bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organometallic complexes in ascidian embryonic development: II. Effects on different stages and larvae
Authors: Mansueto Caterina , Valvo Mario Lo , Pellerito Lorenzo , Girasolo M Assunta 
Published: January 2005

AbstractThe effects of the organometallic compounds Bu2Sn‐D‐(−;)sorbitol, Bu2Sn‐D‐(+)glucose, Bu2Sn‐D‐(−)fructose and Bu2Sn‐D‐(+)glyceraldehyde were tested in vivo on different stages of Ascidian development, larval movement and metamorphosis. Organotin(IV) complexes are organometallic compounds widely used as industrial biocides, antifouling agents and agricultural fungicides and are toxic to a range of organisms. Two‐cell stage embryos, if incubated for one hour in the organotin (IV) solutions, stopped the cleavage, which was restored when they were transferred into normal sea water. The gastrula stage was seriously affected in 10−4mol dm−3 solutions of the above‐mentioned complexes: 85% of the embryos were anomalous neurulae with open neural folds, 5% were twisted larvae. The gastrulae, when incubated for 1 h in 10−5mol dm−3 solutions, developed twisted larvae in ovular envelopes and immobile larvae with twisted tails. Larvae treated with 10−4mol dm−3 and 10−5 mol dm−3 Bu2Sn‐D‐(−)sorbitol, Bu2Sn‐D‐(+)glucose and Bu2Sn‐D‐(+)glyceraldehyde solutions stopped swimming, did not metamorphose and afterwards underwent cytolysis. An initial hyperactivity of circular movements, followed by immobility, was observed in the larvae incubated in Bu2Sn‐D‐(−;)fructose.
Di‐n‐butyltin and diethyltin monofluorobenzoates: Synthesis, spectroscopic characterization and in vitro antitumor activity
Authors: Gielen Marcel , Khloufi Abdelaziz El , Biesemans Monique , Willem Rudolph 
Published: January 2005

AbstractThe di‐n‐butyltin(IV) and diethyltin(IV) fluorobenzoates [FC6H4COO]2SnR2 and (FC6H4COOR2Sn)2O have been synthesized and characterized spectroscopically. Their in vitro antitumor activity against two human tumor cell lines, MCF‐7, a mammary tumor, and WiDr, a colon carcinoma, as well as against the NCI cell panel, is satisfactory.
N‐tributyltin mesylimide—a new water‐soluble fungicide
Authors: Shcherbakov Vladislav I , Frolovaa Svetlana M 
Published: January 2005

AbstractIn addition to the known water‐soluble tributyltin compounds, N‐tributyltin mesylimide [Bu3SnN‐(SO2Me2)2] was prepared and proposed as a fungicide for water‐based preservative formulations. The aqueous solubility of the new compound is in the range of 11.0–11.4% w/w at 25 °C and its activity towards moulds (Aspergillus niger) is near that for tributyltin oxide. The compound has an average toxicity (LD50=740 mg kg−1).
Laser chemical synthesis of clusters and ultrafine particles using organometallics
Authors: Chaiken Joseph 
Published: January 2005

AbstractGas‐phase synthesis of clusters and ultrafine particles using lasers and organometallics is reviewed. The general field of laser chemistry is introduced in the context of using organometallics as reactants. Examples of particle and cluster synthesis in flowing gases and in bulk gases, and during laser chemical vapor deposition, are given. A brief introduction to the general field of random irreversible fractal coagulation provides a basis for describing how powders, clusters and ultrafine particles are synthesized. References to applications and characterization methods are given.
Diorganotin 2‐fluorocinnamates and 4‐fluorophenylacetates: Synthesis, characterization and in vitro antitumour activity
Authors: Gielen Marcel , Khloufi Abdelaziz El , Biesemans Monique , Kayser François , Willem Rudolph 
Published: January 2005

