bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthese und Kristallstrukturen von (Ph4P)4[Bi8I28], (nBu4N)[Bi2I7] und (Et3PhN)2[Bi3I11] – Iodobismutate mit isolierten bzw. polymeren Anionen
Authors: Krautscheid Harald 
Published: January 2005

AbstractBiI3 reagiert in methanolischer Lösung mit NaI und (nBu4N)(PF6) bzw. (Et3PhN)(PF6) zu (nBu4N)[Bi2I7] 1 und (Et3PhN)2[Bi3I11] 2 mit Iodobismutatanionen. In 1 liegen unendliche Stränge von über gemeinsame I‐Atome verknüpften Bi4I16‐Einheiten vor. In 2 bilden verkettete Bi6I24‐Einheiten polymere Anionen. Führt man die Umsetzung von BiI3 mit (Ph4P)(PF6) ohne NaI durch, so kristallisiert aus Methanol (Ph4P)4[Bi8I28] 3. Die Anionen von 1–3 bestehen aus kantenverknüpften BiI6‐Oktaedern.(nBu4N)[Bi2I7] 1: Raumgruppe I2/m (Nr. 13), a = 1 082,3(5), b = 2 597,1(13), c = 1 206,1(6) pm, β = 93,17(2)°, V = 3 385(3) · 106 pm3;(Et3PhN)2[Bi3I11] 2: Raumgruppe P1 (Nr. 2), a = 1 283,5(6), b = 1 345,9(7), c = 1 546,3(8) pm, α = 83,87(2), b = 74,24(2), γ = 68,26(2)°, V = 2 388(2) · 106 pm3;(Ph4P)4[Bi8I28] 3: Raumgruppe P1 (Nr. 2), a = 1 329,3(4), b = 1 337,0(4), c = 2 193,1(5) pm, α = 104,20(2), β = 99,73(2), γ = 100,44(2)°, V = 3 622(2) · 106 pm3.
Synthese, Struktur und magnetische Eigenschaften von [CrCl(μ‐Cl)(TMEDA)]2
Authors: Bachmann Bernd , Heck JÜRgen , Hahn F. , Massa Werner , Pebler JüRgen 
Published: January 2005

AbstractDen Titelkomplex [CrCl(μ‐Cl)TMEDA]2 (1) erhält man in einer äquimolaren Reaktion von CrCl2(THF) mit TMEDA in hohen Ausbeuten. 1 kristallisiert in der monoklinen Raumgruppe P21/c mit a = 843,2(2), b = 1 109,4(2), c = 1 147,4(3) pm, β = 102.99(2)° und Z = 2. Die Molekülstruktur von 1 enthält zwei leicht verzerrte quadratisch pyramidal koordinierte CrL5‐Untereinheiten, die über zwei unsymmetrische Cl‐Brücken verbunden sind. Die μ‐Cl‐Funktionen nehmen die apikale Position der einen und eine basale Position der anderen CrL5‐Einheit ein, wobei die apikale Cr–Cl‐Bindung (277,6(1) pm) deutlich länger als die basale Cr–Cl‐Bindung (240,6(1) pm) ist. Die terminale Cr–Cl‐Bindung ist noch kürzer (237,5(1) pm), Der CrCr‐Abstand mit 381,7(1) pm liegt deutlich außerhalb einer bindenden Cr–Cr‐Wechselwirkung. Dieses wird durch magnetische Suszeptibilitätsmessungen bestätigt, die pro Cr‐Zentrum vier ungepaarte Elektronen nachweisen; allerdings kann eine kleine antiferromagnetische Kopplung von J/k = −7,3 K berechnet werden. Diese Kopplung wird vermutlich durch einen 90°‐σ‐Superaustausch über die Cl‐Brücken erwirkt.
Phosphaniminato‐Komplexe von Titan(IV) und Titan(III). Die Kristallstrukturen von [TiCl2(OMe)(NPPh3)]2, [TiBr2(NPPh3)]2 · 3 C7H8 sowie von [Ph3PNH2]Br · CH2Cl2
Authors: Li Jin‐Shan , Weller Frank , Schmock Fritjof , Dehnicke Kurt 
Published: January 2005

