The Spring 2019 Chemistry Colloquium Series

This Spring, the Chemistry Colloquium will be held flexibly on Mondays or Wednesdays from 9:25–10:40 AM, with occasional presentations on other days as they arise. Seminars may be attended and viewed by ITV simulcast in Edinburg's Academic Services Building 1.104 and Brownsville's Student Union 2.22A (Salon Jacaranda). Refreshments will generally be provided.

The schedule of upcoming talks is currently being populated, with speakers still TBD for many dates. Please contact Dr. Shervin Fatehi, chair of the seminar committee, with nominations for speakers. Dates with confirmed speakers are listed below:


W Feb 06: Dr. Muhammad N. Huda (UT Arlington Physics)

Theoretical predictions and pure-phase stability analyses of complex solar absorber materials

Theoretical prediction of new materials and their experimental realization remains a significant challenge till this time. Once the possible composition of the material of a desired functionality is predicted, the primary problem is to determine whether the material can be synthesized in pure-phase in thermodynamic equilibrium conditions. In this regards, we are particularly interested in multi-cation complex oxides alloys as they offer flexible pathways to tune their electronic and optical properties. Even though metal-oxides are known to be stable, they have relatively higher band gaps. Another bottleneck is their persistent poor photo-conductivity. We will present a density functional theory (DFT) studies on our newly predicted solar absorber materials: CuBiW2O8 (CBTO) and CuSnW2O8 (CTTO). We’ll briefly present their electronic and optical properties and analyze their stabilities. Chemical potential landscape analyses revealed that both could be synthesized at flexible experimental growth conditions. Like other Cu-based compounds, the formations of Cu vacancies are probable and create shallow hole states. On the other hand, Cu2S is earth abundant, non-toxic and an important semiconductor with many applications. Previously it sought wide attention to the scientific community as a promising photovoltaic material since Cu2S based thin film solar cells demonstrated nearly 10% conversion efficiency. The major limitation of this materials is excessive Cu vacancy formation tendency. We have predicted a new phase of Cu2S: acanthite and a strategy to reduce Cu vacancy formations.


M Feb 11: Dr. James A. Dorman (Louisiana State University Chemical Engineering)

Modifying Synthesis and Processing Conditions to Engineer Electronic States in Spatially Controlled Nanostructures

Rare earth ions play a significant role in the global economy due to their unique luminescent, catalytic, and magnetic properties resulting from their f electrons. However, there has been a push to replace these materials with earth abundant counterparts to ensure the US economy is self-sustaining. The transition metal elements offer a viable alternative to the rare earths but a commonly avoided due to the d-orbital susceptibility to the host lattice, resulting in unpredictable properties. On large scales, the d-orbital susceptibility can be overcome via application of pressures and electric fields which is not possible at the nanoscale.  Additionally, the it can be difficult to stabilize specific oxidation states of transition metals necessary for specific electronic and luminescent properties. As such, the ability to tune these properties is dependent on the dopant distribution and defect concentrations, requiring careful synthetic conditions or vacuum deposition methods which limit mass production. In this work, I will present our work engineering the electronic landscape of doped oxides via the synthesis and treatment of precursors for spatially controlled nanostructures. Specifically, I will focus on how this spatially control leads to enhanced chemical stability and catalytic/luminescent properties. Finally, I will discuss how surface decoration with polarized ligands can induce localized crystal field effects similar to those seen when high pressure or electric fields are applied. These polarized ligands allow for the modification optical properties and the ability to enhance/quench the luminescent properties of these materials.


