General

Inorganic Chemsitry Seminar: Dr. Matthew Kieber-Emmons, University of Utah

Tue, 2019-04-23 12:00 - 13:00
Speaker: 
Dr. Matthew Kieber-Emmons
Location: 

Carol Lynch Lecture Hall

Chemsitry Complex

Host: Tomson

Title & Abstract: TBA

inquiries rvargas@sas.upenn.edu

Inorganic Chemistry Seminar; Dr. Xavier Roy, Columbia University

Tue, 2019-04-09 00:00 - 01:00
Speaker: 
Dr. Xavier Roy
Location: 

Carol Lynch Lecture Hall

Chemistry Complex

Host: Dr. Murray

Title & Abstract: TBA

inquiries rvargas@sas.upenn.edu

Organic Chemistry Seminar: Dr. David Nagib, Ohio State University

Mon, 2018-12-10 12:00 - 13:00
Speaker: 

Dr. David Naglib

C-H and C-O functionalization via radical chaperones

 


Our research is focused on harnessing the untapped reactivity of abundant chemical feedstocks to enable late-stage functionalization of medicinally relevant molecules. We have recently developed new approaches for selective C-H and C-O functionalization of alcohols, amines, and carbonyls, using a combination of radical (1e-) and closed shell (2e-) processes that act in concert with one another. These radical chaperone strategies have enabled discovery of new classes of reactivity to streamline the synthesis of complex molecules with biological and industrial significance.

Location: 

Carol Lynch Lectrue Hall

Chemistry Complex

Host: Dr. Walsh

inquiries rvargas@sas.upenn.edu

Inorganic Chemistry Seminar: Dr. Milton Smith, MSU

Tue, 2018-12-04 12:00 - 13:00
Speaker: 

Dr. Milton Smith

 

 

Catalysts that Cleave C–H and N–H Bonds for Fine Chemical Synthesis and Energy Conversion

 

Catalytic transformations of C–H bonds are now common. This wasn’t always the case. Building from the first thermal, catalytic coupling of a borane and a hydrocarbon, our research group2 developed highly active iridium catalysts that exhibit unique regioselectivities for arene substitution and remarkable chemoselectivity for C–H functionalization. For example, sp2-C–X bonds (X = Cl, Br, and I) that are commonly cleaved in reactions with late transition metal complexes are remarkably inert to the Ir catalysts. From the roadmap we created many other groups in academia and industry have made important contributions to C–H borylations. Extensions to heterocyclic substrates and development of one-pot, catalytic reactions where the C–B bonds that result are further transformed make C–H borylation particularly attractive to synthetic chemists. Our recent work has emphasized ligand and reagent design to harness relatively weak interactions (e.g., hydrogen bonding) that are sufficiently strong to achieve  

C–H borylations with high regioselectivities.1,2

More recently, our research group has initiated a program to tap the potential for using ammonia to store, distribute, and release hydrogen gas. Specifically, we have targeted the oxidation ammonia to dinitrogen gas, protons, and electrons.3,4 Combining ammonia oxidation with ammonia synthesis from dinitrogen—the most abundant component of Earth’s atmosphere—and renewable hydrogen, a groundwork for a closed, zero-carbon fuel cycle based on nitrogen gas would be established. We recently have designed the first molecular catalyst that oxidizes NH3 to N2, six “protons,” and six electrons at room temperature. This is the anodic reaction in electrocatalytic NH3 “splitting” to N2 and H2.

 


 

 

(1) Chattopadhyay, B.; Dannatt, J. E.; Andujar-De Sanctis, I. L.; Gore, K. A.; Maleczka, R. E., Jr; Singleton, D. A.; Smith, M. R., III. J. Am. Chem. Soc. 2017, 139, 7864–7871.

(2) Smith, M. R., III; Bisht, R.; Haldar, C.; Pandey, G.; Dannatt, J. E.; Ghaffari, B.; Maleczka, R. E., Jr.; Chattopadhyay, B. ACS Catal. 2018, 8, 6216–6223.

(3) Little, D. J.; Smith, M. R., III; Hamann, T. W. Energy Environ. Sci. 2015, 8, 2775–2781.

(4) Little, D. J.; Edwards, D. O.; Smith, M. R., III; Hamann, T. W. ACS Appl. Mater. Interfaces 2017, 9, 16228–16235.

