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, we have prepared staged materials in which alternating layers are hydrophobic and hydrophilic.
The surfaces of our layered materials react with a variety of molecules to bond them to the surface. We are developing such materials for drug delivery, heterogeneous catalysis, and polymer-nanoparticle composites.
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.
Diaz, Agustin; David, Amanda; Perez, Riviam; Gonzalez, Millie L.; Baez, Adriana; Wark, Stacey E.; Zhang, Paul; Clearfield, Abraham; Colon, Jorge L. Nanoencapsulation of Insulin into Zirconium Phosphate for Oral Delivery Applications. Biomacromolecules (2010), 11(9), 2465-2470.
Konar, Sanjit; Gagnon, Kevin; Clearfield, Abraham; Thompson, Charles; Hartle, Jennifer; Ericson, Clayton; Nelson, Chad. Structural determination and characterization of copper and zinc bis-glycinates with X-ray crystallography and mass spectrometry. Journal of Coordination Chemistry (2010), 63(19), 3335-3347.
Perry, Houston; Zon, Jerzy; Law, Justin; Clearfield, Abraham. Structural variations of SnII pyridylphosphonates influenced by an uncommon Sn-N interaction. Journal of Solid State Chemistry (2010), 183(5), 1165-1173.
Shpeizer, B. G.; Bakhmoutov, V.I.; Zhang, P.; Prosvirin A.V.; Dunbar K. R.; Thommes, M.; Clearfield, A. Transition metal-alumina/silica supermicroporous composites with tunable Porosity. Colloids and Surfaces, A: Physiochemical and Engineering Aspects (2010), 357, 105-115.
Clearfield, Abraham. Seizing the caesium. Nature Chemistry (2010), 2(3), 161-162.
Kirumakki, S.; Huang, J.; Subbiah, A.; Yao, J.; Rowland, A.; Smith, B.; Mukherjee, A.; Samarajeewa, S.; Clearfield, A., Tin(IV) phosphonates: porous nanoparticles and pillared materials. J. Mater. Chem. 19, 2593-2603 (2009).