Upcoming Events

Wednesday, October 23, 2019 - 10:00am

Yen Nguyen Final Oral - VanVeller Group

Wednesday, October 23, 2019 - 2:10pm to 5:00pm

The event will occur in various rooms in Pearson Hall, with full information here: https://www.grad-college.iastate.edu/three-minute-thesis/

Here’s the list of students from Chemistry, in chronological order:

Friday, October 25, 2019 - 1:10pm

Eastman

Javier Grajeda

Eastman Chemical Company

(Vela)

Friday, October 25, 2019 - 2:00pm to 3:00pm

Come meet the 2019 ISU Chemistry Alumi Award receipent on Friday, October 25, 2-3pm in the Hach Hall Lobby.

Friday, October 25, 2019 - 3:10pm

Don Ronning

Don Ronning

Department of Chemistry & Biochemistry, The University of Toledo

(Anderson)

Tuberculosis is responsible for 1.5 million deaths each year. This is more than any other infectious disease caused by a single pathogen and no new first-line drugs for TB have entered the clinic in more than 50 years. My group combines structure/function relationship studies on Mycobacterium tuberculosis drug targets with library screening to improve the TB drug pipeline. The complementary tools of X-ray crystallography and enzyme kinetics/inhibition studies form the basis for identifying new TB-active compounds as well as the characterization of known anti-tubercular compounds with ambiguous mechanism-of-action. In particular, our studies have clarified the mechanism-of-action of Isoxyl, Thiacetazone, and Ebselen anti-bacterial activity against M. tuberculosis and shown that covalent modification of cysteine residues on bacterial protein targets is a valuable inhibitory mechanism. This presentation will discuss how we are applying that understanding and building upon those observations to develop second-generation, dual-function covalent inhibitors of mycobacterial mycolyltransferases. Preliminary results suggest that these compounds function synergistically with b-lactams in non-pathogenic mycobacteria and we are working to understand the mechanistic basis of this apparent synergy.

Monday, October 28, 2019 - 2:00pm

He Nan Final Oral Exam Anderson Group

Friday, November 1, 2019 - 1:10pm

Chengfeng Ke

Chenfeng Ke

Department of Chemistry, Dartmouth College

(Zhao)

Nature long ago solved problems plaguing contemporary chemists with polydispersity and controlled synthesis at the nanoscale. The blueprint of life, DNAs, are synthesized with high precision with the aid of multiple hydrogen bonding interactions. Our research program aims to develop smart organic and polymeric materials with multivalent hydrogen bonding interactions with functions that are currently beyond our grasp. In this talk, I will be presenting two major projects in our group: (1) developing smart 3D printing materials that change their shapes upon external stimuli; and (2) designing elastic crystalline porous organic frameworks for radioactive iodine removal. I will share my experience of designing smart materials from an organic/materials chemist’s perspective and using 3D printers for education and outreach activities.

Wednesday, November 6, 2019 - 10:00am

Peter Spurgeon Thiel Group Final Oral

Friday, November 8, 2019 - 1:10pm

Raymond SchaakRaymond Schaak

Department of Chemistry, Pennsylvania State University

(Kovnir)

Multi-component nanoparticles offer unique opportunities to combine different properties in a single construct, enabling both multi-functionality and the emergence of new synergistic functions. Synthesizing such multi-component nanoparticles requires simultaneous control over size, shape, composition, and structure, as well as interfaces and spatial arrangements. We have been developing two complementary strategies for synthesizing multi-component nanoparticles. The first approach involves heterogeneous seeded growth, where interfaces and asymmetry are introduced by sequentially growing new nanoparticles off of the surfaces of existing nanoparticles. Complex hybrid nanoparticles of a growing number of materials, configurations, and morphologies can now be synthesized. The second approach involves sequential partial cation exchange reactions, where interfaces and asymmetry are introduced by compositional modifications that are made within an existing nanoparticle. A growing library of complex heterostructured metal sulfide nanoparticles can now be rationally designed and then readily synthesized.