AbstractThe synthesis and characterization by spectroscopy of several new di‐n‐butyltin and diethyltin 2‐fluorocinnamates and 4‐fluorophenylacetates are described. In vitro tests on two human tumour cell lines, MCF‐7, a mammary tumour, and WiDr, a colon carcinoma, showed that two of these compounds are more active than cisplatin. Other in vitro tests performed by the NCI, USA on a panel of human tumour cell line show that one of them, bis[di‐n‐butyl(2‐fluorophenylacetato)tin] oxide, is characterized by statistically significant D, DTGI and D sensitivities, but non‐significant DH and MGDH selectivities, whereas the analogous 2‐fluorocinnamate shows no such significant values.
Contributions to the synthesis of some ferrocene‐containing antibiotics
Authors: Scutaru D , Tataru Lucia , Mazilu I , Vata M , Lixandru Tatiana , Simionescu Cr 
Published: January 2005

AbstractThis Review discusses the synthesis and characterization by our Group of new antibiotics belonging to the class of penicillins, cephalosporins and rifamycins with ferrocenyl and 1, 1′‐ferrocenilene residues in the molecule.As reactants for 6‐aminopenicillanic acid (6‐APA) and 7‐aminocephalosporanic acid (7‐ACA) the following were used: 1, 1‐bis(chlorocarbonyl)ferrocene, ferrocenyl sulfochloride, 1, 1′‐ferrocenylenedisulfochloride and thioglycolic acids S‐modified with ferrocene. In the synthesis of rifamycins, the hydrazides of the thioglycolic acids, S‐modified with ferrocene, were employed as nucleophilic agents. The synthesized intermediates were characterized by elemental analysis, TLC, IR, UV and 1H NMR spectra. The characterization of new antibiotics was made by TLC, IR and UV spectral analysis.Biological activity was tested on Gram‐negative and Gram‐positive bacteria. Good activity is reported towards Gram‐positive bacteria in the case of derivatives containing residues of thioglycolic acid S‐modified with ferrocene, the antibacterial activity being similar to that of amoxicillin, carbenicillin and cephalothin. All compounds are inactive towards Gram‐negative bacteria.
Synthesis and spectroscopic characterization of R3SnIV derivatives of N‐acetyldipeptides
Authors: Huber Friedo , Vornefeld Michael , Ruisi Giuseppe , Barbieri Renato 
Published: January 2005

AbstractTriorganotin(IV) derivatives of N‐acetyldipeptides R3SnAcDip; RMe, Et, n‐Bu, n‐Oct, Cy or Ph (HAcDipN‐acetylglycylglycine and N‐acetylglycylvaline; RMe, n‐Bu, Cy, HAcDipN‐acetylglycylalanine) were obtained by neutralization of R3SnOH and HAcDip. The complexes were studied by means of 119Sn Mössbauer, IR and 1H, 13C and 119Sn NMR spectroscopy. The CSnC bond angles have been inferred by rationalization of Mössbauer nuclear quadrupole splittings as well as from NMR coupling constants. Correlations of Mössbauer isomer shifts with partial atomic charges on tin atoms have been determined: Polymeric trigonal bipyramidal structures, with near‐planar R3Sn units and axial carboxylate (unidentate) and CO amide donor groups are inferred for all the compounds in the solid state, except for Cy3SnAcGlyVal for which a tetrahedral structure is proposed. In solution the complexes are monomeric; in methanol a solvent molecule is coordinated to tin which then is still in a trigonal bipyramidal environment.
Monoamineplatinum (II) complexes conjugated to water‐soluble carrier polymers for chemotherapeutic applications
Authors: Mbonyana Carol W N , Neuse Eberhard W , Perlwitz Axel G 
Published: January 2005

