Metal-containing Compounds Research Articles

Chemical reactions occurring between metal-containing antineoplastic drugs and biological molecules

The introduction into human chemotherapy of a platinum-containing drug for the treatment of human neoplasia in the early 1970s represented the first time that metallic complexes had been widely utilized in this capacity. The outstanding success of this agent --cisplatin--has prompted a far-reaching search for analogs of cisplatin with a greater therapeutic efficacy or chemicals containing other metals with similar--or dissimilar but equally effective--physicochemical properties. Dozens of metallic or metalloid elements have been screened for antineoplastic activity in animal screening systems. Thus early transition metals (titanium, vanadium, molybdenum), group IB metals (copper, silver, gold), group IIIA metals (gallium, indium, aluminum), other group VIII metals (palladium) as well as miscellaneous other metals (rhuthenium, rhodium, nickel) have all been tested either in vitro or in vivo for their antitumor activity. Relatively few of the thousands of chemical compounds that have been tested in animals have had sufficient properties to warrant consideration for clinial trials. Unfortunately little success was seen with most of the clinical trials when they were conducted and in spite of numerous examples of metal-containing drugs exhibiting antitumor activity, either in vitro or in animal test systems, none except for several analogs of cisplatin were found to have composite characteristics suitable for clinical trials. There were two major exceptions to this lack of success. One was a drug containing gallium that had a long history of clinical use to study bone diseases, and the other was a novel organic chemical structure discovered in the early 1980s and containing germanium. Most recently the antiarthritic gold complexes have been screened for antitumor activity and some were found to be consistently positive, although no clinical trials have yet been proposed for these agents. The extent of testing of metal-containing compounds was recently highlighted by Dr. Barnett Rosenberg during his remarks following presentation to him of the Galileo Galilei medal of the University of Padua (Italy) at the 5th International Symposium of Metal-Containing Anticancer Drugs. Dr. Rosenberg called attention to the fact that a total of 56 metal or metalloid elements have been tested for in vivo antitumor activity in animals (Sadler, 1982b). Some elements have had only a few compounds tested for in vivo antitumor activity in animals (Y = 10, Ho = Tm = Lu = 11) while others have had greater than a thousand compounds tested (Sn = 1400, As = 1200, Pt = Cu = 1100). As of 1980, 988 metal-containing chemicals containing 35 different metals had sufficient in vitro anticancer activity to be considered positive in the National Cancer Institute (USA) antitumor drug screen (Sadler, 1982b), but as mentioned above, only a handful of these compounds have been tested for clinical activity or toxicity. Once reproducible antitumor activity has been documented and clinical efficacy has been established, the mechanism of action of drugs is then pursued. This review will examine one aspect of that mechanism of action--the reactivity with biological molecules that takes place with several metals found in antineoplastic drugs--notably platinum, gold, gallium and the metallocene dihalides. Because of its more widespread use and more extensive

Separation of metal-containing compounds by supercritical fluid chromatography

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSeparation of metal-containing compounds by supercritical fluid chromatographyMehdi. Ashraf-Khorassani, John W. Hellgeth, and Larry T. TaylorCite this: Anal. Chem. 1987, 59, 17, 2077–2081Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Published inissue 1 September 1987https://doi.org/10.1021/ac00144a016RIGHTS & PERMISSIONSArticle Views126Altmetric-Citations50LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (642 KB) Get e-Alerts Get e-Alerts

Sorption equilibrium of Pt complexes on γ-Al2O3 surface

Sorption equilibrium of H2PtCl6 on γ-Al2O3, both unmodified and promoted by mineral acids, has been studied. Mathematical description for the equilibrium dependences of sorption values on the concentration of dissolved metal-containing compounds that describes well the experimental data is suggested.

Photochemical processing of semiconductors: New applications for visible and ultraviolet lasers

A wide variety of semiconductor and metal films have recently been grown, doped, or etched by laser photochemical processes. While still early in its development, laser-driven processing of semiconductor devices appears promising as a supplement to existing processing techniques and particularly in the fabrication of III-V compound and custom devices. A discussion of film growth and etching shows that the laser is capable of performing all of the basic processing steps required in device fabrication without the need for photolithographic techniques. The boundaries of the field are set only by the number of semiconductor and metal-containing compounds having reasonable vapor pressure (~1 torr) at several hundred degrees centigrade or less.

