Porous organic frameworks

Zhao H, Jin Z, Su H, Jing X, Sun F, Zhu G (2011) Targeted synthesis of a 2D ordered porous organic framework for drug release. Chem Commun 47 6389-6391... 

Pachfule P, Dhavale VM, Kandambeth S et al (2013) Porous-organic-framework-templated nitrogen-rich porous carbon as a more proficient electrocatalyst than Pt/C for the electrochemical reduction of oxygen. Chem Eur J 19 974-980... 

Lots of porous solids, such as porous carbons, porous silica, zeolites and porous organic frameworks, have been reported and investigated for gas sorption. Compared with these porous materials, PAFs show unique advantages of combining high surface area and excellent physicochemical stability. This is especially true for PAF-1, which has a high surface area of 5640 m g and could survive extreme conditions such as boiling in solvent or addition to cold basic or acidic solutions. ... 

Porous organic frameworks (POFs), such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), conjugated micro-porous polymers (CMPs), ° polymers of intrinsic microporosity (PIMs), crystalline triazine-based organic frameworks (CTFs), hyper-crosslinked... 

The search for better catalysts has been facilitated in recent years by molecular modeling. We are seeing here a step change. This is the subject of Chapter 1 (Molecular Catalytic Kinetics Concepts). New types of catalysts appeared to be more selective and active than conventional ones. Tuned mesoporous catalysts, gold catalysts, and metal organic frameworks (MOFs) that are discussed in Chapter 2 (Hierarchical Porous Zeolites by Demetallation, 3 (Preparation of Nanosized Gold Catalysts and Oxidation at Room Temperature), and 4 (The Fascinating Structure... 

Severin and coworkers reported (146) the reaction of tris(2-aminoethyl)amine and 4-formylphenylboronic acid with penta-erythritol to give, via multicomponent assembly, the boronic acid based macrobicyclic cage 35 (Fig. 25). The cage has the form of an ellipsoid with a diameter of 20.5 A and binds two Cud) ions in a fashion similar to the smaller tren-based cryptands. The reversible formation of boronic esters has also been employed to build other hollow structures such as nanotubes (147) and porous covalent organic frameworks (148,149). 

H. Li, M. Eddaoudi, M. O Keeffe, O. M. Yaghi, "Design and synthesis of an exceptionally stable and highly porous metal-organic framework , Nature 1999, 402,276-279. 

Physisorption (i.e., adsorption of hydrogen) of molecular hydrogen by weak van der Waals forces to the inner surface of a highly porous material. Adsorption has been studied on various nanomaterials, e.g., nanocarbons, metal organic frameworks and polymers. 

Four different methods to store hydrogen are currently available compressed gas, liquid hydrogen, metal hydrides and sorption on different porous materials (carbon materials, zeolites, metal organic frameworks, etc).2-4... 

J. L. C. Rowsell and O. M. Yaghi, Metal-organic frameworks a new class of porous materials, Microporous Mesoporous Mater., 73, 3-14 (2004). 

H. Van Bekkum, A. Corma, and E. Schuth), Stud. Surf Sd. Cat., vol. 168, Elsevier, Amsterdam, pp. 327-374 Muller, U., Schubert, M.M., and Yaghi, O.M. (2008) Chemistry and applications of porous metal-organic frameworks, in Handbook of Heterogeneous Catalysis, Wiley-VCH Verlag GmbH, Weinheim, pp. 247-252. 

Up to now, a variety of non-zeolite/polymer mixed-matrix membranes have been developed comprising either nonporous or porous non-zeolitic materials as the dispersed phase in the continuous polymer phase. For example, non-porous and porous silica nanoparticles, alumina, activated carbon, poly(ethylene glycol) impregnated activated carbon, carbon molecular sieves, Ti02 nanoparticles, layered materials, metal-organic frameworks and mesoporous molecular sieves have been studied as the dispersed non-zeolitic materials in the mixed-matrix membranes in the literature [23-35]. This chapter does not focus on these non-zeoUte/polymer mixed-matrix membranes. Instead we describe recent progress in molecular sieve/ polymer mixed-matrix membranes, as much of the research conducted to date on mixed-matrix membranes has focused on the combination of a dispersed zeolite phase with an easily processed continuous polymer matrix. The molecular sieve/ polymer mixed-matrix membranes covered in this chapter include zeolite/polymer and non-zeolitic molecular sieve/polymer mixed-matrix membranes, such as alu-minophosphate molecular sieve (AlPO)/polymer and silicoaluminophosphate molecular sieve (SAPO)/polymer mixed-matrix membranes. 

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). 

Wuest et al. have also prepared a related tetrahedral tecton 8.63, which also produces a diamondoid polymeric framework. In this case, the solid-state network is seven-fold interpenetrated, with one diamondoid lattice filling much of the large cavities in those adjacent. It is possible that the interpenetration in this instance is a result of the self-complementary nature of the host, which contains an equal number of hydrogen bond donor and acceptor sites. However, even in this case small cavities exist, which are filled by two molecules of butyric acid per host formula unit. The formation of these kinds of framework materials opens entirely new possibilities for tailor-made porous materials with very large cavities, although it is unlikely that purely organic frameworks will ever rival aluminosilicate-based materials for sheer mechanical strength. 

---