摘要:

AbstractPhotochemistry of organometallic compounds achieves a marriage of a rich variety of organometallic chemistry and the full potential of electronically excited states of molecules. The application of lasers as light sources adds a great many new features to these studies, which cannot be attained by other means, because lasers provide light of such a high quality, e.g. a high‐intensity, energetic (i.e. wavelength) purity, a high degree of coherence, and a high spatial and temporal resolution. Laser photochemistry of organometallic compounds, such as laser photochemical vapor deposition (LPCVD), laser ablation, and photochemical dry etching, forms the basis of many important industrial processes which sustain the present‐day microelectronics industries. Lasers are used not only to photodissociate organometallic molecules, but to monitor the reaction steps by probing the starting material, chemical intermediate, or final product by many laser‐based spectroscopic methods. Although it is a very young area of science (the first laser was operated in 1960), this research area is now really ebullient, as a result of strong interest from both the fundamental and the practical sides. Laser photochemistry of organometallic compounds extends a wide and fertile research frontier, full of challenge and novel possibilities. In the present review, the present status of laser (ultraviolet and visible) photochemistry of organometallic compounds related to these industrial applications is briefly reviewed, with special emphasis on the basic studies of the relevant photochemistry and their relationship to photochemical processes on solid sur

ISSN:0268-2605    

DOI:10.1002/aoc.590030502

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractButyltin concentrations have been measured at eight freshwater sites (rivers and lakes) in the Norfolk Broads, UK, during 1986 and 1987. Tributyltin (TBT) was found in water samples from seven of the sites. Wherever TBT was present, dibutyltin and (usually) monobutyltin occurred. Levels of TBT exceeded 100 ng dm−3in open stretches of both the Rivers Bure and Yare in 1986 and 1987. The highest concentration of TBT recorded for Wroxham Broad (a shallow lake) was 898 ng dm−3. Values of up to 3.26 μg dm−3were measured in water samples taken from a marina. A depth profile for Wroxham Broad showed TBT to be uniformly distributed throughout the shallow water column. The results are discussed in relation to toxicity of TBT to freshwater organisms. Laboratory measurements of the degradation of TBT in freshwater from a marina gave a half‐life of six days at 20°C in

ISSN:0268-2605    

DOI:10.1002/aoc.590030503

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe alkylation of monoazoles, diazoles, triazoles and tetrazoles with dimethylheptyl(3‐iodopropyl)silane using liquid/liquid phase‐transfer catalysis affords the corresponding [3‐(N‐azolyl)propyl]silanes in high yield, by which means the nonsymmetric ambident heterocycles 1,2,4‐triazole and tetrazole undergo alkylation regiospecifically in position 1 and 2, respectively. Dimethylheptyl[3‐(N‐imidazolyl)propyl]silane demonstrated high fungistatic activity with respect toS. cerevisiaeandT.rubrumin combination with high

ISSN:0268-2605    

DOI:10.1002/aoc.590030504

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractBiologically important arsenic species such as arsenobetaine, arsenocholine iodide, tetramethylarsonium iodide, methylarsonic acid, and dimethylarsinic acid can be separated and quantitated by HPLC. The pH‐sensitive separations on a weak anion‐exchange column are described, as well as separations on a reverse‐phase column with the aid of tetrabutylammonium nitrate or heptanesulfonic acid as ion‐pairing agents. The thermospray mass spectra of these arsenicals in addition to those of sodium arsenate and an arsenosugar derivative are described. This technique is suitable for HPLC MS

ISSN:0268-2605    

DOI:10.1002/aoc.590030505

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTributyltin (TBT), a biocidal antifoulant in many marine paints, was measured in near‐surface and near‐bottom water over a 25 h period at the entrance to a marina in San Diego Bay, USA. Surface water concentrations varied from 20 to 225 nanograms per liter (ng dm−3) as TBT chloride and bottom water varied from non‐detectable (<1 ng dm−3) to 77 ng dm−3. Surface water concentrations varied, with highest concentrations associated with ebbing tides, and lowest concentrations with flooding tides, indicating that the yacht basin is a source of TBT. Bottom water TBT concentrations were almost always lower than corresponding surface water concentrations. The highest bottom water concentrations were associated with flooding tides and lowest surface water TBT concentrations. Physical water column measurements indicate that vertical stratification developed during ebbing tides and dissipated during flooding tides. This accounted for maximum bottom water and minimum surface water TBT concentrations during flooding tides, due, at least in part, to vertical mixing and dilution during

