bluuebunny/crossref_metadata_2025 huggingface dataset:
Methylation of tin(II) and lead(II) in sediment by carbanion donors
Authors: Rapsomankis Spyridon , Donard Olivier F X , Weber James H
Published: January 2005

A factorial experimental design determined separate and combined effects of MeCoB12 (methylcobalamin) and Me2Co(N4)+ (a methylcobalamin model) on methylation of Sn(II) and Pb(II) in sediment matrices. Total methyltin yields ranged from 1.4% to 3.2%, and total methyllead yields varied from 0.037% to 0.11%. No methylmetal products occurred in the absence of Me2Co(N4)+.
Synthesis, 119Sn NMR and Mössbauer studies and bioassay data of O‐tricyclohexylstannyl derivatives of substituted 8‐hydroxyquinolines
Authors: Blunden S J , Patel B N , Smith P J , Sugavanam B
Published: January 2005

Eight novel tricyclohexyltin derivatives of substituted 8‐hydroxyquinolines have been synthesised and their structures studied in the solid state by 119mSn Mössbauer and, in solution, by 119Sn NMR, spectroscopy. Bioassay data are reported for these compounds against an organophosphorus‐resistant species of the two‐spotted spider mite, Tetranychus urticae, and a range of fungal and bacterial diseases of crops. The relationship between the activity and the coordination number of the tin atom is discussed, and it is shown that the anionic group can, in some cases, significantly affect the biological properties.
Synthesis of metal‐containing carbohydrate polymers employing crown ether phase transfer catalyzed interfacial condensation
Authors: Naoshima Y , Carraher C E , Iwamoto S , Shudot H
Published: January 2005

Phase transfer catalyzed interfacial reaction of the polysaccharide dextran (C6H10O5)n with organotitanium and organotin dichlorides to form metal‐containing carbohydrate polymers has been carried out in the presence of two bases, sodium hydroxide and triethylamine. Interfacial systems employing sodium hydroxide with a crown ether phase transfer catalyst (PTC) gave generally greater yields compared with the analogous systems without a PTC. The trend of maximum yield for triethylamine systems with organotin dichloride not containing a PTC was different from that observed for the sodium hydroxide systems without a PTC, probably because of the ability of triethylamine to act as a PTC.
Synthesis of 14C‐radiolabelled trimethyllead chloride
Authors: Blais J S , Marshall W D
Published: January 2005

Two synthetic routes to 14C‐labelled trimethyllead chloride ((CH3)3PbCl) from 14C‐methyl iodide (CH3I) were investigated. Alkylation of (CH3)3PbCl with labelled methylmagnesium halide, on a microscale, was less efficient for the synthesis of tetramethyllead ((CH3)4Pb) than was an electrochemical reduction of labelled CH3I at a sacrificial lead cathode. In the Grignard approach, unlabelled decyl bromide served as an initiator for the reaction of 14C‐CH3l with excess Mg and as a carrier during the subsequent alkylation of (CH3)3PbCl. In the electrochemical approach a two‐compartment cell, using dimethylformamide as solvent and sodium perchlorate as supporting electrolyte, offered several advantages over a single compartment reactor. The labelled (CH3)4Pb from both reactions was isolated by extraction, converted to (CH3)3PbCl by controlled oxidation with HCl and purified by thin layer chromatography.
The synthesis and tin‐119m Mössbauer spectra of a series of di (4‐substituted phenyl) tin dichloride complexes with nitrogen‐donor ligands
Authors: Biddle B N , Gray J S , Crowe A J
Published: January 2005

The synthesis and 119mSn Mössbauer spectra of a series of 12 new and 3 other organotin complexes of general structure (4‐ZC6H4)2SnCl2.L2.(Z = CH3, CF3, F, Cl, OCH3, L2=2,2′‐bipyridyl, 1,10‐phenanthroline, 2‐aminomethylpyridine) arereported. A convenient method for the preparation of the intermediate diaryltin(IV) dihalides is given. The complexes fall into two isomeric types with either a trans‐ or cis‐[ArSnAr] geometry. For this series 2‐aminomethylpyridine gives exclusively the cis‐[ArSnAr] geometry in its complexes.
Catalysis of hydrosilylation XIII. Gas‐phase hydrosilylation of acetylene by trichlorosilane on functionalised silica supported rhodium and ruthenium phosphine complexes
Authors: Marciniec Bogdan , Foltynowicz Zenon , Urbaniak WŁOdzimierz , Perkowski Juliusz
Published: January 2005

Gas‐phase hydrosilylation of acetylene by tri‐chlorosilane catalyzed in a continuous flow apparatus by rhodium and ruthenium phosphine complexes immobilized on the silica via mercapto, phosphine, amine and nitrile ligands has been studied. GLC analysis of the reaction products showed vinyltrichlorosilane to be accompanied by products of double hydrosilylation of acetylene and the redistribution of trichlorosilane followed by the hydrosilylation and hydrogenative hydrosilylation of acetylene with dichlorosilane. A scheme for this complex competitive–consecutive reaction was proposed. The yield and selectivity of vinyltrichlorosilane can be much improved under special reaction conditions, e.g. rate flow of the particular substrates, temperature, given catalyst and others. Kinetic measurements carried out in the range of 115–140°C allowed us to evaluate the activation energy, Ea, for the vinyltrichlorosilane synthesis, which varied between 20.5 and 27.6 kJ mol−1 for the selected rhodium and ruthenium supported complexes.
Metal catalysed Brooke rearrangement of 3‐Halo‐1‐(trimethylsilyl) propan‐2‐one (Halo = Cl or Br)
Authors: Jones Michael D , Kemmitt Raymond D W
Published: January 2005

The complexes [IrH(CO)(PPh3)3], trans‐[IrCI(CO)‐ (PPh3)2], [RhH(PPh3)4], [Pd(PPh3)4], [Pt(trans‐stilbene)(PPh3)2] and [Pt(η3‐CH2‐COCH2)‐(PPh3)2] catalyse the rearrangement of Me3SiCH2C(O)CH2Cl to CH2C(OSiMe3)‐CH2Cl.
Antifeedant effects of mixed methylphenyl hexaorganoditin compounds of the type PhnMe6–nSnSn on larvae of Spodoptera littoralis and Epilachna varivestis
Authors: Ascher K R S , Eliyahu M , Bultent E J , Meinema H A
Published: January 2005

