Hybrids, inorganic frameworks

Macroporous substrates with interconnected voids can be used as platforms for biomacromolecule separation and enzyme immobilization. These assemblies are likely to find application in biocatalysis and bioassays. The inorganic framework can provide a robust substrate, while their large and abundant pores allow the transportation of biomolecules. The availability of various morphologies for macroporous materials provides another level of control over the function of the hybrids. 

In this paper, we report about a recent in situ SANS study of the synthesis of the SBA-15 materials [5]. Our results demonstrate that SANS (using D20 instead of H20 as a solvent) is a powerful tool for the determination of size and shape of hybrid inorganic-organic micelles during the first synthesis step when the precursor species undergo hydrolysis and form an inorganic framework around the copolymer micelles. 

Hybrid material with interpenetrated 3D organic and inorganic framework... 

B. J. Melde, B. T. Holland, C. F. Blanford, and A. Stein, Mesoporous sieves with unified hybrid inorganic/organic frameworks, Chem. Mater. 11, 3302-3308 (1999). 

Structural diversity and chemical trends in hybrid inorganic-organic framework materials... 

The purpose of this feature article is to give an overview of developments in the field of hybrid inorganic-organic framework structures over recent years, especially during the last decade. We have not attempted to be comprehensive because of the huge amount of activity in the area, but instead we have focused on placing these developments in a broader context. We shall illustrate the enormous chemical and structural diversity of these materials and discuss some of the systematic trends that are starting to appear in synthetic routes for... 

We define hybrid inorganic-organic framework materials as compounds that contain both inorganic and organic moieties as integral parts of a network with infinite bonding connectivity in at least one dimension. This definition excludes systems that are molecular or oligomeric, such as the... 

The nature of the solvent is an important parameter in hybrid synthesis, especially as it can sometimes be problematic to identify a solvent that is suitable for both the inorganic and the organic reactants. Obviously, the use of non-aqueous or mixed solvents has been widely adopted, just as it has in the case of purely inorganic frameworks, and the use of immiscible biphasic solvents,18 whereby the products form at the solvent interface, is an interesting strategy. Ionic liquids, which have been shown to be effective in the synthesis of inorganic framework materials,62 are just starting to be applied to hybrid frameworks.63... 

Fig. 15. Projection of the structures of the vanadium phosphonate MIL-2 (left) and of a lanthanide glutarate (right), two hybrid inorganic-organic open frameworks.

Microporous materials are formed with hydrated inorganic cations or organic species located within cavities of the extended inorganic or inorganic-organic hybrid host framework. Extra-framework organic species are usually protonated amines, quaternary ammonium cations, or neutral solvent molecules. Dehydration (or desolvation) and calcination are two methods frequently used to remove extra-framework species and generate microporosity. 

Figure 9.9 Inorganic-organic hybrid interfaces for mesostructure formation. S corresponds to the surfactant species and I to the inorganic framework. M and X are corresponding counterions. Solvent molecules are represented as triangles. See text for details. (Reproduced with permission from G. J. A. A. Soler-Ilha et al., Chem. Rev. 2002, 102, 4093. Copyright 2002 American Chemical Society.)...

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