Location: 

Carol Lynch Lecture Hall

Chemistry Complex

Host: Dr. Mindiola

inquiries rvargas@sas.upenn.edu

Inorganic Chemistry Seminar: Dr. Katherine J. Franz, Duke

Tue, 2019-02-19 12:00 - 13:00
Speaker: 

Dr. Katherine Franz

Location: 

Carol Lynch Lecture Hall

Chemistry Complex

Host: Dr. Tomson/ Dmochowski

Title & Abstract TBA

inquires rvargas@sas.upenn.edu

Joe Francisco Joins Penn

Joseph Francisco has joined Penn as the President's Distinguished Professor of Earth & Environmental Sciences. Prof. Francisco will have a secondary appointment in the Chemistry Department. 

 

Karen Goldberg Elected to National Academy

Karen Goldberg, the Vagelos Professor of Energy Research, has been elected to the National Academy of Sciences. Prof. Goldberg joined Penn in 2017 from the University of Washington, where she was the Nicole A. Boand Endowed Professor in Chemistry. She received her A.B. degree from Barnard College, Columbia University and her Ph.D. from the University of California, Berkeley.

Physical Chemistry Seminar: Dr. Josh Vura- Weis, University of Illinois

Thu, 2019-01-17 13:00 - 14:00
Speaker: 

Dr. Josh Vura-Weis

Ultrafast extreme ultraviolet spectroscopy reveals short-lived states in transition metal complexes and organohalide perovskite semiconductors



University of Illinois at Urbana/Champaign, 600 S Mathews Ave, Urbana, IL USA    X-ray absorption near edge spectroscopy (XANES or NEXAFS) is a powerful technique for electronic structure determination.  However, widespread use of XANES is limited by the need for synchrotron light sources with tunable x-ray energy. Recent developments in extreme ultraviolet (XUV) light sources using the laser-based technique of high-harmonic generation have enabled core-level spectroscopy to be performed on femtosecond to attosecond timescales.  We have extended the scope of tabletop XUV spectroscopy and demonstrated that M2,3-edge XANES, corresponding to 3p→3d transitions, can reliably measure the electronic structure of first-row transition metal coordination complexes with femtosecond time resolution.  We use this ability to track the excited-state relaxation pathways of photocatalysts and spin crossover complexes.  In semiconductors such as CH3NH3PbI3, distinct signals are observed for photoinduced electrons and holes, allowing the dynamics of each carrier to be tracked independently.  This work establishes extreme ultraviolet spectroscopy as a useful tool for mainstream research in inorganic, organometallic, and materials chemistry.  
Location: 

Carol Lynch Lecture Hall

Chemistry Complex

Host: Dr. Subotnik

inquiries rvargas@sas.upenn.edu

Organic Chemistry Seminar: Dr. Jennifer Roizen, Duke

Mon, 2019-04-22 12:00 - 13:00
Speaker: 

Dr. Jennifer Roizen

Location: 

Carol Lynch Lecture Hall

Chemistry Complex

Host: Molander

Title & Abstract TBA

inquiries rvargas@sas.upenn.edu

Organic Chemistry Semianr: Dr. Maciej Walczak, University of Colorado

Mon, 2019-01-14 12:00 - 13:00
Speaker: 

Dr. Maciej Walczak

University of Colorado Boulder

 

 Next-generation tools for the synthesis of small molecules and biologics

 

The Walczak group studies methods to prepare and manipulate complex natural products and biologics such as (oligo)saccharides, peptides, and proteins. Our current interests are focused on the synthesis and chemical biology of mammalian and bacterial glycans that are known to engage in biological recognition and signaling events and show a promising therapeutic and diagnostic potential. While chemical synthesis has enabled a better understanding of the role of saccharides in homeostatic and developmental processes, key obstacles such as suboptimal selectivities in chemical glycosylation reactions await broadly applicable solutions. In this presentation, I will describe the development of metal-catalyzed methods that capitalize on stereoretentive reactions of anomeric nucleophiles suitable for the formation of C(sp3)-C and C(sp3)-heteroatom bonds. This seminar will also feature selected applications of the glycosyl cross-coupling method, mechanistic and computational studies that guided new reaction discovery, and integration with modern automation technologies.

Location: 

Carol Lynch Lecture Hall

Chemistry Complex

Host: Dr. Huryn

inquiries rvargas@sas.upenn.edu

Department of Chemistry

231 S. 34 Street, Philadelphia, PA 19104-6323

215.898.8317 voice | 215.573.2112 fax | web@chem.upenn.edu

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