M Feb 18: Dr. Jin Z. Zhang (University of California Santa Cruz)

Novel Optical Properties of Plasmonic Metal Nanostructures: A Case Study of Hollow Gold Nanospheres (HGNs) and Their Applications in Sensing, Imaging, and Cancer Therapy

As an important member of the family of plasmonic metal nanostructures, hollow gold nanospheres (HGNs) exhibit unique optical and photothermal properties useful for many applications including SERS (surface enhanced Raman scattering) sensing, optical imaging, drug delivery, and photothermal therapy (PTT) of cancer. We have conducted extensive studies of the mechanism behind the growth of HGNs and determined the important role several factors including oxygen in the reaction process using a number of spectroscopic techniques including X-ray spectroscopy. Based on the understanding of the growth mechanism, we are able to control the synthesis of HGNs with well-defined size and shell thick, allowing surface plasmon resonance (SPR) at specific wavelength to be achieved, especially the highly desired near IR (NIR) region. In addition, we can control the surface morphology of the HGNs by varying surface ligand molecules or pH. The synthesized HGNs have been used for in vitro studies of HGN-mediated PTT of oral squamous cell carcinoma (A431), with the primary goal to optimize the bioconjugation and the HGNs for best PTT performance. I will also give some background information about our previous work that led to the development of the HGNs.


R Mar 28: Dr. Mitsuhiro Arisawa (Osaka University Grad. School of Pharmaceutical Sciences)

Recyclable, Low-Leaching, and Ligand-Free Suzuki–Miyaura Coupling Using Ruthenium(0) Nanoparticles

We previously developed a sulfur-modified Au-supported Pd catalyst (SAPd) and used it to catalyze Suzuki–Miyaura coupling, Buchwald–Hartwig coupling, C–H functionalization, double carbonylation, removal of the allyl protecting groups of allyl esters and redox switching. We found that SAPd consists of approximately ten layers of self-assembled Pd(0) nanoparticles with a size of less than 5 nm on a sulfur-modified Au surface. These Pd nanoparticles are encapsulated in a sulfated p-xylene polymer matrix. We speculated that the self-assembled Pd nanoparticles were constructed by in situ metal nanoparticle and nanospace simultaneous organization (PSSO). This involves four simultaneous procedures: i) reduction of a high-valence metal source, ii) growth of transition-metal nanoparticles of appropriate size, iii) growth of a matrix with appropriate pores, and iv) encapsulation of the metal nanoparticles in matrix nanopores. This method is quite different from conventional nanoparticle-immobilizing methods using solid supports with preformed pores or coordination sites. Here, we report a conceptually and methodologically novel Ru(0) nanoparticle catalyst, sulfur-modified gold-supported Ru nanoparticles (SARu). SARu is easily prepared through a three-step procedure involving simultaneous in situ PSSO method. SARu is an ideal Ru catalyst for liquid-phase combinatorial synthesis because it repeatedly catalyzes ligand-free Suzuki–Miyaura coupling of aryl halides, including aryl chlorides, with arylboronic acids with low Ru leaching. Physical analysis of SARu showed that the active species in these reactions were Ru (0) nanoparticles with a size of 1–3 nm.


W Apr 17: Dr. HyeongJun Kim (UTRGV Physics)

Single-molecule studies of how MORC protein functions and condenses DNA

Microrchidia (MORC) proteins are a highly conserved family of GHKL (Gyrase, HSP90, Histidine Kinase, MutL) ATPases that are critical for gene silencing and chromatin compaction in both plants and animals. However, the functional mechanism by which MORCs act is poorly understood. Here we show that C. elegans MORC-1 protein binds to DNA in a length-dependent yet non-sequence specific manner. To further elucidate mechanisms of MORC function, various single-molecule techniques based on fluorescence and force were employed. First, our single-molecule flow-stretching experiments show that it can robustly compact naked DNA in a mildly ATP-dependent manner. After initial binding to DNA, MORC-1 forms multimeric assemblies that grow as DNA compaction proceeds, which is consistent with our observations that MORC-1 forms discrete nuclear puncta in C. elegans. Another single-molecule technique called DNA motion-capture assay based on the laminar flow nature of our microfluidic flowcell indicates that this DNA condensation activity appears to act via a loop trapping mechanism. Furthermore, the multimeric assemblies do not leave the flow-stretched DNA upon high salt wash when the free end of the DNA is taggedwith a bulky quantum dot, which suggests that they topologically entrap the DNA. These results highlight several aspects of MORC-1 complex assembly on DNA that are relevant to understanding the fundamental mechanism of MORC action in a variety of organisms.