Friday, November 8, 2019 - 3:10pm

Clifford Russell Bowers

Clifford Russell Bowers

Department of Chemistry, University of Florida

(Huang)

Nuclear spin singlet-states are attracting a lot of attention nowadays because they can significantly extend the useable lifetime of hyperpolarization. Singlet order decays more slowly than ordinary magnetization because the former is protected from the intra-pair dipole-dipole relaxation mechanism. Singlet-triplet imbalance (STI), which refers to the population differential between the singlet and triplet manifolds for a pair of strongly coupled spin-1/2 nuclei, can be prepared directly from parahydrogen, the singlet spin isomer of dihydrogen that is easily generated by cooling the gas in the presence of an ortho-para conversion catalyst. With perfect magnetic equivalence and isolation, the parahydrogen singlet is the quintessential long-lived state with a lifetime of many weeks. The transformation of singlet order into observable Zeeman order can be achieved by symmetry breaking chemistry.1 The key requirement is pairwise addition with retention of inter-pair spin-spin coupling. This talk will survey some highlights from our recent research utilizing heterogeneous catalysis to convert dihydrogen STI into magnetization on various target molecules in gases and solution. One of the main challenges that needs to be overcome is the fast diffusion of H ad-atoms that is typically observed on the catalytically active metal surfaces. We show that through rational design of heterogeneous catalysts, significant improvements can be made in the efficiency of the singlet-to-magnetization transformation.2-3 Three examples are presented: ultra-low loadings of Pt on shaped cerium oxide nanocrystal supports, PtSn intermetallic nanoparticles for hyperpolarization of water and alcohols, and certain other bimetallic combinations that have delivered substantially higher performance than monometallic nanoparticle catalysts. Lastly, a new approach utilizing heterogeneous catalysis for the continuous-flow synthesis of symmetric and pseudo-symmetric parahydrogen adducts hosting long-lived states will be presented.

Acknowledgements: NSF grants CHE-1808239 (CRB and WH), CBET-1933723 (HH-W and CRB) and the NHMFL-UCGP which is supported by the National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida.

1. CR Bowers, DP Weitekamp, PRL, 1986; CR Bowers, DP Weitekamp, JACS, 1987

2. Evan Wenbo Zhao, Raghu Maligal-Ganesh, Yong Du, Tommy Yunpu Zhao, James Collins, Tao Ma, Lin Zhou, Tian-Wei Goh, Wenyu Huang, Clifford R Bowers - Chem, 2018

3. Evan W Zhao, Raghu Maligal‐Ganesh, Chaoxian Xiao, Tian‐Wei Goh, Zhiyuan Qi, Yuchen Pei, Helena E Hagelin‐Weaver, Wenyu Huang, Clifford R Bowers -Angew. Chem. 2017

Friday, November 15, 2019 - 1:10pm

Zachary Ball

Zachary Ball

Department of Chemistry, Rice University

(VanVeller)

Chemists are fascinated by metalloenzymes and their chemistry. The reactivity and selectivity of enzyme processes would be powerful practical advances if harnessed in designed transition-metal catalysts. But designing enzyme-like catalysts from scratch has proven exceedingly challenging. Substrate selectivity in polyfunctional environments and highly reactive intermediates incompatible with the bulk aqueous media are properties that are typically too complex and challenging to replicate in simplified, designed systems. Our own efforts have taken advantage of diverse concepts, such as molecular recognition, biomimetic assembly, and structure–function relationships to pursue new methods for site-selective chemistry.