AbstractIn the light of the observed carcinostatic activity of the monoamineplatinum complexes K[PtCl3(NH3)] and K[PtCl3(t‐butylamine)], it has been of interest in this laboratory to develop water‐soluble, antineoplastic conjugates in which square‐planar platinum complex structures of the monoamineplatinum type are linked to suitable carrier polymers possessing water solubility for improved pharmacokinetics. In the present paper the synthesis is described of conjugates in which each platinum atom is coordinated to a single, primary amine ligand provided by a water‐soluble polyaspartamide‐type carrier. Microanalytical data suggest the remaining three coordination sites on the metal center to be occupied on average by one aquo and two chloro ligands. The carriers, prepared by a known method from polysuccinimide by stepwise aminolytic ring‐opening, are designed so as to feature randomly placed hydrosolubilizing units and metal‐binding units in a ratio of 3:1, thus providing spatial insulation between the latter and minimize intramolecular interaction between the platinum complexes incorporated subsequently. Platination of the carriers is brought about by treatment with K2PtCl4in aqueous solution at 25–60 °C in the pH range 5–6, and the polymer–platinum conjugates are purified and isolated in 50–70% yield by aqueous‐phase dialysis and freeze‐drying. The extent of platination attained dependsinter aliaon the Pt/NH2feed ratio (equivalents of tetrachloroplatinate per carrier base unit); in optimal cases complete metal coordination to the carrier‐attached primary‐amine ligands is achieved with a feed ratio of 1.4:1. The conjugates, initially showing complete solubility in water, tend to undergo an ageing process on storage believed to involve intermolecular solid‐state interaction of the bound platinum complexes with proximate amine sites, resulting in gradual loss of solubility. In frozen aqueous solution, however, the conjugates are stable for extended periods of time.
Diorganotin(IV) dipeptide complexes with potential antitumour activity
Authors: Guli G , Gennaro G , Pellerito L , Stocco G C 
Published: January 2005

AbstractA series of complexes of the dimethylltin(IV) moiety with dipeptides has been synthesized. The dipeptides are L‐alanyl‐L‐histidine (H2AlaHis), L‐methionyl‐L‐methionine (H2MetMet), L‐glycyl‐L‐histidine (H2GlyHis) and L‐histidyl‐L‐glycine (H2HisGly). The complexes have been characterized by IR and 119Sn Mössbauer spectroscopy in the solid state and by 1H NMR in CD3OD and D2O solutions. They consist of monomeric entities, with the tin atom arranged in a pentacoordinated trigonal bipyramidal structure. The dipeptides are coordinated via the amino group, deprotonated peptide nitrogen and carboxylate group. Neither imidazole in histidine‐containing dipetides, nor the thioether group in MetMet, is involved in bonding; they act as pendant arms on the outer surface of the complexes.
Improvements in methylmercury determination prior to the certification of two tuna fish materials
Authors: Quevauviller Ph , Drabaek I , Muntau H , Griepink B 
Published: January 2005

AbstractAn account is given of a systematic, collaborative investigation to detect problems and sources of error in the determination of methylmercury (MeHg) in biological samples. The work was done by a group of analytical laboratories under the auspices of the Community Bureau of References (BCR) of the Commission of the European Communities (EC). The paper presents the organization of three intercomparisons on organic mercury in solution and solid matrices, and the results obtained by the participants. The different analytical steps of the methods used (extraction, clean‐up, separation, final detection) are compared and assessed.
Identification and quantification of inorganic and organic selenium compounds with highperformance liquid chromatography
Authors: Kölbl Gottfried , Kalcher Kurt , Irgolic Kurt J , Magee Robert J 
Published: January 2005

AbstractSelenium appears in the natural selenium cycle in the form of several organic and inorganic compounds. The biologically beneficial and deterimental effects of ‘selenium’ must be ascribed to particular selenium compounds. The identification and quantification of selenium compounds in biological and environmental samples is required for an understanding of the role of selenium. The high‐performance liquid‐chromatographic (HPLC) methods for the separation, identification and quantification of selenite, selenate, hydrogen selenide, methaneselenol, bis(organothio) selenides, trimethylselenonium salts, selenonamino‐acids, selenium derivatives of carbohydrates, selenoproteins, selenonucleosides and other miscellaneous selenium compounds are summarized (193 references) and pertinent detection modes discussed. Advantages and disadvantages of the methods are pointed out. The literature is covered since 1974, the year of the first publication in this field.
Rhodium(I) and platinum(II) complexes of aminomethylphosphines as hydrogenation and hydroformylation catalysts
Authors: Hoye P A T , Kemmitt R D W , Law D L 
Published: January 2005