Compounds of the series PhnMe6–nSn2 were prepared and tested for their antifeedant effects against Spodoptera littoralis (Boisduval) and Epilachna varivestis (Mulsant) larvae. In addition, phytotoxicity towards bean seedlings was measured. The most active compound against both Spodoptera and Epilachna was Ph3Me3Sn2. The compound at 50 mg dm−3 was comparatively innocuous in phytotoxicity tests against bean seedlings.
Regioselective phthalation and succinylation of D‐glucose and D‐galactose using protecting groups: Conversion of the products to organotin derivatives
Authors: Patel Atula , Poller Robert C , Rathbone Elner B
Published: January 2005

1,2: 5,6‐Di‐O‐isopropylidene‐α‐D‐glucofuranose was acylated at the free 0‐3 position with phthalic and succinic anhydrides. Removal of the protecting groups gave the 3‐O‐acylglucopyranose compounds which were converted to their acetyl and organostannyl derivatives. A similar sequence of reactions was carried out with 1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranose.
Molybdenum‐Containing polysalts of the poly[ferricene‐1,2(1,3:1,1′)diyl‐methylene] cation
Authors: Neuse Eberhard W , Khan Fathima B D
Published: January 2005

Poly(ferricene‐1,2(1,3:1,1′)diyl‐methylene) polycations, generated from the neutral precursor polymer 1 (M̄n=2800) by dioxygen (O2) oxidation in sulfuric acid medium, are paired first, in a model reaction, with the hexafluorophosphate anion and, in the principal series of experiments, with the two molybdenum‐containing complex anions, octamolybdate and phosphododecamolybdate. The model poly(hexafluorophosphate) 2b, as well as the polymolybdates 2c and 2d, precipitate from aqueous acidic solution of the corresponding polysulfate 2a after anion exchange; scopically. In addition to the hexafluorophosphate anion, the model polysalts 2b contain small proportions, typically 5‐15%, of sulfate anion (probably present as HSO), indicating incompleteness of the anion exchange process. Analytical data suggest similarly incomplete exchange of anions also for the polymolybdates 2c and 2d. Oxidation of ferrocene units along the polymer chain is practically complete in the great majority of polysalts 2 synthesized. The molybdenum‐containing polymers are of interest as plant micronutrients possessing slow‐release properties.
Hydrosoluble transition‐metal coordination compounds of triphenylphosphine m‐trisulfonate
Authors: Larpent Chantel , Patin Henri
Published: January 2005

By using 31P NMR and IR techniques it is established that the basicities of triphenylphosphine m‐trisulfonate (TPPTS) and triphenylphosphine (PPh3) are in the same order of magnitude. This highly hydrosoluble phosphine is a convenient ligand for the synthesis of hydrosoluble coordination compounds of molybdenum(0), palladium(II), platinum(II) and rhodium(I). The exchange of TPPTS with ligands other than PPh3 (nitriles, carbon monoxide, olefins, chloride) can be used to obtain the desired complexes. However, because redox reactions between metal salts, water and TPPTS are possible, the synthesis of lowvalent precursors must be carried out and the experimental conditions have to be carefully controlled to avoid side‐reactions and the participation of the sulfonate anions in competitive reactions.
Samarium(II)‐induced coupling of acid chlorides with allylic halides
Authors: Araki Shuki , Hatano Masahiro , Ito Hirokazu , Butsugan Yasuo
Published: January 2005

Samarium(II)‐induced coupling of acid chlorides with allylic halides gave diallylated tertiary alcohols. Monoallylated allylic ketones could not be obtained.
Organic lead compounds in vehicle exhaust
Authors: Hewitt C Nicholas , Rashed M B
Published: January 2005

Species‐specific measurements of the five tetraalkyllead compounds used in gasoline and their intermediate decomposition products, the tri‐ and di‐alkyllead species, have been made in vehicle exhaust fumes. Under normal engine running conditions 0.3–3% of the lead emitted in exhaust is as an organic compound, but cold, choked engines emit proportionally much larger amounts of alkyllead. Alkyllead is emitted in both the gas and the aerosol phases.
Preparation of di(n‐butyl) tin and di(n‐octyl) tin dihalides by the direct synthesis method
Authors: Chee Ong Ghee , Das V G Kumar
Published: January 2005

The direct synthesis of the two industrially important organotin intermediates, di(n‐butyl)tin and di(n‐octyl)tin dihalides, has been investigated by reacting the appropriate alkyl halide with metallic tin undervarying conditions. Observations were made on the influences of temperature, pressure, reaction time, nature of the tin metal, organic halide/tin reactant ratios and the presence of catalysts on the extent of tin conversion and yields of the organotin products. The efficacy of the onium halides, notably n‐Bu4NI, Me3SI and Ph3MeAsI, either singly or in binary combinations with iodine or inorganic iodine compounds, in catalysing the synthesis of the above dialkyltins as well as higher di(n‐alkyl)tin analogues is described.
Synthesis and psychotropic properties of furyl‐ and thienyl‐germatranes
Authors: Lukevics Edmunds , Ignatovich Lubov , Porsiurova Natalia , Ǧērmane Skaidrīte
Published: January 2005

Trihalogermyl‐furans and ‐thiophenes magnified image were prepared by inserting germanium dibromide (GeBr2) generated from the dibromogermane(II) dioxanate complex into the carbon‐halogen bond of halo‐furans and ‐thiophenes. Their ethanolysis and transesterification by triethanolamine yielded the germatranes magnified image which were subjected to psychotropic activity assays. The psychotropic properties of germatranes were found to depend on the type of the heterocycle and on the position of the germatrane moiety.
Speciation of butyltin compounds in oyster samples
Authors: Rapsomanikis S. , Harrison Roy M
Published: January 2005

Experimental instrumentation for the speciation of butyltin compounds by hydride generation and gas chromatography‐quartz furnace atomic absorption spectrometry is described. Evaluation of a number of extraction methods revealed that simple acid leaching of oyster samples gave adequate recoveries. The levels of each butyltin species in oyster flesh and gill are reported together with the tentative identification of a mixed methylbutyltin compound.
Correlation of molecular total surface area with organotin toxicity for biological and physicochemical applications
Authors: Eng G , Tierney E J , Bellama J M , Brinckman F E
Published: January 2005

There exists a high correlation between molecular total surface area (TSA) values and diorganotin toxicity towards several distinct types of organisms. This correlation was found for N2a neuroblastoma cells, 3T3 fibroblasts, Daphnia magna Rhithropanopeus harrisii and Ankistrodesmus falcatus. In the case of Rhithropanopeus harrisii, a high correlation was also found between TSA and toxicity for triorganotins as well. This study suggests that the relationship between TSA and toxicity is a function of the hydrophobicity of the organotin compounds rather than electronic or steric effects.
The lifetimes of organosulphur compounds in the troposphere
Authors: Hewitt C Nicholas , Davison Brian M
Published: January 2005

Dimethyl sulphide and other reduced sulphur compounds, produced by marine biogenic activity and other processes, play a significant role in the global biogeochemical cycling of the element. The rates of their reactions with atmospheric oxidants are reviewed and their lifetimes in the troposphere due to the various reactions are computed. Sufficient data are available on the tropospheric abundance of the hydroxyl radical (OH) and on the rates of its reactions with the sulphur compounds for reasonable estimates to be made of the sulphur lifetimes with respect to OH. Summertime lifetimes of 14–87 h for (CH3)2S are computed at different latitudes. In the case of the tropospheric concentrations of the nitrate radical (NO3), few data are available. There is a similar paucity of data on its rates of reactions with the sulphur compounds, and so large uncertainties exist in the computed lifetimes. These are, in any case, much longer than those due to OH. The possibility exists that iodine photochemistry, producing iodoxyl (IO) radicals, may efficiently oxidize the reduced sulphur and other organic compounds in the marine troposphere leading to lifetimes of the order of hours. Few data exist on the rates or mechanisms of these reactions and these are identified as representing the greatest uncertainties in the estimates of organosulphur lifetimes in the troposphere.
A 119Sn Mössbauer spectroscopic study on complexes of di‐and tri‐organotin(IV) moieties with 2‐mercaptoethanesulfonates, in the solid state and in aqueous solution
Authors: Barbieri Renato , Silvestri Arturo , Huber Friedo
Published: January 2005

The configuration of the bonding environment of tin in the complexes [R2Sn(SCH2CH2SO3)2]2− (R = Me, Ph) and [Me3Sn(SCH2CH2SO3)]− has been determined to be tetrahedral both in the solid state and in aqueous solution (for the methyl derivatives). The coordination number of tin increases to five in aqueous solutions for the Me2Sn(IV) complexes in Hepes buffer (N‐2‐hydroxyethylpiperazine‐N′‐2‐ethanesulfonic acid; at least in fivefold excess, at pH 7.4) due to coordination by the tertiary amino nitrogen atom. No effect is detected due to the surfactant 2‐hydroxypropylcellulose concerning both coordination to tin and influence on the Mössbauer parameters. The stoichiometry of mixed complex formation in aqueous solution of Me2Sn(IV), 2‐mercaptoethanesulfonate and Hepes is 1:2:1, according to a procedure of ‘Mössbauer titration’. All complexes in aqueous solution undergo slow lysis of the tin‐sulfur bonds. Structural assignments have been generally effected on the basis of the magnitude of experimental values of Mössbauer nuclear quadrupole splittings, measured at 77 K for both solid and frozen aqueous absorbers, and comparison with data calculated by the point‐charge model approach.
Gallium‐induced Barbier coupling of carbonyl compounds with allyl iodide
Authors: Araki Shuki , Ito Hirokazu , Butsugan Yasuo
Published: January 2005

Gallium metal readily prompted the allylation of aldehydes and ketones with allyl iodide. α, β‐Unsaturated carbonyl compounds underwent only 1,2‐addition.
The synthesis of heteronuclear transition‐metal clusters derived from methylidyne tricobalt cluster precursors: The reaction of Mn(CO) with (μ3‐CCl)Co3(CO)7(μ‐dppm). The crystal and molecular structure of (μ3‐CH)Co2Mn(CO)8(μ‐dppm), a methylidyne cluster containing a seven‐coordinate manganese atom
Authors: Duffy D Neil , Kassis Maram M , Rae A David
Published: January 2005

The reaction of manganese pentacarbonyl anion with chloromethylidyne tricobaltnonacarbonyl, (μ3‐CCl)Co3(CO)9, leads to reduction of the cluster with formation of Mn2(CO)10 and Co(CO), whilst reaction of Mn(CO) with the bis(diphenylphosphino)methane (dppm)‐stabilised cluster (μ3‐CCl)Co3(CO)7(μ‐dppm) leads to the formation of (μ3‐CH)Co2Mn(CO)8(μ‐dppm), 1. The unique feature of the structure of 1 is the incorporation of a seven‐coordinate manganese atom into the metal triangle.
Ambidentate coordination of the tripyridyl ligands 2,2′:6′,2″‐terpyridyl, tris(2‐pyridyl)‐amine, tris(2‐pyridyl)methane and tris(2‐pyridyl)phosphine to carbonylrhenium centres: Structural and spectroscopic studies
Authors: Anderson Peter A , Keene F Richard , Horn Ernst , Tiekink Edward R T
Published: January 2005

