bluuebunny/crossref_metadata_2025 huggingface dataset:
Schwefeldioxid als Ligand und Synthon. XIII. Reaktionen von Isocyanid‐tris(triphenylphosphan)nickel(0)‐Komplexen mit Schwefeldioxid und N‐p‐Tolylsulfinylamin
Authors: Wilhelm D. , Wenschuh E. , Baumeister U. , Hartung H.
Published: January 2005

Reaktionen der Isocyanid‐tris(triphenylphosphan)‐nickel(0)‐Komplexe [(RNC)Ni(PPh3)3] (R = tBu, Cy, PhCH2, p‐TosCH2) mit SO2 und p‐TolNSO werden beschrieben. Die Charakterisierung der durch PPh3‐Ligandensubstitution resultierenden Schwefeldioxid‐ sowie N‐p‐Tolylsulfinylamin‐Komplexe erfolgte mit Hilfe der IR‐ und 31P‐NMR‐Spektroskopie. Für [(Ph3P)2(CyNC)Ni(SO2)] · 0,5 PhMe und (Ph3P) · (tBuNC)Ni(η2‐p‐TolNSO) wurden die Kristallstrukturen bestimmt.
Synthese und Kristallstrukturbestimmung von Dimethyldi‐(N‐Methylimidazolium)siliciumbromid
Authors: Burger Harald , Hensen Karl , Pickel Peter
Published: January 2005

Die Reaktion von Dibromdimethylsilan mit N‐Methylimidazol (NMI) führt zu einer bei Raumtemperatur stabilen 1:2‐Verbindung. Die Umsetzung wurde bei Raumtemperatur durchgeführt, und durch Sublimation ließen sich farblose, feuchtigkeitsempfindliche Einkristalle der Verbindung erhalten. Die Additionsverbindung kristallisiert in der orthorhombischen Raumgruppe Pcam (Nr. 57) mit den Gitterkonstanten a = 1 110,96(8) pm, b = 1 142,3(2) pm und c = 1 238,9(3) pm. Unter Verwendung von 1 317 symmetrieunabhängigen Reflexen konnte die Struktur, gemessen bei 21°C, bis auf R = 0,040 und Rw= 0,041 verfeinert werden.
Studies on ABX6 Compounds. II. The BaThBr6 structure type
Authors: Beck H. P. , Kühn F.
Published: January 2005

The compounds AThBr6 (A: Ca, Sr, Ba) crystallize in an ordered substitution variant of the PuBr3 type. Their syntheses and special features of the crystal structures are described.
Zum chemischen Transport von Cobaltmonophosphid mit Iod. Experimente und Modellrechnungen
Authors: Schmidt A. , Glaum R.
Published: January 2005

CoP ist bei hinreichender Zugabe von Iod als Transportmittel über einen großen Temperaturbereich (650°C ⩽ T̄ ⩽ 1000°C; T̄ (T1 + T2)/2, ΔT = 100 K) aufgrund endothermer Reaktionen transportierbar. Zentrale Bedeutung für die Wanderung des Cobaltmonophosphids hat das heterogene Gleichgewicht

Bei niedrigen Transporttemperaturen (T̄ ≤ 800°C) und genügend hohen Transportmitteldichten (D ≥ 7,5 mg · cm−3) liegt CoI2,l neben CoP in der Senke vor. Thermodynamische Modellrechnungen zum chemischen Transport von CoP mit Iod unter Verwendung überarbeiteter thermodynamischer Daten für CoI2,l, CoI2,g und Co2I4,g geben die beobachteten Phasenverhältnisse im Bodenkörper sowie die Transportraten für CoP gut wieder. Detaillierte Aussagen zur Zusammensetzung der Gleichgewichtsgasphase sind möglich. Der Einfluß von Feuchtigkeitsspuren auf das Transportverhalten wird erörtert.
Zur Chemie des Kanemits [NaHSi2O5 · 3 H2O]x
Authors: Wieker W. , Heidemann D. , Ebert R. , Tapper A.
Published: January 2005

Kanemit wurde aus δ‐Na2Si2O5 durch einen direkten Austausch von Na+ gegen H+ in wasserhaltigem Reaktionsmedium hergestellt. Mit Hilfe von 29Si‐, 23Na‐ und 1H‐MAS‐NMR‐Untersuchungen wurde nachgewiesen, daß der Kanemit ein Schichtsilicat der Zusammensetzung [NaHSi2O5 · 3 H2O]x ist. Bei der thermischen, wie auch bei der Entwässerung im Vakuum bei Raumtemperatur entsteht ein Monohydrat, in dem die Schichtstruktur weitgehend erhalten bleibt. Bei Temperaturen zwischen 100 und 110°C läßt sich auch eine Hydratphase der Zusammensetzung [NaHSi2O5 · 0,25 H2O]x nachweisen, in der aber eine veränderte Schichtsilicatstruktur vorliegt.
Ternäre Lithium‐Selten‐Erd‐Nitrate mit einsamen Nitrationen: Li3[M(NO3)5](NO3) (M = GdLu, Y). Die Kristallstruktur von Li3Er(NO3)6
Authors: Manek Elke , Meyer Gerd
Published: January 2005

Einkristalle des ternären Nitrates Li3Er(NO3)6 erhält man durch Lösen von „Er(NO3)3”︁ in einer Schmelze von LiNO3. In Li3Er(NO3)6 (monoklin, P21/n, Z = 4; a = 776,0(1); b = 748,86(8); c = 2 396(1) pm; β = 90,76(3)°; R1 = 0,0490; wR2 = 0,0792) ist Er3+ von fünf Nitratliganden jeweils zweizähnig in Form der anionischen Einheit [Er(NO3)5]2− umgeben. Diese Einheiten sind längs der 21‐Schraubenachse angeordnet. In der Mitte dieser „Spirale”︁ befinden sich zwei einsame NO3−‐Ionen, die über Li+‐Ionen mit den Anionen [Er(NO3)5]2− verbunden sind. Die „Spiralen”︁ sind um die halbe Gitterkonstante a gegeneinander verschoben und über weitere Li+‐Ionen verknüpft.
Synthesis and Characterisation of N,N′‐Disubstituted 1,2‐phenylenebis(amido)tin(II) Compounds; X‐Ray structures of 1,2‐ and of [1,2‐ (tmeda)
Authors: Braunschweig Holger , Gehrhus Barbara , Hitchcock Peter B. , Lappert Michael F.
Published: January 2005

