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Results for “Organometallic Compounds”

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At least 19 recordsLinked to original sources
PubMed2000

Separation of metal chelates and organometallic compounds by SFC and SFE/GC.

Supercritical fluid chromatography (SFC) combines the high diffusion coefficients of gas chromatography (GC) and the solubility properties of liquid chromatography (LC). SFC generally requires lower temperatures for chromatographic separations and thus is more suitable for analyzing thermally labile compounds including a number of metal chelates and organometallic compounds. SFC also allows interfacing between supercritical fluid extraction (SFE) and chromatographic analysis of metal-containing compounds. A large number of metal chelates and organometallic compounds can be separated by SFC. This article summarizes SFC separation of various chelates of transition metals, heavy metals, lanthanides and actinides as well as organometallic compounds of lead, mercury, and tin reported in the recent literature. This article also discusses SFC detection systems and the determination of solubility of organometallic compounds by SFC.

Actinoid Series Elements↗
PubMed1990

[Biochemistry of organometallic compounds].

Recent studies have demonstrated that organometallics can be substrates of enzymes and may undergo biotransformations in the presence of microorganisms. Latest achievements in organometallic biosynthesis, applications of organometallics in biosensor systems and the properties and models of novel enzymes which attack the core of organometallic compounds, i.e., the metal-carbon bond, are discussed.

Enzymes↗
PubMed2004

Full automation of derivatization--solid-phase microextraction-gas chromatography-mass spectrometry with a dual-arm system for the determination of organometallic compounds in aqueous samples.

The determination of organometallic compounds in aqueous samples by in-vial derivatization and headspace solid-phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) has been fully automated using a Twin PAL dual-arm robotic system. Linearity, accuracy, sensitivity for a series of n-methyl, n-ethyl, and n-phenyl metal substituted chloride compounds of tin, lead, and mercury were investigated. The automated method was compared to similar manual methods and improved precision, speed and throughput was achieved. By originally programming the Twin PAL dual-arm system with the supplier's software (Cycle Composer, Version 1.5.0) the arms on the robot were only able to work in sequence. However, in order to have a flexible system and exploit time efficiently the robotic arms must work simultaneously. This was accomplished by programming the robot with the new software package called Cruise Control 4-2 for Twin PALs. Compared to Cycle Composer, Cruise Control 4-2 enhanced the speed and throughput of the automated system further. In addition, with a built-in crash prevention protocol and an improved user interface a more user-friendly system was obtained.

Automation↗
PubMed2000

Analytical potential of fullerene as adsorbent for organic and organometallic compounds from aqueous solutions.

In this work, the analytical potential of C60 fullerene as a sorbent for organic and organometallic compounds from aqueous solutions was studied for the first time. Fullerene adsorbs many types of organic substances (e.g., N-methylcarbamates, phenols, polycyclic aromatic hydrocarbons, amines) with efficiencies that depend on the nature of the compound concerned and never exceed 60%. Conventional sorbents such as XAD-2 or polyurethane foam are more efficient than C60 for this purpose. Organometallic compounds (viz. metalocenes and organoleads) are quantitatively adsorbed on C60 via the formation of neutral complexes or chelates; the adsorption constant is dramatically increased by the use of classical reagents such as pyrrolidinedithiocarbamate or diethyldithiocarbamate. A complementary comparative study on the adsorption of organometallic complexes on RP-C18 and silica gel 100, among others, showed C60 to be superior as sorbent. All experiments in this work were carried out by using continuous flow configurations and gas chromatography-atomic absorption spectrometry techniques.

Adsorption↗
PubMedDate not supplied

Rhodium, iridium, copper and gold antitumor organometallic compounds (review).

Recent results on the antitumor activity of organometallic compounds of rhodium, iridium, copper and gold are reviewed. Coordination compounds of some organic ligands are also briefly mentioned. The most promising seem to be copper and gold complexes which exhibited remarkable activity against several tumor systems.

Animals↗
PubMed1985

Liquid chromatographic retention behavior of organometallic compounds and ligands with amine-, octadecylsilica- and beta-cyclodextrin-bonded phase columns.

Effects of solvent composition and ligand variation on the retention of organometallic compounds have been studied using an amino, an octadecylsilica (ODS) and a beta-cyclodextrin (beta-CD) bonded phase column in either a normal-phase or a reversed-phase mode. The retention behavior for the organometallic compounds with the amino column can be rationalized using the displacement model. The "apparent" molecular areas are greater for compounds capable of strong hydrogen bonding. The retention in the ODS column roughly follows an argument based on the expected solubility behavior while mixed retention mechanisms are involved for the solubility behavior while mixed retention mechanisms are involved for the beta-CD column, i.e. both inclusion process and solubility or solvophobic interactions are possibly operative.

Amines↗
PubMed2001

Separation and identification of organic and organometallic compounds by use of a liquid chromatography-particle beam-glow discharge mass spectrometry combination.

Evaluation of the particle beam glow discharge mass spectrometry (PB-GDMS) system as a detector for liquid chromatography (LC) is described for the analysis of polycyclic aromatic hydrocarbons, steroids, selenoamino acids, and alkyllead compounds. A particle beam interface is used to introduce analyte species from the LC into a glow discharge source for subsequent vaporization and ionization. Mass spectra display classic EI fragmentation patterns for the organic compounds, as well as elemental and molecular information for the organometallic compounds. Chromatographic separations display good temporal correlation between UV and PB-GDMS detection modes. Detection limits for Pb in lead nitrate, triethyllead, and triphenyllead fall in the sub-ppb (ng) range.

Amino Acids↗
PubMed2006

Deamination of the amino acid fragment in imine metallacycles: unexpected synthesis of an NH-aldimine organometallic compound.