EFFECTS OF ASPHALTENE PRECIPITATION AND A MODIFIED D 2007 SEPARATION ON THE MOLECULAR SIZE OF VANADIUM-AND NICKEL-CONTAINING COMPOUNDS IN HEAVY RESIDUA

ABSTRACT Boscan vacuum residuum (VR), and Maya atmospheric residuum (AR), were separated into operationally defined components by an isooctane asphaltene precipitation followed by a modified D 2007-80 separation of the isooctane soluble material. These collected fractions were examined by size exclusion chromatography (SEC) with element specific detection employing inductively coupled plasma emission spectroscopy (ICP) to investigate the effect the separation has on the the V and Ni compounds. The V and Ni SEC-ICP profiles of the asphaltene fractions indicated some of the metal-containing molecules are substantially larger in size than those observed in the residua. The asphaltene precipitation appears to cause an increase in molecular size through agglomeration of smaller constituents, and accomplishes only limited size separation of the metal-containing compounds. The resin fraction, the polar fraction obtained by modified D 2007-80 chromatography of the isooctane soluble portion, contained much of the ...

EFFECTS OF ASPHALTENE PRECIPITATION AND REPRECIPTION ON THE METAL-CONTAINING COMPOUNDS IN HEAVY RESIDUA

ABSTRACT Boscan vacuum residuum (VR) has been separated into isooctane insoluble asphaltenes and isooctane soluble maltenes. The asphaltenes were dissolved in a minimum of toluene and were further separated by two additional reprecipitations using isooctane as the precipitating solvent. We examined the fractions, including the recovered isooctane soluble material, by size exclusion chromatography (SEC) with inductively coupled plasma (ICP) emission spectroscopy to determine the effects, if any, the reprecipitations have on the size distribution of the metal-containing compounds. The asphaltene fractions show little change in size upon reprecipitation, but removal of a small amount of the metal components does occur. The first reprecipitation produces isooctane soluble material which is very similar in size to the original maltene fraction. However, the second reprecipitation removes small amounts of material in the size range of the asphaltenes. When the amounts were weight balanced, the resulting separat...

CHARACTERIZATION OP VANADIUM COMPOUNDS IN SELECTED CRUDES II. ELECTRON PARAMAGNETIC RESONANCE STUDIES OP THE FIRST COORDINATION SPHERES IN PORPHYRIN AND NON-PORPHYRIN FRACTIONS

ABSTRACT We applied electron paramagnetic resonance spectroscopy (EPR) to heavy petroleum fractions to characterize the first coordination sphere around the vanadyl +2 ion. The fractions were generated using a modified porphyrin extraction procedure. For the residual oil from the extraction, which contains the non-porphyrin metals, the first coordination sphere was dominated by 4N and N O 2S for Boscan, Beta, Morichal, and Arabian Heavy crudes. Maya had distinctively different parameters. These findings are significant for determining the overall structure of metal-containing compounds in heavy crude oils. We discuss the difference between the porphyrin and non-porphyrin behavior, possible blogenic precursors, and some process implications.

Thermal analysis and flammability of polymers Effect of halogen-metal additive systems

Thermal analyses have been carried out on systems containing a thermoplastic polymer (ABS or HDPE), a halogenated hydrocarbon (decabromobiphenyl or a chlorinated wax) and one or two metal-containing compounds. The results were compared with flammability measurements on the same systems, as determined by limiting oxygen index. Thermal analyses of the additives on their own has shown the extent to which the metal compounds are volatilised as their metal halides, thus indicating their possible similarity to the mechanism of flame-retardant action of antimony oxide. Such results are shown to be misleading in terms of providing an indication of flame-retardant efficiency. However it is possible to obtain meaningful correlations between the information obtained from thermal analysis of complete systems, i.e. including the polymeric substrate, and comprehensive studies (e.g. by triangular diagrams) of the flammability.

Negative response mode of a silicon-selective hydrogen-atmosphere flame ionization detector for gas chromatography