Cyclic bis(amido)tin(II) compounds 1,2‐ [R = SiMe3] (4), SiMe2But (5) and CH2But (6)], as well as (4)2(μ‐tmeda) 7 have been obtained either from (i) the corresponding dilithium compound 1,2‐C6H4[N(R)Li]2 1–3 and SnCl2 for 4–6, respectively, (or for 4) 2 1 + [Sn(μ‐Cl){N(SiMe3)2}]2; or (ii) 1,2‐C6H4[N(H)R]2 + Sn[N(SiMe3)2]2 for 4–6; or for 7 from 4 and tmeda. Compounds 4–6 are monomeric, yellow, thermochromic (becoming redder on heating), diamagnetic, crystalline and are lipophilic and sublimable in vacuo. Compound 7 is colourless. The molecular structures of 6 and 7 have been determined from single crystal X‐ray diffraction data. Compound 6 crystallises in bimolecular aggregates, in which there is a weak η‐C6 … Sn contact.
Magnetic Structure of CsPd2F5
Authors: Ruchaud N. , Grannec J. , Tressaud A. , Ferey G.
Published: January 2005

The structure of CsPd2F5 has been confirmed from neutron diffraction data on powdered sample. CsPd2F5 crystallizes in the orthorhombic Imma space group. At 100 K, the unit‐cell constants are a = 6.473(2) Å, b = 7.853(5) Å, c = 10.718(3) Å and the calculation carried out using the Rietveld method leads to R1 = 0.020. The network is formed of PdF6 octahedra chains containing half of Pd in high‐spin configuration, connected one to each other by square planes containing the other half of Pd in low‐spin configuration. CsPd2F5 orders antiferromagnetically below TN = 38 K. In the ordered state a weak ferromagnetic component occurs (σ0 = 0.098 μB at 2 K). The magnetic structure determined at 4 K is consistent with the magnetization data and can be described in the Im′m′a′ magnetic group without any doubling of the unit‐cell parameters. Within the chains, Pd2+ are coupled antiparallel. The magnetic moments are located in the (x0z) plane, the angle between the moments and the z axis being 18°.
Struktur von Bis[salicylaldehyd‐2‐hydroxyanilato(2—)]vanadium(IV)
Authors: Hefele H. , Ludwig E. , Uhlemann E. , Weller F.
Published: January 2005

Durch Reaktion von Tris(acetylacetonato)vanadium(III) mit Salicylaldehyd‐2‐hydroxyanil wurde der oxofreie Vanadium(IV)‐Komplex dieses Liganden dargestellt und durch Röntgenkristallstrukturanalyse die Struktur bestimmt. Bis[salicylaldehyd‐2‐hydroxyanilato(2—)]vanadium(IV) besitzt eine verzerrt‐oktaedrische Struktur. Raumgruppe P1, Z = 4, 2722 beobachtete, symmetrieunabhängige Reflexe, R = 7,1%. Gitterabmessungen bei 293 K: a = 964,6(1) pm, b = 1285,4(1) pm, c = 1788,9(2) pm, α = 81,42(1)°, β = 74,39(1)°, γ = 89,33(1)°.
Zur Polymorphie von Sm2Se3
Authors: Grundmeier Thorsten , Urland Werner
Published: January 2005

Zwei Modifikationen von Sm2Se3 konnten durch chemischen Transport in Form von Einkristallen erhalten werden. Es wurden einmal ausgehend von pulverförmigem Sm2Se3 rotbraune, plättchenförmige Einkristalle von Sm2Se3 im defekten Th3P4‐Strukturtyp mit der Raumgruppe I43d und a = 878,2 pm dargestellt, zum anderen ausgehend von SmSe1,9 und Samariummetall schwarze, prismenförmige Einkristalle von Sm2Se3 im U2S3‐Strukturtyp mit der Raumgruppe Pnma und a = 1 127,3 pm, b = 409,1 pm und c = 1 103,2 pm.
Synthese der Silatetraphospholane (tBuP)4SiMe2, (tBuP)4SiCl2 und (tBuP)4Si(Cl)SiCl3 Molekül‐ und Kristallstruktur von (tBuP)4SiCl2
Authors: Riegel B. , Pfitzner A. , Heckmann G. , Binder H. , Fluck E.
Published: January 2005

Bei der Reaktion zwischen dem Diphosphid K2[(tBuP)4] 7 und den Halogensilanen Me2SiCl2, SiCl4 bzw. Si2Cl6 im Molverhältnis 1:1 findet eine [4 + 1]‐Cyclokondensationsreaktion statt, bei der die Silatetraphospholane (tBuP)4SiMe2, 1,1‐Dimethyl‐1‐sila‐2,3,4,5‐tetra‐t‐butyl‐2,3,4,5‐tetraphospholan, 1, (tBuP)4SiCl2, 1,1‐Dichloro‐1‐sila‐2,3,4,5‐tetra‐t‐butyl‐2,3,4,5‐tetraphospholan, 2, und (tBuP)4Si(Cl)SiCl3, 1‐Chloro‐1‐trichlorsilyl‐1‐sila‐2,3,4,5‐tetra‐t‐butyl‐2,3,4,5‐tetraphospholan, 3, mit dem binären P4Si‐Fünfringgerüst gebildet werden. Bei der Synthese von 1 entsteht ferner das kettenförmige Nebenprodukt Me2(Cl)Si–(tBuP)4–Si(Cl)Me2 1a (5:1), das beim Erwärmen auf 100°C unter Bildung von 1 und Me2SiCl2 zerfällt. Die Verbindungen 2 und 3 reagieren nicht mit überschüssigem 7, was auf eine starke sterische Abschirmung der Ring‐Si‐Atome durch die benachbarten t‐Butyl‐Gruppen zurückzuführen ist. 1, 2 und 3 konnten in reiner Form isoliert und NMR‐spektroskopisch charakterisiert werden; 1a konnte nur 31P‐NMR‐spektroskopisch identifiziert werden. Von 2 wurde eine Einkristallstrukturanalyse durchgeführt.
Darstellung und Eigenschaften von 3‐(N,N‐Dimethylamino)propyl‐Verbindungen des Thalliums
Authors: Thiele Karl‐Heinz , Herbrich Thomas
Published: January 2005

