There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Kenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Long

Carbon Dioxide Capture in Metal–Organic Frameworks

It is possible to say that zeolites are the most widely used catalysts in industry They are crystalline microporous materials which have become extremely successful as catalysts for oil refining, petrochemistry, and organic synthesis in the production of fine and speciality chemicals, particularly when dealing with molecules having kinetic diameters below 10 A The reason for their success in catalysis is related to the following specific features of these materials:1 (1) They have very high surface area and adsorption capacity (2) The adsorption properties of the zeolites can be controlled, and they can be varied from hydrophobic to hydrophilic type materials (3) Active sites, such as acid sites for instance, can be generated in the framework and their strength and concentration can be tailored for a particular application (4) The sizes of their channels and cavities are in the range typical for many molecules of interest (5-12 A), and the strong electric fields2 existing in those micropores together with an electronic confinement of the guest molecules3 are responsible for a preactivation of the reactants (5) Their intricate channel structure allows the zeolites to present different types of shape selectivity, ie, product, reactant, and transition state, which can be used to direct a given catalytic reaction toward the desired product avoiding undesired side reactions (6) All of these properties of zeolites, which are of paramount importance in catalysis and make them attractive choices for the types of processes listed above, are ultimately dependent on the thermal and hydrothermal stability of these materials In the case of zeolites, they can be activated to produce very stable materials not just resistant to heat and steam but also to chemical attacks Avelino Corma Canos was born in Moncofar, Spain, in 1951 He studied chemistry at the Universidad de Valencia (1967−1973) and received his PhD at the Universidad Complutense de Madrid in 1976 He became director of the Instituto de Tecnologia Quimica (UPV-CSIC) at the Universidad Politecnica de Valencia in 1990 His current research field is zeolites as catalysts, covering aspects of synthesis, characterization and reactivity in acid−base and redox catalysis A Corma has written about 250 articles on these subjects in international journals, three books, and a number of reviews and book chapters He is a member of the Editorial Board of Zeolites, Catalysis Review Science and Engineering, Catalysis Letters, Applied Catalysis, Journal of Molecular Catalysis, Research Trends, CaTTech, and Journal of the Chemical Society, Chemical Communications A Corma is coauthor of 20 patents, five of them being for commercial applications He has been awarded with the Dupont Award on new materials (1995), and the Spanish National Award “Leonardo Torres Quevedo” on Technology Research (1996) 2373 Chem Rev 1997, 97, 2373−2419

From Microporous to Mesoporous Molecular-Sieve Materials and Their Use in Catalysis

This critical review will be of interest to the experts in porous solids (including catalysis), but also solid state chemists and physicists. It presents the state-of-the-art on hybrid porous solids, their advantages, their new routes of synthesis, the structural concepts useful for their ‘design’, aiming at reaching very large pores. Their dynamic properties and the possibility of predicting their structure are described. The large tunability of the pore size leads to unprecedented properties and applications. They concern adsorption of species, storage and delivery and the physical properties of the dense phases. (323 references)

Hybrid porous solids: past, present, future

Metal Organic Frameworks in Biomedicine Patricia Horcajada,* Ruxandra Gref, Tarek Baati, Phoebe K. Allan, Guillaume Maurin, Patrick Couvreur, G erard F erey, Russell E. Morris, and Christian Serre* Institut Lavoisier, UMR CNRS 8180, Universit e de Versailles St-Quentin en Yvelines, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France Facult e de Pharmacie, UMR CNRS 8612, Universit e Paris-Sud, 92296 Châtenay-Malabry Cedex, France Institut Charles Gerhardt Montpellier, UMR CNRS 5253, Universit e Montpellier 2, 34095 Montpellier cedex 05, France EaStChem School of Chemistry, University of St. Andrews Purdie Building, St Andrews, KY16 9ST U.K.

Metal-organic frameworks in biomedicine.

Zeolites are versatile and fascinating materials which are vital for a wide range of industries, due to their unique structural and chemical properties, which are the basis of applications in gas separation, ion exchange and catalysis. Given their economic impact, there is a powerful incentive for smart design of new materials with enhanced functionalities to obtain the best material for a given application. Over the last decades, theoretical modeling has matured to a level that model guided design has become within reach. Major hurdles have been overcome to reach this point and almost all contemporary methods in computational materials chemistry are actively used in the field of modeling zeolite chemistry and applications. Integration of complementary modeling approaches is necessary to obtain reliable predictions and rationalizations from theory. A close synergy between experimentalists and theoreticians has led to a deep understanding of the complexity of the system at hand, but also allowed the identification of shortcomings in current theoretical approaches. Inspired by the importance of zeolite characterization which can now be performed at the single atom and single molecule level from experiment, computational spectroscopy has grown in importance in the last decade. In this review most of the currently available modeling tools are introduced and illustrated on the most challenging problems in zeolite science. Directions for future model developments will be given.

https://biblio.ugent.be/publication/6977178/file/8575390.pdf

Advances in theory and their application within the field of zeolite chemistry.