The reactions of [Re(CO)5Cl] with the ligands tpy (2,2′:6′,2″‐terpyridine), py3N {tris(2‐pyridyl)‐amine}, py3CH {tris(2‐pyridyl)methane}, and py3P {tris(2‐pyridyl)phosphine} in toluene solution realize compounds with the general formulation [Re(ligand)(CO)3Cl] in which the tripyridyl ligands are bidentate. X‐ray structural determinations of fac‐[Re(typ)(CO)3Cl].H2O and fac‐[Re(py3N)(CO)3Cl] confirm these assignments. [Re(tpy)(CO)3Cl].H2O (C18H13ClN3O4Re) is monoclinic, space group P21/n, with cell dimensions a = 7.432(2) Å, b = 17.016(4) Å, c = 14.466(2) Å, β = 93.51(2)°, and Z = 4; full‐matrix least‐squares refinement on 2435 reflections with I ⩾ 2.5σ(I) converged to a final R = 0.028 and Rw = 0.029. [Re(py3N)(CO)3Cl] (C18H12ClN4O3Re) is triclinic, space group P1 with cell dimensions a = 13.761(2) Å, b = 14.636(6)Å, c = 11.110(2) Å, α = 110.70(2)°, β = 102.45(2)°, γ = 107.48(2)°, and Z = 4; full‐matrix least‐squares refinement on 3459 reflections with I ⩾ 2.5σ(I) converged to a final R = 0.038 and Rw = 0.039. If the synthetic procedure is undertaken under irradiation by visible light, for the ligand py3N a species [Re(py3N)(CO)2Cl] (characterized by infrared spectroscopy and conductance measurements) is also formed, in which the ligand py3N is tridentate. No analogous tridentate species is formed with the ligands tpy or py3P, although there is evidence that it also forms for py3CH.
In vitro antitumour activities of a novel 2:3 condensation product of salicylaldoxime with di‐n‐butyltin(IV) oxide
Authors: Bouǎlam Mohammed , Biesemans Monique , Meunier‐Piret Jacqueline , Willem Rudolph , Gielen Marcel
Published: January 2005

The antitumor activities of three novel condensation products of salicylaldoxime with di‐n‐butyltin(IV) oxide (compound 1), di‐t‐butyltin oxide (compound 2) and diphenyltin oxide (compound 3) are presented. Against MCF‐7, a human mammary tumor cell line, compounds 1 and 2 are characterized by inhibition doses ID50 in vitro of 67 and 49 ng cm−3 respectively, whereas cis‐platin, an antitumor drug used clinically, has an ID50 of 850 ng cm−3. Against WiDr, a colon carcinoma, they also score better than cis‐platin: 215 and 121 ng cm−3 versus 624 ng cm−3. In contrast, the diphenyltin compound, 3, is inactive against both tumor cell lines.

The results of a pre‐screening performed on compound 1 by the National Cancer Institute (NCI) on a panel of 60 human tumor cell lines show that two of the selectivity parameters calculated by the NCI for that compound are statistically significant, namely DG150 (51.9>50) and MGDH (80.1>75). One is almost satisfactory (DH = 72.4 = ca75). The other two, DTGI (40.0<50) and DLC50 (16.7<50) are not. (Abbreviations are explained in the text and in Gielen, M. and Willem, R. Anticancer Res., 1992, in press).
Bioaccumulation of arsenic and its fate in a freshwater food chain
Authors: Maeda Shigeru , Ohki Akira , Kusadome Katsuhiro , Kuroiwa Takayoshi , Yoshifuku Isami , Naka Kensuke
Published: January 2005

Accumulation, biomethylation and excretion of arsenic by an autotrophic freshwater alga, and the transport and transformation of the arsenic in the freshwater food chain [alga (autotroph)‐moina (planktonic grazer) or shrimp (herbivore)‐guppy (carnivore)] were investigated.

These experimental results lead to the conclusion that total arsenic concentrations in organisms after accumulation from foods decreased one order of magnitude per elevation of the trophic level and biomethylation of the arsenic increased successively with an elevation in the trophic level. Predominant methylated arsenic species in moina and guppy were dimethyl‐ and trimethyl‐arsenic compounds, respectively. Shrimp accumulated dimethyl‐ and trimethyl‐arsenic compounds in nearly equivalent quantities. No or little monomethylarsenic compound was detected either in herbivores or carnivores.
The anti‐neoplastic activity of ethylamine‐carboxyborane and triphenylphosphine‐carboxyborane in L‐1210 lymphoid leukemia cells
Authors: Hall Iris H , Hall E Stacy , Chi L K , Iii M C Miller , Bastow Ken F , Sood A , Spielvogel B F
Published: January 2005

Studies on the mode of action of two boroncontaining anti‐neoplastic agents, ethylamine‐carboxyborane and triphenylphosphine‐carboxyborane, are reported. The major site of inhibition was in the pyrimidine de nove synthetic pathway at orotidine monophosphate decarboxylase activity. Additional sites which may facilitate the inhibition of cell growth were IMP dehydrogenase, thymidine kinase, TMP kinase and TDP kinase, m‐RNA, r‐RNA and t‐RNA polymerase activities as well as topoisomerase II activity. The reduction in enzyme activities led to sufficient reduction of d(NTP) levels to suppress DNA synthesis and cell growth. DNA strand scission was evident in the presence of drug. Multiple modes of action are common with amine‐carboxyboranes. Acute toxicity studies in mice showed that both agents were safe in their therapeutic range based on organ weights, histological tissue sections, clinical chemistry values and hematopoietic parameters.
Synthesis and psychotropic properties of 1‐triorganylsiloxy‐ and 1‐triorganylgermoxy‐germatranes
Authors: Lukevics Edmunds , Ignatovich Lubov , Shilina Natalia , Ǧērmane Skaidrīte
Published: January 2005

Triorganylsiloxy‐ and triorganylgermoxy‐germatranes have been prepared by the interaction of the easily available 1‐hydroxygermatrane with various hetaryl‐silanes and ‐germanes. The compounds were of the general structure: magnified image