W May 01: Maj. Francesco J. Echeverria, Ph.D. (United States Air Force Academy Physics)

Opportunities for STEM Students & Faculty in the United States Department of Defense

The Department of Defense $686B budget for FY2019 is every indication that national security will remain a top priority for many years.  From the development and production of critical aircraft such as the F-35 Joint Strike Fighter to investing in missile defense programs such as the AEGIS Ballistic Missile Defense System, the military services look to major warfighting investments for homeland defense and preeminent military superiority around the world.  It is for those reasons that the Department of Defense and the military services are in high demand for Science, Technology, Engineering, and Mathematics (STEM) career fields.  Major Francesco J. Echeverria will primarily discuss some of the opportunities that he has encountered and experienced throughout his 16 year career as a scientist and military officer in the United States Air Force.  From assistant professor in academia to supervising technological programs, he will look to provide insight to undergraduate and graduate students on the enormous demand of technical degrees and requirements within the military services and the Department of Defense.

The Fall 2018 Chemistry Colloquium Series

This Fall, the Chemistry Department is introducing a Chemistry Colloquium presented by a range of internal and external speakers on Thursdays from 3:05–4:20 PM. Seminars may be attended and viewed by ITV simulcast in Edinburg's Engineering Building 1.262 and Brownsville's Main Building 1.220. Refreshments will generally be provided.

The schedule of upcoming talks is currently being populated, with speakers still TBD for many dates. Please contact Dr. Shervin Fatehi, chair of the seminar committee, with nominations for speakers. Dates with confirmed speakers are listed below:


Sep 27: Dr. Yuanbing Mao (UTRGV Chemistry)

Exploration of the Synthesis and Properties of Metal Oxide Nanomaterials

Scaling metal oxides to nanoscale dimensions substantially alters their phase stabilities and interfacial activities with tremendous consequences for the manifestation of unique physical phenomena. Developing novel metal oxide nanomaterials and understanding their synthesis-structure-property relationship have paramount importance to meet the materials needs and challenges of our evolving and expanding society. In this seminar, an overview of my research will be given on three areas, i.e. luminescence, catalysis, and environmental remediation. For luminescent nanomaterials useful for solid-state lighting, X-ray scintillators, and bioimaging, we focus on pyrochlore A2M2Onanoparticles. We have achieved substantial tunability of their particle size, crystal phase, and more importantly, luminescence properties. We have gained clear understanding of the influences of the synthesis conditions, particle morphology and composition on their photoluminescence and radioluminescence. For catalysis, we have explored (i) delafossites with CuIMIIIOcomposition and (ii) branched ZnO nanostructures as cost-effective and active electrode materials for (photo)electrical water splitting. Regarding environmental remediation, we developed a facile coating method for TiO2particles with a thin organic layer to increase their photocatalytic water purification efficiency of both cationic and anionic contaminants. In sum, we have explored three types of functional metal oxide nanomaterials, which offer bright promise of producing innovative advances across multiple technologies, and thus will continue impacting our lives in substantial ways.


Oct 18: Dr. Myoung-Hwan Kim (UTRGV Physics)

Tailoring Evanescent Light on Surface

Optical index engineering using metamaterials has been quite successful in creating a new class of artificial optical materials, which bends light at will. Two-dimensional metamaterials called metasurfaces represent a much more attractive platform for the shorter wavelengths due to the ease of fabrication taking advantage of current planar integrated circuit technology. Particularly, metasurfaces can create gradient optical responses including amplitude, phase, polarization, and impedance which can mold the wavefronts of light. In this talk I will introduce the basic concept of metasurfaces to control light propagation in free space and in optical waveguides. Furthermore, I will present our recent experimental demonstration of a new metasurface platform with hyperbolic materials to control light localized on the surface. We observed a near-perfect absorption from tunable surface phonon polariton resonances confined in subwavelength-thin nanostructures. This metasurface platform can be used as the main building block in mid-/far infrared flat optical devices and integrated nanophotonic devices.


