Anion complexes mono

A substantial effort has been directed toward the synthesis of cation-deficient, anionic complexes to improve electrical conductivity (see Section 16.5.4.1). Dithiolenes with ligands such as mnt, tfd and dmit, usually stablest as the mono- or di-anion, have been partially oxidized by a battery of methods to achieve this goal. 

While anion complexation might more appropriately be divided according to the complexity of the anion, the format followed in the preceding two subsections will be maintained for this section, i.e. subdivision according to the dimensionality of the macrocycles (mono-, bi- and tri-cyclic systems). A brief overview of anion complexation will, however, be presented in this introductory subsection. The types of anions which undergo complexation with macrocyclic ligands are categorized below. 

Other salts probably have similar effects but have not been studied extensively. Lithium salts have little influence on the termination reaction but can increase the propagation rate, presumably by complexing the growing nitrile radical (14). Anions complex with the growing chain in the order Cl> N03> C104. Complex formation between salt and mono-... 

Covalent mono-, tri-, tetra-, and pentavalent hahdes tend to form anionic complexes with coordination numbers of two (equation 19), four (equations 20 and 21), and six (equations 22 and 23). Such reactions take place mostly through the addition of halide anions. 

An rFIA-asynchronous merging zones configuration has be used for the speciation of up to nine different chromium forms —aquo complex, mono-, di- and tetrahydroxylated Cr(III) and molecular, anionic and dimeric Cr(VI). It Includes a glass-calomel microelectrode Inserted In the sample stream prior to the merging with the reagents, and a microcomputer which acquires the measured pH and chromium concentrations —Cr(VI) and total Cr. These data are pro-cesssed by a computation program In which the equilibrium constants of the... 

Other chromium-based catalysts have been explored which, when supported, afford polyethylene with relatively narrow molecular weight distribution. These are based on mono(cyclopentadienyl) chromium alkyl complexes first explored by Theopold. These may be Cr(II) compounds such as [Cp -CrMe]2, Cr(III) oxo compounds such as Cp Gr(0)-Me2, neutral and cationic Cr(III) compounds such as Cp CrMe2(THF) and [Cp CrMe(THF)2][BPh4],227 mixed valence dimers such as Gp Gr( -GH2Ph)(M- 7 7 -CH2Ph)CrCp, or even anionic complexes such as [Li] [Cp Cr(CH2Ph)3] (Table... 

TV, IX, and X in Chart 1, respectively) have been shown to induce singlestrand breaks in plasmid DNA in the absence of added oxidants or reductants (37, 209, 210). A cationic Cr(V) complex, X, has recently been shown to act as a specific oxidant of dG sites in DNA (445), in contrast with an anionic complex, IV, which predominantly oxidizes deoxyribose residues (446). Complex X also induces oxidative degradation of a glycoprotein from human blood plasma (232), and may be considered as a model of intracellular Cr -peptide complexes (22, 175, 445). The reactions of DNA or mono- and oligonucleotides with IV have been smdied in detail (209, 400, 403, 446 52), and the proposed mechanism of DNA damage, based on all of these results, is shown in Schemes... 

ABSTRACT. Upon protonation, salts of the anionic complexes [c/oso-1,2-R 2-3-(=CR)-3,3-(C0)2-3,1,2-MC2B9H9]- (1) and [doso-l,6-R 2-4-(CRH,4-(CO)2-4,l, 6-MC2BioHio] (2) (M = W or Mo, R = alkyl, aryl or alk5myl R = Hor Me) afford a remarkable variety of unusual mono- or di-metal complexes,. resulting from the juxtaposition of MhCR and B-H groups on the surface of the respective metallacarbaborane cages. The nature of the products isolated depends on many factors including ... 

The order of ligand -field effect for the various anions is complex and is probably not obtainable from the type of data presented above as it is not known whether the anions are mono- or bi-dentate. The nephelauxetic effect as measured in these complexes is again complex. However, the results show unequivocally that the anions [CIO ], [CF COO] , and [BF ] derived from very strong acids Interact with transition metal cations in non-aqueous solvents of relatively low basicity. 

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