M = Si; X = S, CH = CH (viz. phenyl); n = 0,1,2

M = Ge; X = CH = CH (viz. phenyl); n = 0

All siloxy‐ and germoxy‐germatranes obtained were subjected to psychotropic assays. Some of phenylsiloxygermatranes are effective for memory enhancement (inhibition of retrogradal amnesia by triphenylsiloxygermatrane was 80%).
Subchronic oral toxicity (six months) of carboxyethylgermanium sesquioxide [(HOOCCH2CH2Ge)2O3]n in rats
Authors: Anger F , Anger J P , Guillou L , Papillon A , Janson C , Sublet Y
Published: January 2005

After briefly renewing toxicological data on germanium compounds, the authors report on the subchronic oral toxicity of carboxyethylgermanium sesquioxide in rats. During six months, male and female animals received 1 g kg−1. day−1. No particular toxic symptoms, and no behaviour problems except a small decrease of body weight in male rats, at the end of the six‐month experimentation period, were observed. A significant decrease of erythropoiesis and some significant changes in leucocyte ratios were demonstrated. The main marked effect was a moderate renal dysfunction characterized by a tubular disease with the presence of cylinders, swelling of tubulus cells and flocculus deposits. Germanium urinary excretion was constant and linked to the received dose. Six months later, no preferential accumulation in organs was evident.
GC FPD method for the simultaneous speciation of butyltin and phenyltin compounds in waters
Authors: Gomez‐Ariza J L , Morales E , Ruiz‐Benitez M
Published: January 2005

A method is described for the simultaneous determination of nanogram amounts of mono‐, di‐ and tri‐butyltin compounds in water. The procedure is based on the conversion of tin compounds to volatile species by Grignard pentylation and analysis using GC with flame photometric detection (GC FPD). The ionic compounds are extracted from diluted acidified (HBr) aqueous solutions by using a pentane‐tropolone solution. The extracted organotin compounds are pentylated by a Grignard reagent and purified on a Fluorisil column before analysis by GC FPD. The detection limits are 20 ng dm−3 for butyltin compounds and 50 ng dm−3 for phenyltin compounds. Recoveries from spiking experiments in tap‐water and natural seawater matrices, in which no organotin compounds were detected, were greater than 90% for most of the alkyltin compounds.
Characterization of organic arsenic compounds in bivalves
Authors: Shibata Yasuyuki , Morita Masatoshi
Published: January 2005

Water‐soluble arsenic compounds were extracted with methanol/water (1:1, v/v) from various species of bivalves and also from certified reference materials (NIES No. 6, mussel tissue, and NBS 1566, oyster tissue). The extracts were analyzed with a high‐performance liquid chromatograph combined with an inductively coupled argon plasma mass spectrometer serving as an arsenic‐specific detector. A certified reference material (NIES No. 6) was used to check the reproducibility of the analysis. The relative standard deviations (RSDs) of the peak area of major arsenic compounds among repeated measurements (n = 6) on the same extrct were less than 3.3%, indicating good reproducibility of the technique. The RSDs of some peaks among measurements of independent extracts, on the other hand, were more than 10%, possibly reflecting the heterogeneity of the sample in terms of the chemical species under the present experimental conditions. In many of the samples analyzed in the present study, two arsenic‐containing ribofuranosides were detected in addition to arsenobetaine. A compound bearing a glycerophosphoryl glycerol moiety was dominant in such cases. Interestingly, a bivalve living in an estuary (Corbicula japonica) did not contain a detectable amount of arsenobetaine though it had arsenic‐containing ribofuranosides. The distribution of arsenic species in the various parts of a clam (Meretrix lusoria) and a mussel (Mytilus coruscum) was also analyzed.
Acute toxicity and metabolism of arsenocholine in mice
Authors: Kaise Toshikazu , Horiguchi Yoshiya , Fukui Shozo , Shiomi Kazuo , Chino Makoto , Kikuchi Takeaki
Published: January 2005

The acute toxicity of arsenocholine was examined in mice by oral administration and intravenous injection. The LD50 values of arsenocholine were 6.5 g kg−1 for oral administration and 187 mg kg−1 for oral administration and 187 mg kg−1 for intravenous injection. Decreases of respiration and spontaneous motility were observed in the mice dosed orally at 12 g kg−1. The animals exhibited ataxia and finally showed paralysis of the hind legs within 20 min of administration. When arsenocholine was administered orally to mice at 5 or 50 mg As kg−1, the greater part of the arsenic administered was recovered in urine within 96 h. The metabolite of arsenocholine in urine was identified as arsenobetaine by high‐performance liquid chromatography‐inductively coupled plasma emission spectrometry (HPLC ICP) and fast atom bombardment mass spectrometry (FAB MS). These results suggested that the major part of orally administered arsenocholine was absorbed from the gastrointestinal tract in mice and then rapidly excreted in urine with biotransformation.
Formation of arsenobetaine from arsenocholine by micro‐organisms occurring in sediments
Authors: Hanaoka Ken'Ichi , Satow Takeharu , Tagawa Shoji , Kaise Toshikazu
Published: January 2005

As one of the experiments to pursue marine circulation of arsenic, we studied microbiological conversion of arsenocholine to arsenobetaine, because arsenocholine may be a precursor of arsenobetaine in these ecosystems. Two culture media, 1/5 ZoBell 2216E and an aqueous solution of inorganic salts, were used in this in vitro study. To each medium (25 cm3) were added synthetic arsenocholine (0.2%) and about 1 g of the sediment, and they were aerobically incubated at 25°C in the dark. These conversion experiments were performed in May and July 1990. In both seasons, two or three metabolites were derived in each mixture. These metabolites were purified using cation‐exchange chromatography. Their structures were confirmed as arsenobetaine, trimethylarsine oxide and dimethylarsinic acid by high‐performance liquid chromatography, thin‐layer chromatography, FAB mass spectrometry and a combination of gas‐chromatographic separation with hydride generation followed by a cold‐trap technique and selected‐ion monitoring mass spectrometric analysis. From this and other evidence it is concluded that, in the arsenic cycle in these marine ecosystems, as recently postulated by us, the pathway arsenocholine → arsenobetaine → trimethylarsine oxide → dimethylarsinic acid → methanearsonic acid → inorganic arsenic can be carried out by micro‐organisms alone.
Arsenic distribution in rats fed a Hijiki diet
Authors: Katayama Masayuki , Sugawa‐Katayama Yohko , Tamura Tomoko
Published: January 2005

