Abraham Clearfield
Distinguished Professor
Ph. D., Rutgers University
Contact
Information:
Department of Chemistry
Texas A&M University
College Station, TX 77842
Phone:
(979) 845-2936
Fax: (979) 845-4719
clearfield@mail.chem.tamu.edu
Our research interests are focused in solid state and materials chemistry and encompass a wide variety of projects. An important goal is the ability to design and synthesize new materials whose structure and properties can be predicted and controlled. Layered compounds are amenable to manipulation to produce new structures because of the weak forces between layers. We have learned how to separate the layers of several classes of compounds and are reconstituting them into novel materials. For example, photochemically active species may be encapsulated to produce permanently porous structures of controlled pore size. Such compounds may prove to be selective catalysts.
Layered proton conductors and self-assembled supramolecules of novel structures and properties have been prepared. Some of these find utility in the separation of radioactive ions from nuclear waste.
Zeolites are among the most powerful and versatile catalysts known. We have initiated a program to synthesize new materials with pores in the 10-20Å range. These materials include organic-inorganic hybrids as well as mixed metal oxides.
Single crystal X-ray diffraction has been the key tool in elucidating the structure of solids. For many compounds, single crystals are unavailable so that indirect methods need to be used. We pioneered the solution of crystal structures from X-ray powder data and have had considerable success. The methods need to be improved and extended to more complex systems such as poorly crystallized materials. Combined use of X-ray, neutron and synchrotron methods are in progress and extension to EXAFS and amorphous scattering techniques is contemplated.
Addition of layered materials to polymers is our most recent project. Complete dispersal of the layers within the polymer has been obtained and properties of the composite determined.
C.V.K. Sharma and A. Clearfield, Macrocyclic Leaflets, J. Am. Chem. Soc. 122, 1558 (2000).
A. Clearfield, Inorganic Ion Exchangers, Past, Present and Future, Solv. Extrn. Ion Exch. 18, 655-678 (2000).
C.V.K. Sharma and A. Clearfield, Three-Dimensional Hexagonal Structures from a Novel Self-Complementary Molecular Building Block, J. Am. Chem. Soc. 122, 4394-4402 (2000).
Z. Wang, J. Heising and A. Clearfield, Sulfonated Microporous Organic-Inorganic Hybrids as Strong Bronsted Acids , J. Am. Chem. Soc., 125, 10375-10383 (2003)
A. Tripathi, D.G. Medvedev, M. Nyman and A. Clearfield, Selectivity for Cs and Sr in Nb-Substituted Titanosilicate with Sitinakite Topology, J. Solid State Chem . , 175, 72-83, (2003)
A. Tripathi, T. Hughbanks and A. Clearfield, The First Framework Solid Composed of Vanadosilicate Clusters , J Am. Chem. Soc., 125, 10528-10529, (2003).