Nov 1: Dr. Jyoti Prakash (Arizona State University/Bhabha Atomic Research Centre)

Innovative Societal Applications of Solar Energy: Moving Beyond Photovoltaic Modules

I will be talking about innovative use of solar energy to fuel different sectors of society using nonconventional solar devices. The lecture will cover current renewable energy status (especially solar energy) and how we can innovate new devices to harvest solar light to fuel major energy consuming sectors such as domestic and industrial heating/cooling, and transport. I will be covering basic material design & development and integrating components for harvesting light efficiently.


Nov 8: Dr. Evangelia Kotsikorou (UTRGV Chemistry)

Exploring the reliability of a homology model of GPR119 receptor to predict the EC50s of a set of agonist compounds

GPR119 receptor is a target for type 2 diabetes therapies. Many different compounds have been synthesized to date in hopes of discovering an orally available and effective therapy for T2D. Crystal structures assist in the development of potent ligands for the receptor, but there is no crystal structure of this receptor available today. In the absence of a crystal structure, we constructed a homology model of the receptor that can be used to identify and develop new potent compounds. To test the reliability of the homology model, we conducted a blind computational study to evaluate the relative potency of a set of compounds. Docking studies followed by analysis of the interactions between the docked ligands and the receptor shed light on the types of interactions these compounds have with the receptor, the magnitude of these interactions and the importance of specific amino acids of the binding pocket in ligand binding. The analysis showed that the homology model estimated correctly the energy of interaction of these compounds with the receptor. The energy of interaction of a compound correlates with the potency for activating the receptor. The experimental EC50s were in agreement with the predicted potency of the set of compounds, validating the GPR119 receptor homology model and suggesting that it is a valuable tool for predicting compound potencies.


Nov 15: Dr. Sarah Co (AbbVie Inc.)

Large-Scale Tales: Active Pharmaceutical Ingredients from Development to Commercial Manufacturing at AbbVie 

AbbVie may have a new name, since its separation from Abbott Laboratories in 2013, but it has a rich heritage from its Abbott roots, dating from 1888. AbbVie defines itself as a biopharmaceutical company, meaning we combine the resources of a large, established corporation with the focus and innovation of a biotech. Our patient-centered approach focuses on areas of unmet medical need, including oncology, virology, immunology, and neuroscience. 

Chemists at AbbVie, working in different functions, make significant contributions to the discovery, development, and commercialization of a medicine. An overview of process development and commercialization of small-molecule active pharmaceutical ingredients (APIs) will be presented, highlighting the roles of chemists along a medicine’s path from discovery through approval and beyond. Vignettes from process development and commercial manufacturing will be described.


Nov 29: Dr. Bandana Chatterjee (UT Health Science Center San Antonio Dept. of Molecular Medicine)

Leveraging Androgen-Androgen Receptor Axis for Prostate Cancer Inhibition

Oncogenic activities of androgen receptor (AR) and mTORC1 (Mechanistic Target oRapamycin Complex-1) are key drivers of prostate cancer progression to the metastatic castration resistant prostate cancer (mCRPC), which is aggressive, incurable and fatal. The AR-mediated intracellular signaling remains active throughout the disease continuum.  Furthermore, the PI3K/AKT/TORC1 axis is activated in most cases of late-stage, treatment resistant prostate cancer. The current standard of care for prostate cancer is effective for a limited period.  Novel treatment avenues are needed for sustained success in prostate cancer inhibition. Several new strategies for the inhibition of advanced prostate cancer will be discussed.