摘要:

AbstractAlmost three decades ago, the field of nonlinear optics evolved with the discovery of lasers. In the beginning, nonlinear optical (NLO) phenomena were investigated in inorganic materials, leading to the development of traditional NLO materials such as lithium niobate, potassium titanyl phosphate, quartz and gallium arsenide. In the 1970s, the importance of organic materials was realized because of the promise of large NLO responses, high laser damage thresholds, fast optical responses, architectural flexibility and ease of fabrication. Following work with organic materials, the scrutiny of organometallics also began recently. In organometallics, the metal‐ligand bonding is expected to display large molecular hyperpolarizability because of the transfer of electron density between the metal atom and the conjugated ligand system. In organometallics, the diversity of central metals, oxidation states and ligands fosters in optimization of the charge‐transfer interactions. Keeping this in view, second‐ and third‐order NLO properties of organometallics have been reviewed here, highlighting new materials that are emerging. Organometallics may have a wide range of applications in opto‐electronics including integrated optics, optical switching, telecommunications, bistability and m

ISSN:0268-2605    

DOI:10.1002/aoc.590050502

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTriethylbenzylammonium chlorometallates [Et3NCH2Ph] +m[MCln]m−(M = Pt, Pd, Rh, Ir, Fe, Co, Cu,m= 1–3,n= 3–6), polymer‐anchored ionic metal complexes [℗—CH2PBu3] +m[MCln]n−and some other chlorometallates and complexes of platinum, rhodium, ruthenium and osmium were studied as catalysts in the hydrogermylation of phenylacetylene with triethylgermane. All the complexes containing platinum, palladium and rhodium were found to be effective catalysts. Thecis/transratio of the products obtained is determined by the metal atom involved and decreases in the following ord

ISSN:0268-2605    

DOI:10.1002/aoc.590050503

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractDi‐ and tri‐organotin derivatives ofN‐benzoylglycylglycine (HBzGlyGly) were synthesized and characterized by infrared,1H,13C NMR and119Sn Mössbauer spectroscopy. Diorganotin derivatives appear to be dimer distannoxanes ([R2SnBzGlyGly]2O)2(R = CH3, n‐C4H9, n‐C8H17) with a ladder‐type structure where tin atoms are five‐coordinated and N‐benzoylglycylglycine alternatively acts as a unidentate or bridging bidentate ligand through the carboxylate group. For triorganotin derivatives R3SnBzGlyGly (R= CH3, n‐C4Hg) we propose a polymeric structure whereN‐benzoylglycylglycine bridges planar SnC3units through t

ISSN:0268-2605    

DOI:10.1002/aoc.590050504

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractUsing sodium tetraethylborate as an alkylation reagent, one‐step ethylation and extraction of organotin compounds in seawater was performed directly in the aqueous phase to obtain optimal rection conditions. No further purification or concentration of the extract was required before GC FPD analysis. The detection limit for monobutyl‐dibutyl‐and tributyl‐tin was approximately 0.4 ng dm−3, which is adequate for any currently know toxicity effect. The linearity range (0–200 ng dm−3) was solely dependent on the detector response curve. Compared with the Grignard reaction after extraction in an organic solvent, this new ethylation procedure reduces the number of analytical steps, thus saving time and improvin

ISSN:0268-2605    

DOI:10.1002/aoc.590050505

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractA modified method for the determination of tributyl‐, dibutyl‐, and monobutyl‐tin in fish and sediment samples is proposed. The samples are digested with hydrochloric acid and the butyltin compounds are extracted into a tropolone solution in pentane and pentylated by a Grignard reaction. The products are cleaned up by washing with a sodium hyrdoxide solution, dried over sodium sulphate, concentrated by evaporation and analysed by gas chromatography with flame photometric detection, using an interence filter at 610 nm. Problems peculiar to the fish and sediment samples are overcome by this improved clean‐up procedure. The limit of detection for tributyltin in fish is 0.04 m̈g g−1and the reproducibility at 0.06 μg g−1, expressed as the relative standard deviation, is 6.8%. Contaminated sediment samples were found to contain the mixed methylbutyl‐tin compounds Me2Bu