AbstractHydrogenation of α‐acetamidocinnamic acid with chiral aminomethylphosphine complexes of rhodium(I), [Rh(cyclo‐octa‐1, 5‐diene) {(R2PCH2)2NR1}]‐PF6 (R = Ph or Cy, R1 = D(+)‐CHMePh, L‐CHMeCO2Et, (R)(+)‐bornyl) shows no asymmetric induction. The hydroformylation of styrene using the catalyst mixture [PtCl2(P–P)]/SnCl2 shows asymmetric induction with up to 31% enantiomeric excess of 2‐phenyl‐propanol being observed.
Assessment of recent trends in concentrations of alkyl‐lead compounds in rainwater
Authors: Turnbull Alan B , Wang Yun , Harrison Roy M 
Published: January 2005

AbstractConcentrations of tetra‐, tri and di‐alkyl‐lead compounds in rain have been measured at rural and urban sites in England. The measurements are compared with similar data collected in the early 1980s, prior to a 72% reduction in the emission of lead from combustion of leaded petrol. Whilst concentrations of inorganic lead have fallen broadly in line with emissions of automotive lead, alkyl‐lead concentrations in rain have fallen by only 50% or less, and thus the ratio of alkyl‐lead to inorganic lead in rain has increased appreciably. The reason for this phenomenon is unclear. The data suggest that lead in rainwater would fall to approximately 2 μg dm−3 if automotive lead emissions fell to zero.
Enhancing effects of an organic arsenic compound, dimethylarsinic acid (cacodylic acid), in a multi‐organ carcinogenesis bioassay
Authors: Yamamoto Shinji , Konishi Yoshitsugu , Murai Takashi , Shibata Masa‐Aki , Matsuda Tsutomu , Kuroda Koichi , Endo Ginji , Fukushima Shoji 
Published: January 2005

AbstractThe modifying effects of dimethylarsinic acid (DMA) on tumor induction in various organs were examined using a multi‐organ rat carcinogenesis bioassay. A total of 124 six‐week‐old male F344/DuCrj rats were divided randomly into seven groups. For establishment of wide‐spectrum initiation, animals in Groups 1–5 were treated with five carcinogens, namely N‐nitrosodiethylamine (DEN), N‐methyl‐N‐nitrosourea (MNU), 1,2‐dimethylhydrazine (DMH), N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine (BBN) and N‐bis(2‐hydroxypropyl)nitrosamine (DHPN) in the first four weeks. After a two‐week interval, Groups 1–5 were then given 0, 50, 100, 200 and 400 ppm DMA, respectively, in drinking water. Groups 6 and 7 received 100 and 400 ppm DMA without any carcinogen pretreatment. All rats were sacrificed at the end of week 30. In the initiated groups (Groups 1–5), DMA enhanced tumor development in the urinary bladder, kidney, liver and thyroid gland. The main arsenic species in urine samples was DMA itself. In conclusion, the observed enhancement of carcinogenesis in the urinary tract as well as in the liver and thyroid gland may be directly due to this arsenic compound.
17O NMR spectroscopy in the study of group 14 organometallic compounds
Authors: Zicmane I. , Lukevics E. 
Published: January 2005

AbstractA study of Group 14 organometallic compounds using 17O NMR spectroscopy carried out at the Latvian Institute of Organic Synthesis has been reviewed. The main areas of 17O NMR application—studies of electronic effects, conformational analysis and coordinative interactions—have been characterized.
Preparation and catalytic properties of NR‐stabilized palladium colloids
Authors: Bönnemann Helmut , Brinkmann Rainer , Neiteler Peter 
Published: January 2005

