Polyoxometalate-based functional

Bringing the Components Together-Towards Prototype Polyoxometalate-based Functional Nanosystems... 

Preparation of phosphorus acids of the formula RP(0)(OH)2 may develop the synthesis of the functionalized nano-phosphate materials and also polyoxometalate-based organic/inorganic hybrid compounds in which the phosphorus atom is trapping between... 

Proust A, Matt B, Villanneau R, Guillemot G, Gouzerh P, Izzet G (2012) Functionalization and post-functionalization a step towards polyoxometalate-based materials. Chem Soc Rev 41 7605-7622... 

Lacunary polyoxometalates feature extensively in systematic functionalization strategies, and it is possible to generate these nucleophilic species by base degradation in nonaqueous solvents. For... 

When basic LDH is mixed or intercalated with acidic solid component, such as a zeolite, the composite will show a dual functional adsorption for CO2 and NH3. Okada et al. investigated the adsorption behaviors of MgAl-LDH/alumi-nosilicate composites and found that the adsorptivity of the composites for both of the probe molecules is dependent on the preparation pathways. The composite prepared via sol/precipitation shows a superior adsorption for both acidic and basic gases to those prepared via mechanical mixing and reconstruction methods (360). This is quite similar to the case of the dual acid/base properties of LDH-derived oxides, especially the LDH-polyoxometallate-derived oxides, which have been carefully examined by a similar adsorption method (361). 

In this respect inorganic systems can also be manipulated to form functional compartments. Similar to the crystal gardens [11-13] we, in preliminary work, have demonstrated that it is possible to take crystals of a polyoxometalate material and transform the crystalline state into a functional semi-permable membrane and osmotically pump material through a tubular structure formed by the metal-oxide membrane during crystal dissolution, see Fig. 5.5. Such processes could well be used to develop a POM-based CHELL. 

Polyoxometalates (POMs) are transition metal oxygen clusters with well-defined atomic coordination structures. POMs are used as functional nano-colloidal materials and also as supports for catalysts via ion-pair interactions due to their acidic properties. Combinations of chiral diamines and POM 225 effectively catalyze enamine-based aldol reactions. Less than 1 mol% of chiral amine loading is suf-ficientto catalyze the reaction (Table 28.10, entries 1 and 2) [114]. Highly diastereo-and enantioselective cross-aldol reactions of aldehydes are accomplished using chiral diamine-POM 226 under emulsion conditions (entries 3 and 4) [115]. Sul-fonated polystyrene or fluoropolymer Nafion NR50 are also good supports for the immobilization of primary-tertiary diamines. The catalyst 227 can be recovered by filtration and reused for at least four cycles with no loss of stereoselectivity (entries 5 and 6) [116]. 

The preparation of cellulose/silica hybrid materials functionalized with Keggin-type polyoxometalates employing sol-gel synthesis tmder mild conditions has been also developed. These bio-based materials were composed by a 37 % of propylamine-modified silica dispersed over cellulosic fibres (56 wt%) and a small... 

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