When a silicon-selective hydrogen-atmosphere flame ionization detector Is dopedl with vapors from metal-containing compounds In excess of that required for posltlve responses of silicon-contalnlng compounds, an ionizatlon quenching phenomenon occurs vvhlch produces negative chromatographic peaks that are easily identlfied end quantlfied. With optimized doping condltions of about 35 ppm ferrocene vapor in the hydrogen atmosphere, the detector exhlblted a minimum detectable limlt of 200 pg/s when the coilectlng electrode was posltloned 1'10 mm above the flame. Silicon sensltivlty can be Increasebd by a factor of 6 by sacrlflcing detector selectivity and lowerlng the collector electrode to a position 30 mm above the flame. When responses of a varlety of chemlcals were investlgated, alcohols, hydrocarbons, ethers, fluorocarbons, and nitrogen-containing compounds were found to produce1 positive responses while chlorine-, bromlne-, sulfur-, phosptwus-, and lron-contalnlng compounds produced potentially interferlng negatlve responses. A silylated mlxture of alcohols and hydrocarbons was chromatographed with FID and IHAFID detection to demonstrate potentlal applicatlons of tlhis detector. Silylation has served for years as a reliable step in many analytical procedures to increase volatility of polar compounds for gas chromatographic separation. The most common method which has been employed for the detection of silyl derivatives after gas chromatography (GC) is the flame ionization detector (FID). Because the FID responds primarily to carbon atoms, silyl derivatives are detected along with other nonderivatized organic material eluting from the gas chromatograph. Thus for trace analysis of silyl derivatives in complex mixtures, this universal detector creates complicated chromatograms which are often difficult to evaluate. Selective detection of only those comlpounds containing silicon atoms would, in many cases, simplify chromatograms and aid the analyst in the identification and quantification of these derivatives. Although a number of silicon-selective detectors for GC have been proposed (1-5), the hydrogenatmosphere flame ionization detector (HAFID) appears most promising for developing an inexpensive, routine method for the determination of silyl derivatives. This detection method was first propoHed by Hill and Aue in 1977 when they demonstrated that ions produced in a hydrogen atmosphere flame from silicon-containing organics could be formed and collected more efficiently than those from compounds containing only atoms of carbon and hydrogen (6). They also demonstrated that the addition of small quantities of ferrocene vapor to the detector's atmosphere enhances silicon responsies and that the ferrocene concentration could be increased to a point where responses of sil'Present address:

Microdetermination of selenium, tellurium, and arsenic in organic compounds

A method is described for determination of selenium, tellurium and arsenic in organic compounds. Decomposition is carried out either by oxygen-flask combustion or by wet digestion with sulphuric and nitric acids. The analysis is completed by argentometric titration, at pH 8–8.5, of the selenite, tellurite or arsenate formed. Halogens can often be determined simultaneously, and procedures are given for dealing with metal-containing compounds. Results obtained are within the usual limits for microanalysis (±0.3%).

The role of adsorption effects in formation of metallic films by decomposition of volatile metal-containing compounds: L M Gert et al, Neorg Mater, 6 (5), 1970, 971–977 ( in Russian).

The role of adsorption effects in formation of metallic films by decomposition of volatile metal-containing compounds: L M Gert et al, Neorg Mater, 6 (5), 1970, 971–977 ( in Russian).

The preparation of thin films of some oxides by the pyrolysis method

It is shown that the pyrolysis method is quite an attractive technique for the preparation of oxide films of many metals with predetermined properties in a wide range of compositions. The use of oxygen in the pyrolysis process has made it possible to obtain filmsmore perfect in structure (oriented and single-crystal). Some experimental data on the preparation of semi-conductor and dielectric oxide films (ZnO, In 2O 3, Al 2O 3) by pyrolysis of corresponding metal-containing organic compounds (Zn propionate, In acetylacetonate, Al ethylate) are described. A relationship was established between the structure of the films and the conditions of their formation. In the process it was revealed that the nature of the substrate and its temperature were the determining factors. Electron diffraction analysis showed that the structure of the In 2O 3 films changed from an amorphous to a well oriented one and this corresponded with a change of resistivity from 10 12 to 10 2 ohm cm. It was possible to obtain ZnO single-crystal films on mica with a resistivity of 10 8 ohm cm. Films with different resistivities (10 7–10 12 ohm cm) were obtained by the decomposition of previously co-deposited aluminium and chromium acetylacetonates. The difference in resistivity was shown to depend on the Cr 2O 3 content of the deposited films. The high dielectric strength of Al 2O 3 polycrystalline films (thickness 3–5μ) made it possible to use them as insulating coatings for radio valve heaters.

The vapour phase deposition of metals and their compounds: Applications in electronics

The electronic applications of metal-containing chemical compounds are outlined with reference to the formation of metallic conducting layers or tracks and dielectric compounds in producing circuit components. A classification of compounds based on proposed compound requirements is presented and followed by a discussion and survey of the individual compounds that have been commonly employed in vapour deposition. Methods of decomposition, other than thermal, are briefly mentioned.

Metal-Containing Compounds of the Anion (C2H5)2NN2O2

Metal-Containing Compounds of the Anion (C₂H₅)₂NN₂O₂