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Metallated species

Anodic-stripping voltaimnetry (ASV) is used for the analysis of cations in solution, particularly to detemiine trace heavy metals. It involves pre-concentrating the metals at the electrode surface by reducmg the dissolved metal species in the sample to the zero oxidation state, where they tend to fomi amalgams with Hg. Subsequently, the potential is swept anodically resulting in the dissolution of tire metal species back into solution at their respective fomial potential values. The detemiination step often utilizes a square-wave scan (SWASV), since it increases the rapidity of tlie analysis, avoiding interference from oxygen in solution, and improves the sensitivity. This teclmique has been shown to enable the simultaneous detemiination of four to six trace metals at concentrations down to fractional parts per billion and has found widespread use in seawater analysis. [Pg.1932]

A novel interface to connect a ce system with an inductively coupled plasma mass spectrometric (icpms) detector has been developed (88). The interface was built using a direct injection nebulizer (din) system. The ce/din/icpms system was evaluated using samples containing selected alkah, alkaline earths, and heavy-metal ions, as well as selenium (Se(IV) and Se(VI)), and various inorganic and organic arsenic species. The preliminary results show that the system can be used to determine metal species at ppt to ppb level. [Pg.247]

METAL SPECIES IN THE AQUATIC ECOSYSTEMS AND THEIR EFFECT ON THE WATER QUALITY... [Pg.27]

The methods of investigation of metal species in natural waters must possess by well dividing ability and high sensitivity and selectivity to determination of several metal forms. The catalytic including chemiluminescent (CL) techniques and anodic stripping voltammetry (ASV) are the most useful to determination of trace metals and their forms. The methods considered ai e characterized by a low detection limits. Moreover, they allow detection of the most toxic form of metals, that is, metal free ions and labile complexes. [Pg.27]

Several mixed metal species, MoAV, Mo/V, W/V and W/Nb, in which some atoms of the parent metal are replaced, have been identified (see pp. 54-7 of ref. 7) but no new principles are as yet discernible. [Pg.1014]

The formed metal carbide (M-C) is then hydrogenated to a reactive methylene metal species. [Pg.129]

The methylene intermediate abstracts a hydrogen and is converted to an adsorbed methyl. Reaction of the methyl with the methylene produces an ethyl-metal species. Successive reactions of the methylene with the formed ethyl produces a long chain adsorbed alkyl. [Pg.129]

A retrosynthetic analysis of fragment 152 can be completed through cleavage of the C16-C17 bond in enone 155, the projected precursor of epoxide 152. This retrosynthetic maneuver furnishes intermediates 156 and 157 as potential building blocks. In the forward sense, acylation of a vinyl metal species derived from 156 with Weinreb amide 157 could accomplish the construction of enone 155. Iodide 153, on the other hand, can be traced retrosynthetically to the commercially available, optically active building block methyl (S)-(+)-3-hydroxy-2-methyIpropionate (154). [Pg.603]

The stereochemistry of the carboxylation of 4-substituted ( + )-(/ S)-fra ,v-1-(4-mcthylphcnyl-sulfinylmethyl)cyclohexane after metalation with methyllithium and quenching with carbon dioxide was reported64. The results listed in Table 1 show that the d.r. of around 75 25 under kinetic control changes to 25 75 under thermodynamic control. This is the result of the equilibration of the two diastereomeric metalated species. As shown by the experiment in hexamethylphosphoric Iriamide (IIMI A) (d.r. = 57 43 under kinetic control) an electrophilic assistance of the lithium cation to the electrophilic approach is probably involved. [Pg.646]

N2, C2H4) or internally metallated species. Reactions such as extended refluxing of Pt(PPh3)4 in benzene yields clusters [49] (Figure 3.12). [Pg.191]

A variety of routes are available for the preparation of allylsilanes (/) with the simplest and most direct being the silylation of allyl-metal species. Other routes exemplified in this chapter include Wittig methodology, the use of silyl anions/anionoids in allylic substitution, and hydrometallation of... [Pg.107]

Phenol-formaldehyde reactions catalyzed by zinc acetate as opposed to strong acids have been investigated, but this results in lower yields and requires longer reaction times. The reported ortho-ortho content yield was as high as 97%. Several divalent metal species such as Ca, Ba, Sr, Mg, Zn, Co, and Pb combined with an organic acid (such as sulfonic and/or fluoroboric acid) improved the reaction efficiencies.14 The importance of an acid catalyst was attributed to facilitated decomposition of any dibenzyl ether groups formed in the process. It was also found that reaction rates could be accelerated with continuous azeotropic removal of water. [Pg.380]

Besides the effect of the presence of alkali on CO adsorption, there is also a stabilizing effect of adsorbed CO on the adsorption state of alkali. Within the high alkali coverage range the number of CO molecules adsorbed on promoted surface sites becomes practically equal to the number of alkali metal species and their properties are not dependent on the CO coverage. In this region CO adsorption causes also stabilization of the adsorbed alkali, as indicated by the observed high temperature shift of the onset of alkali desorption. [Pg.42]