AbstractTiCl3(NPPh3) reagiert mit einer Lösung von Methyllithium in Diethylether in Gegenwart von Lithiummethylat unter Bildung von gelbem [TiCl2(OMe)(NPPh3)]2. Bei der Umsetzung mit Benzylmagnesiumbromid wird TiCl3(NPPh3) in Diethylether unter Reduktion und Ligandenaustausch in grünes [TiBr2(NPPh3)]2 umgewandelt, das aus Toluol mit drei Molekülen C7H8 kristallisiert. Als Nebenprodukt dieser Reaktion entsteht [Ph3PNH2]Br · CH2Cl2. Die Produkte werden durch die IR‐Spektren und durch Kristallstrukturanalysen charakterisiert.[TiCl2(OMe)(NPPh3)]2. Raumgruppe P1 Z = 2, Strukturlösung mit 2 909 unabhängigen Reflexen, R = 0,063. Gitterkonstanten bei 20°C: a = 1005,1; b = 1044,5; c = 1068,6 pm; α = 66,98°; β = 89,35°; γ = 80,24°. Die Verbindung bildet zentrosymmetrische dimere Moleküle mit μ2‐OMe‐Brücken und fünffach koordinierten Titanatomen. Der (NPPh3−)‐Ligand ist terminal gebunden mit einem TiN‐Abstand von 174,8 pm und einem TiNP‐Bindungswinkel von 165,3°.[TiBr2(NPPh3)]2 · 3 C7H8. Raumgruppe P1, Z = 2, Strukturlösung mit 5548 unabhängigen Reflexen, R = 0,053. Gitterkonstanten bei −70°C: a = 983,3; b = 1162,7; c = 1376,5 pm; α = 100,53°; β = 110,30°; γ = 105,24°. Die Verbindung bildet zentrosymmetrische dimere Moleküle mit μ2‐NPPh3‐Brücken und tetraedrischer Koordination an den Titanatomen. Die Ti–N‐Bindungen entsprechen mit 195,9 pm Einfachbindungen. Der Ti …︁ Ti‐Abstand ist mit 260,0 pm ungewöhnlich kurz.[Ph3PNH2]Br · CH2Cl2. Raumgruppe P1, Z = 1, Strukturlösung mit 3091 unabhängigen Reflexen, R = 0,049. Gitterkonstanten bei 20°C: a = 909,4; b = 1004,4; c = 1158,5 pm, α = 108,09°; β = 94,67d; γ = 91,92°. Die Bromidionen sind über Wasserstoffbrückenbindungen des Kations und des Dichlormethans zu einem eindimensional unendlichen Netzwerk verknüpft.
An analysis of mutual assistance
Authors: Levine Murray 
Published: January 2005

ConclusionWhy should community psychology be interested in mutual assistance? Mutual assistance organizations represent not an alternative to professional care by an addition to resources in the community of a kind that makes for a more competent community (Iscoe, 1974). Mutual assistance also reflects the values of empowerment that many community psychologists accept as primary (Rappaport, 1981). For those persons who suffer with conditions that may be attributed to oppressive social environments, there is no alternative to collective political and social action to produce change. The developing mutual assistance movement provides an unparalleled opportunity to enhance our understanding of the meaning and significance of social support and the conditions under which people change. Those of us in the field have every reason to embrace this movement for it is truly in keeping with the vision of community psychology.
The effect of role change on intellectual ability and on the ability self‐concept in Chinese children
Authors: Dewei Li 
Published: January 2005

ConclusionsAccording to the findings of the present study, the following conclusions are warranted:1. The ability self‐concept of Chinese schoolchildren was significantly enhanced by the role‐changing procedure. Therefore, schools may be able to establish positive situations involving a change in the children's role as a means for improving children's ability self‐concepts.2. The children's motives for achievement and their language abilities were improved by the role‐change procedure.
Social networks and social competence: Exploring the effects of early adolescent friendships
Authors: Cauce Ana Mari 
Published: January 2005

