulis after accumulation from seawater spiked with arsenic compounds
Authors: Gailer Jürgen , Lrgolic K. J. , Francesconi Kevin A. , Edmondsxs John S. 
Published: January 2005

AbstractBlue mussels (Mytilus edulis) were exposed to 100 μg As dm−3 in the form of arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium iodide or dimethyl‐(2‐hydroxyethyl)arsine oxide in seawater for 10 days. The seawater was renewed and spiked with the arsenic compounds daily. Analyses of water samples taken 24 h after spiking showed that arsenobetaine and arsenocholine had been converted to trimethylarsine oxide, whereas trimethylarsine oxide and tetramethylarsonium iodide were unchanged. Arsenobetaine was accumulated by mussels most efficienty, followed in efficiency by arsenocholine and tetramethylarsonium iodide. None of the other arsenic compounds was significantly accumulated by the mussels. Extraction of mussel tissues with methanol revealed that control mussels contained arsenobetaine, a dimethyl‐(5‐ribosyl)arsine oxide and an additional arsenic compound, possibly dimethylarsinic acid. Mussels exposed to arsenobetaine contained almost all their experimentally accumulated arsenic as arsenobetaine, and mussels exposed to tetramethylarsonium iodide contained it as the tetramethylarsonium compound. Mussels exposed to arsenocholine had arsenobetaine as the major arsenic compound and glycerylphosphorylarsenocholine as a minor arsenic compound in their tissues. The results show that arsenobetaine and arsenocholine are efficiently accumulated from seawater by blue mussels and that in both cases the accumulated arsenic is present in the tissues as arsenobetaine. Consequently arsenobetaine and/or arsenocholine present at very low concentrations in seawater may be responsible for the presence of arsenobetaine in M. edulis and probably also among other marine animals. The quantity of arsenobetaine accumulated by the mussels decreases with increasing concentrations of betaine. HPLC‐ICP‐MS was found to be very powerful for the investigation of the metabolism of arsenic compounds in biological systems.
Catalytic asymmetric synthesis of propranolol and metoprolol using a La–Li–BINOL complex
Authors: Sasai Hiroaki , Suzuki Takeyuki , Itoh Noriie , Shibasaki Masakatsu 
Published: January 2005

AbstractThe La–Li–(R)‐BINOL complex prepared from either lanthanum(III) chloride [LaCl3 · 7H2O] or [La(O‐i‐Pr)3] has made possible effective catalytic asymmetric syntheses of therapeutically important ß‐blockers such as propranolol and metoprolol. The possible stereochemical course of asymmetric nitroaldol reactions has been also clarified.
Syntheses of monodispersed methyl methacrylate oligomers via organolanthanide complexes and introduction of hydroxyl groups into the oligomer
Authors: Ihara Eiji , Taguchi Motoko , Yasuda Hajime 
Published: January 2005

AbstractMethyl methacrylate (MMA) oligomers (Mn ≃ 2500) with a narrow molecular weight distribution (Mw/Mn>1.10) were synthesized by using a Cp*2SmMe(THF) initiator (Co=η −C). The oligomerization proceeds via a samarium enolate as the propagating species and the reaction of the living oligomer with p‐tolualdehyde produced p‐tolyl hydroxymethyl‐terminated oligoMMA.
Carbon–Halogen bond cleavage reaction catalyzed by organoyttrium hydride (in situ) and lanthanide alkoxides
Authors: Qian Changtao , Zhu Chengjian , Zhu Dunming 
Published: January 2005

AbstractOrganic halides can be ubiquitous long‐lived contaminants to the environment. Dehalogenation of organic halides with sodium hydride (NaH) as reductant catalyzed by two varieties of lanthanides was reported in respect of environmental remediation. The first catalyst is a dicyclopentadienyl yttrium halide, and organoyttrium hydride was thought to be the reactive species. The second catalyst is a lanthanide isopropoxide which showed higher catalytic reactivity, and an aggregate is involved in the suggested mechanism.
Acetalization of ketones and aldehydes catalyzed by lanthanoid trisulfonates
Authors: Okano Tamon , Michihashi Tomonori , Kiji Jitsuo 
Published: January 2005

AbstractLanthanoid sulfonates are found to be good catalysts for the acetalization of aldehydes and ketones with methyl orthoformate in methanol. The catalytic activity of Ln(OTf)3 (OTf, trifluoromethanesulfonate) increases in the order of La<Sm<Gd<Er<Yb. As sulfonates such as trifluoromethylsulfonates and (1S)‐10‐camphorsulfonates are more soluble in organic solvents than the chlorides, the acetalization in ether or dichloromethane and the exchange reaction of alkoxy groups between acetals and alcohols can be achieved under mild conditions.