TlCl3 reagiert mit Me2NCH2CH2CH2Li im Molverhältnis 1:2 zu (Me2NCH2CH2CH2)2TlCl (1), welches mit MeLi in (Me2NCH2CH2CH2)2TlMe (2) und mit weiterem Me2NCH2CH2CH2Li in (Me2NCH2CH2CH2)3Tl (3) übergeht. Bei der Komproportionierung von 1 mit TlCl3 entsteht das wenig stabile Me2NCH2CH2CH2TlCl2 (4), das in situ mittels MeLi in das beständige Me2NCH2CH2CH2TlMe2 (5) übergeführt werden kann. Die 1H‐ und 13C‐NMR‐Spektren von 1–3 sowie 5 werden mitgeteilt und die Strukturverhältnisse diskutiert.
Induced change and stability in psychological and social systems
Authors: Glidewell John C.
Published: January 2005

This research showed important new cyclical causal connections derived from prior knoweldge and extending it. The cyclical causal connections appeared between a paricular kind of training, negotiation skills (psychological), influence (social), self‐esteem (psychological), and risk taking (social), and back to negotiaion skills (psychological) in a particular community action group, andperhaps in most community action groups in similar conditions. The theory explicates a theory of community empowerment, a cyclical series of pyschological and social forces that move in revolution and respond to shock with both change and restabilization. The findings provide an explication of the paradox of social change and stability in a community: Both the change (developmental or decremental) and the stability (sustaining or stifling) lie in the relationships between social and psychological variables, the very relationships that both propel and limit change in the levels of the variables, once the change is initiated.
Responsible to whom? Responsible for what? Some ethical issues in community intervention
Authors: O'Neill Patrick
Published: January 2005

Conclusion

Each ethical decision is a blend of general principles and contextual features. Many require compromises between competing values, must be made in the absence of perfect information, and require the courage to confront mistakes.

In community intervention, we have seen that adopting a collaborative paradigm imposes the freedom to determine to whom we are responsible for our actions. A rationale was offered for giving priority to the most vulnerable group, even though this strategy leaves us with an accountability gap in which the group to whom we owe primary loyality is least likely to be able to call us to account.

When we reject the professional‐client paradigm in community psychology, we lose the formal contract as a device for setting the terms and limiting the scope of our responsibility. We do the best reconnaissance we can, but even with careful data‐gathering we are condemned to act on the basis of imperfect information. We must follow through on unforseen consequences even when we have no formal role to mandate our perseverence.

The community as a setting for psychological intervention faces us, then, with ethical challenges: we work for the well‐being of groups too broad to give informed consent to our interventions; we act in collaboration with others, but collaborative action does not free us from professional obligation; we reconnoiter, but reconnaissance does not provide us with perfect information; we may advise while others act, but we cannot walk away from the consequences of their actions. Ethical decision making, in the community as elsewhere, is a creative act in which we invent our profession choice by choice.
Restructuring help: A human services paradigm for the 1990s
Authors: Riessman Frank
Published: January 2005

Conclusion

The new paradigm calls for the restructuring, redistribution, and expansion of helping behavior by those who ordinarily function as consumers of help. Consumers are to become producers of prosumers. By so doing they expand the help‐giving resources quantitatively by converting helpees into helpers. The help is also changed qualitatively because the peers and the self‐helpers possess an indigenous or inside understanding of the problems and the people to whom they offer help. Heins Kohut, the brilliant psychoanalyst, suggests that the key to therapeutic change may not be insight or understanding, but rather being understood. Who better to understand than those who have been there?
Organometallic cation–exchanged phyllosilicates: A high spacing intercalate formed from N‐methyl‐(3‐triphenylstannyl)pyridinium exchanged montmorillonite
Authors: Molloy K C , Breent C , Quillt K
Published: January 2005

N‐methyl‐3‐(triphenylstannyl)pyridinium cations have been prepared and exchanged with sodium ions of montmorillonite to yield a pillar‐interlayered phyllosilicate with d(001) = 19.1 Å (hydrated) or 17.7 Å after pumping in vacuo. 119Sn Mössbauer spectroscopy is used to characterise the structure and interlayer environment of the cation.
An NMR and mössbauer spectroscopic study of antifouling rubbers containing organotin compounds
Authors: Blunden S J , Crowe A J , Monk A W
Published: January 2005

An NMR study of the carbon tetrachloride and benzene extracts of bis(tributyltin) oxideimpregnated neoprene and natural rubbers revealed the presence of tributyltin chloride, tributyltin stearate and dibutyltin distearate in the former, and bis(tributyltin) sulphide and tributyltin stearate in the latter. The implications of these findings together with 119mSn Mössbauer parameters for the formulated rubbers are discussed.
1,3‐Adamantanyl dimethylsiloxane copolymers. Preparation and properties
Authors: Pai Yi‐Ming , Weber William P
Published: January 2005

1,3‐bis(Dimethylhydroxysilyl)adamantane(I) has been prepared. Thermal condensation polymerization of this monomer yields poly‐1,3‐adamantyl‐1,1,3,3‐tetramethyldisiloxane. Condensation of I with bis(dimethylamino)dimethylsilane or 1,3‐bis(dimethylamino)‐1,1,3,3‐tetramethyldisiloxane gave the expected 1,3‐adamantyl dimethylsiloxane copolymers (II and III) respectively. These polymers have been characterized by 1H,13C, and 29SiNMR as well as GPC and TGA. They have unusually high thermal stability.
Germapharmaca: Some recent studies on biologically active organogermanium compounds
Authors: Thayer John S.
Published: January 2005

Recent research results on biologically active organogermanium compounds are described. Emphasis is placed on two categories based on (1) carbethoxyethylgermanium sesquioxide and (2) the ‘spirogermanium’ system. Other organogermanium derivatives covered include various mono‐, di‐, tri‐ and tetra‐compounds. Mention is also made of organogermanium compounds as food additives and as the products of biological methylation.
Transmethylation of metals in aquatic systems
Authors: Chau Y K , Wong P T S , Mojesky C A , Carty Arthur J
Published: January 2005