AbstractPalladium colloids revealing narrow particle size distributions can be obtained by chemical reduction using tetra–alkylammonium hydrotriorganoborates. Combining the stabilizing agent [NR] with the reducing agent [BEt3H−] provides a high concentration of the protecting group at the reduction centre. Alternatively, NR4X (X = halogen) may be coupled to the metal salt prior to the reduction step: addition of N(octyl)4Br to Pd(ac)2 in THF, for example, evokes an active interaction between the stabilizing agent and the metal salt. Reduction of NR‐stabilized palladium salts with simple reducing agents such as hydrogen at room temperature yields stable palladium organosols which may be isolated in the form of redispersible powders. The anion of the palladium salt is crucial for the success of the colloid synthesis. Electron microscopy shows that the mean particle size ranges between 1.8 and 4.0 nm. An X–ray–photoelectron spectrscopic examination demonstrated the presence of zerovalent palladium.These palladium colloids may serve as both homogeneous and heterogeneous hydrogenation catalysts. Adsorption of the colloids onto industrially important supports can be achieved without agglomeration of palladium particles. The standard activity of a charcoal catalyst containing 5% of colloidal palladium determined through the cinnamic acid standard test was found to exceed considerably the activity of the conventional technical catalysts. In addition, the lifespan of the catalyst containing a palladium colloid, isolated from the reduction of [N(octyl)4]2PdCl2Br2 with hydrogen, is superior to conventionally prepared palladium/charcoal (Pd/C) catalysts. For example, the activity of a conventional Pd/C catalyst is completely suppressed after 38×103 catalytic cycles per Pd atom, whereas the colloidal Pd/C catalyst shows activity even after 96times;103 catalytic cycles.
Influence of tropolone on voltammetric speciation analysis of butyltin compounds
Authors: Ferri T. , Roberti F. , Chiavarini S. , Cremisini C. , Morabito R. 
Published: January 2005

AbstractAnalysis of organotin compounds in environmental matrices is usually performed by chromatographic or spectroscopic techniques. Only a few papers dealing with organotin voltammetric determination have so far been published and this techniques does not seem very promising for organotin speciation. The reasons are likely to be found in the very low organotin concentration levels in the marine environment, in the complexity of environmental matrices and in the presence of several organotin compounds (butyl‐ and phenyltins), together with other metals, in samples; the latter leads to peak overlapping. In this paper we present a study of the influence of tropolone (2‐hydroxycyclohepta‐2,4,6‐trienone) on the voltammetric speciation of butyltin compounds. Results suggest that tropolone, being able to form complexes of different stability with tin and its compounds, improves the applicability of voltammetry to organotin determination by enhancing sensitivity and resolution.
Determination of trimethyl‐lead in rainwater and road dust by capillary GC MIP‐AE spectrometry after in situ ethylation and extraction
Authors: Witte Claudia , Szpunar‐Lobinska Joanna , Lobinski Ryszard , Adams Freddy C. 
Published: January 2005

AbstractA rapid and sensitive method for the determination of trimethyl‐lead in water and road dust is described. It is based on in situ ethylation of ionic methyl‐lead by sodium tetraethylborate and the extraction of the compound formed into hexane. The extract is gas‐chromatographed and the lead species determined by microwave‐induced plasma atomic emission spectrometry (MIP‐AES). The reaction conditions are optimized and the method is applied to the analysis of artificial rainwater and road dust in the framework of an international round‐robin exercise.
Improvement of sample pretreatment for gas chromatographic determination of methylmercury in marine biota
Authors: Harms Uwe 
Published: January 2005

AbstractExisting methods for analysis of methylmercury in biota consist of an initial extraction of the determinand at low pH with an organic solvent, followed by clean‐up and gas chromatographic determination. The complex biological matrix causes considerable interferences in the extraction process and makes the calibration of the method a difficult task. Results from the calibration method (standard addition) will only be correct if the calibrant added and the determinand are in the same chemical form and homogeneously distributed in the sample to be analysed. It is shown here that this presupposition is fulfilled if the sample is pretreated with an aqueous solution of sodium hydroxide (alkaline hydrolysis). In order to avoid uncontrolled losses of methylmercury at high pH, cysteine is added at the beginning of the pretreatment procedure. As a reagent forming strong complexes with mercury compounds, it protects methylmercury from disintegration during alkaline hydrolysis of the sample.
Conclusions of the workshop trends in speciation analysis—an overview of discussions on organometallic speciation
Authors: Quevauviller Ph. 
Published: January 2005

