Metal-organic frameworks MOFs characterization

The first part of the book documents the history, structure, chemistry, formulation and characterizations of zeolites in Chapters 1-4. The past 60 years have seen a progression in molecular sieve materials from aluminosilicate zeolites to micro-porous silica polymorphs, microporous aluminophosphate-based polymorphs, metallosihcate and metallophosphate compositions, octahedral-tetrahedral frameworks, mesoporous molecular sieves and, most recently, hybrid metal organic frameworks (MOFs). 

Burgess et al. reported and Mg ssNMR characterization of a series of metal organic frameworks (MOFs). These were benzoate and salicylate with magnesium complexes, based around the featuring Mg ions in organic coordination environments. The Cq for Mg species were determined and compared with computational studies. ... 

The focus of this chapter is porous (aluniino)silicates, with an emphasis on zeolitic materials. Porous phosphate materials such as aluminophosphates and metalloalumi-nophosphates are quite interesting in their own right but beyond the scope of this chapter. There are several excellent overviews of the synthesis, characterization, and application of these materials elsewhere (12, 13). This chapter also will not describe MOFs, or metal-organic framework materials. 

All synthesized MOF samples are characterized by proper crystallinity. The synthesis procedure does not remarkably influence the textural parameters of the resulted metal organic framework. The specific surface areas for the 2(5)-pyridinedicaiboxylate samples 1 and 2 are 270-300 mVg. These values are lower, than for 1,4-benzenedirboxylate (MOF-5) sample 4 (1000 mVg). Despite the crystallinity retention after evacuation, the 2(5)-pyrazinedicarboxylate sample 3 has no surface area. Tentatively, such difference in snrface areas conld be explained by lower micropore volume for the samples 1 and 2 or lake the permanent porosity for the 2(5)-pyrazinedicarboxylate framework (sample 3). 

PTPy) with Fe [18], have been characterized by STM. Surfece-supported metal-organic MOFs are often nsed as host frameworks for small organic molecules, such as fiillerene [5,16], Oiganometalhc 2-D nanosheets were formed on Au(lll) by the reaction of telra-cyanobenzene with Fe at elevated tanperatures under UHV [19], Thus, the choice of coordination metal makes it possible to precisely control these kinds of nanostructure. 

NMR can be also used to characterize the organic framework mobility in MOFs. Organic linkers that bridge the metal clusters in MOFs and constitute the three-dimensional porous structure of these materials could be rather mobile and are involved in a certain type of rotational motion. This rotational motion can be probed with NMR, if the studied material is deuterated. Thus, valuable information on the mechanism of intramolecular motion of MOFs organic fragments and its kinetic parameters can be derived. 

---