Clusters cluster-polymer hybrids

Cluster-Polymer Hybrids with Enhanced Properties... 

The preparation of solids with covalently attached POM complexes is a serious and worthwhile research target because these materials might be expected to be rather stable to POM leaching in solutions. Many new materials of this type have been reported in the literature [16,49,74,137-143] however, catalytic studies on covalently boimd POMs still remain a rare event. In 1992, Judeinstein reported the first POM-polymer hybrid where a lacunary Keggin POM cluster was covalently linked to polystyrene or polymethacrylate backbone through Si-0 bonds [137]. This approach has been further developed by several research groups. 

Approaches to the formation of three new types of micro-porous materials that complement zeolites will be discussed. In each case, whether metal coordination polymers, metal-linked ceramic oxide clusters, or new hybrids containing both coordination and ceramic components, engineering of the Secondary Building Unit (SBU) is of critical importance. Successful examples of these approaches include the first thermally stable 3-D micro-porous coordination polymer with chemical functionalizability [Cu3(TMA)2(H20)3] , as well as a 3-D micro-porous cluster based material [V,2B18O60H8(Cd(en)(H2O) 3]". ... 

Figure 4 A possible discotic arrangement of flat clusters in the hybrid polymers.

Investigation of the materials properties of the cluster-based hybrid polymers is in its infancy, and the properties of the new hybrid polymers are far from being exploited. We have seen two clear trends in the materials properties of inorganic-organic hybrid polymers prepared by polymerization of metal oxo clusters with organic comonomers. They depend on the portion of incorporated cluster and, surprisingly, also on the kind of incorporated cluster. ... 

Using Dye/amine/alkyl bromide, iridium-containing photoluminescent polyacrylate films have also been manufactured. Polyoxometallate (POM)/polymer hybrid materials exhibiting modified mechanical properties (polymerized EPOX/TMPTA matrix with inserted POM clusters [XIA 15]) were synthesized in a one-step process using a silicon or phosphor polyoxomolybdate/iodonium salt/silane system. 

Bielinska et al. define DNCs as hybrid nanoparticles formed by the dispersion and immobilization of guest atoms or small clusters in dendritic polymer matrices. These authors describe the synthesis of 5-25 nm DNCs of Au NPs and G5-PAMAM dendrimers through UV decomposition of the PAMAM-HAuCf precursor. These nanoparticles have been imaged by in both in vitro and in vivo conditions [135]. 

This section describes systems which are at the border of what has been defined as being the scope of this review and therefore does not pretend to be comprehensive. Indeed, if there is a wealth of strictly inorganic materials and glasses into which NIR-crnitting lanthanide ions have been incorporated and which are clearly excluded from the review, there also exist a continuum between these materials and molecular entities, for instance coordination polymers and clusters which have been described in the two preceding sections. In continuity with these concepts are micro- and mesoporous materials into which lanthanide salts or complexes can be incorporated or attached. These are essentially zeolites and sol-gel materials, either conventional or the so-called inorganic-organic hybrids, as well as polymers. 

The map of hybrid nanomaterials in Figure 24.2 not only helps us view which are the distinct research topics but also how they are related to each other. It illustrates, for example, that the cluster on coordination polymers, crystal engineering, and metal-organic frameworks (top left) is very weakly related to the rest of the network. 

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