Monday, November 18, 2019 - 9:00am

Likun Duan Final Oral Zhao Group

Tuesday, November 19, 2019 - 4:00pm

Zhuoran Wang Final Oral Pruski Group

Thursday, November 21, 2019 - 4:30pm

Justin Mark Final Oral Exam Kovnir Group

Friday, November 22, 2019 - 3:00pm

William Bradley, Final Oral, Kraus Group

Tuesday, December 3, 2019 - 9:00am

Kasuni Boteju Final Oral Sadow Group

Friday, December 6, 2019 - 1:10pm

Julia Chan

Julia Chan

The University of Texas at Dallas

(Zaikina)

The discovery and characterization of novel intermetallic compounds is important for broadening the understanding of structure-property relationships of magnetic materials. Our current research interests in superconductivity and unusual magnetism rely heavily on the intimate relationship between structure and physical properties. Likewise, the determination of anisotropic physical properties from high quality single crystals is vital in probing the intrinsic electrical and the competing magnetic interactions to understand the chemistry and physics of these materials. The discovery of novel magnetic and electronic properties in low-dimensional materials has led to the pursuit of hierarchical materials with specific substructures. Low-dimensional solids are highly anisotropic by nature and show promise in new quantum materials leading to exotic physical properties not realized in three dimensional materials.  In this talk, I will highlight the crystal growth, characterization, and properties of germanides and stannides and layered antimonides and the potential for compounds in reduced dimensions.

Friday, December 6, 2019 - 3:10pm

Facundo Fernandez

Facundo Fernandez

Georgia Institute of Technology

(Lee)

Abstract

he highly dynamic nature of metabolites and their abundances makes metabolomics a powerful endpoint of the ‘omics’ cascade, yielding a molecular profile that is closest to the physiological phenotype. Metabolomic profiles are therefore sensitive to subtle perturbations observed in early disease stages or disease progression, which may be difficult to detect at the proteome or transcriptome levels. Human diseases are multi-factorial in nature, and studying small parts of their associated molecular changes is generally insufficient for understanding the full spectrum of disease phenotypes.

The metabolome is the total collection of biologically-active small molecules with molecular weights lower than about ~1.5 kDa in an organism. This includes endogenous molecules that are biosynthesized by metabolic networks in “primary metabolism”, specialized “secondary metabolite” signaling or defense molecules, molecules derived from diet or environmental exposures (the exposome), and molecules derived from the biosynthetic interactions with associated microbes (the microbiome). Metabolomics can either be “targeted” to a set of known compounds, for example certain lipids, or “non-targeted”, which attempts to detect and relatively quantify as many metabolites as possible.

The vast chemical diversity of the metabolome (lipids, sugars, amino acids, etc.), and its wide dynamic range (mM to fM) implies that no single analytical method can adequately profile all metabolites in one metabolomics experiment. Along these lines, the “fusion” of mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) is emerging as one of the most powerful avenues to increase metabolome coverage. Nested separations that work in a time frame compatible with mass spectrometry, such as those performed by ion mobility, are also playing a key analytical role in metabolomics as a way of increasing peak capacity, and identifying metabolites through ion mobility collision cross section measurements. Further, localization of metabolites at the tissue level with imaging mass spectrometry experiments, allows linking their abundance with changes observed in biofluids. In this seminar, I will highlight progress along these various fronts, with emphasis on the detection, screening and treatment of complex diseases such as prostate and ovarian cancer, and cystic fibrosis.

Friday, January 17, 2020 - 1:10pm

Sen Zhang

Sen Zhang

University of Virginia

Huang

Friday, January 24, 2020 - 1:10pm

Nancy Pleshko

Nancy Pleshko

Temple University

Society for Applied Spectroscopy (SAS) Student Chapter

Friday, January 24, 2020 - 3:10pm

Lauren Webb

Lauren Webb

Department of Chemistry, The University of Texas at Austin

(VanVeller)

Friday, January 31, 2020 - 1:10pm

Steven Zimmerman

University of Illinois - Champaign-Urbana

(Zhao)

Friday, January 31, 2020 - 3:10pm

Peter Sushko

Peter Sushko

Pacific Northwest National Lab

(Winter)

Friday, February 7, 2020 - 1:10pm

James E. (Ned) Jackson

James E. (Ned) Jackson

Michigan State University

(VanVeller)

Friday, February 7, 2020 - 3:10pm

Chuck Henry

Chuck Henry

Colorado State University

(Anand)

Pages