Very large doses of sodium arsenate (Na2HAsO4), 14 mg As kg−1 of body weight, were administered to Sprague‐Dawley male rats (body weight 300 g) fed a 5% Hijiki diet by stomach tube twice within two days. After 24 h, the rats were sacrificed and various organs were dried for subsequent neutron activation analysis. The distribution of arsenic (As) in selected organs was determined by neutron activation analysis. The highest concentration of As was found in blood cells with a rather high concentration in the liver and heart. As the control, rats which were fed on a 5% cellulose diet were used. Control rats which were administered arsenate showed that the arsenic distribution and the concentration in their organs were similar to those on the 5% Hijiki diet. Even the blood cells of the controls without any arsenic administration were found to contain a small amount of arsenic.
Uptake and excretion of total inorganic arsenic by the freshwater alga Chlorella vulgaris
Authors: Maeda Shigeru , Kusadome Katsuhiro , Arima Hiroyuki , Ohki Akira , Naka Kensuke
Published: January 2005

Arsenic‐tolerant freshwater alga Chlorella vulgaris which had been collected from an arsenicpolluted environment were tested for uptake and excretion of inorganic arsenic.

Approximately half the quantity of arsenic taken up by C. vulgaris was estimated to be adhered to the extraneous coat (10 wt %) of the cell. The remainder was bioaccumulated by the cell. Both adhered and accumulated arsenic concentrations increased with an increase in arsenic(V) concentration of the aqueous phase.

Arsenic(V) accumulation was affected by the growth phse: arsenic was most actively accumulated when the cell was exposed to arsenic during the early exponential phase and then accumulation decreased with an increase in culture time exposed to arsenic.

The alga grew well in the modified Detmer (MD) medium containing 1 mg As(III) dm−3 and the growth curve was approximated by a ‘logistic equation’. Arsenic(III) was accumulated up to the second day of the culture time and arsenic(III) accumulation decreased with an increase in the culture time after that.

Arsenic accumulation was also largely affected by various nutrients, especially by managanese, iron and phosphorus compounds. A modified MD medium with the three nutrients was proposed for the purpose of effective removal of arsenic from the aqueous phase.

Using radioactive arsenate (Na2H74AsO4), the arsenic accumulated was found to be readily excreted under conditions which were unfavourable for the multiplication of C. vulgaris.
2,5‐Dimethylthiophene coordination to three metal centers in the complexes (η4, S‐μ3‐2,5‐Me2T)(IrCp*) [M(CO)2Cp]2 where MMo or W
Authors: Chen Jiabi , Angelici Robert J
Published: January 2005

The 2,5‐dimethylthiophene (2,5‐Me2T) ligand in the isomers Cp*Ir(η4‐2,5‐Me2T) (1) and Cp*Ir(C,S‐2,5‐Me2T) (2) is activated to react with the dimers Cp(CO)2MM(CO)2Cp[MMo (3), W (4)] to give complexes (5,6) in which the thiophene is coordinated to three metals. Oxidation of 5 with Cp2Fe+ removes magnified image the Mo dimer to give Cp*Ir(η5‐2,5‐Me2T)2+. Reaction of 5 with CO displaces the Mo as [CpMo(CO)3]2 to give Cp*Ir(CO)(C,S‐2,5‐Me2T) (7). Ultraviolet photolysis of 1 provides a convenient route to the ring‐opened isomer 2. Despite the remarkable nature of the thiophene coordination in 5 and 6, its reactivity does not suggest new pathways that would lead to the hydrodesulfurization of thiophenes.
Model reactions for abiotic mercury(II) methylation: Kinetics of methylation of mercury(II) by mono‐, di‐, and tri‐methyltin in seawater
Authors: Cerrati Gabriella , Bernhard Michael , Weber James H.
Published: January 2005

The usual presence of mercury(II) with monodi‐, and tri‐methyltin in water, sediments, and plants in estuarine environments suggests possible abiotic formation of methylmercury via methyl transfer from methyltin compounds. Kinetics studies of reactions between mercury(II) and methyltin compounds under pseudo‐first‐order conditions in seawater show that relative rate of methylmercury formation under the same conditions are: monomethyltin  dimethyltin. This order is explainable mainly by the speciation and charge of methyltin compounds in seawater and by the existence of mercury(II) as a tetrachloro anion. A factorial experiment with the variables pH and salinity (seawater diluted with deionized water) showed that pH, but not salinity, is significant at the 95% confidence level; and that reaction rates increase as pH increases. These results suggest the possibility of abiotic methylation of mercury(II) in seawater. Additional experiments in seawater demonstrated an absence of methylation of mercury(II) (14 days) and mercury(0) (35 days) by methyl iodide.
Organometallic chemical vapor deposition using allyl precursors
Authors: Kirss Rein U
Published: January 2005

Homoleptic allyl derivatives of many Main‐Group and transition metals, M(C3H5)n, are readily available through one‐pot syntheses using metal halides and allyl Grignard reagents or by alkylation of alkali‐metal salts. The relatively low molecular weight of a C3H5 ligand contributes to high vapor pressures whilst the stability of the allyl radical is predicted to reduce decomposition temperatures. These compounds represent a class of volatile precursors for organometallic chemical vapor deposition (OMCVD) of thin films. Film growth studies using iridium, molybdenum, palladium, platinum, rhodium, selenium, tellurium and tungsten compounds are reviewed and the relationships between pyrolysis pathways and film purity are discussed.
Organochromium precursors for low‐temperature OMCVD of chromium‐based coatings
Authors: Maury F
Published: January 2005