We report that the action of Lewis bases, such as triphenylphosphine, pyridine, or trimethylamine, on imine metallacycles derived from amino acids leads to the formation of the first organometallic compound of an NH aldimine, a highly reactive organic species, and the corresponding alpha-ketoester, in a deamination reaction that mimics the metabolism of alpha-amino acids. The synthesis of different cyclopalladated compounds by a reaction between palladium acetate and the Schiff bases 2,4,6-Me(3)C(6)H(2)CH=NCH(R(1))COOR(2) (R(1) = CH(2)Ph, R(2) = Et and R(1) = Ph, R(2) = Me) is also reported.

Organometallic Compounds↗
PubMed2005

Ruthenium (II)-derived organometallic compounds induce cytostatic and cytotoxic effects on mammalian cancer cell lines through p53-dependent and p53-independent mechanisms.

The metallic compound cisplatin has been used for many years to treat various human cancers. Here, we describe the cytostatic and cytotoxic properties of a new class of organometallic compounds that contain a ruthenium (II) atom covalently linked to carbon and nitrogen atoms. We found that several ruthenium-derived compounds (RDCs) led to G1 arrest and induced apoptosis in tumor cell lines derived from glioblastomas, neuroblastomas, and lymphoid tumors at least as efficiently as cisplatin. We further analyzed the signaling pathways underlying these effects, and we showed that both RDCs and cisplatin induced p53 and p73 protein levels but with different intensities and kinetics. This accumulation of p53 and p73 proteins correlated with an increase in p21 and Bax expression, two p53 target genes linked to cell growth arrest and apoptosis. However, in contrast to cisplatin-induced apoptosis, overexpression of DeltaNp73, a p53 and p73 dominant-negative isoform, only partly reduced RDC-induced apoptosis, suggesting p53-dependent and p53-independent modes of action. This observation was further confirmed by the ability of RDC to induce apoptosis in p53-/- cells. Altogether, this study highlights key cellular and molecular features of RDCs and suggests that further development of this new class of compounds may contribute to improve future chemotherapeutic protocols.

Animals↗
PubMed2004

Multielemental speciation analysis of organometallic compounds of mercury, lead and tin in natural water samples by headspace-solid phase microextraction followed by gas chromatography-mass spectrometry.

The development of a simple and rapid multielemental speciation method is described with the ultimate goal to simultaneously determine various organometallic compounds of mercury, lead and tin (inorganic mercury, methylmercury, trimethyllead, triethyllead, monobutyl-, dibutyl- and tributyltin) in natural water samples. The analytical method consists on the ethylation with NaBEt4, simultaneous headspace-solid phase microextraction (HS-SPME) of the derivatives and final gas chromatographic-mass spectrometric (GC-MS) analysis. After optimization of important process parameters, like SPME fiber coating, extraction time and extraction temperature, the analytical characteristics were evaluated. Detection limits in the low ng l(-1) level, linearity over three orders of magnitude and repeatability in the range of 3-20% were achieved for all compounds under study. The accuracy of the method in terms of average percentage recovery of the compounds in spiked river water and seawater samples was better than 90%. Finally, application of the proposed method to real natural aqueous samples enabled the simultaneous determination of all the compounds under study in seawater samples obtained from the marina area of Gijón (Asturias, Spain).

Gas Chromatography-Mass Spectrometry↗
PubMed2006

Organometallic compounds with biological activity: a very selective and highly potent cellular inhibitor for glycogen synthase kinase 3.

A chiral second-generation organoruthenium half-sandwich compound is disclosed that shows a remarkable selectivity and cellular potency for the inhibition of glycogen synthase kinase 3 (GSK-3). The selectivity was evaluated against a panel of 57 protein kinases, in which no other kinase was inhibited to the same extent, with a selectivity window of at least tenfold to more than 1000-fold at 100 microM ATP. Furthermore, a comparison with organic GSK-3 inhibitors demonstrated the superior cellular activity of this ruthenium compound: wnt signaling was fully induced at concentrations down to 30 nM. For comparison, the well-established organic GSK-3 inhibitors 6-bromoindirubin-3'-oxime (BIO) and kenpaullone activate the wnt pathway at concentrations that are higher by around 30-fold and 100-fold, respectively. The treatment of zebrafish embryos with the organometallic inhibitor resulted in a phenotype that is typical for the inhibition of GSK-3. No phenotypic change was observed with the mirror-imaged ruthenium complex. The latter does not, in fact, show any of the pharmacological properties for the inhibition of GSK-3. Overall, these results demonstrate the potential usefulness of organometallic compounds as molecular probes in cultured cells and whole organisms.

Animals↗
PubMed1993

In vitro action of new organometallic compounds against Trypanosomatidae protozoa.

The effects of 10 newly synthesized organometallic rhodium complexes (5 of Rh(I), 4 of Rh(III) and one of Rh(IV) complex salt) and 2 antimony (III) complexes against epimastigote forms of Trypanosoma cruzi and promastigote forms of Leishmania donovani have been studied in vitro. Of the 10 rhodium complexes tested three proved 100% efficient in inhibiting the growth of the epimastigote forms of T. cruzi while only one worked against the promastigote forms of L. donovani. The two antimony complexes inhibited the growth of L. donovani totally and were fairly successful against T. cruzi.

Animals↗
PubMed2003

Tailoring the separation selectivity of metal complexes and organometallic compounds resolved by capillary electrophoresis using auxiliary separation processes.

The use of auxiliary separation mechanisms to manipulate the separation selectivity of metal complexes and organometallic species is reviewed. Auxiliary separation mechanisms included in the review are micellar electrokinetic capillary chromatography, ion-pairing and ion-exchange electrokinetic chromatography. This paper discusses how these secondary mechanisms can be effectively employed to tailor separation selectivity.

Chromatography, Ion Exchange↗