ConclusionsPerhaps the main significance of this work was in its methodological contributions. Most noteworthy were its attempts to expand network analysis beyond the examination of supportive functions, the use of a more objective measure of social support, and the use of a multivariate hierarchical strategy of analysis.This study obtained correlations between social network variables and social competence indices that were highly suggestive. However, it is important to keep in mind that the sample under investigation was fairly small and relatively homogeneous with respect to ethnicity, social class, and even values. Whether the exact nature of these relationships will generalize to different samples remains an empirical question. In fact, one would suppose that some of the results would be quite different for a population that does not highly value school. Further research, ideally longitudinal in nature, is sorely needed to address some of the issues raised by this study, both in terms of the social support/network literature and the possibly changing characteristics of minority children and their social environments as they move from preadolescence to adolescence.
Effects of inorganic and organic lead compounds on chromosomal length in human lymphocytes
Authors: Andersen Ole , Grandjean Philippe 
Published: January 2005

AbstractIn vitro exposure of human lymphocyte cultures to spindle inhibitors reduce the average chromosome length1,2. In this report chromosome length measurements were used for indirect but quantitative evaluation of the effects of inorganic and organic lead compounds on spindle function. The data indicate that organic compounds are much more powerful spindle inhibitors than inorganic lead compounds, almost as potent as colchicine. Occupational exposure to organic lead compounds may result in partial spindle inhibition, leading to a high probability of nondisjunction.
A novel flow process for metal and ore solubilization by aqueous methyl iodide
Authors: Thayer John S , Olson Gregory J , Brinckman Frederick E 
Published: January 2005

AbstractAqueous solutions of methyl iodide (CH3I) react with metal ores and with metals, causing them to dissolve in water. This dissolution has been investigated in both static extraction and flow systems. Aqueous concentrations of metals are enhanced anywhere from 3‐ to 242‐fold. The proposed mechanism involves electrophilic attack on the solid surface, thereby breaking the linkages binding the metal to the solid lattice and causing dissolution. Because biogenic sources constitute a major component of global CH3I flux, prospects for related polyfunctional algal haloorganics as aqueous ore or metal solubilizers are noted.
Studies of the degradation of organotin stabilizers in poly(vinyl chloride) during gamma irradiation
Authors: Allen David W , Brooks John S , Unwin John , McGuinness John D 
Published: January 2005

AbstractOrganotin stabilizers of the type Bu2SnX2 (X = SCH2CO2C8H17 or O2CCHCHCO2C8H17) present in poly(vinyl chloride) (PVC) and subjected to varying doses of gamma irradiation in the range 1–200 kGy (0.1–20 Mrad) are shown to suffer degradation with dealkylation to form monobutyltin trichloride and tin(IV) chloride, which have been characterized by a subsequent alkylation procedure followed by gas chromatographic analysis. The extent of degradation of the stabilizers on prolonged gamma irradiation is much more severe than during thermal degradation leading to comparable blackening of the polymer.
The acute toxicity of tri‐n‐butyltin taurocholate
Authors: Sherman Larry R , Soma Denise M , Thoman Charles J 
Published: January 2005

AbstractThe acute toxicity for tri‐n‐butyltin taurocholate (TBT‐TA), a newly synthesized organotin steroid, was determined using Long Evans rats. The organotin compound was suspended in corn oil and administered by gavage using standard techniques. The TBT‐TA exhibited a taurocholic acid toxicity at 24 h and a tributyltin toxicity at three days. The LD50 values were 611 and 384 mg kg−1 respectively. The dead rats exhibited distended stomachs, enlarged cecums, and lesions in the gastrointestinal tract. The toxicity is similar to that observed with other trialkyltin compounds.
Quaternary onium chlorometallates as hydrosilylation catalysts
Authors: Lovel I , Goldberg Yu , Shymanska M , Lukevics E 
Published: January 2005