Transmethylation reactions between organometals and metal ions in aqueous solutions in biotic and abiotic systems, with and without the presence of sediment, were investigated. It was found that alkyllead compounds can transfer their alkyl groups to Sn(II) and Sn(IV) ions to form various methyltin compounds in biotic and abiotic systems. The presence of sediment enhanced the transmethylation reactions. Methyltin compounds do not transfer their methyl groups of Pb(II). Methylarsenic acids transfer their methyl groups to Sn(II) and Sn(IV) in an abiotic system, but not in a biotic system containing sediment. The strong adsorption of tin onto sediment was the reason for the non‐availability of tin ions for methylation. Methylarsenic acids do not transmethylate Pb(II). Other alkyllead compounds, such as ethyllead and butyllead species were also able to transfer their alkyl groups to tin. When both trimethyllead and triethyllead species are present in the same system, only the individual monoalkyl tin species were formed in both the Sn(II) and Sn(IV) solutions. No mixed alkyltin was produced. The findings of this study suggest that alkyllead compounds, if present in the environment, could be potential methylating agents for the formation of other methylmetals, such as methyltins. Methyltin compounds have already been documented to methylate mercuric ions in aqueous solution. Thus the study of transmethylation reactions opens up a new area of research that is essential in predicting the fate of organometals in the environment.
Biomethylation of tin (II) complexes in the presence of pure strains of Saccharomyces cerevisiae
Authors: Ashby Janet , Craig P J
Published: January 2005

The methylation of several tin compounds by strains of Saccharomyces cerevisiae strains (yeast) is described. The production of the methyl tin species was established by gas chromatography and mass spectrometry. Monomethyl tin (IV) products dominated but some dimethyl tin products were observed. This appears to be the first report of a tin methylation by a pure strain of a methylating species rather than a complex mixture obtained from an environmental source.
A 119mSn variable‐temperature Mössbauer study of tin(IV) chloride and dibutyltin dichloride when dispersed in a poly(vinyl chloride) matrix
Authors: Brooks John S , Allen David W , Unwin John
Published: January 2005

Variable‐temperature Sn‐119m Mössbauer studies of tin(IV) chloride (SnCl4) and dibutyltin dichloride (Bu2SnCl2) when dispersed in a poly(vinyl chloride) (PVC) matrix have been interpreted using a Debye model. Recoilless fractions have been determined which indicate that at 80 K the Mössbauer technique is nearly three times as sensitive to the presence of SnCl4 compared with Bu2SnCl2 within the poly(vinyl chloride) matrix. These observations have been explained in terms of structural changes occurring on dispersion in the polymer matrix which result in the tin atom in tin(IV) chloride becoming six‐coordinate whereas that in dibutyltin dichloride reduces its coordination to five. The implications of these results for future applications of Mössbauer spectroscopy to the study of organotin compounds present in polymers are considered.
Organotin compounds in agriculture since 1980. Part 2. Acaricidal, antifeedant, chemosterilant and insecticidal properties
Authors: Crowe Alan J
Published: January 2005

The object of this review paper is to provide a guide to agrochemical research involving organotin compounds which has been performed since 1980. The information is presented in a tabular form and is divided into four main sections as indicated by the title. Each section is then subdivided to cover the various commercial organotin compounds. A final subsection lists investigations involving novel compounds. An additional section covers the effects of organotin agrochemicals on non‐target organisms. A table of the contents has been provided to enable ease of reference. Acaricidal, antifeedant, chemosterilant and insecticidal properties are covered here. Fungicidal, bactericidal and herbicidal aspects are covered in Part 1.
Bioaccumulation of arsenic by freshwater algae (Nostoc sp.) and the application to the removal of inorganic arsenic from an aqueous phase
Authors: Maeda Shigeru , Kumeda Kosuke , Maeda Mitsuru , Higashi Shiro , Takeshita Toshio
Published: January 2005

An arsenic‐resistant blue‐green alga, Nostoc sp., was screened from an arsenic‐polluted environment. The effects of the culture conditions on the growth and the arsenic bioaccumulation were investigated. In five culture media tested, Microcystis aeruginosa medium was found to be optimum for the growth. The effects of the concentration of five nutrients (P, Co, Fe, Mo and N) in the MA medium on arsenic bioaccumulation by the Nostoc sp. were also investigated. From the experimental results, the authors proposed a new culture medium which was designed for effective arsenic bioaccumulation by the Nostoc sp. The new medium was named the Modified MA medium (abbreviated as MMA).

Removal of arsenic from an aqueous phase by means of arsenic bioaccumulation by the Nostoc sp. was investigated. When arsenic‐polluted water was enriched with the nutrients of MMA, the arsenic level was found to be effectively lowered by the Nostoc sp. to 0.05 ppm.
Complexes in polymers: FT‐IR spectra and photochemistry of some monomeric organometallic carbonyl complexes in polystyrene, poly(methyl methacrylate), polystyrene—poly(methyl methacrylate) and polystyrene—polyacrylonitrile copolymers
Authors: Shaver Alan , Butler Ian S. , Eisenberg Adi , Gao Jian Ping , Xu Zhen H , Fong Bertwin , Uhm Haewon , Klein David
Published: January 2005

A convenient method for embedding organometallic complexes in polymer films has been developed and the FT‐IR spectra of these films have been investigated at room temperature. Infrared data in the n̈(CO) stretching region are reported for M(CO)6 (M = Cr, Mo, W), CpMn(CO)3 (Cp = η5‐C5H5), η‐C6H6Cr(CO)2L [L = CO, P(n‐Bu)3], (η6‐C6H5NH2)Cr(CO)3, [η6‐o‐C6H4(NH2)MeCr(CO)3], CpFe(CO)LR [L = CO, PPh3; R = Me, C(O)Me] embedded in poly(methyl methacrylate) (PMMA), polystyrene (PS), polystyrene‐poly(methyl methacrylate) (PS‐PMMA), and polystyrene–polyacrylonitrile (PS‐AN) plastic films. These matrices appear to approximate the common solvents ethyl acetate, toluene, toluene–ethyl acetate, and toluene–acetonitrile, respectively, with respect to n̈(CO) vibrational band behavior. Several of the films have been subjected to UV irradiation and the photoproducts formed have been identified by FT‐IR spectroscopy. PS‐AN effectively traps photogenerated coordinatively unsaturated species via coordination of its pendant nitrile groups.
Catalysis of hydrosilylation. XV. A poly(phosphino‐organosiloxanyl)silicate‐supported rhodium(I) catalyst for gas‐phase hydrosilylation of acetylene
Authors: Marciniec Bogdan , Foltynowicz Zenon , Urbaniak WŁOdzimierz
Published: January 2005