Many organochromium compounds have been used as volatile chromium sources to prepare chromium‐based coatings by chemical vapor deposition. Chromium carbides, nitrides, oxides and alloys have been deposited on different substrates at low temperature (<500 °C). Organochromium precursors are reviewed and some of their draw‐backs are discussed. They are classified according to the nature of the chromium‐ligand bonds (carbonyls, amides, arenes or alkyls). Furthermore, experimental results obtained in the same apparatus for a series of representative precursors are reported to discuss, with literature data, how the ligand affects the composition and the structure of the films.
Complexes in polymers IV. FTIR microscopic characterization of thin organic polymer films containing embedded transition‐metal carbonyl complexes
Authors: Markwell Ross D , Butler Ian S , Gao Jian Ping , Shaver Alan
Published: January 2005

Thin films of polystyrene (PS), poly(methyl methacrylate) (PMMA) and polystyrene‐polyacrylonitrile copolymer (PS‐AN), containing various embedded transition‐metal complexes, have been studied by FTIR microscopy. The spatial distributions of the transition‐metal carbonyl complexes throughout the thin organic polymer films have been determined by a two‐dimensional IR mapping procedure. The spectral variations observed in the distribution of the metal carbonyls throughout the different polymer films are discussed. The IR data show that the technique used to prepare the organometallic‐embedded thin films (viz. freeze‐drying of solutions followed by hot mechanical pressing of the residues) does in general lead to homogeneous films which may eventually find industrial application, e.g. as membrane sensors for small molecules.
Novel nonionic siloxane surfactants
Authors: Wersig R , Sonnek G , Niemann C
Published: January 2005

A new method for ethoxylation without application of pressure is described. Butynediololigo(oxyethylene) [H(OCH2CH2)nOCH2CCCH2O(CH2CH2O)nH with n=1–16] has been prepared in the presence of an electrophilic catalyst in a specially developed reciruculating apparatus. The products have been characterized by NMR and IR spectroscopy.

New nonionic silicone surfactants have been synthesized by hydrosilylation of these butynediololigo(oxyethylenes) with defined siloxanes and polysiloxanes. Protection of the hydroxyl group before hydrosilylation was not necessary. Hydrosilylation was carried out in the presence of a solvent. It has been possible to obtain surfactants with a surface tension of about 21‐22 mN m−1 and an interfacial tension of 2 mN m−1.
In vitro antitumour activity of two isomeric cyclopalladiated compounds derived from benzoylbenzylidenimines
Authors: Navarro‐Ranninger C , LóPez‐Solera I , Pérez J M , Masaguer J R , Alonso C
Published: January 2005

The DNA thermal stabilizing effect and antitumour properties of two diastereoisomeric cyclopalladiated compounds, Pd2 [4‐CH3O–C6H4NC(COC6H5)C6H4]2(μ‐OAc)2 (I and II), derived from benzoylbenzylideneimines have been studied. The atropisomers containing two acetate‐bridged PdL2 units have a folded structure in boat form. The results show that both complexes interact with the DNA double helix but that compound II stabilizes the DNA more than compound I. It was also observed that the in vitro antiproliferative activity of compound II against colon (CX‐1) and lung (LX‐1) human tumour cells is higher than that of compound I. It is probable that the higher reactivity of compound II relative to compound I is due to the specific orientation of the benzoyl group with respect to the COCN chiral bond.
Antitumor effects of binuclear ferrocene derivatives
Authors: Popova L V , Babin V N , Belousov Yu A , Nekrasov Yu S , Snegireva A E , Borodina N P , Shaposhnikova G M , Bychenko O B , Raevskii P M , Morozova N B , Iiyina A I , Shitkov K G
Published: January 2005

On the basis of an earlier model of chemical carcinogenesis, the antitumor activity of the mono‐, bi‐ and poly‐nuclear ferrocene derivatives ferricenium tri‐iodide (1), ferricenium tetrachloroferrate (2), 1, 1′‐diethylferricenium triiodide: (3), N‐(ferrocenylmethyl)hexamethylenetetramine tetrafluoroborate (4), bis(ferrocenylmethyl)benzotriazolium tetrafluoroborate (5), bis(ferrocenyl‐α‐ethyl)benzotriazolium tetrafluoroborate (6) and bis(ferrocenylmethyl)‐2‐methylbenzimidazolium tetrafluoroborate (7), and the oligomer (—Fc—CH2—Fc+˙—CH2—)7–8− (PF6)7–8 (8) was studied in vivo (FcC10H8Fe). The tumor models studied included MCH‐11 (mouse sarcoma induced by methylcholantrene), P‐815 (mouse mastocytoma of DBA/2 origin) and virus‐induced Raucher leukemia (RLV). The cytotoxic effects of these preparations were examined against in vitro cultured normal murine cells (line L‐929). The binuclear ferrocene derivatives 5, 6 and 7 inhibited the development of experimental tumors in mice. Ferricenium tri‐iodide (1) was effective in Rauscher leukemia. Kinetic dependencies for most complexes had a two‐phase character: the region of inhibition of tumorogenesis was followed by a region in which the complexes accelerated the development of this process. The link between the structure of compounds 1–8 and their antitumor effects is discussed.
The analysis of organic mercury compounds using liquid chromatography with on‐line atomic fluorescence spectrometric detection
Authors: Hintelmann H , Wilken R‐D
Published: January 2005

A new method for the analysis of organic mercury compounds is reported. The organomercurials are separated by high‐performance liquid chromatography (HPLC). The compounds are converted to mercury(0) in a continuous‐flow system by means of an oxidizing and a subsequent reducing solution. The elemental mercury generated is swept into the cell of an atomic fluorescence spectrometer (AFS) by a stream of argon. The compositions of the oxidizing solution, which contains peroxodisulphate and copper(II) in dilute sulphuric acid, and the reducing solution, which contains alkaline tin(II) chloride, were optimized, as were the gas–liquid separator (GLS), the condensing system and the geometry of the reaction coils. The method is applied to extracts of certified reference material (CRM) and to river sediments. High concentrations of methylmercury were found in the sediment samples. At one location, the presence of ethylmercury is derived from the sample chromatogram.
The effects of salinity and pH on the speciation of some triphenyltin compounds in estuarine sediments using Mössbauer spectroscopy
Authors: Whalen Deborah , Lucero Rosemarie , May Leopold , Eng George
Published: January 2005