ISSN:0268-2605    

DOI:10.1002/aoc.590030506

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe synthesis of trioganostannylmethyl 2,3:5,6‐di‐O‐isopropylidene‐α‐D‐mannofuranoside (compound 3, R*OCH2SnR2R′:RR′Me or Ph) fromD‐mannose is reported. The compound 3 (RR′Ph) is transmetallated by PhLi to compound 5, R*OCH2Li, Which can be trapped by HgCl2[as (R*OCH2)2Hg] and by ketones, R3COMe [as compound 7, R*OCH2CR3MeOH]. Two stereoisomers of this compound (7a, R3Ph) were formed in a ratio of 40:60, indicating some asymmetric induction, arising from the chiral R* moiety. Reactions of compound 3, (RR′Ph), with I2, HO2CCF3and Cl2PtCOD result in Ph–Sn bond cleavage and formation of compound 3 with RPh; R′I, OCOCF3and Cl respectively. Reactions of compound 3 (RR′Me) with electrophiles can lead to cleavage of either of both types of C–Sn bonds present (e.g. by I2, Br2, Cl2PtCOD or SnCl4) or to attack at the C5–C6protecting group with release of acetone (e.g. by CF3CO2H, SO2or CH3COCl). Pesticidal and fungicidal activities of compound 3(RR′Ph) as well as of 1,2:5,6‐di‐O‐isopropylidene‐3‐O(triphenylstannylmethyl)‐α‐D‐glucofuranose (compound 2, RPh) and methyl 4, 6‐O‐benzyli

ISSN:0268-2605    

DOI:10.1002/aoc.590030507

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe addition rections oftrans‐Ir(PPh3)2(CO)Cl embedded in films of polystyrene (PS) with hydrogen, oxygen, sulfur dioxide, carbon monoxide and gaseous iodine were monitored by infrared spectroscopy and found to be similar to those occurring in toluene. While the reaction with iodine was rapid at the surface of the film as determined by attenuated‐total‐reflectance infrared spectroscopy, the reaction was much slower in the body of the film, as shown by transmission infrared spectroscopy. No such difference was observed for oxygen. The complex CpRu(COD)Cl (Cp = η‐C5H5, COD = 1,5‐cyclooctadiene) in PS readily undergoes ligand substitution by carbon monoxide (CO and13CO) to give CpRu(CO)2Cl and CpRu(13CO)2Cl embedded in PS, re

ISSN:0268-2605    

DOI:10.1002/aoc.590030508

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractEleven antitumor‐active octahedral organotin complexes of the type R2SnX2L2, where R = methyl, ethyl or phenyl, X = chloride or bromide, and L2=o‐phenantholine ((phen), 2‐)2‐(pyridyl)‐benzimidazole (PBI) or two dimethylsulfoxides (2DMSO), were examined for their broad‐spectrumin vitroantiviral activity against a number of DNA and RNA viruses. The DNA viruses included in this study were herpes simplex virus type 1 and type 2, a TK–(thymidine kinase deficient) strain of herpes simplex virus type 1, and vaccinia virus. The RNA viruses were vesicular stomatitis virus, Coxsackie virus type B4, Sindbis virus, Semliki forest virus, parainfluenza virus type 3, and human immunodeficiency virus (HIV). Overall, the complexes showed weak antiviral activity and low selectivity. With the exception of (CH3)2SnBr2·PBI and (C6H5)2SnCl2·2DMSO, all of the complexes were active against one or more of the three strains of herpes simplex viruses. On the other hand, only three complexes, (CH3)2SnBr2·PBI, (CH3)2SnBr2·phen, and (C6H5)5SnBr2·PBI, exhibited marginal activity against some of the RNA viruses. None of the complexes was active against vesicular stomatitis or parainfluenza virus. Similarly, there was no inhibitory activity towards HIV‐1‐associated reverse transcriptase or HIV‐1‐induced cytopathogenicity in human T‐lymphocyte MT4 cell culture

ISSN:0268-2605    

DOI:10.1002/aoc.590030509

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper presents a study of methylation of inorganic tin (SnCl4·5H2O) by humic materials (humic and fulvic acids) isolated from the sediment of Tianjin Harbor, Tianjin, China, and the effects of pH, salinity, and the concentration of inorganic tin on the production of methyltin were investigated.These humic materials could methylate inorganic tin, and the methyltin product was mainly monomethyltin. Low molecular weight compounds of the humus fraction (i.e. fulvic acid) were more active in the methylation, which could be facilitated by salinity and affected by pH

ISSN:0268-2605    

DOI:10.1002/aoc.590030510

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe interaction of triorganotins with cell membranes has been examined using synthetic phospholipid membranes (vesicles). Electron microscopy and NMR methods indicate that the organotin is in a five‐coordinate environment at the membrane surface, and is associated weakly with the phosphate headgroups of the vesicle components. Both trimethyl‐ and tributyl‐tin cause extensive modifications to the vesicles including fusion, aggregation, blebbing and total rupture, these effects being initiated at concentrations as low as 25 μmo

ISSN:0268-2605    

DOI:10.1002/aoc.590030511

出版商:Longman Group UK Ltd    

年代:1989

数据来源: WILEY