AbstractSixteen triethylbenzylammonium chlorometallates [Et3 NCH 2Ph][MCIn]m− (M= transition metal, m= 1–3, n= 3–6) and nine anchored ionic metal complexes [℗–CH2PBu3][MCIn]m− derived from ‘polymer‐bound tributylmethylphosphonium chloride’ have been prepared. All the complexes were studied as catalysts in the hydrosilylation of phenylacetylene with triethylsilane. The homogeneous RhIII, PtIV, IrIII, CuII, ZnII, FeIII and anchored PtIV, RhIII, OsIV complexes were found to be active in this reaction. The regio‐ and stereoselectivity of the following catalyst types is determined by the metal atom involved, being a weak function of the chemical environment; neutral chloride (MCln–m); acid (H2MCl6); salt containing the lipophilic organic cation ([Et3NCH2Ph][MCln]m−); polymer‐supported metallate anion ([℗–CH2PBu3] [MCln]m−).
Organoelement derivatives of steroids: Synthesis and structural features of organosilicon, ‐tin and ‐lead derivatives of cholesterol and desoxycholic acid
Authors: Saxena A , Huber F , Pellerito L , Girasolo A 
Published: January 2005

AbstractSome organo‐Main‐Group‐IV‐element compounds of steroids of the type R3M(COL), R2Sn(COL)2 and (R3M)2(HDCA) (where R = Me or Ph; M = Si, Sn and Pb; HCOL = cholest‐5‐en‐3β‐ol; H3DCA = 3α, 12α‐dihydroxy‐5β‐cholan‐24‐oic acid), have been synthesized. The structures of these compounds have been investigated by vibrational, mass, NMR (1H, 13C, 29Si, 119Sn and 207Pb) and 119Sn Mössbauer spectroscopy. For Me3Sn(COL) both in solution and in the solid state an associated structure with distorted trigonal bipyramidal geometry around tin and three‐coordinated oxygen atoms is postulated. Discrete tetrahedral geometries are assigned to Ph3M(COL) complexes and to R2Sn(COL)2 complexes in solution. The latter compounds probably have an associated distorted trigonal bipyramidal structure in the solid state. The complexes (Ph3M)2(HDCA) also have tetrahedral geometries around the central atoms M in solution, but for (Ph3Sn)2(HDCA) a polymeric structure with both tin atoms pentacoordinated in the solid state is proposed.
Methylation of inorganic arsenic by arsenic‐tolerant freshwater algae
Authors: Maeda Shigeru , Wada Hiroshi , Kumeda Kosuke , Onoue Miyuki , Ohki Akira , Higashi Shiro , Takeshita Toshio 
Published: January 2005

AbstractFive arsenic‐resistant freshwater algae which had been isolated from an arsenic‐polluted environment were studied for the biotransformation of arsenic compounds accumulated by them from the aqueous phase. The algal cells bioaccumulating arsenic were digested by 2 mol dm−3 NaOH at 95°C, the AsC bonds except for AsCH3 were cleaved by the treatment and the methylated arsenic compounds were reduced to the corresponding arsines by sodium borohydride (hydride generation). The arsines were chromatographically separated on the basis of their boiling‐point difference and determined by atomic absorption spectrophotometry.Methylated arsenic compounds were found in all algal cells. The predominant arsenic species in the cells, however, were non‐methylated arsenic compounds which were mainly present in the residue of a chloroform–methanol extract. The non‐methylated arsenic compounds were found to be not present in the free inorganic arsenic substrate and to be bound strongly with proteins or polysaccharides in the cells. Methylated arsenic compounds were found mainly in the lipid‐soluble fractions and the major form was a dimethylarsenic compound. Trimethyl‐ and monomethyl‐arsenic compounds were detected but at very low level. The dimethylarsinic acid was not present in the free form in the lipid‐soluble fraction and should be bound with a lipid molecule.It was also found that the accumulation of arsenic by Nostoc occurred only in living cells.
Dehydrogenative condensation of monohydrosilanes yielding disilanes in the presence of platinum complex catalysts
Authors: Tanaka Masato , Kobayashi Toshi‐Aki , Hayashi Teruyuki , Sakakura Toshiyasu 
Published: January 2005

AbstractDimethylphenylsilane was catalytically dehydrogenated and condensed in the presence of platinum complexes to give 1,1,2,2‐tetramethyl‐1,2‐diphenyl‐disilane.
The toxicity of alkyllead compounds to Scrobicularia plana (Da Costa)
Authors: Marshall S J , Jarvie A W P 
Published: January 2005

AbstractConventional (whole animal) toxicity tests were made with Scrobicularia plana (Da Costa), an infaunal estuarine bivalve, and compared with the responses recorded from siphonal preparations. Exposure of Scrobicularia to low concentrations of triethyllead chloride and trimethyllead chloride, for 35 and 60 days respectively, produced typical response curves. However, mortality had not become asymptotic with time at lower concentrations, suggesting further mortality with increased exposure time. An approximate incipient lethal concentration was predicted.A siphonal preparation technique with isolated and in‐situ inhalent siphons of Scrobicularia was used to estimate the lowest effect concentrations of alkyllead compounds. Response to alkyllead was indicated by contraction of the siphon, recorded via an isotonic transducer. Trialkyllead compounds were more toxic than the respective dialkylleads and inorganic lead. Toxicity of trialklleads and inorganic lead. Toxicity of trialkylleads increased with alkyl chain length. Pure tetraethyllead did not cause any siphonal contraction even when applied directly to the preparation. It was concluded that tetraethyllead has a low toxicity or is non‐toxic in pure form.
Optically active alkylbipyridines as chiral ligands in asymmetric catalysis. Synthesis of 2‐(2′‐pyridyl)‐5,6,7,8‐tetrahydro‐8,9,9‐trimethyl‐5,8‐methanoquinoline and rhodium‐promoted asymmetric transfer hydrogenation of acetophenone
Authors: Gladiali Serafino , Chelucci Giorgio , Soccolini Franco , Delogu Giovanna 
Published: January 2005

AbstractThe title compound, a new chiral alkyl 2,2′‐ bipyridine containing a rigid alkyl framework, can be prepared through a six‐step reaction sequence from (+)‐camphor. Coordination of the new ligand to rhodium(I) procatalysts occurs with difficulty and the resulting species display a very low stereoselectivity in the catalytic transfer hydrogenation of acetophenone.
Distribution of arsenic in the natural environment with emphasis on rocks and soils
Authors: Tanaka Takeshi 
Published: January 2005

AbstractArsenic is ubiquitous in the environment. Although the average arsenic concentrations in rocks (∼2 mg kg−1), soils (∼2 mg kg−1), freshwater (∼1 m̈g dm−3), seawater (∼2 m̈g dm−3) and organisms is generally low, high arsenic concentrations in limited areas are not uncommon. Whereas terrestrial organisms appear not to accumulate arsenic, marine organisms effectively concentrate arsenic to levels thousand of times higher than in ocean waters. The geochemical cycle and mineralogy of arsenic are reviewed with some emphasis towards Japanese locations and arsenic concentrations (averages, ranges) found in samples from the lithosphere, pedosphere, hydrosphere and biosphere are tabulated and discussed.
Arsenic compounds in marine and terrestrial organisms: Analytical, chemical and biochemical aspects
Authors: Irgolic Kurt J. 
Published: January 2005

AbstractArsenic has a reputation as a poison, because arsenic trioxide was used during medieval times as an agent for murder. Lingering memories of these events make any arsenic‐containing material suspect. Toxicity is a property of a specific compound and varies with the composition and structure of compounds. Developments in analytical methodology made it possible not only to determine total arsenic in a variety of matrices but also arsenic compounds. Knowledge about the arsenic cycle in marine systems has expanded considerably during the past decade. The marine arsenic cycle appears to be more complex than the cycle in the terrestrial environment. More attention must be given to the minor arsenic‐containing compounds detected in organisms and experiments should be undertaken that provide information about the biochemical pathways used for the transformation of arsenic compounds.
Arsenic accumulation by arsenic‐tolerant freshwater blue‐green alga (Phormidium sp.)
Authors: Maeda Shigeru , Fujita Saori , Ohki Akira , Yoshifuku Isami , Higashi Shiro , Takeshita Toshio 
Published: January 2005