Wilkinson's complex [RhCl(PPh3)3], anchored to phosphino‐organosiloxane macromolecules grafted onto chrysotile asbestos, appeared to be an unusually effective and selective catalyst for the synthesis of vinylsilanes via gas‐phase hydrosilylation of acetylene, particularly by methyldichlorosilane in a continuous‐flow microreactor as well as in a laboratory reactor. Catalytic and kinetic parameters show an advantage for the catalyst based on the chrysotile‐polyorganosiloxane support (catalyst CHR–Rh) over the phosphinated silica (catalyst A).
Environmental aspects of tributyltin
Authors: Maguire R. James
Published: January 2005

The tributyltin species, the active ingredient in some antifouling paint formulations, is perhaps the most acutely toxic chemical to aquatic organisms ever deliberately introduced to water. It has been demonstrated to have an adverse effect on shellfish in France and England, and as a consequence the use of tributyltin‐containing antifouling paints has been restricted in these countries. Other countries have banned the use of tributyltin‐containing antifouling paints or are contemplating restrictions. This article reviews such environmental aspects of tributyltin as methods of analysis, toxicity, environmental occurrence, persistence and fate. Tributyltin concentrations in many locations may be high enough to cause chronic toxicity or harmful effects in some aquatic organisms, and in some locations the tributyltin concentrations may be high enough to be acutely toxic to some organisms. Biological degradation of tributyltin in water and sediment appears to be the most important factor limiting the persistence of tributyltin in aquatic environments. To some degree, then, the persistence of tributyltin in aquatic environments depends upon the nature of the ecosystem. Tributyltin exhibits low‐to‐medium persistence in water and moderate persistence in sediment. A summary is given of the regulatory status of tributyltin in some countries, and recommendations are made for further research.
Linear trimerization of 1‐ethynylcyclohexan‐1‐ol catalysed by nickel(II) complexes
Authors: Carusi P , Cerichelli G , Furlani A , Russo M V , Suber L
Published: January 2005

The catalytic reaction of 1‐ethynylcyclohexan‐1‐ol (EC) in the presence of bisphosphine nickel(II) complexes yields a linear trimer. The trimer could be isolated and characterized by means of MS, IR and NMR spectroscopies. The reaction mechanism is also discussed.
Complexes in polymers II: FT‐IR spectra, iodine oxidation, and photochemistry of [(η5‐C5H)Fe(CO)2]2, [(η5‐C5H5)Mo(CO)3]2 and Mn2(CO)10 in polystyrene, poly(methyl methacrylate) and polystyrene–polyacrylonitrile copolymer
Authors: Shaver Alan , Gao Jian Ping , Butler Ian S
Published: January 2005

The infrared spectra of [CpFe(CO)2]2, [CpMo(CO)3]2 and Mn2(CO)10 (Cp=η‐C5H5) embedded in films of polystyrene (PS), poly(methyl methacrylate) (PMMA), and polystyrene‐polyacrylonitrile (PSAN), are comparable with those of the dimers in toluene, ethyl acetate and acetonitrile, respectively. Irradiation of the embedded dimers with UV light led to decomposition in PS and PMMA, while in PSAN the complexes Cp2Fe2(CO)3PSAN and Mn2(CO)9PSAN were formed, wherein a pendant nitrile group is coordinated to one of the metal atoms. Exposure of the embedded dimers to iodine vapour gave CpFe(CO)2I, CpMo(CO)3I and Mn(CO)5I with the reaction being much slower in PMMA than in PS.
The analysis of inorganic and organometallic antimony, arsenic and tin compounds using an on‐column hydride generation method
Authors: Clark S , Craig P J
Published: January 2005

A novel method of analysis of inorganic and organometallic compounds is reported. Essentially this utilizes the well‐documented hydride generation technique, but in the present method the hydrides are generated from their involatile precursors (e.g. chlorides) on a GC column and separated from each other and from extraneous materials on the same GC column in a single process. Using the method, a solution of butyltin chlorides can be directly injected into a GC AA system to yield the volatile hydrides for separation, detection and quantification.

To date, species analysed by this method include inorganic As(III), Me2AsOOH, inorganic Sb(III) and Sb(V), MeSnCl3, Me2SnCl2, Me3SnCl, Et2SnCl2, Et3SnCl, BuSnCl3, Bu2SnCl2, Bu3SnCl and Pr3SnCl.

With the use of the internal standard Pr3SnCl and with the almost complete hydridization afforded by the technique, the procedure is shown to eliminate errors and to reduce the time involved in the analysis. The use of on‐column derivatization also allows for the possibility that, in some cases, organotin hydrides reported to be found in the natural environment may, in fact, be organotin chlorides being reported as hydrides owing to inadvertent hydride production on the column. Some reports of successful gas chromatography for organotin halides could also conceivably be due to on‐column hydride generation.
The in vitro antiherpes activity of some selected antitumor organotin compounds
Authors: Ward Sarah G. , Craig Taylor R. , Crowe Alan J.
Published: January 2005

A number of antitumor‐active octahedral organotin complexes of the type R2SnX2L2, where R=ethyl or phenyl, X = chloride or bromide, and L2 = o‐ phenanthroline or 2‐(2‐pyridyl)benzimidazole, have been shown to exhibit in vitro antiherpes activity towards both herpes simplex virus types 1 and 2 (HSV‐1 and HSV‐2). In addition, a series of mono‐, di‐, and tri‐organotin halides (alkyl and phenyl) demonstrated weak antiherpes activity in the same viral assay system. Selectivity indexes for the tin compounds were calculated and compared with those available in the literature for a number of well‐characterized and commercially important antivirals, e.g. adenine‐9‐β‐D‐arabinofuranoside (ara‐A), cytosine‐β‐D‐arabinofuranoside (ara‐C), 5‐iodo‐2′‐deoxyuridine (IDU) and 9‐(2‐hydroxyethoxymethyl)guanine (acyclovir, ACY). Although the organotin complexes are less effective in vitro than either ACY or IDU, as determined by their selectivity indexes, they are comparable in activity with both ara‐A and ara‐C in this particular assay. With few exceptions, most notably (C2H5)2SnBr2(o‐phen), the organotin compounds examined in this study are more active against HSV‐1 (F strain) than HSV‐2 (MS strain). The results presented here represent the first study of the potential antiviral properties of organotin compounds.
Relationship of cytotoxic groups in organotin molecules and the effectiveness of the compounds against leukemia
Authors: Sherman Larry R , Huber Friedo
Published: January 2005

