Hybrid materials based frameworks

The past nearly six decades have seen a chronological progression in molecular sieve materials from the aluminosilicate zeolites to microporous silica polymorphs, microporous aluminophosphate-based polymorphs, metallosilicate and metaHo-phosphate compositions, octahedral-tetrahedral frameworks, mesoporous molecular sieves and most recently hybrid metal organic frameworks (MOFs). A brief discussion of the historical progression is reviewed here. For a more detailed description prior to 2001 the reader is referred to [1]. The robustness of the field is evident from the fact that publications and patents are steadily increasing each year. 

Coordination Polymers Use of hybrid materials composed of metal ions and organic groups (metal-organic framework based on chemical engineering) and their preparation and/or fabrication. 

In conclusion, zinc sulfite-based coordination polymers and hybrid networks of different dimensionalities have been synthesized and characterized. An open-framework hybrid sulfite—sulfate, where both SO32- and S042- are part of a two-dimensional layer, has also been synthesized and characterized. On the basis of the present studies, it appears that many more metal sulfite-based open-framework and hybrid materials can be synthesized. 

Before concluding this subject, mention is made here of two more novel approaches for using SBE. Pollard et al. (143) have reported that SBE can be used to prepare a pseudo-graphitic char suitable as a low-cost replacement for activated carbon in the stabilization/solidification of industrial wastes. In their process, they char 2 1 blends of SBE and ZnCl2 at 450°C/1 hour and then activate the material at 600°C/1 hour. The resultant hybrid material is as effective as activated carbon for fixing toxic organics and, because of its aluminosilicate framework, exhibits additional pozzolanic activity in the cement-based stabilization/solidification reactions in which these materials are used. Very recently (144), Bohling reported on... 

Livage and Ferey used the fiexible, a,co-dicarboxylate succinic acid to prepare several structures, MIL-9 [146] and MIL-16 [147], with two dimensional Co-O-Co sheets. Nickel succinate [148] (Figure 18.9) provides a striking example of this new class of hybrid materials with a honeycomb framework based on a three-... 

There are some excellent review articles on different aspects of mesostructured materials, such as synthesis, properties, and applications. " Extensive research effort has been devoted to the exploitation of new phases (lamellar, cubic, hexagonal structures), expansion of the pore sizes (about 2-50 nm are accessible), and variable framework compositions (from pure silica, through mixed metal oxides to purely metal oxide-based frameworks, and inorganic-organic hybrid mesostructures). Another research focus is on the formation of mesostructured materials in other morphologies than powders, e.g. monolithic materials and films, which are required for a variety of applications including, but not limited to, sensors (based on piezoelectric mass balances or surface acoustic wave devices), catalyst supports, (size- and shape-selective) filtration membranes or (opto)electronic devices. The current article is focused... 

There are only a few reports on the preparation of open-framework hybrid aluminophosphate-based materials, since the majority of the studies on hybrid aluminophosphates resulted in formation of chain- or layered-structures (98). In 2000, Kedamath and co-workers reported the first framework structure of aluminophosphate-oxalate possessing large circular channels similar to that of... 

Al-based porous frameworks were also reported to moderately conduct protons above lOO C through the incorporation of imidazole (Im) within the pores. A higher proton-conductive MOF was obtained by introducing adipic acid in a layered oxalate-bridged framework (NH4)2[Zn2(ox)3]-3H20. Also, hybrid materials comprising a MOF and POMs were investigated. ... 

To accommodate the new material on acids and bases m Chapter 1 the orbital hybridization model of bonding m organic compounds has been rewrit ten and placed m Chapter 2 In keeping with its ex panded role Chapter 2 m now titled Hydrocarbon Frameworks Alkanes... 

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