Coordination Polymer Heterostructures, More than the Sum of the Parts
Daniel R. Talham
Department of Chemistry, University of Florida
Assembled from molecular precursors, coordination polymer solids offer the ability to alter behavior through molecular synthesis, an advantage often attributed to molecular materials or organic polymers, yet they can possess physical properties more commonly associated with the inorganic solid state. While coordination polymer materials were a relatively late addition to the nanoscience revolution, even more recent is a focus on nanoscale and mesoscale heterostructures of coordination polymer solids. At the mesoscale, surfaces and interfaces play key, sometimes dominant roles in dictating properties. Using primarily cyanometallate coordination polymers, this presentation will look at some examples for which new behavior is seen in submicron heterostructures, properties that are different from those observed in the bulk or in smaller nanoparticles. Examples include studies of magnetism and light-switchable magnetism, structural phase transitions, and alkali-ion storage for battery applications.
Can a Catalytic Process for oxidation of N2 or N2O to nitrate be developed?
Elena V. Rybak-Akimova1, Taryn D. Palluccio1, Christopher C. Cummins2, Steven P. Nolan3, Catherine S. J. Cazin3, Manuel Temprado4, Jack Davis5, Leonardo F. Serafim5, Burjor Captain5, Carl D. Hoff5
1. Tufts University, 2. Massachusetts Institute of Technology, 3. University of Ghent, 4. University of Alcala, 5. University of Miami.
Production of ammonia in the Haber process is one of the largest industrial users of hydrogen gas, due to the large demand of NH3 by the fertilizer industry. Close to half of the ammonia produced is combusted in the Ostwald process to form HNO3. During that process N2O and NOx are produced as waste gases which are removed by the BASF DeNOx process. Nitrous oxide in particular is a potent greenhouse gas, approximately three hundred times more potent in infrared absorption than isoelectronic CO2. Energetic savings in both of these processes can in principle be achieved by development of new technologies and catalysts.
Thermochemical calculations of Lewis in the 1920’s showed that production of dilute HNO3 directly from N2, O2, and H2O was marginally favorable at ambient temperatures. Addition of a base can readily be calculated to yield a strong driving force as shown in reactions (1) and (2). The feedstock for these processes do not involve energy costs comparable to current technologies.
N2(g) + 2.5 O2 + Na2O(s) --> NaNO3(s) ) dG300 = -76 kcal/mol (1)
N2O(g) + 2 O2 + Na2O(s) --> NaNO3(s) dGo300 = -109 kcal/mol (2)
Development of a catalyst for reaction (1) has not been extensively studied in spite of the fact that it could represent a significant reduction in H2 to produce NH3 which is later combusted in the Ostwald process. In the BASF DeNOx process NH3 is added to the flue gas stream to reduce N2O to N2 by NH3. This also corresponds to a loss in H2 equivalents in the emerging hydrogen economy. Development of a catalyst for reaction (1) presents greater kinetic barriers than does reaction (2) making it more challenging but also more rewarding. In this presentation studies of binding and activation of O2, N2, and NxOy will be discussed together with relevant literature reports to analyze the prospects for developing better methods to clean up the waste gas stream from the Ostwald process as a first step toward the long range goal of replacing it.
Drug Discovery Efforts at UNF
Kenneth K. Laali
Department of Chemistry, University of North Florida
Parent curcumin CUR (a natural product constituent in turmeric) has a wide spectrum of biological activity as anti-inflammatory, anti-tumor, antioxidant, and antibacterial agent, but efforts to develop CUR as a therapeutic agent have not met with success due to major drawbacks associated with its low solubility, low bioavailability, and rapid metabolism.
In a quest to find "hit-compounds" inspired by CUR, but with improved physicochemical characteristics for clinical development, we are working on a multi-faceted project that combines synthesis, NMR studies and X-ray analysis with DFT optimizations, computational/docking studies and in-vitro bioassay. To date several libraries of curcuminoids (over 80 compounds) have been synthesized and characterized, and a significant number have been tested for anti-tumor activity against a host of cancer cell lines. A progress review will be presented.