Open-framework materials

Late Transition Metal-Oxo Compounds and Open-Framework Materials that Catalyze Aerobic Oxidations Rui Cao, Jong Woo Han, Travis M. Anderson, Daniel A. Hillesheim, Kenneth I. Hardcastle, Elena Slonkina, Britt Hedman, Keith O. Hodgson, Martin L. Kirk, Djamaladdin G. Musaev, Keiji Morokuma, Yurii V. Geletii and Craig L. Hill... 

LATE TRANSITION METAL-OXO COMPOUNDS AND OPEN-FRAMEWORK MATERIALS THAT CATALYZE AEROBIC OXIDATIONS... 

III. Open-Framework Materials that Catalyze Aerobic Oxidations Acknowledgments References... 

Fig. 11. Synthesis of an open-framework material, 6 (structure of 6-Gd given in Figs. 12 and 13). Condensation of a bis(triester)hexavanadate unit with the pendant triester groups terminating in carboxylic acids, 5, with lanthanide ions form the open-framework catalytic materials.

Figs. 12 and 13 show the crystal structure of 6-Gd. Four of the linear POM-catalyst dicarboxylic acid units, 5, are linked by di-lanthanide paddle wheel junctions (Fig. 12) into the open-framework material 96). Fig. 13 shows the large channels in 6-Gd. These are filled with dimethylformamide (DMF) molecules that are hard to remove (the boiling point of DMF at 1.0 atmosphere — 151 °C). Thus while the solvent-accessible internal volume of 6-Gd is 50.5% of the crystal... 

Treatment of the open-framework materials at high vacuum and 70 °C results in collapse of the pores that are readily visible in the X-ray crystal structure (Fig. 13) and a nonporous structure (surface area[Pg.267]

The open-framework materials catalyze peroxide-based oxidations such as sulfoxidation, but significantly more noteworthy, 6-Tb catalyzes 02-based oxidations and does so at ambient or nearly ambient temperature (96). A case in point is the oxidation of thiols, a common odorant in human environments and a mildly toxic class of compounds, to disulfides that have almost no odor and are less toxic. The stoichiometry for oxidation of a representative substrate, 71-propane thiol, was established to be that in Eq. (1). After 30 days at 45 °C, 6-Tb produces ca. 19 turnovers of disulfide product based on the bis(trisester)Vg groups in the open-framework material, using only ambient air as the oxidant. 

Late Transition Metal- Compounds and Open-Framework Materials that Catalyze Aerobic Oxidations Rui Coo, Jong Woo Han, Travis M. Anderson, Daniel A. Hilleskeim, Kenneth... 

Maspoch D Ruiz-Molina D Veciana J, Old materials with new tricks Multifunctional open-framework materials, Chem. Soc. Rev., 2007, 36, 770-818. 

Feng, P. Bu, X. Stucky, G. D, Designed assemblies in open-framework materials synthesis An interrupted sodalite and an expanded sodalite. Angew. Chem., Int. Ed. Engl. 199S, 34, 1745. 

Meenakshi Dan is a student of the Integrated Ph.D. program at the Indian Institute of Science. Bangalore. She has a M.S degree in Chemistry from the Indian Institute of Science and works on open-framework materials. 

The literature on inorganic open-framework materials abounds in the synthesis and characterization of metal silicates, phosphates and carboxylates. Most of these materials have an organic amine as the template. In the last few years, it has been shown that anions such as sulfate, selenite and selenate can also be employed to obtain organically templated open-framework materials. This tutorial review provides an up-to-date survey of organically templated metal sulfates, selenites and selenates, prepared under hydrothermal conditions. The discussion includes one-, two-, and three-dimensional structures of these materials, many of which possess open architectures, The article should be useful to practitioners of inorganic and materials chemistry, besides students and teachers. The article serves to demonstrate how most oxy-anions can be used to build complex structures with metal-oxygen polyhedra. 

Inorganic open-framework compounds constitute an important class of materials that has attracted much attention as evidenced by the vast number of research papers published in the last few years. Although work in this area started with aluminium silicates1,2 because of their important uses in sorption and catalysis, much of the recent work pertains to the structure and characterization of open-framework metal phosphates and carboxylates. Both these families of open-framework materials have been reviewed recently.3 7 Since open-framework silicates and phosphates can essentially be... 

J. N. Behera obtained his MSc and BEd degrees from Utkal University and is now pursuing his PhD studies at the Indian Institute of Science, Bangalore. His work pertains to open-framework materials. 

Coordination polymers, open-framework materials, and hybrid compounds built up with various anions have been described in the literature. The most common anions employed in open-framework structures are silicates and phosphates.1-3 Metal carboxylates with a variety of structures and dimensionalities have also been described in the recent literature.4 5 In recent years, other oxyanions such as sulfate, selenate, selenite, and tellurite have also been employed to design these structures.6,7 Surprisingly, coordination polymers... 

Open-framework materials based on oxalates have been isolated in the presence of structure-directing amines. Although honeycomb architectures of transition metal oxalates has been known for some time, it is only in the past two years that open architectures of oxalates have been synthesized in the presence of amines. The first such materials synthesized are tin(II) oxalates [43,44], followed by oxalates of zinc [45], Bi-dentate carboxylates of metals are, however, known to form open-framework structures [46,47],... 

A new class of mixed open-framework materials consisting of both the phosphate and the oxalate units has been synthesized in the presence of structuredirecting agents [51-54], The solids thus prepared usually contain sheets made on metal phosphates, which are pillared by the oxalate units. In addition to the interesting architectures exhibited by them, the phosphate-oxalates also show remarkable adsorptive and other properties. In the case of the transition metal phosphate-oxalates, interesting magnetic properties have also been observed. We will discuss some select cases of the phosphate-oxalates of iron in the following. 

Besides zeolites, a diverse range of microporous materials with novel open-framework structures have been discovered. The framework atoms of microporous materials have expanded to include most of the elements in the periodic table.151 The framework elements are not limited to A1 and Si atoms alone, and the primary building units are not only confined to tetrahedra. This chapter will mainly describe the structural characteristics of zeolites and some zeolitic open-framework materials. 

Despite the limited number of framework types reported, the number of hypothetical topologies that can be designed by computational methods is infinite (see Chapter 7). It is believed that advances in synthetic chemistry, especially the use of hydrothermal/ solvothermal combinatorial techniques, will significantly accelerate the rapid discovery of new open-framework materials with diverse framework structures. 

The known classes of open-framework materials, such as zeolites, phosphates, and oxides, are primarily dominated by oxo frameworks. In 1989, however, Bedard and Wilson at of UOP[31] extended this kind of material to include metal sulfide compounds R-M MS-n (R indicates organic SDA M is a 3d or 4d metal M is Ge, Sn, Sb, or In). Their frameworks are constmcted by the corner-sharing or bridging of connected MS, clusters... 

J. Zhu, X. Bu, P. Feng, and G. Stucky, An Open-framework Material with Dangling Organic Functional Groups in 24-ring Channels. J. Am. Chem. Soc., 2000, 122, 11563-11564. 

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