Research in the Alexanian Group focuses on the general areas of reaction development and chemical synthesis. Our studies are ultimately driven by the discovery of new and useful forms of chemical reactivity. A theme of these studies is an emphasis on catalytic transformations employing easily accessed substrates and common molecular functionality. We also use the wide array of unique architectures found in nature to challenge and inspire ourselves to develop creative solutions to current problems in complex molecule synthesis.
One current area of investigation is the utilization of simple hydroxamic acids to develop general, radical-mediated approaches to the metal-free difunctionalization of alkenes. We are also exploring novel approaches to the catalytic activation of alkyl electrophiles for the development of new carbon-carbon bond-forming processes, and the development of new complexity-generating multi-component cycloadditions for synthesis. Ultimately, we strive to apply these new processes to the efficient syntheses of bioactive natural and un-natural products.
The research in the Rubinstein Group is in the field of polymer theory and computer simulations. The unique properties of polymeric systems are due to the size, topology and interactions of the molecules they are made of. Our goal is to understand the properties of various polymeric systems and to design new systems with even more interesting and useful properties. Our approach is based upon building and solving simple molecular models of different polymeric systems. The models we develop are simple enough to be solved either analytically or numerically, but contain the main features leading to unique properties of real polymers. Computer simulations of our models serve as an important bridge between analytical calculations and experiments.
Solar energy has long been used as a clean alternative to fossil fuels such as coal and oil, but it could only be harnessed during the day when the sun's rays were strongest.
Now researchers led by Tom Meyer at the Energy Frontier Research Center at UNC-Chapel Hill have built a system that converts the sun's energy not into electricity but hydrogen fuel and stores it for later use, allowing us to power our devices long after the sun goes down.
Presently, there are few estimates of the number of molecules occupying membrane domains. In a collaborative work published in the journal Traffic, researchers in the Thompson Group describe how they, using a total internal reflection fluorescence microscopy (TIRFM) imaging approach, based on comparing the intensities of fluorescently labeled microdomains with those of single fluorophores, measured the occupancy of DC-SIGN, a C-type lectin, in membrane microdomains.
DC-SIGN or its mutants were labeled with primary monoclonal antibodies (mAbs) in either dendritic cells (DCs) or NIH3T3 cells, or expressed as GFP fusions in NIH3T3 cells. The number of DC-SIGN molecules per microdomain ranges from only a few to over 20, while microdomain dimensions range from the diffraction limit to > 1 µm. The largest fraction of microdomains, appearing at the diffraction limit, in either immature DCs or 3 T3 cells contains only 4–8 molecules of DC-SIGN, consistent with the group's preliminary super-resolution Blink microscopy estimates. The article further discusses how these small assemblies are sufficient to bind and efficiently internalize a small (∼50 nm) pathogen, dengue virus, leading to infection of host cells.
Carolina Chemistry's David Nicewicz has received the 2013 New Investigator Award in Organic Chemistry. Sponsored by Boehringer Ingelheim, the world's largest privately held pharmaceutical company, the award of $50,000 will be given to David towards the funding of a post-doctoral fellow in his laboratory.
The Nicewicz Group conducts research in the broadly defined fields of asymmetric catalysis and target-oriented synthesis. Concerning the area of asymmetric catalysis, the group focuses primarily on the development of novel catalytic processes to access highly reactive intermediates under operationally mild conditions. Methods encompassing the general areas of electron transfer and atom abstraction are of particular interest.
In studying a material that prevents marine life from sticking to the bottom of ships, researchers led by Carolina Chemistry's Joseph DeSimone, have identified a surprising replacement for the only inherently flammable component of today's lithium-ion batteries: the electrolyte.
The work, published in the Proceedings of the National Academy of Sciences, not only paves the way for developing a new generation lithium-ion battery that does not spontaneously combust at high temperatures, but also has the potential to —after recent lithium battery fires in Boeing 787 Dreamliners and Tesla Model S vehicles— renew consumer confidence in a technology that has attracted significant concern.
Artificial photosynthesis and the production of solar fuels could be a key element in a future renewable energy economy providing a solution to the energy storage problem in solar energy conversion. Published in PNAS and chosen as "paper of the month" by The Latest Science, researchers in the Meyer Group describe a hybrid strategy for solar water splitting based on a dye sensitized photoelectrosynthesis cell.
Solar water splitting into H2 and O2 with visible light has been achieved by a molecular assembly. The dye sensitized photoelectrosynthesis cell configuration combined with core–shell structures with a thin layer of TiO2 on transparent, nanostructured transparent conducting oxides (TCO), with the outer TiO2 shell formed by atomic layer deposition. In this configuration, excitation and injection occur rapidly and efficiently with the injected electrons collected by the nanostructured TCO on the nanosecond timescale where they are collected by the planar conductive electrode and transmitted to the cathode for H2 production. This allows multiple oxidative equivalents to accumulate at a remote catalyst where water oxidation catalysis occurs.
Scientists in the Johnson Group, in collaboration with researchers from GlaxoSmithKline, as published in Organic Letters, show how a high throughput screening enabled the development of a copper-based catalyst system for the asymmetric hydrogenation of prochiral aryl and heteroaryl ketones that operates at H2 pressures as low as 5 bar.
A ligand combination of (R,S)-N-Me-3,5-xylyl-BoPhoz and tris(3,5-xylyl)phosphine provided benzylic alcohols in good yields and enantioselectivities. The electronic and steric characteristics of the ancillary triarylphosphine were important in determining both reactivity and selectivity.
At the Department of Chemistry, we feel strongly that diversity is crucial to our pursuit of academic excellence, and we are deeply committed to creating a diverse and inclusive community. We support UNC's policy, which states that "the University of North Carolina at Chapel Hill is committed to equality of opportunity and pledges that it will not practice or permit discrimination in employment on the basis of race, color, gender, national origin, age, religion, creed, disability, veteran's status, sexual orientation, gender identity or gender expression."