Cytotoxicity of organotin compounds is assessed and their effectiveness against leukemia is discussed. The functional groups attached to the tin atom in organotin compounds control the cytotoxicity of the compound towards the thymus gland. The four organotin moieties which have the greatest toxic effect upon the thymus gland are the tri‐n‐butyltin, di‐n‐butyltin, tri‐n‐propyltin and di‐n‐octyltin groups. Compounds containing these groups also exhibit the poorest test‐control ratio (T/C) values when tested as anti‐cancer agents against leukemic mice using NCI protocol.
Synthesis, structural and biocidal activity studies of triorganotin(IV) compounds of some N‐protected amino‐acids
Authors: Mesubi M Adediran , Eke U Basil , Bamgboye T Tunde
Published: January 2005

Seven new triorganotin(IV) complexes of the type R3SnL (L=N‐phthaloyl derivatives of glycine, DL‐alanine or N‐acetyl‐ and N‐benzoyl‐glycine and ‐cysteine; R‐n‐C4H9 or C6H5) have been prepared by reacting the sodium salt of the ligand and the triorganotin(IV) chloride in 1:1 molar ratio in methanol. The complexes have been characterized by elemental analysis, molecular mass determination, IR and 1H NMR spectroscopy. The complexes are monomeric in molten camphor and are moderateely soluble in the common organic solvents. The spectral data support cis five‐coordinate complexes with an unsymmetrical bidentate coordination of the carboxylate group to tin.

The complexes exhibit some insecticidal effect on Bean Weevils (Sitophilus granaria) even at low concentration and they also show fungicidal activity on Aspergillus niger and Helminthosporium taulosum. Some of the complexes are found to be more effective than tri‐n‐butyltin and triphenyltin chlorides.
Organosilicon sonochemistry
Authors: Goldberg Yu , Sturkovich R , Lukevics E
Published: January 2005

Sonochemical reactions involving organosilicon compounds are reviewed. Possible applications of ultrasonic irradiation for acceleration and initiation of various types of reactions are demonstrated along with examples from organic synthesis using organosilicon compounds. Also described are the sonochemical reactions of organic compounds containing the Group IVB elements germanium and tin, chemically related to silicon.
Ultrasonic irradiation in a single‐stage synthesis of chloroiodomethane from iodoalkanes and dichloromethane under aluminum mediation
Authors: Lin Yih‐Tsung , Chang Ming‐Ju , Lou Chong‐Yean
Published: January 2005

In the presence of iodine, a mixture of dichloromethane, iodoalkanes (alkyl = Me, Et, Pr, iso‐Pr, Bu, iso‐Bu, pentyl) and aluminum powder was irradiated at room temperature with ultrasound to give readily chloroiodomethane ICH2Cl. The preferred reactant to give the best yield of ICH2Cl was PrI. Alkylaluminum sesqui‐iodides were postulated as intermediates.
Glutathione and methylation of inorganic arsenic in hamsters
Authors: Hirata Miyuki , Hisanaga Akira , Tanaka Akiyo , Ishinishi Noburu
Published: January 2005

The effect of giutathione (GSH) concentrations in livers and kidneys of hamsters on the toxicity and methylation of arsenite in these animals was studied. No significant changes in hepatic and renal GSH concentrations were observed after a single arsenite administration (5 mg As kg−1, p.o.). When buthionine sulfoximine (BSO), an inhibitor of GSH synthesis, was given (4 mmol kg−1, i.p.) two hours before administration of arsenite, hepatic and renal GSH concentrations were more severely and persistently depressed than in the case of BSO administration not followed by arsenite. Hamsters treated with BSO plus arsenite suffered from severe nephrotoxicity (acute renal failure) characterized by increases in plasma creatinine and urea nitrogen and by proximal tubular necrosis. Concurrently, transient hepatotoxicity was observed in the BSO plus arsenite group. Neither arsenite alone nor BSO alone produced liver or kidney injury. The BSO plus arsenite‐treated animals excreted in the urine only 3.5% of the arsenic dose during the 72 h period after administration of arsenite, probably because of a decrease in urine volume caused by kidney injury, whereas the arsenite‐only group excreted 27%. In addition, BSO pretreatment influenced the relative proportion of arsenic metabolites excreted in the urine during the first 24 h after administration. Urinary metabolites in the BSO plus arsenite group were predominantly inorganic arsenic. These results suggest that GSH provides protection against arsenic toxicity.
Comparative chronic toxicity, including tumorigenicity, of gallium arsenide and arsenic trioxide intratracheally instilled into hamsters
Authors: Ohyama Shiro , Ishinishi Noburu , Hisanaga Akira , Yamamoto Akiyo
Published: January 2005

Chronic toxicity, including tumorigenicity, of gallium arsenide (GaAs) and arsenic trioxide (As2O3) were studied using Syrian golden hamsters given intermittent intratracheal instillations. GaAs particles (0.25 mg × 15 times/animal) were likely to produce relatively severe lung damage and the survival of the animals was shortened significantly compared with a control group. The tumor incidence of each group examined was GaAs (3.3%), As2O3 (3.3%) respectively, at a dose of 3.75 mg total metal given during 15 weeks. In this experiment, both arsenic trioxide and gallium arsenide had no apparent carcinogenicity or tumorigenicity.
Arsenic‐containing ribofuranosides and dimethylarsinic acid in green seaweed, Codium fragile
Authors: Jin Kazuo , Hayashi Takaaki , Shibata Yasuyuki , Morita Masatoshi
Published: January 2005

