Clay complexes Synthetic

Clay minerals or phyllosilicates are lamellar natural and synthetic materials with high surface area, cation exchange and swelling properties, exfoliation ability, variable surface charge density and hydrophobic/hydrophilic character [85], They are good host structures for intercalation or adsorption of organic molecules and macromolecules, particularly proteins. On the basis of the natural adsorption of proteins by clay minerals and various clay complexes that occurs in soils, many authors have investigated the use of clay and clay-derived materials as matrices for the immobilization of enzymes, either for environmental chemistry purpose or in the chemical and material industries. 

Figure 3.5. (A) JH NMR spectrum of the Brooksville fulvic acid (BFA) dissolved in d6-DMSO and (B) HR-MAS NMR spectrum of the BFA-clay complex swollen in g 6-DMSO. Inset shows that lower abundance aromatic species are present in the spectrum in part B. Reprinted from Simpson, A. I, Simpson, M. I, Kingery, W. L., Lefebvre, B. A., Moser, A., Williams, A. I, Kvasha, M., and Kelleher, B. R (2006). The application of 1H high-resolution magic-angle spinning NMR for the study of clay-organic associations in natural and synthetic complexes. Langmuir 22,4498 1503, with permission from the American Chemical Society.

Rebhun, M., Kalabo, R., Grossman, L., Manka, J., and Rav-Acha, C. (1992). Sorption of organics on clay and synthetic humic-clay complexes simulating aquifer processes. Water Res. 26,79-84. 

Rebhun, M. Kalabo, R. Grossman, L. Manka, J. Rav-Acha, Ch. Sorption of Organics on Clay and Synthetic Humic-Clay Complexes Simulating Aquifer Processes, Wat. Res. 1992, 26, 7-84. 

The thermal characteristics of synthetic organo-clay complexes are of interest for several reasons. First, since clay synthesis takes place at elevated temperatures (100-300 C), the stability of each constituent must be assured. The degree to which the thermal characteristics of a template are affected by a support is also of importance. In addition, the porphyrin-clay complexes are of interest as advanced materials in such areas as electrochemistry and catalysis (7), and as highly organized molecular assemblies (S). Since thermal stability... 

The first examples of cationic exchange of bis(oxazoline)-metal complexes used clays as supports [49,50]. Cu(II) complexes of ligands ent-6a, 6b, and 6c (Fig. 15) were supported on three different clays laponite (a synthetic clay), bentonite, and montmorillonite KIO. The influence of the copper salt from which the initial complexes were prepared, as well as that of the solvent used in the cationic exchange, was analyzed. 

Brindley, G. W., and Moll, W. F., Jr. (1965). Clay-organic studies. IX. Complexes of natural and synthetic Ca-montmorillonites with fatty acids. Am. Min. 50,1355-1370. 

Complexation by metal oxides and clays. The adsorption processes of metals on silica, alumina, hydrated ferric oxide and a range of other minerals are well documented for laboratory studies performed with synthetic materials (Buffle, 1988 Dzombak and Morel, 1990 Stumm, 1992). The approaches described for major sites are applicable in this case. Nevertheless, the relevance of these data to natural water... 

Later, a complete chromatographic resolution of Co(acac)3 and Cr(acac)3 on an optically active poly(triphenyhnethyl methacrylate) column was accomplished. The optical data of the pure enantiomers were obtained. Extensive use was made of columns composed of clay plus metal complex adducts. Thus, optical resolution was accomplished by LC on a column packed with an ion-exchange adduct of synthetic hectorite and optically active [Ni(II)](phen)3 and [Ru(II)](phen)3 . Using these systems, Co(acac)3, Cr(acac)3, Rh(acac)3 and [Co(acac)2(en)]+ (en = ethelenediamine) were resolved completely into enantiomers . Enantiomers of these four species were separated by LC on a column packed with ion-exchange adduct of synthetic hectorite and optically active metal complexes . One optically active metal complex used was tris(LlO-phenanthroline)-nickel(n), which was ion exchanged into synthetic hectorite. Racemic Co(acac)3, Cr(acac)3 and Ru(acac)3 were also enantiomerically separated via LC using poly(t-butylisocyanide) as stationary phase . ... 

Historically, oxide catalysts have been used primarily for vapor phase reactions in the petroleum and petrochemical industries. Recent work, however, has shown that these catalysts can also be effective in promoting a number of synthetically useful reactions. While simple oxides show activity for some oxidations they are more commonly used as solid acids or bases. Complex oxides can act as acids or bases as well as oxidation catalysts. Complex oxides can range in composition from the simple, amorphous, binary oxides to the more complex ternary and quaternary systems. The use of zeolites and clays can impart shape selectivity to a number of reactions, a feature that makes these systems particularly appealing for use in synthesis. 

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