Karen Goldberg

Last updated
Karen Ila Goldberg
Alma mater Barnard College A.B. 1983
University of California, Berkeley Ph.D. 1988
Scientific career
Fields Organometallic Chemistry, Catalysis
Institutions University of Pennsylvania

University of Washington
Illinois State University

Ohio State University
Thesis Synthetic and mechanistic studies of carbon-carbon and carbon-hydrogen bond formation and cleavage in transition metal systems  (1988)
Doctoral advisor Robert G. Bergman
Other academic advisors Roald Hoffmann, Stephen J. Lippard, Bruce E. Bursten

Karen Ila Goldberg is an American chemist, currently the Vagelos Professor of Energy Research at University of Pennsylvania. [1] Goldberg is most known for her work in inorganic and organometallic chemistry. Her most recent research focuses on catalysis, particularly on developing catalysts for oxidation, as well as the synthesis and activation of molecular oxygen. [1] In 2018, Goldberg was elected to the National Academy of Sciences. [2]

Contents

Career

Karen Goldberg received her A.B. degree in Chemistry in 1983 from Barnard College of Columbia University. Her undergraduate research included work with Professors Roald Hoffmann, Stephen Lippard at Cornell University and Columbia University respectively, as well as with Doctors Tom Gradel and Steven Bertz at AT&T Laboratories. She earned her Ph.D. in Chemistry in 1988 with Professor Robert Bergman at the University of California at Berkeley. She completed a postdoctoral year under Professor Bruce Bursten at Ohio State University before becoming a faculty member of Illinois State University in 1989. In 1995, Goldberg began at the University of Washington as the Assistant Professor of Chemistry, and she was awarded tenure and promoted to Associate Professor in 2000, and to Professor in 2003. [3] In 2017, Goldberg moved her research group to the University of Pennsylvania, where she is the Vagelos Professor of Energy Research in the department of chemistry. [1] [4]

Research

Goldberg's research interests include understanding the mechanism and application of catalysts on fundamental organometallic reactions. This culminates into a goal to design more efficient, cheaper, and greener chemical products and fuels from a variety of feedstocks, such as alkanes. One such process that Goldberg has helped develop is the dehydrogenation of ammonia borane using an iridium pincer catalyst, a reaction that took place under mild conditions at high rates with efficient catalyst regeneration. [5]

Electrophilic Oxidation Catalysis

Over thirty years ago, Shilov discovered the selective oxidization of alkanes in the presence of platinum-based metals. This was impractical because it required a stoichiometric oxidant in addition to the catalytic Pt(II) metal, which led Goldberg to inquire deeper into understanding C-H bond activation, oxidation, and C-heteroatom bond formation, leading to the development of more practical products. In recent studies of utilizing alkanes, Goldberg has investigated the functionalization of alkanes through oxidation reactions using platinum-based catalysts. [6]

The reaction of pivaldehyde with water catalyzed by para-cymene Ru complexes to form a carboxylic acid and hydrogen gas. Ruthenium based catalyst.jpg
The reaction of pivaldehyde with water catalyzed by para-cymene Ru complexes to form a carboxylic acid and hydrogen gas.

Pt(II) methyl complexes are key intermediates in both the Shilov methane oxidation system and in more recent catalytic Pt methane oxidation systems. Goldberg's research involves formation of alcohols from alkanes using platinum or other late metal catalysts, including ruthenium, iridium and rhodium. As a result, her research discovered a method of using a family of Ru(II) diamine complexes as a precatalyst to provide selectivity and high conversion of aldehydes to carboxylic acids over the competing aldehyde disproportionation reaction. [7]

Lithium aluminum hydride has widely been used as strong reducing reagent. However, it is difficult to reduce resonance stabilized carbonyl groups present in esters and lactones to alcohols. It was then that her research group came up with idea of hydrogenation of esters and lactones to form alcohol using base-free metal-catalyzed complexes. The catalyst that gave rise to a high yield of formate esters is a half-sandwich iridium bipyridine complex. The same half-sandwich complexes of iridium and rhodium were used as competent catalysts to hydrogenate carboxylic acids under relatively mild conditions. The mechanism behind this reaction involves hydride transfer from catalyst to formic acid as the main part of the reaction. [8]

Through the Center for Enabling New Technology through Catalysis (CENTC), [9] Goldberg also contributed to finding methods of activating strong bonds such as C-H, C-C, C-O, C-N, and N-H. Through this, the Goldberg research group discovered how to functionalize these bonds once they are activated through oxidative addition and reductive elimination. This investigation provided detailed mechanisms, intermediates, and kinetic barriers for these catalytic processes. [6]

Anti-Markovnikov Hydroamination of Alkenes

Recognizing the importance of linear anti-Markovnikov products, Goldberg's research focuses on discovery of transition metal catalysts which helps in catalysis of anti-Markovnikov hydroamination of alkenes. In one of her publications, she introduces a method to catalyze the hydroarylation of unactivated alkenes using Pt(II) complexes with unsymmetrical pyrrolide ligands. Selectivity was provided by using benzene and 1-hexene and an optimized catalyst. The result was production of high olefin concentration using propylene as the substrate. [10]

Most of her research on the subject has involved experimental studies of reductive elimination and oxidative addition reactions involving carbon-containing molecules in order to gain information on the reaction coordinates of such processes. Her further studies on using platinum-based catalysts for the reductive eliminations of alkane products have also included crystallography characterizations of platinum complexes and selected intermediates to determine the mechanism of such reactions. [11]

Molecular Oxygen Catalysis

An example of a palladium catalytic cycle that uses oxygen as a final oxidant. Palladium based catalytic cycle.jpg
An example of a palladium catalytic cycle that uses oxygen as a final oxidant.

Goldberg's research interests also include harnessing molecular oxygen as a selective oxidant in catalysis. As molecular oxygen is readily available and environmentally benign, the Goldberg group, along with other research groups involved in the CENTC, have attempted to better comprehend oxygen's reactivity and to activate it to utilize it to its fullest capacity. Current research has aimed to understand how reactions between transition metal complexes and oxygen occur. Goldberg has recently investigated the insertion of molecular oxygen into palladium-hydride bonds, with results suggesting that this insertion reaction does not involve radical chain mechanisms. [12] This research of the capabilities of oxygen to insert into palladium-hydride bonds have been expanded by the study of the general reactivity of molecular oxygen with middle- to late-transition metals, such as platinum. [13] This contribution to the understanding of molecular oxygen's method of reaction with palladium and other transition metals may lead to further development and perfecting of molecular oxygen as a selective oxidizer.

Gem-Dialkyl Ligands

A platinum tetramethyl complex undergoes elimination of a molecule of ethane by way of its chelating bidentate ligand. Platinum complex that demonstrates gem-dialkyl behavior.jpg
A platinum tetramethyl complex undergoes elimination of a molecule of ethane by way of its chelating bidentate ligand.

Further research by Goldberg on the study of transition metal-catalyzed reactions places additional emphasis on the metal-complex ligands. Recent publications have reported that gem-dialkyl substituents on platinum-based metal complexes can be utilized to determine the mechanism of reaction pathway and whether the mechanism includes chelate opening. [14] The gem-dialkyl substituents have been used in the past for recognizing thermodynamic properties of chemical systems, though recent studies have pushed those discoveries to the understanding of kinetic systems as well. Goldberg's research on the effects of these types of substituents on bidentate ligands and how these effects change the mechanisms and rates of reductive elimination reactions has helped advance improvements of transition metal-based inorganic and organic catalysis.

Awards and honors

Her accolades include:

Related Research Articles

Catalysis chemical process

Catalysis is the process of altering the rate of a chemical reaction by adding a substance known as a catalyst. Catalysts are not consumed in the catalyzed reaction hence they are unchanged after the reaction. Often only very small amounts of catalyst are required. The global demand for catalysts in 2010 was estimated at approximately US$29.5 billion.

Organometallic chemistry Study of chemical compounds containing at least one bond between a carbon atom of an organic compound and a metal

Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkaline, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide, cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complexes are representative members of this class. The field of organometallic chemistry combines aspects of traditional inorganic and organic chemistry.

Epoxide

An epoxide is a cyclic ether with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile.

Dehydrogenation is the a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At its simplest, it is useful way of converting alkanes, which are relatively inert and thus low-valued, to olefins, which are reactive and thus more valuable. Alkenes are precursors to aldehydes, alcohols, polymers, and aromatics. As a problematic reaction, the fouling and inactivation of many catalysts arises via coking, which is the dehydrogenative polymerization of organic substrates.

Hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group (CHO) and a hydrogen atom to a carbon-carbon double bond. This process has undergone continuous growth since its invention: Production capacity reached 6.6×106 tons in 1995. It is important because aldehydes are easily converted into many secondary products. For example, the resulting aldehydes are hydrogenated to alcohols that are converted to detergents. Hydroformylation is also used in speciality chemicals, relevant to the organic synthesis of fragrances and drugs. The development of hydroformylation is one of the premier achievements of 20th-century industrial chemistry.

In chemistry, homogeneous catalysis is catalysis in a solution by a soluble catalyst. Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants, principally in solution. In contrast, heterogeneous catalysis describes processes where the catalysts and substrate are in distinct phases, typically solid-gas, respectively. The term is used almost exclusively to describe solutions and implies catalysis by organometallic compounds. Homogeneous catalysis is established technology that continues to evolve. An illustrative major application is the production of acetic acid. Enzymes are examples of homogeneous catalysts.

Reductive elimination is an elementary step in organometallic chemistry in which the oxidation state of the metal center decreases while forming a new covalent bond between two ligands. It is the microscopic reverse of oxidative addition, and is often the product-forming step in many catalytic processes. Since oxidative addition and reductive elimination are reverse reactions, the same mechanisms apply for both processes, and the product equilibrium depends on the thermodynamics of both directions.

Oxidative addition and reductive elimination are two important and related classes of reactions in organometallic chemistry. Oxidative addition is a process that increases both the oxidation state and coordination number of a metal centre. Oxidative addition is often a step in catalytic cycles, in conjunction with its reverse reaction, reductive elimination.

Wilkinsons catalyst Chemical compound

Wilkinson's catalyst is the common name for chloridotris(triphenylphosphine)rhodium(I), a coordination complex of rhodium with the formula [RhCl(PPh3)3] (Ph = phenyl). It is a red-brown colored solid that is soluble in hydrocarbon solvents such as benzene, and more so in tetrahydrofuran or chlorinated solvents such as dichloromethane. The compound is widely used as a catalyst for hydrogenation of alkenes. It is named after chemist and Nobel laureate Sir Geoffrey Wilkinson, who first popularized its use.

Transition metal pincer complex

In chemistry, a transition metal pincer complex is a type of coordination complex with a pincer ligand. Pincer ligands are chelating agents that binds tightly to three adjacent coplanar sites in a meridional configuration. The inflexibility of the pincer-metal interaction confers high thermal stability to the resulting complexes. This stability is in part ascribed to the constrained geometry of the pincer, which inhibits cyclometallation of the organic substituents on the donor sites at each end. In the absence of this effect, cyclometallation is often a significant deactivation process for complexes, in particular limiting their ability to effect C-H bond activation. The organic substituents also define a hydrophobic pocket around the reactive coordination site. Stoichiometric and catalytic applications of pincer complexes have been studied at an accelerating pace since the mid-1970s. Most pincer ligands contain phosphines. Reactions of metal-pincer complexes are localized at three sites perpendicular to the plane of the pincer ligand, although in some cases one arm is hemi-labile and an additional coordination site is generated transiently. Early examples of pincer ligands were anionic with a carbanion as the central donor site and flanking phosphine donors; these compounds are referred to as PCP pincers.

Alkane metathesis is a class of chemical reaction in which an alkane is rearranged to give a longer or shorter alkane product. It is similar to olefin metathesis, except that olefin metathesis cleaves and recreates a carbon-carbon double bond, but alkane metathesis operates on a carbon-carbon single bond.

Carbon–hydrogen bond functionalization is a type of reaction in which a carbon–hydrogen bond is cleaved and replaced with a carbon–X bond. The term usually implies that a transition metal is involved in the C-H cleavage process. Reactions classified by the term typically involve the hydrocarbon first to react with a metal catalyst to create an organometallic complex in which the hydrocarbon is coordinated to the inner-sphere of a metal, either via an intermediate "alkane or arene complex" or as a transition state leading to a "M−C" intermediate. The intermediate of this first step can then undergo subsequent reactions to produce the functionalized product. Important to this definition is the requirement that during the C–H cleavage event, the hydrocarbyl species remains associated in the inner-sphere and under the influence of "M".

Jean-Marie Basset is a French chemist, and is currently the director of KAUST catalysis research center.

A migratory insertion is a type of reaction in organometallic chemistry wherein two ligands on a metal complex combine. It is a subset of reactions that very closely resembles the insertion reactions, and both are differentiated by the mechanism that leads to the resulting stereochemistry of the products. However, often the two are used interchangeably because the mechanism is sometimes unknown. Therefore, migratory insertion reactions or insertion reactions, for short, are defined not by the mechanism but by the overall regiochemistry wherein one chemical entity interposes itself into an existing bond of typically a second chemical entity e.g.:

Organoplatinum chemistry is the chemistry of organometallic compounds containing a carbon to platinum chemical bond, and the study of platinum as a catalyst in organic reactions. Organoplatinum compounds exist in oxidation state 0 to IV, with oxidation state II most abundant. The general order in bond strength is Pt-C (sp) > Pt-O > Pt-N > Pt-C (sp3). Organoplatinum and organopalladium chemistry are similar, but organoplatinum compounds are more stable and therefore less useful as catalysts.

Georgiy Borisovich Shul’pin was born in 1946 in Moscow, Russia. He graduated with a M.S. degree in chemistry from the Chemistry Department of Moscow State University in 1969. Between 1969 and 1972, he was a postgraduate student at the Nesmeyanov Institute of Organoelement Compounds under the direction of Prof. A. N. Nesmeyanov and received his Ph.D. in organometallic chemistry in 1975. He received his Dr. of Sciences degree in 2013.

In chemistry, metal-catalysed hydroboration is a reaction used in organic synthesis. It is one of several examples of homogeneous catalysis.

Roy A. Periana American organometallic chemist (born 1957)

Roy A. Periana is an American organometallic chemist.

In coordination chemistry and catalysis hemilability refers to a property of many polydentate ligands which contain at least two electronically different coordinating groups, such as hard and soft donors. These hybrid or heteroditopic ligands form complexes where one coordinating group is easily displaced from the metal centre while the other group remains firmly bound; a behaviour which has been found to increase the reactivity of catalysts when compared to the use of more traditional ligands.

Methane functionalization is the process of converting methane in its gaseous state to another molecule with a functional group, typically methanol or acetic acid, through the use of transition metal catalysts.

References

  1. 1 2 3 "Department of Chemistry". www.chem.upenn.edu. Retrieved 2017-05-02.
  2. 1 2 "National Academy of Sciences Members and Foreign Associates Elected". National Academy of Sciences. 1 May 2018. Retrieved 12 May 2018.
  3. ↑ "Karen I. Goldberg – UW Dept. of Chemistry". depts.washington.edu. Retrieved 2017-04-21.
  4. ↑ "Karen Goldberg Joining Penn Chemistry". University of Pennsylvania Department of Chemistry. Retrieved 12 May 2018.
  5. ↑ Denney, Melanie C.; Pons, Vincent; Hebden, Travis J.; Heinekey, D. Michael; Goldberg, Karen I. (2006). "Efficient Catalysis of Ammonia Borane Dehydrogenation". Journal of the American Chemical Society. 128 (37): 12048–12049. doi:10.1021/ja062419g. PMID   16967937.
  6. 1 2 Look, Jennifer L.; Fekl, Ulrich; Goldberg, Karen I. (2004). Activation and Functionalization of C—H Bonds. ACS Symposium Series. 885. pp. 283–302. CiteSeerX   10.1.1.610.3949 . doi:10.1021/bk-2004-0885.ch017. ISBN   978-0-8412-3849-7.
  7. ↑ Prantner, J. D; Goldberg, Karen. I (2014). "Methylplatinum(II) and Molecular Oxygen: Oxidation to Methylplatinum(IV) in Competition with Methyl Group Transfer to Form Dimethylplatinum(IV)". Organometallics. 33 (13): 3227–3230. doi:10.1021/om500243n.
  8. ↑ Brewster, T. P; Goldberg, Karen. I (2016). "Base-Free Iridium-Catalyzed Hydrogenation of Esters and Lactones". ACS Catal. 6 (5): 3113–3117. doi:10.1021/acscatal.6b00263.
  9. 1 2 Catalysis, CENTC, Center for Enabling New Technologies through. "CENTC- Center for Enabling New Technologies through Catalysis". depts.washington.edu. Retrieved 2017-05-10.
  10. ↑ Clement, M. L; Goldberg, K. I (2014). "Platinum(II) Olefin Hydroarylation Catalysts: Tuning Selectivity for the anti-Markovnikov Product". Chemistry: A European Journal. 20 (52): 17287–91. doi:10.1002/chem.201405174. PMID   25377546.
  11. ↑ Crumpton-Bregel, Dawn M.; Goldberg, Karen I. (2003). "Mechanisms of C−C and C−H Alkane Reductive Eliminations from Octahedral Pt(IV): Reaction via Five-Coordinate Intermediates or Direct Elimination?". Journal of the American Chemical Society. 125 (31): 9442–9456. doi:10.1021/ja029140u. PMID   12889975.
  12. ↑ Denney, Melanie C.; Smythe, Nicole A.; Cetto, Kara L.; Kemp, Richard A.; Goldberg, Karen I. (2006). "Insertion of Molecular Oxygen into a Palladium(II) Hydride Bond". Journal of the American Chemical Society. 128 (8): 2508–2509. doi:10.1021/ja0562292. PMID   16492014.
  13. ↑ Schuermann, M.L.; Goldberg, K.I. (10 October 2014). "Reactions of Pd and Pt Complexes with Molecular Oxygen". Chemistry: A European Journal. 20 (45): 14556–14568. doi: 10.1002/chem.201402599 . PMID   25303084.
  14. ↑ Arthur, Kathryn L.; Wang, Qi L.; Bregel, Dawn M.; Smythe, Nicole A.; O'Neil, Bridget A.; Goldberg, Karen I.; Moloy, Kenneth G. (2005). "Thegem-Dialkyl Effect as a Test for Preliminary Diphosphine Chelate Opening in a Reductive Elimination Reaction†". Organometallics. 24 (19): 4624–4628. doi:10.1021/om0500467.
  15. ↑ ROUHI, MAUREEN (1995). "EDUCATION". Chemical & Engineering News. 73 (15): 39–40. doi:10.1021/cen-v073n015.p039.
  16. ↑ "Goldberg, Karen". American Association for the Advancement of Science. Retrieved 12 May 2018.
  17. ↑ "Three Videos released on the 2015 IPMI Premier Professional Awards" (PDF). International Precious Metals Institute. September 15, 2015.
  18. ↑ "2016 National Award Recipients – American Chemical Society". American Chemical Society. Retrieved 2017-05-09.
  19. ↑ Langston, Jennifer (19 April 2017). "Two UW faculty named to American Academy of Arts and Sciences". UW News. Retrieved 12 May 2018.
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