AbstractAccumulation, biomethylation and excretion of arsenic by the arsenic‐tolerant freshwater blue–green alga, Phormidium sp., which had been isolated from an arsenic‐polluted environment, were investigated.The cellular growth curves were in fair agreement with a ‘logistic curve’ equation. The growth increased with an increase in the surrounding arsenic concentration up to 100 m̈g g−1. The cells survived even at 7000 m̈g g−1. The arsenic concentration of the cells increased with an increase of the surrounding arsenic concentration up to 7000 m̈g g−1. Phosphorus concentrations in the medium affected the growth and arsenic accumulation. No arsenic was accumulated by cells killed by ethanol.The arsenic was methylated to the extent of 3.2% of the total arsenic accumulated. When the cells were transferred into an arsenic‐free medium, 85% of the arsenic accumulated was excreted; 58% of the excreted arsenic was in methylated form implying extensive methylation in the arsenic‐free medium.
Acute toxicity and rapid excretion in urine of tetramethylarsonium salts found in some marine animals
Authors: Shiomi Kazuo , Horiguchi Yoshiya , Kaise Toshikazu 
Published: January 2005

AbstractAcute toxicity in mice, and excretion in their urine, of tetramethylarsonium salts which are arsenic compounds found in some marine animals, were examined using synthetic tetramethylarsonium iodide. The oral, intraperitoneal and intravenous LD50 values of tetramethylarsonium iodide [(CH3)4As+I−] were determined to be 890, 175 and 82 mg kg−1, respectively. When sublethal doses of tetramethylarsonium iodide were orally administered to mice, 53–58% of the arsenic administered was recovered in urine after 6 h and 65–81% after 72 h. High‐performance liquid chromatography–inductively coupled plasma (HPLC–ICP) and fast atom bombardment mass spectrometric (FAB MS) analyses revealed that a tetramethylarsonium salt was the only arsenic compound excreted in urine. These results suggested that the major part of orally administered tetramethylarsonium iodide was absorbed from the gastrointestinal tract in mice and then rapidly excreted in urine without biotransformation.
Metabolism of trimethylarsine oxide
Authors: Pickett A Wendy , McBride Barry C , Cullen William R 
Published: January 2005

AbstractTrimethylarsine oxide [(CH3)3AsO] has been shown to be easily reducible by various biological species, including both aerobic and anaerobic micro‐organisms, some skin organisms, soil bacteria, sludge and rumen fluid. The results suggest an enhanced mobility for arsenic owing to facile production of the volatile (CH3)3As species.
The structure and dynamics of FeH(DMPE)2(BH4), FeH(DEPE)2(BH4) and FeH(DPrPE)2(BH4): Iron complexes containing monodentate borohydride ligands
Authors: Baker Murray V , Field Leslie D 
Published: January 2005

AbstractFeH(DMPE)2(BH4) [DMPE = 1,2‐bis(dimethylphosphino)ethane] is a stable, diamagnetic complex which can be synthesized readily by borohydride reduction of FeH(DMPE)2Cl or by treatment of Fe(DMPE)2H2 with borane. The complex contains an unsupported BHFe hydrogen bridge. Analogous complexes with bulkier ligands, FeH(DEPE)2(BH4), [DEPE = 1,2‐bis(diethylphosphino)ethane] and FeH(DPrPE)2(BH4) [DPrPE = 1,2‐bis(di‐n‐propylphosphino)ethane], are less stable. In all complexes, in solution the borohydride ligand undergoes rapid internal motion, with all four boron‐bound hydrogens interchanging environments. The barriers for BH4 reorientation (measured by NMR spectroscopy) are in the sequence FeH(DMPE)2(BH)4 > FeH(DEPE)2(BH)4 > FeH(DPrPE)2(BH4).
Synthesis and properties of bis(dialkylphosphino)ethane iron dihydrides
Authors: Baker Murray V , Field Leslie D , Young David J 
Published: January 2005

AbstractSyntheses and properties of the iron bisphosphinoethane complexes FeH2(PP)2 and FeHCl(PP)2[PPR2PCH2CH2CH2PR2, where RMe (PPDMPE), Et(PPDEPE), and n‐Pr (PPDprPE)] are reported. The complexes can be formed by reduction of the corresponding dichlorides FeCl2(PP)2 with lithium aluminium hydride in THF solution provided that ethanol or more acidic reagents are not employed during the reaction work‐up. The dihydrides are notably basic compounds and can be protonated reversibly by alcohols.The dihydrides exist as equilibrating mixtures of cis and trans isomers in solution. The cis isomers of each of the dihydrides are fluxional on the NMR timescale and NMR studies indicate that the interconversion of cis isomers does not necessarily proceed via the trans isomer.