Three water‐soluble arsenic compounds were isolated from the green seaweed Codium fragile. These compounds were identified as 1‐glycerophosphoryl‐2‐hydroxy‐3‐[5′‐deoxy‐5′‐(dimethylarsinoyl)‐β‐ribofuranosyloxy]propane (1a), 1′ ‐(1,2‐dihydroxypropyl)‐5′ ‐deoxy‐5′ ‐(dimethylarsinoyl)‐β‐ribofuranoside (1b), and dimethylarsinic acid ((CH3)2AsOOH). The structures of these compounds were ascertained by 1H NMR spectroscopy. Compounds 1a and 1b accounted for 60 % and dimethylarsinic acid for 5% of the water‐soluble arsenic.
Ubiquity of arsenobetaine in marine animals and degradation of arsenobetaine by sedimentary micro‐organisms
Authors: Hanaoka Ken'Ichi , Yamamoto Hideki , Kawashima Keishiro , Tagawa Shoji , Kaise Toshikazu
Published: January 2005

Arsenic compounds were extracted with chloroform/methanol/water from tissues of marine animals (four carnivores, five herbivores, five plankton feeders). The extracts were purified by cation and anion exchange chromatography. Arsenobetaine [(CH3)3As+CH2COO−], dimethylarsinic acid [(CH3)2AsOOH], trimethylarsine oxide [(CH3)3AsO] and arsenite, arsenate, and methylarsonic acid [(CH3)AsO(OH)2] as a group with the same retention time were identified by high‐pressure liquid chromatography. Arsenic was determined in the collected fractions by graphite furnace atomic absorption spectrometry. Arsenobetaine found in all the animals was almost always the most abundant arsenic compound in the extracts. These results show that arsenobetaine is present in marine animals independently of their feeding habits and trophic levels.

Arsenobetaine‐containing growth media (ZoBell 2216E; solution of inorganic salts) were mixed with coastal marine sediments as the source of microorganisms. Arsenobetaine was converted in both media to trimethylarsine oxide and trimethylarsine oxide was converted to arsenite, arsenate or methylarsonic acid but not to dimethylarsinic acid. The conversion rates in the inorganic medium were faster than in the ZoBell medium. Two dominant bacterial strains isolated from the inorganic medium and identified as members of the Vibro–Aeromonas group were incapable of degrading arsenobetaine.
Bioaccumulation of alkyllead compounds from water and from contaminated sediments by mussels
Authors: Chau Y K , Wong P T S , Bengert G A , Wasslen J
Published: January 2005

The bioconcentration of alkyllead compounds from water and from contaminated sediments by freshwater mussels (Elliptio complanata) has been investigated. Higher levels of trimethyllead than triethyllead species are accumulated for the same exposure period. In‐vivo transformation of the trialkyllead species by a series of dealkylation reactions giving dialkyllead and inorganic lead(II) species appears to take place. Rates of accumulation are higher for the more contaminated sediments.
Methylation of tin(II) by methyl iodide in porewater
Authors: Lee Dong Sup , Weber James H
Published: January 2005

The methylation of tin(II) chloride by methyl iodide in porewater and formation of monomethyltin as the only methyltin product are described. A factorial experiment tested the effects of concentrations of tin(II), methyl iodide, and oxygen on monomethyltin yields. The experiments gave 0.18 to 12.8 % yield. Analysis of variance (ANOVA) calculations showed that all three variables were significant at the 95 % level. Comparison of yields in aqueous 23 g kg−1 sodium chloride solutions to those in porewater and to those containing fulvic acid, salicylic acid, and EDTA showed that only fulvic acid significantly reduced yields. Reasons for this observation are discussed and the findings in the model system are related to methylation of tin compounds in sediments.
Trace speciation by HPLCGF AA for tin‐ and leadbearing organometallic compounds, with signal increases induced by transition‐metal ions
Authors: Parks E J , Brinckman F E , Jewett K L , Blair W R , Weiss C S
Published: January 2005

High‐performance liquid chromatography coupled with graphite furnace atomic absorption spectroscopy (HPLCGF AA) gives element‐specific detection of environmental samples containing trace amounts of organotin or organolead species. The direct GF AA of organotin and organolead species is subject to errors arising primarily from loss of analyte prior to atomization, probably through the formation of refractory carbides and of compounds or complexes that are volatile at low temperatures. Examples abound in the literature of signal suppression in the GF AA of organometallic species in environmental samples, and several furnace tube modifications have been developed to overcome this suppression. Here, the analyte and a modifier are co‐pipetted into a conventional furnace tube, from either a solution of analyte or an HPLC effluent. Oxides of transition metals (e.g. chromium, manganese, or tungsten) are shown to enhance both tin and lead signals, whereas chlorides do not, suggesting the low‐temperature formation of relatively involatile metal oxides or volatile metal chlorides, respectively. In the absence of modifier, GF AA signal intensities decrease consecutively for equal quantities of mono‐, di‐, tri‐ and tetra‐butyltin species, but are nearly equal for the first three in the presence of complexing dichromate (Cr2O72−). The lesser signal increase for tetrabutyltin indicates a dissimilar low‐temperature complexation chemistry for the fully ligated neutral organometal to that for the ligated ions. similar results are demonstrated in post‐column addition of a matrix modifier to effluent containing either organotin or organolead species.
Kinetics and mechanism of nucleophilic addition at the bridging vinyl ligand of the cluster [HOs3 (η2‐CHCH2) (CO)10]
Authors: Kane‐Maguire Leon A P , Ghazy Tahany
Published: January 2005

Kinetic and spectroscopic studies are reported for the addition of a range of neutral phosphorus and nitrogen nucleophiles to the bridging η2‐vinyl ligand of the cluster [HOs3(η2‐CHCH2)(CO)10]. With PPh3, the reaction is reversible, and the rate law, kobs = k1[Nuc] + k−1, is observed. This rate law is consistent with direct bimolecular addition (k1) of PPh3 to the η2‐vinyl ligand. With more basic triarylphosphine nucleophiles, the simple expression, kobs = k1[PR3], is obeyed. The second‐order rate constant, k1, varies markedly with the phosphine basicity. For the series P(4‐XC6H4)3, a linear Brönsted plot of log k1 vs pKa is obtained with a slope α of 0.46. The reversible addition of cyclohexylamine to this cluster also obeys a two‐term rate law. Overall, nucleophilicity towards [HOs3(η2‐CHCH2)(CO)10] decreases in the order C6H11NH2 > P(4‐MeOC6H4)3 > P(4‐MeC6H4)3 > PPh3, which quantitatively parallels that previously found for the related mononuclear cation [CpFe(CO)2(η2‐CH2CH2)]+.
Reactivity and reaction pathways of electrochemically generated 17‐electron tricarbonyl steroid chromium cations
Authors: Bond Alan M , Mocellin Enrico , Pascual Cherrie B , Wedkanjana Panit , Jaouen Gérard , Top Siden
Published: January 2005