ISSN:0268-2605    

DOI:10.1002/aoc.590050506

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractSix triorganotin compounds—Ph3SnOH, BuPh2SnOH, (p‐CIC6H4)Ph2SnOH, (cyclo‐C5H9)Ph2SnOH, Ph3SnO2CCH2CS2NMe2and Bu3SnOSO2Et—were tested for their mutagenic potential in somatic and germinal cells in ICR mice by using the micronucleus and spermhead abnormality assays, respectively. In somatic cells, the compunds significantly induced chromosomal disorders at half their respective estimated LD50(i.p.) values (5.00–6.25 mg kg−1body wt), and one compound, Ph3SnOH, even at 1/20 of its estimated LD50value. In germinal cells, five compounds significantly induced chromosomal disorders at 1/64 of their respective estimated LD50(i.p.) values, whereas one, (p‐CIC6H4)Ph2SnOH, caused such disorders only at 1/8 of its estima

ISSN:0268-2605    

DOI:10.1002/aoc.590050507

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe synthesis and characterization of metal poly‐yne polymers containing disilane, disiloxane and phosphine groups in the main chain are described. The platinum and palladium poly‐yne polymers were synthesized by polycondensation reactions between a metal chloride and an α, ω‐bisethynyl complex in amines in the presence of cuprous iodide as a catalyst. The nickel poly‐yne polymers were synthesized by an alkynyl ligand exchange reaction between a nickel acetylide and an α, ω‐bisethynyl complex in diethylamine in the presence of cuprous iodide as a catalyst. The reaction of the platinum poly‐yne polymer, containing disiloxane groups in the main chain, with copper (I) salts afforded adducts of η‐2‐bonded σ‐acetylide polymer complexes. The reactions of the palladium poly‐yne polymer, containing phosphine groups in the main chain, with transition‐metal carbonyl complexes afforded polymer complexes which have phosphorus in the main chain‐transition‐metal bonds. A concentrated solution of the platinum poly‐yne polymer containing disiloxane groups in the main chain forms a lyotropic liquid crystal in dichl

ISSN:0268-2605    

DOI:10.1002/aoc.590050508

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe intestinal micro‐organisms ofLiolophura japonicachitons converted arsenobetaine [(CH3)3As+CH2COO−] to trimethylarsine oxide [(CH3)3AsO] and dimethylarsinic acid [(CH3)2AsOOH] in the arsenobetaine‐containing 1/5 ZoBell 2216E medium under aerobic conditions, no conversion being observed in an inorganic salt medium. This conversion pattern of arsenobetaine → trimethylarsine oxide ← dimethylarsinic acid was comparable with that shown by the microorganisms associated with marine macroalgae. On the other hand, no conversion was observed in either medium under anaerobic c

ISSN:0268-2605    

DOI:10.1002/aoc.590050509

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThere have been many methods available for the determination of butyltin compounds in sediment. The variations of these methods are not in the methods of determination but rather in the extraction of these compounds from the complex matrices. All of these methods have not been critically compared or evaluated, mainly because of the lack of a suitable reference sediment for butyltin compounds.Recently, the National Research Council of Canada has introduced a reference sediment (PACS‐1) which contains certified values of butyltin compounds. The present study compares the recoveries of ten extraction techniques for butyltin species using ethylation derivatization and GC AA as the method of determination. Of these ten methods, only four were found satisfactory for extraction of the dibutyltin and tributyltin species. None of the methods evaluated, however, could quantitatively extract monobutyltin from sedimen

ISSN:0268-2605    

DOI:10.1002/aoc.590050510

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractArsenobetain [(CH3)3As+CH2COO‐]‐containing growth media (1/5 ZoBell 2216E and solution of inorganic salts) were inoculated with two bacterial strains, which were isolated from a coastal sediment and identified as members of theVibro‐Aeromonasgroup, and incubated under aerobic and anaerobic conditions. Arsenobetaine was converted to a metabolite only under aerobic conditions. This arsenic metabolite was identified as dimethylarsinic acid [(CH3)2AsOOH] by hydride generation/cold trap/GC MS/SIM analysis and high‐performance liquid‐chromatographic behaviour. The conversion pattern shown by these arsenobetaine‐decomposing bacteria (that is, arsenobetaine → dimethylarsinic acid) was fairly different from that shown by the addition of sediment itself as the source of arsenobetaine‐decomposing micro‐organisms (that is, arsenobetaine → trimethylarsine oxide → inorganic arsenic). This result suggests to us that various micro‐organisms, including the arsenobetaine‐decomposing bacteria isolated in this study, participate in the degradation of arsenobetai

ISSN:0268-2605    

DOI:10.1002/aoc.590050511

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY