������Ƶ

17th Biannual: John Eisch Lectureship In
Inorganic/Organometallic Chemistry

Friday, April 5, 2024
4 P.M.
Smart Energy Building, Fountain Room

---

Professor Gregory H. Robinson

UGA Foundation Distinguished Professor of Chemistry
Department of Chemistry
The University of Georgia

N-Heterocyclic Carbenes and Dithiolene Radicals: Counterintuitive Main Group Chemistry

Our laboratory has long pursued the synthesis, structure and reactivity of unusual molecules that prominently feature main group elements. These efforts resulted in several discoveries, including the experimental realization of “metalloaromaticity” (the concept that metallic rings may also display traditional aromatic behavior as exhibited by benzene), the first example of a molecule containing a triple bond between two main group metals (the gallium analog of acetylene), and the first compound containing a boron-boron double bond — the first “diborene”. Recent research efforts have concerned N-heterocyclic carbene stabilization of highly reactive main group molecules such diphosphorus (P2), diarsenic (As2), and disilicon (Si2). Furthermore, we have utilized carbene-stabilization to trap elusive main group oxides such as Si2O4 and P2O4. This presentation will prominently feature our recent efforts to augment the molecular template of N-heterocyclic carbenes and their unexpected conversion to stable dithiolene-based chemical radicals. These novel radicals have shown promise in the activation of small molecules, such as ammonia.

• Information about Professor Gregory H. Robinson

  Gregory H. Robinson is a native of Anniston, Alabama. As both a gifted athlete and honor student in high school, he earned a football scholarship to Jacksonville State University (Alabama). A four- year letterman on the Gamecock football team while earning All-Gulf South Conference and Gulf South Conference Defensive Player of the Year honors, Robinson earned his BS in chemistry from JSU (1980). He received his PhD (1984) from the University of Alabama, where he studied synthetic inorganic main group chemistry in the laboratory of Professor Jerry L. Atwood. After spending a decade on the faculty of Clemson University (South Carolina), Professor Robinson joined the faculty of the University of Georgia (1995) and presently holds the title of Foundation
  Distinguished Professor of Chemistry. Robinson’s research, concerning the synthesis, structure, and reactivity of unusual molecules of the main group (earth abundant) elements, has been described as “provocatively innovative and strikingly creative.” Research highlights include: (a) experimental realization of the concept of metalloaromaticity — proof that molecules containing properly constrained metallic ring systems can exhibit traditional aromatic behavior; (b) synthesis and molecular structure of the first compound containing a metal-metal triple bond between two main group metals — the first “digallyne” — the gallium analog of acetylene; (c) synthesis and molecular structure of the first compound containing a boron-boron double bond — the first “diborene” — the boron analog of ethylene; and (d) carbene-stabilization of highly reactive diatomic allotropes such as silicon, phosphorus, and arsenic. Robinson has published more than 170 peer-reviewed research articles in journals such as Science, Nature Chemistry, Angewandte Chemie and the Journal of the American Chemical Society. Notably, he has received numerous honors including the Southern Chemist Award (1998), the Humboldt Research Prize (2012), the F. Albert Cotton Award in Synthetic Inorganic Chemistry (2013), and the Southeastern Conference (SEC) Faculty Achievement Award (2014). Robinson is a fellow of the Royal Society of Chemistry (2017) and was recently elected to the National Academy of Sciences (2021).

---

• Information about Professor John J. Eisch

  John Joseph Eisch joined the Department of Chemistry at ������Ƶ in 1972, as chair and professor of chemistry, with the mandate of fostering the national reputation of its graduate teaching and research. Over the next six years as chair, he guided the recruiting of six senior and junior faculty with this goal in mind, while expanding his own research in organometallic chemistry to a yearly group of eight to 12 graduate and postdoctoral students, with support from federal and industrial resources. In 1983, his composite achievements were recognized by his promotion to the SUNY-wide rank of distinguished professor of chemistry. Further recruiting, notably during the chair tenure of professors Eugene Stevens, Alistair Lees, Wayne Jones and currently, Eriks Rozners, expanded the scope of advanced research into areas of immediate importance, such as nano materials, homogeneous catalysis, analytical sensors, biological transformations and energy storage.

  Eisch received the BS degree in chemistry, summa cum laude, from Marquette University in 1952; earned the PhD degree in 1956, with Henry Gilman, at Iowa State University; and served as Union Carbide Research Fellow with Karl Ziegler at the Max-Planck-Institut für Kohlenforschung, Mülheim, Germany (1956–57).  After junior professional appointments at St. Louis University and the University of Michigan, he became ordinary professor and department head at the Catholic University of America (1963–1972). He retired from his professorial career of 57 years in 2014, the latter 42 years of which were spent at ������Ƶ.

  The Eisch Group initially had concentrated on the preparation and organic synthetic uses of organometallic reagents of Li, Na, Mg, B and Al, but we were struck by the lack of definitive molecular mechanistic studies in previous work. In ensuing research encompassing reaction kinetics, trapping of any intermediates, IR, UV and X-ray crystallographic measurements, both heterolytic and homolytic C-M cleavages could be involved, as well as 4-centertrapesoidal transition states. Reviews are available in a) “Fifty Years of Ziegler- Natta Polymerization: From Serendipity to Science,” Organometallics, 2012, 31, 4917–4932 and b) Dalton Transactions, (DOI: 10:1039/c4dt010362) “Emergence of Electrophilic Alumination as the Counterpart of Established Nucleophilic Lithiation.” The original seven articles dealing with the reactions of RLi with the azomethyne groups have been recently published by the Eisch and the Rheingold Crystallographic Group in the European Journal of Organic Chemistry.

  Over the years, the research involved the fruitful collaboration of more than 200 students as master’s, doctoral, postdoctoral or baccalaureate associates. The results have been reported in more than 410 scientific publications, in some 280 invited lectures worldwide, in the monograph “The Chemistry of Organometallic Compounds” (Macmillian, 1967) and in the edited series, “Organometallic Syntheses” (four volumes, J. J. Eisch and R. B. King, authors and editors). He has been an industrial consultant on organometallic chemistry and an expert witness in several patent litigations on Ziegler-Natta polymerization catalysis.

   One of the significant discoveries of our studies is that the reaction of organic carbanionic reagents is not a one-step nucleophilic C alpha attack (i) but a two-step electrontransfer and electron-coupling process (ii)(iii).

• Previous Lectureship Recipients

  2012

  Stephen L. Buchwald - MIT
  “Palladium-Catalyzed CarbonNitrogen and Carbon-Carbon Bond-Forming Reactions: Progress, Applications and Mechanistic Studies”

  ---

  2013

  David W. C. MacMillan - Princeton University
  “The Use of Photoredox Catalysis in New Organic Bond Forming Reactions”

  ---

  2014

  Brian M. Stoltz - California Institute of Technology
  “Complex Natural Products as a Driving Force for Discovery in Organic Chemistry”

  ---

  2015

  Eric N. Jacobsen - Harvard University
  “Anion-Binding Catalysis”

  ---

  2016

  Bob Crabtree - Yale University
  “Organometallic Catalysis for Solar Fuels and Storage”

  Phil S. Baran - The Scripps Research Institute
  “Translational Chemistry”

  ---

  2017

  Stephen J. Lippard - MIT
  “Understanding and Improving Platinum Anticancer Drugs”

  Daniel A. Singleton - Texas A&M Uniersity
  “Dynamic Effects and Energy Labeling in Free-Radical Reactions”

  ---

  2018

  Clifford P. Kubiak - University of California, San Diego
  “If You Make a Solar Fuel From CO2, What Should It Be?”

  Scott E. Denmark - University of Illinois at Urbana-Champaign
  "Lewis-base Activation of Lewis Acids: An Evolving Paradigm for Catalysis in Main Group Chemistry"

  ---

  2019 

  Professor Gregory C. Fu - California Institute of Technology                                                            "Nucleophilic Substitution Reactions: A Radical Alternative to SN1 and SN2 Reactions"

  John F. Hartwig - University of California, Berkeley
  "Selective, Catalytic Functionalization of C-H Bonds with Small and Large Catalysts"

  ---

  2021

  Professor Vern L. Schramm - Albert Einstein College of Medicine
  "Enzymatic Transition States and Transition State Analogues" 

  ---

   2022

  Karen Goldberg - University of Pennsylvania
  "Molecular Oxygen as a Reagent in Late Transition Metal Organometallic Chemistry"

  ---

  2023

  Kendall N. Houk - University of California, Los Angeles                                                                    "Pericyclic Reactions: Theory, Mechanisms, Dynamics and Role in Biology"

  Polly L. Arnold - University of California, Berkeley 
  "F-Block Dinitrogen Chemistry; from Rarity to Catalysis in a Few Simple Steps"