This project aims to design and study metal-oxide organic frameworks with multifunctional properties. The possibility of finding unique physical properties in these compounds is the goal of the research. Metal-oxide organic frameworks will be constructed from metal-oxide chains cross-linked by organic anions as a large class of solids that possess the properties usually associated with porous solids. Metal-oxide organic frameworks are of special interest because they provide a unique platform for the study of dimensionality and size effects on magnetic, optical and dielectric properties. They are inherently multi-functional in that they combine the extended properties of the oxide component such as conductivity, magnetism, dielectric behavior, and optical properties with the properties of the organic species used to link the oxide chain or layer and the pore space that results. The research program will provide cutting-edge cross-disciplinary education aimed at training and developing scientists suitably equipped to contribute to academia and the advanced technology industries being based on the development and use of new materials. The program also aims to integrate diversity and research excellence into the workforce. %%% Recent advances in materials synthesis have led to the discovery of a large class of new hybrid organic-inorganic compounds with applications in catalysis and in processes for the selective separation of chemicals. A good possibility of finding unique physical properties in these compounds is expected because the compounds combine the characteristics of the inorganic component such as conductivity and magnetism with those of the organic species used to link the inorganic parts together and the pore space that results. The combination of properties may lead to useful devices such as sensors for toxic gases. The research program will provide cutting-edge cross-disciplinary education aimed at training and developing scientists suitably equipped to contribute to academia and the advanced technology industries being based on the development and use of new materials. The program also aims to integrate diversity and research excellence into the workforce.
The research that we have carried out has been concerned with specific topics on the synthesis, characterization, properties, and practical applications of porous solids usually known as metal-organic frameworks. As this field has developed, increasing attention has been given to the properties of these structures, for example, as sorbents, and catalysts, and in medicine for drug delivery. In the work funded by NSF, we have made an extensive study of a particular class of metal-organic frameworks usually designated as MIL-53. The MIL-53 compounds are a remarkable series that have flexible structures, large surface areas, high stability, and unusual molecule sorption properties. We have prepared several new examples of this class of compounds in single crystal form and investigated their adsorption properties for different molecule types. We discovered that one specific example has an unusual selectivity and high capacity for the removal of sulfur containing compounds from hydrocarbons with possible application in hydrodesulfurization of diesel and for clean-up of natural gas for use in high temperature fuel cells. In the latter case, the high capacity and the ease of regeneration are attractive for commercial use. In other work, we have discovered a new approach to the synthesis of porous-chiral frameworks based on commonly available chiral building blocks (aspartic acid, tartaric acid) combined with transition metal ions. Such new materials have potential applications for enantiomeric separations and heterogeneous asymmetric catalysis of importance in the pharmaceutical industry but which also have interesting optical and/or magnetic properties. We have built magnetic chiral frameworks using l-aspartic acid in which helical chains formed by coordination of aspartate to nickel ions are connected by cross linking them with organic bridges to form pores that can take up molecules. We have also made recently an unusual chiral-microporous antimony tartrate-iron oxide sandwich structure which is one of a large family of new frameworks containing iron and other transition metal ions Broader impact. The findings have impact on related disciplines including heterogeneous catalysis and separations by providing new compounds that can be used as bases for new selective chemical conversions, separations and as gas storage systems. Integration of research and education. The research program has broadly impacted science and education through the incorporation of minority and traditionally underrepresented groups at all levels of the program. To date, at the graduate and postgraduate level, female scientists have made up 33% of my group; at the undergraduate level the number is 50%. All of the students funded by the grant have benefitted directly from a cross-disciplinary education and scientific training in the Chemistry Department and at the Texas Center for Superconductivity (TcSUH). Outreach activities have included working with the UH Department of Curriculum and Instruction to provide tours and presentations on materials science for Houston ISD Middle School Teachers and visits to Thompson Elementary School and North Shore High School. I have participated as a judge in the Houston area School Science Fair. TcSUH sponsors three awards in materials at the Science Fair. These efforts toward cross-disciplinary education are aimed at training and developing scientists suitably equipped to contribute to academia and the advanced technology industries being based on the development and use of new materials. They are also aimed at integrating diversity and research excellence into the workforce.