AbstractThe development of analytical techniques for the determination of chemical species has been one of the growing features of the 1990s in analytical chemistry. The need for good quality control of these determinations has led the Measurements and Testing Programme (formerly the BCR) to organize series of interlaboratory studies in the field of speciation analysis over the last five years. The state‐of‐the‐art speciation analysis has been discussed in a first workshop in 1990 (Arcachon, France) and, at this stage, it was thought necessary to discuss the progress achieved and the trends which should be developed in the near future. A workshop on Trends in Speciation Analysis was therefore held in Rome in February 1994 which allowed recommendations to be made based round‐table discussions. This paper gives a summary of these recommendations in the field of organometallic speciation. Projects currently undertaken in the field of organometallic speciation within the M&T programme are also described. An outline of the programme and a list of the panel of experts participating in this workshop are given in the appendix.
Organometallic complexes with biological molecules, IV. Di‐ and tri‐organotin(IV) amoxicillin derivatives: Solid‐state and solution‐phase spectroscopic investigations
Authors: Pellerito Lorenzo , Maggio Francesco , Consiglio Mario , Pellerito Alessandro , Stocco Gian Carlo , Grimaudo Stefania 
Published: January 2005

AbstractNovel di‐ and tri‐organotin(IV) derivatives of amoxicillin (amoxicillin− = Amox− = 6‐[D(‐)‐ß‐ amino ‐ p ‐ hydroxyphenylacetamido]penicillinate) have been prepared. The isolated compounds showed stoichiometries of the type R2SnClAmox ˙ 2H2O, R3SnClAmoxNa ˙ 2H2O and R2SnAmox2 ˙ 2H2O (R = Me, Bu, Ph). The infrared spectra suggest that Amox−, in both R2SnClAmox ˙ 2H2O and R2SnAmox2 ˙ 2H2O, behaves as a monoanionic bidentáte ligand, coordinating the tin(IV) atom through the ester‐type carboxylate, as well as through the lactamic carbonyl.In R3SnClAmoxNa ˙ 2H2O, Amox− coordinates the organotin(IV) moieties through the lactamic carbonyl. In all of the compounds, water molecules are not involved in coordination, as inferred by thermogravimetric (TG) investigation. In both R2SnClAmox ˙ 2H2O and R3SnClAmoxNa ˙ 2H2O, trigonal bipyramidal configurations are proposed in the solid state, on the basis of infrared (IR) and Mössbauer spectroscopy, while in R2SnAmox2 ˙ 2H2O the coordination geometry at tin could be a skew‐trapezoidal bipyramid, with two chelating amoxicillin residues which act as bidentate ligands in the trapezoidal plane, and with the organic groups in axial positions. The CSnC angles calculated from the experimental Mössbauer quadrupole splitting predict a bent skeleton in all the R2SnAmox2 2H2O derivatives.
1H and 13C NMR measurements showed that both R2SnClAmox ˙ 2H2O and R2SnAmox2 ˙ 2H2O are stable in DMSO‐d6 solutions, maintaining their solid‐state configuration, while R3SnClAmoxNa ˙ 2H2O dissociates.Coordination hypotheses have been checked through the correlation between the Mössbauer isomer shift (δ) and the partial atomic charge on tin atoms (QSn) performed, for all the new organotin(IV) compounds, on the basis of an equalization procedure applied to idealized trigonal bipyramidal structures for R2SnClAmox ˙ 2H2O and R3SnClAmoxNa ˙ 2H2O and octahedral trans‐R2 for R2SnAmox2 ˙ 2H2O.