The speciation of some triphenyltin compounds i.e. triphenyltin hydroxide, triphenyltin chloride, triphenyltin fluoride, under varying salinity and pH conditions, was studied by Mössbauer spectroscopy in both anoxic and oxic estuarine sediments. The results indicate that altering the pH or salinity of the sediment environment does not apparently affect the speciation of these compounds.
Hybrid organosilazane/organosilylamine telechelic oligomers—I. Two‐dimensional NMR spectroscopy characterization of dimethylsilylethylenediamine oligomers
Authors: Feng Ke , Abrahams Paul , Mariam Yitbarek H
Published: January 2005

The detailed characterization of multifunctional hybrid organosilazane/organosilylamine telechelic oligomers by IR and 1H, 13C and 29Si NMR spectroscopy in one and two dimenions has been undertaken. The specific multifunctional oligomers, comprising NH/NH2 or SiCl functionalities depending on the monomer feed‐ratio, were prepared from mono‐ and di‐functionally reacted dichlorodimethylsilane (DDS) and mono‐, di‐, tri‐ and tetra‐functionally reacted ethylenediamine (EDA). Varying the feed‐ratio afforded control of the microstructures of the oligomers and the preparation of oligomers with, in some cases, conterminously located silicon–chlorine (SiCl) groups. The combination of the NMR methods with the IR technique has enabled the detailed microstructural characterization of the oligomers and the identification of the functionalities therein. This approach and the knowledge gained from the DDS/EDA system has been applied to the microstructural characterization of other hybrid organosilazane/silylamine preceramic telechelic oligomers.
Fungicidal activity of tributyltin alkylsulfate esters
Authors: Roengsumran Sophon , Petsom Amorn , Thaniyavarn Suthep , Prachyakul Surat
Published: January 2005

Tributyltin alkyl sulfate esters, e.g. tributyltin dodecyl sulfate, tributyltin hexadecyl sulfate and tributyltin octadecyl sulfate, were synthesized from the reaction of bis(tributyltin) oxide and appropriate alkyl hydrogen sulfates. The resulting tributyltin alkyl sulfate esters were found to exhibit fungicidal activity on Penicillium, Aspergillus and Syncephalustrum species.
Alkylation of ionic mercury to methylmercury and dimethylmercury by methylcobalamin: Simultaneous determination by purge‐and‐trap GC in line with FTIR
Authors: Filippelli Marco , Baldi Franco
Published: January 2005

A new approach was used to determine the reaction products of methylcobalamin and ionic mercury: purge‐and‐trap gas chromatography in line with Fourier transform infrared spectroscopy (PT GC/FTIR). This technique simultaneously and specifically determines the spectrum of dimethylmercury (DMeHg) and methylmercury produced by the reaction. No interference from other known organic mercury species could be detected. The method is different from others because it does not require solvent extraction of the organomercurials from aqueous solution, but relies on immediate volatilization from the reaction vessel by addition of 100 μl of 10 mM NaBH4. The sample was purged with nitrogen for 10 min. The volatile species of mercury were trapped in a column at −120°C, injected into the gas chromatograph and detected by FTIR. The efficiency of DMeHg and MeHg formation depended on different parameters: pH, temperature, reaction time, and the methylcobalamin/ionic mercury ratio. The initial reaction product was MeHg which was further transformed to DMeHg. The first methylation rate was two times faster than the second. MeHg formed first, reaching a maximum at higher temperatures (28°C and 37°C) and later decreasing as DMeHg formed. At lower temperatures (20°C) the rate of MeHg formation was slower, being similar to the formation rate of DMeHg. Different species of inorganic mercury such as HgSO4, Hg(NO3)2, Hg(SCN)2, HgCl2 and Hgl2 were used to study differences in methylation by methylcobalamin under standard conditions of acidity, temperature and cofactor Hg(II) ratio.
Synthesis and neurotropic activity of silyl‐substituted fufural thiosemicarbazones
Authors: Lukevics E , Demicheva L , Erchak N , Germane S
Published: January 2005

5‐Silyl‐substituted‐2‐furaldehyde thiosemicarbazones were prepared by the condensation of the corresponding furfurals or furfural diethylace‐tals with thiosemicarbazide. The neurotropic activity of the synthesized thiosemicarbazones has been studied. The majority of the compounds examined possess high or medium neurotropic activity of the depressant type. They also show antihypoxic activity and decrease the duration of phenamine stereotype behaviour. Structure‐activity correlation has been found.
Crystal structure and fungitoxicity of aquatributyltin N‐phthaloylglycinate
Authors: Ng Seik Weng , Kuthubutheen A. J. , Kumar Das V. G. , Linden Anthony , Tiekink Edward R. T.
Published: January 2005

The [nBu3Sn(N‐phthaloylglycinate)(OH2)] compound has been prepared and characterized. The crystal structure reveals the tin atom, in each of the two molecules comprising the asymmetric unit, to exist in a distorted trigonal bipyramidal geometry in which the trigonal plane is defined by the three organic substituents and the axial sites are occupied by an oxygen atom derived from a monodentate carboxylate ligand and a coordinated water molecule. The [nBu3Sn(N‐phthaloylglycinate)(OH2)] compound and three other triorganotin derivatives of N‐phthaloyl‐protected amino acids display marked toxicity against several economically important plant pathogenic fungi.
How gallium arsenide wafers are made
Authors: Kitsunai Minoru , Yuki Takayoshi
Published: January 2005

Ten Japanese gallium arsenide wafer manufacturers voluntarily formed The Japan Manufacturers' Society of Compound Semiconductor Materials (JAMS‐CS) in 1983. This report summarizes the theories, the systems, and the operations of gallium arsenide production: the gradient freeze (GF) method, the liquidencapsulated Czochralski (LEC) method, the wafer processing, the vapor‐phase epitaxial (VPE) growth method, the liquid‐phase epitaxial (LPE) growth method, the metalorganic chemical vapor deposition (MO‐CVD) method and the molecular beam epitaxial (MBE) method.