A central theme in our approach, which we believe to be different from those of others, is to focus on the changing chemistry associated with higher, middle and lower oxidation state compounds. The chemical stability of radical species and open-shell Werner-type complexes, on the one hand, and the governance of the 18-electron rule, on the other, are presented as consequences of the changing nature of the valence shell in transition-metal species of different oxidation state. [Pg.218]

We have already shown how simultaneous codeposition of two metals in inert-gas matrices can lead to the formation of mixed-metal dimers. As in the case of silver, it was found that irradiation into the atomic absorptions of Cr or Mo results in formation of their respective dimers and trimers (114). In addition to this, however, irradiation into the atomic resonances of the two metals in the presence of each other results (114) in formation of the mixed-metal species CrMo, CrjMo, and CrMo2. It would seem that selective irradiation into the 300-400-nm bands of atomic Cr or Mo excites the 3d 4p, 3dMs 4p , or 4d 5p, ... [Pg.108]


See other pages where Metallated species is mentioned: [Pg.202]    [Pg.263]    [Pg.387]    [Pg.2422]    [Pg.89]    [Pg.381]    [Pg.169]    [Pg.352]    [Pg.348]    [Pg.181]    [Pg.172]    [Pg.89]    [Pg.174]    [Pg.154]    [Pg.275]    [Pg.77]    [Pg.224]    [Pg.55]    [Pg.56]    [Pg.226]    [Pg.233]    [Pg.150]    [Pg.110]    [Pg.173]    [Pg.131]    [Pg.227]    [Pg.114]    [Pg.70]    [Pg.437]    [Pg.607]    [Pg.27]    [Pg.294]    [Pg.107]    [Pg.73]    [Pg.218]   


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2- allyl metal species

Actinoid metals species

Acyl-transition metal species

Adsorption of Carbonaceous Species on Platinum Metals

Ammine complexes Complex species that metal ions

An all-metal aromatic species Al

Applications metal species

Aromaticity metal aromatic species reactivity

Bonding metal dioxo species

Bridged species metal alkyls

Bridged species metal alkynyls

Bridged species metal aryls

By metal ions and related species

Cationic metal species

Cationic metal-hydrocarbyl species

Cluster Species of Alkali Metals

Containing metal-oxygen bonds species

Copper species speciation/metals

DFT Methods Benchmarking against Systems with Transition Metal Species

Dehydrated surface metal oxide species

Dioxo species, transition metal

Dioxygen species support metals

Dioxygen species transition metal oxides

Dissolution of metal species

Dissolution, metal species

Distribution of metallic species

Electrochemically generated species transition metal complexes

Excited-state species, transition metal

Excited-state species, transition metal complexes

Hydrated surface metal oxide species

Identification of Metallic Species

Mechanism group 4 metal imido species

Mercury solution/metal species toxic metals

Metal Species and Oxide Clusters Encapsulated in Zeolites

Metal adsorbed species structure

Metal carbonyl species

Metal carbonyl species CpFe

Metal catalytic species, extraction from

Metal excess surface species

Metal hydride species

Metal hydride species reactions

Metal ion species

Metal ions diamagnetic species

Metal ions lower coordination number species

Metal ions paramagnetic species

Metal oxide surface species, determination

Metal polychalcogenide species

Metal species

Metal species

Metal species , catalysis

Metal species interaction with biological

Metal species interphases

Metal species, aqueous, solubility

Metal species, aqueous, solubility environment

Metal species, translocation

Metal-Monohydride Species Hydride Ligands can be Acidic

Metal-bridged species

Metal-dioxygen species

Metal-hydroperoxo species

Metal-hydroperoxy species

Metal-ligand species

Metal-oxo species

Metal-oxygen species

Metal-support effects, silver species

Metalated Epoxides into Organozirconium Species

Metalated species

Metalation heterometallic species

Metallic species, oceanic

Metals Organometallic species

Negatively Charged Species with Metal Cations

Nitroxyl species metal complexes

O-H bonds in metal-containing species

Organically complexed metal species

Organometallic radicals metal-centered species

Oxophilic species, early transition metals

Particulate-bound metal species, sequential

Polymeric species ligands with metal substrates

Polymerized species, molecular surface metal oxides

Radical species metal reduction

Radical species reductive metal insertion

Rare earth metal species

Redox reactions, metal species

Reduction of Uranyl(VI) species by individual metals

Reduction of aqueous metal species

Silylation of Allyl-Metal Species

Species Existing in Solution When a Metallic Ion Is Titrated with EDTA

Species containing interstitial transition-metal atoms

Species humic substance metal complexes

Supported metal species

Surface diffusion of oxygen species on supported metal catalysts

Surface metal oxide species

Surface metal oxide species molecular structures

Surface metal oxide species structure

Surface metal oxide species structure studies

The Stable Complex Species in Melts of Alkali Metal Halides Quantum-Chemical Approach

Transition Metals Oxoanions and Polynuclear Species

Transition metal clusters and mononuclear species

Transition metal species, adsorption

Transition-Metal Ionic Species

Tri-metallic species

Volatile metal halide species formation

Zeolite chemistry metal species

Zeolites metal species encapsulated

Zwitterionic metal alkyl species

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