Terminally oxidized hydrocarbons are of considerable interest as potential feedstocks for the chemical and pharmaceutical industry, but the selective oxidation of only the terminal methyl groups in alkanes remains a challenging task. It is accomplished with high efficiency and selectivity by some enzymes; but inorganic catalysts, although inferior in overall performance under benign conditions, offer significant advantages from a processing standpoint1. Controlled partial oxidation is easier to achieve with ‘sacrificial’ oxidants, such as hydrogen peroxide2, alkyl hydroperoxides oriodosylbenzene3, than with molecular oxygen or air. These sacrificial oxidants, themselves the product of oxidation reactions, have been used in catalytic systems involving tailored transition-metal complexes in either a homogeneous state4,5,6, encapsulated in molecular sieves7,8,9 or anchored to the inner surfaces of porous siliceous supports10. Here we report the design and performance of two aluminophosphate molecular sieves containing isolated, four-coordinated Co(III) or Mn(III) ions that are substituted into the framework and act, in concert with the surrounding framework structure, as regioselective catalysts for the oxidation of linear alkanes by molecular oxygen. The catalysts operate at temperatures between 373 K and 403 K through a classical free-radical chain-autoxidation mechanism. They are thus able to use molecular oxygen as oxidant, which, in combination with their good overall performance, raises the prospect of using this type of selective inorganic catalyst for industrial oxidation processes.

Molecular-sieve catalysts for the selective oxidation of linear alkanes by molecular oxygen

Molecular Dynamics Simulations of Breathing MOFs: Structural Transformations of MIL‐53(Cr) upon Thermal Activation and CO2 Adsorption

Framework-substituted, molecular-sieve, aluminophosphate, microporous solids are the centerpieces of a new approach to the aerobic oxyfunctionalization of saturated hydrocarbons. The sieves, and the few percent of the AlIII sites within them that are replaced by catalytically active, transition-metal ions in high oxidation states (CoIII, MnIII, FeIII), are designed so as to allow free access of oxygen in to and out of the interior of these high-area solids. Certain metal-substituted, molecular sieves permit only end-on approach of linear alkanes to the active centers, thereby favoring enhanced reactivity of the terminal methyl groups. By optimizing cage dimension, with respect to that of the hydrocarbon reactant, as well as adjusting the average separation of active centers within a cage, and by choosing the sieve with the appropriate pore aperture, highly selective conversions such as n-hexane to hexanoic acid or adipic acid, and cyclohexane to cyclohexanol, cyclohexanone, or adipic acid, may be effected...

Molecular sieve catalysts for the regioselective and shape- selective oxyfunctionalization of alkanes in air.

Based on computational studies, we propose new metal−organic framework materials, in which the bridging ligands have been functionalized by different substituents, with the aim of improving the CO2 adsorption capacity of the material. The materials are based on the large-pore form of MIL-53(Al3+), with the following functional groups: OH-, COOH-, NH2-, and CH3-. For each form, adsorption heats and isotherms were simulated using the Grand Canonical Monte Carlo method which were found to be consistent with DFT calculations. The study illustrates the enormous impact of the functional groups in enhancing CO2 capture in the pressure range 0.01−0.5 bar and at room temperature. It also provides important insights into the structural factors which play a key role in the CO2 adsorption process in the functionalized MOFs. We propose the material (OH)2-MIL-53(Al3+) as an optimal candidate for improved CO2 capture at low pressures.

/pdf/functionalized-mofs-for-enhanced-co2-capture-1485yo4mxv.pdf

Robert G. Bell

Papers

Advances in theory and their application within the field of zeolite chemistry.

Molecular-sieve catalysts for the selective oxidation of linear alkanes by molecular oxygen

Molecular Dynamics Simulations of Breathing MOFs: Structural Transformations of MIL‐53(Cr) upon Thermal Activation and CO2 Adsorption

Molecular sieve catalysts for the regioselective and shape- selective oxyfunctionalization of alkanes in air.

Functionalized MOFs for Enhanced CO2 Capture