Prof. Jonah Jurss will present “Artificial Photosynthesis: Progress Toward Visible-Light Driven Water Splitting.”

Prof. Sasan Nouranian will present “Atomistic and Molecular Dynamics Simulations of Interfacial Nanochemistry and Nanomechanics of Polymers and Polymer Composites.”

Dr. David Jenkins from the University of Tennessee will present “Developing small-ringed macrocyclic tetracarbene ligands for catalytic systems.”

Abstract:
Despite the numerous advances in homogeneous catalysis that have been achieved through the use of N-heterocyclic carbenes (NHCs) as auxiliary ligands, very few macrocyclic polydentate carbenes have been synthesized.  Our group has synthesized a new ligand platform based on small-ringed (18 atoms) macrocyclic tetraimidazoliums as tetra-NHC precursors.  These small-ringed tetracarbene macrocycles form novel and reactive complexes on group 5, 6, 7, 8, 9, 10, and 11 metals.  Numerous novel tetracarbene complexes have been characterized by spectroscopic methods and X-ray crystallography, which demonstrates that the four carbenes bind to the metal in an equatorial configuration.  Our group is currently pursuing catalytic oxidative group transfer reactions with group 8 and 9 metal complexes.  One challenging catalytic reaction under investigation is the aziridination of unactivated aliphatic alkenes with simple organic azides.  Since the aziridine functional group is found in natural products and pharmaceuticals, broadening the scope of the reaction is significant.  The catalyst reacts with aryl azides and a wide variety of substituted aliphatic alkenes, including tetrasubstituted ones, to give aziridines in a C2 + N1 addition reaction.  Furthermore, this novel iron catalyst can be recovered and reused up to three additional times without significant reduction in yield.

Dr. Jie Zhang will present “Luminescent Metal Nanoparticles: Molecular Nanoprobes for Biomedical Imaging.”

Dr. Iryna O. Lebedyeva  from the University of Georgia will present “Identification and Design of Novel Chemical Entities in Early Drug Discovery.”

Dr. Hongshan He present “Broadband porphyrin dyes for nanocrystalline solar cells.”

Dr. David Graves from the University of Alabama-Birmingham will present “Protein Targeting of the G-Quadruplex Structure: Recognition Drives DNA Unfolding.”

Dr. Thomas Vaid from the University of Alabama will present “Main-Group Porphyrin Complexes, Including a (C=C)-Centered Porphyrin; Semiconducting Inorganic-Organic Hybrid Frameworks.”

Abstract:  The organic ring systems of porphyrin and phthalocyanine complexes have long been known to be electrochemically redox-active, and we have taken advantage of that redox activity to isolate oxidized and reduced (yet neutrally charged) main-group porphyrin and phthalocyanine complexes.  For example, the radical aluminum tetraphenylporphyrin bis(tetrahydrofuran), Al(TPP)(THF)₂, was synthesized and structurally characterized, and found to undergo a Jahn-Teller distortion that leads to alternating shortened and lengthened C‑C bonds on the porphyrin ring periphery, an effect that had not been observed previously.  In Si(TPP)(THF)₂ both structural and spectroscopic data indicate that the doubly reduced porphyrin is a 20 pi-electron antiaromatic system :  its ring system has alternating single and double C-C bonds, with a strong paratropic ring current evident in its NMR spectra.  Aromatic GeII(TPP) undergoes a remarkable reversible reaction with pyridine, forming antiaromatic GeIV(TPP)(py)₂.  The doubly oxidized [Li(TPP)][BF₄] contains an antiaromatic 16 pi-electron circuit.  Similar results concerning phthalocyanine complexes will be presented.

The vast majority of known metal-organic frameworks (MOFs) are electrically insulating, and there has been increasing interest in the creation of conducting MOFs, which could find use in high-surface-area electrodes and other applications.  In most MOFs the linkage between the metal and bridging ligand is formed by oxygen or nitrogen.  In analogy in to inorganic sulfides and selenides, MOFs containing sulfur or selenium are likely to have smaller band gaps and therefore more likely to be electrically conducting.  We have synthesized several sulfur and selenium-containing nonporous MOFs, and will discuss the salient structural features and electrical properties.

Title: Dr. Randy Wadkins’ Biochemical Research (CHEM 251/351)

Learn about the workings of biomedical science in the context of private and government agencies.  Prequisites. Dates: May 11-24. Scholarships available. Visit the Study USA page for information: http://www.outreach.olemiss.edu/study_usa/baltimore_dc14.html