Electrochemical oxidation of α‐ and β‐diastereomers of a range of steroid hormone receptor marker chromium tricarbonyl complexes, (steroid)Cr(CO)3, have been examined at platinum electrodes in dichloromethane. Data confirm the general nature of previously published conclusions on the oxidation of (arene)Cr(CO)3 complexes (arene = benzene or steroid). That is, with 0.1 M Bu4NPF6 as the electrolyte, and in the absence of nucleophiles, a reversible oneelectron process, (steroid)Cr(CO)3 ⇌ [(steroid)Cr(CO)3]+ + e−, is observed, followed by an irreversible one‐electron process at considerably more positive potentials. The reversible half‐wave potentials (approximately E°‐values) calculated for the [(steroid)Cr(CO)3]+/(steroid)Cr(CO)3 redox couple are shown to be dependent on whether the α‐ or β‐diastereomer is oxidized. Similarly the rate of nucleophilic attack on the 17‐electron cation [(steroid)Cr(CO)3]+ by nucleophiles such as ClO, PPh3 and bis(diphenylphosphine)methane confirms a previous observation that the stereochemistry of this class of compound is important with respect to redox, kinetic and hormone receptor properties. The nature of the electrochemical data obtained on the (arene)Cr(CO)3 complexes in the presence of nucleophiles suggests that reactions associated with the nucleophilic attack on the 17‐electron cations are complex and that a range of reaction pathways occur simultaneously. Electrochemical studies on the oxidation of (benzene)Cr(CO)2PPh3 and (oestradiol)Cr(CO)2PPh3 confirm some aspects of the proposed mechanisms, although it is clear that a great deal still has to be learned concerning mechanistic aspects of nucleophilic attack on these 17‐electron complexes.
Comparative study of the biological activity of organosilicon and organogermanium compounds
Authors: Lukevics E , Ignatovich L
Published: January 2005

The literature data and the results of our own investigations on the comparative study of the biological activity of isostructural organogermanium and organosilicon compounds have been summarized. It has been shown that the series of organogermanium and organosilicon compounds is more active than the carbon analogues, the majority of organogermanium compounds are less toxic than the sila analogues, the biological activity of the compounds under study appears to be similar but can dramatically differ in the degree of activity, and, moreover, in some particular cases sila and germa analogues exhibit the opposite biological effects.
Chemical methylation of germanium(II) in model aqueous solutions
Authors: Mayer H P , Rapsomanikis S
Published: January 2005

Inorganic germanium(II) in micromolar concentrations was reacted with methyl iodide (CH3I) and methylcobalamin (CH3‐CoB12) at various pH values and with different salt matrices. In all experiments monomethylgermanium was the only product. The reaction with CH3‐CoB12 at pH 1 yielded approximately 1.3% of the added germanium, whereas no methylation occurred at pH 7. Reaction yields with CH3I were lowest at pH 1 in 0.1 mol dm−3 KCl (1.6%) and highest at pH 7.6 in artificial seawater (6%). For the reaction of CH3−CoB12 with germanium(II) a free‐radical mechanism is assumed, whereas methylation by CH3I is most likely an oxidative addition mechanism.
The use of liposomes in predicting the biological mobility of arsenic compounds
Authors: Cullen William R , Nelson John
Published: January 2005

Efflux studies of radio‐labelled methylarsonic acid (MMA) and dimethylarsinic acid (DMA) encapsulated in liposomes afford the following permeability values for the two arsenicals: 1.4 × 10−13 cm s−1 and 4.5 × 10−11 cm s−1 for MMA and DMA, respectively. These data are compared with the octanol/water partition coefficients which are 7.4 × 10−3 and 8.4 × 10−3 for MMA and DMA, respectively.
Inorganic arsenic: A dangerous enigma for mankind
Authors: Tsuda Toshihide , Babazono Akira , Ogawa Takanori , Hamada Hirohisa , Mino Yoshio , Aoyama Hideyasu , Kurumatani Norio , Nagira Tsuyoshi , Hotta Nobuyuki , Harada Masazumi , Inomata Shigemi
Published: January 2005

Human being have been using inorganic arsenic for a long time. Many reports on arsenic poisoning have been published: eg case reports, examination reports, post mortem reports, and epidemiological studies. Several aspects and features of arsenic poisoning are discussed in this report. Methods of inferring arsenic‐related disease, disease classification according to acute or chronic criteria, exposure route, interaction, confounding factors, and the oxidation state of arsenic are all discussed. The effects of arsenic are classified into skin, respiratory system, gastrointestinal tract, liver, cardiovascular system, nervous system, and bone marrow effects. Carcinogenicity is an important chronic effect of arsenic poisoning, so special attention is paid to it in this review. In Japan, there have been many incidents of arsenic poisoning. In this review, we often use data from these cases, such as the Morinaga powdered‐milk poisoning case, the Ube soy‐sauce poisoning case, the Toroku mine incident, and the Nakajo well‐water poisoning case. We emphasize here the necessity of planning follow‐up studies and total health care for patients exposed to arsenic.
Biomethylation of arsenic and its excretion by the alga Chlorella vulgaris
Authors: Maeda Shigeru , Kusadome Katsuhiro , Arima Hiroyuki , Ohki Akira , Naka Kensuke
Published: January 2005

Experimental results in this paper lead to the following conclusions. (1) Cell homogenates of Chlorella vulgaris adsorbed the inorganic arsenic compound Na2HAsO4 but no methylation of the arsenic occurred in vitro. (2) A small part of the arsenic bioaccumulated by C. vulgaris was methylated in vivo. The quantity of arsenic methylated in the cell increased with an increase of arsenic concentration in the medium. (3) When the arsenic‐accumulating cells were transferred into arsenic‐free media, the arsenic was excreted and the relative quantity of the methylated arsenic in the excrement was larger than that in the cell. (4) In the growth phase of C. vulgaris, a small fraction of the arsenic accumulated in the cell was first transformed to monomethyl and dimethyl‐arsenic compounds during the early exponential phase, and after a short time a fraction was transformed to trimethylarsenic species.