Hetero-polyanions

Iso- and Hetero-polyanions. Potentiometric titrations of H against WO ions have shown that the product formed in the first 0.01 s of reaction is not paratungstate A, [HW Oji] , nor any other discrete ion intermediate between this and WO , but is a mixture of a number of ill-defined products. These may be colloidal hydrated W oxides formed very rapidly in local regions of high acidity before complete mixing can occur and which are converted into [HW602i] in ca. 1 s. Steps in the aggregation of [M04] (M = Mo or W) ions have also been studied by cryoscopy, spectrophotometry, and pH measurements.  

Kamenar, M. Penavic, and C. K. Prout, Cryst. Struct. Comm., 1973, 2, 41, 

Deodata de Azevedo, R. Gomes-Costa, and K. Jacobsohn, Enzymologia, 912. 43, 105 Chem. Abs., 1973,78,133005n). 

Schiller, Angew. Chem. Internat. Edn., 1973, 12, 420. 

Thouvenot. C. Rocchiccioli-Deltcheff, and P. Souchay, Compt. rend., 1974, 278, C. 455. 

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M. T. Pope, Iso- and Hetero-polyanions, Chap. 38 in Comprehensive Coordination Chemistry, Vol. 3, pp. 1028-58, Pergamon Press, Oxford, 1987. 

The iso- and hetero-polyanions of the vanadium and chromium subgroups have been the part-subjects of several monographs in recent years (1, 2, 3). Good accounts have been given of their structural chem-... 

Kimberlin, R.H., and Walker, C.A. (1986). Suppression of scrapie infection in mice by hetero- polyanion 23, dextran sulfate, and some other polyanions. Antimicrob. Agents Chemother. 30, 409-413. 

Poly-3-methylthiophene Hetero polyanion Electrocatalytic activities 12... 

Such heteropolyanions are voluminous and thus much more easily polarisable. In the vicinity of the cathode surface in the electric double layer, these anions are strongly polarized and finally disintegrate to smaller particles from which metallic molybdenum is deposited. By the diffraction analysis of solid deposit on the walls of the reaction chamber it was found, that the deposit was completely composed of K2S1F6, which supports the hypothesis of formation of hetero-polyanions according to the above... 

A review of the hetero- and iso-polyanions of niobium and tantalum has been published. 

Ruths, J., Essler, F., Decher, G., Riegler, H. (2000). Polyelectrolytes I polyanion/polycation multilayers at the air/ monolayer/water interface as elements for quantitative polymer adsorption studies and preparation of hetero-superlattices on solid surfaces. Langmuir 16 8871-8. 

Polyoxometallates. Polyoxometallates of the group 6 transition metals (iso- and hetero-polyoxoanions) form a special class of metallate ligands for the actinide elements. These species can incorporate other atoms as either primary or secondary (peripheral) heteroatoms. Primary heteroatoms are necessary to complete the polyoxoanion structure secondary heteroatoms can be removed without disruption of the stable polyanion unit. The early actinides serve in both roles in known compounds. 

Recently, we (82) and others (82-84) have shown that similar hetero-structures can be prepared by using two-dimensional inorganic sheets (made by exfoliation of various lamellar solids) in place of the organic polyanion. This technique offers a potentially powerful alternative to the construction of multi-component electron transfer systems, because it can, in principle, be used to stack up an arbitrary number of redox-active polymers without interpenetration (85). This chapter describes the preparation and photochemistry of simple multilayer composites on high-surface-area silica. Specifically, the synthesis and electron transfer kinetics of systems containing a polycationic sensitizer, poly-[Ru(bpy)2(vbpy)(Cl)2] (1), (abbreviated [Ru(bpy)3 ]n bpy = 2,2 -bipytidine and vbpy = 4-vinyl-4 -methyl-2,2 -bipyridine), and an electron-acceptor polycation poly[(styrene-co-]V-vinylbenzyl-N -methyl-4,4 -bipyridine)(Cl)2] (2), (PS-MV ) are presented. Using a solution-phase electron donor, 3, as the third electroactive component, it was possible to prepare and study the photoinduced electron transfer reactions of several different diad and triad combinations. 

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