Megan K. Youmans

Assistant Professor, Department of Chemistry and BioChemistry

Hello!

I am an Assistant Professor of Chemistry at Wilkes University. In addition to teaching, I serve on the Faculty Development Committee, advise the American Chemical Society Student Chapter (Chem Club), and oversee an active research laboratory. In my time away from campus, I enjoy figure skating, baking, traveling, and playing with my daughters.

I have a background in both inorganic and medicinal chemistry. As such, I am interested in exploring the interface between inorganic chemistry and biology. My research program uses metal complexes as biomimetic models of metalloenzymes in an attempt to better understand the chemical and physical properties of enzymes such as sulfite oxidase and carbon monoxide dehydrogenase. Research in my lab combines airfree organic synthesis, catalysis, and electrochemistry. You can read more about the current happenings in my lab below.

My primary teaching responsibilities include general and inorganic chemistry. I enjoy the breadth of topics covered in both classes as it allows me to emphasize the necessity of chemistry to a range of disciplines be it medicine, geology, or environmental sciences. I also enjoy inventing (for better or worse) new pedagogical techniques aimed at increasing student participation and helping students transition into college. My objective in both courses is to teach students to problem solve creatively through the combination of multiple concepts, to think critically about their world and to apply chemical concepts to their area of study.

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Education.

  • 2014-2015

    Postdoctoral Associate
    Boston University, Boston, Massachusetts

    Dinuclear Cobalt Complexes for Water Oxidation and Reduction

    An Oxygen-Donating Scorpionate Ligand System

  • 2009-2014

    Ph.D. Medicinal Chemistry
    University of Utah, Salt Lake City, Utah

    Thesis: Novel Probes for the Detection of Hydrogen Sulfide and their Biological and Industrial Applications

  • 2004-2008

    B.S. Chemistry, honors
    University of Southern California, Los Angeles, California

    Spectroscopic Investigations of Gold-Mediated Disulfide Exchange

    Towards a General Hydride Abstraction Catalyst: Mechanistic Studies of C–H Oxidation with Cyclopentadienone-Ligated Metal Carbonyls

Research.

Current Research

Research interests in the Youmans group lie at the interface of inorganic chemistry and biology. Specifically, we are interested in the electronic structure and mechanistic details of metalloenzymes critical to human health. Click to learn more about current projects.

Molybdenum-containing enzymes catalyze essential redox reactions in nearly all forms of life. Yet the electronic properties governing the activity of these enzymes are poorly understood. While the extent of work in the field has focused on the pterin dithiolene ligand, the effect of the placeholder ligands on enzyme model systems has been neglected. We are currently synthesizing and characterizing a novel set of small molecule coordination complexes utilizing the hydrotris(imidazole) borate family of ligands as models for the sulfite oxidase family of molybdoenzymes. We hypothesize that these complexes will have reduction potentials more closely resembling that of sulfite oxidase.

Students

Research in the Youmans group is conducted exclusively by undergraduate Wilkes students and visiting high school students. Click to see who is currently in the group and find out where past students are now.

  • Kelly Megargel Wilkes '22
  • Matthew Schwarztrauber Wilkes '23
    Wilkes University Nesbitt School of Pharmacy Pharm.D. '25
  • Shawnessey Koebel Wilkes '23
  • Courtney Novak Wilkes '23
  • Lauren Herman Dickinson College '23
  • Mengying Shi Wilkes ’21
    Wilkes University Nesbitt School of Pharmacy Pharm.D. '23
  • Michael Pettit Wilkes ‘21
    Environmental Chemist/Technician at Resource Environmental Management
  • Max Mendrzycki (Hanover Area HS ’19)
    University of Delaware
  • Nicholas Fitzpatrick Wilkes ’19
    Doctoral student Worcester Polytechnic Institute
  • Martina Barna Wilkes ’18
    Production Technician at Sanofi Pasteur Vaccines
  • Benjamin Sharp Wilkes ’18
  • Sarah Nichols Wilkes ’18
    Chemist at Avidea Technologies

Funding

Research in the Youmans group is supported by a number of internal grants at Wilkes University and the Wilkes University Department of Chemistry and Biochemistry.

Funding allows for the purchasing of chemicals and equipment and for the compensation of student researchers each summer.

2021 Wilkes University Mentoring Project Fund Grant
Awarded $9,120.00
2018 – 2022 Wilkes University Research and Scholarship Grant
Biomimetic Complexes of Sulfite Oxidase Utilizing Soft Tripodal Ligand Systems
Awarded $29,856.00
2018 Wilkes University Mentoring Project Fund Grant
Awarded $4,191.00
2017 Wilkes University Faculty Development Committee – Type I Grant
Investigating the Effect of Non-Pterin Ligand Systems on Molybdoenzyme Mimetic Complexes
Awarded $3,551.73
2017 Wilkes University Mentoring Project Fund Grant
Awarded $9,158.60

It is my earnest desire that some of you should carry on this scientific work and keep for your ambition the determination to make a permanent contribution to science.
- Marie Curie

Our Lab

In addition to the advanced instrumentation available at Wilkes University, the Youmans group has additional equipment designed to help us work with air- and moisture-sensitive compounds. These include a Schlenk line and glovebox.

In addition to the advanced instrumentation available at Wilkes University, the Youmans group has additional equipment designed to help us work with air- and moisture-sensitive compounds. These include a Schlenk line and glovebox.

Publications.

Dr. Megan K Youmans chemistry publications

Going Remote: How Teaching During a Crisis is Unique to Other Distance Learning Experiences

Journal of Chemical Education, 2020

Concerns over the spread of COVID-19 closed many university campuses during the spring of 2020 and resulted in a shift to remote instruction. This communication argues that the rapid nature of the transition and the circumstances surrounding the pandemic made the experience distinct from traditional online learning. The corresponding community shutdowns impacted students and may have had mental health consequences. This is a concern because depression, stress, and anxiety affect the ability of students to learn. The challenges faced by general chemistry students at a small, private university during this period are described. The implementation of trauma-informed teaching principles to create a supportive learning community and promote resilience are outlined.

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Dr. Megan K Youmans chemistry publications

Lanthanide Complexes as Luminogenic Probes to Measure Sulfide Levels in Industrial Samples

Analytica Chimica Acta, Volume 896, 2015

A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil.

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Dr. Megan K Youmans chemistry publications

Marine Natural Products as Inhibitors of Cystathionine Beta-Synthase Activity

Bioorganic & Medicinal Chemistry Letters, Volume 25, Issue 5, 2015

A library consisting of characterized marine natural products as well as synthetic derivatives was screened for compounds capable of inhibiting the production of hydrogen sulfide (H2S) by cystathionine beta-synthase (CBS). Eight hits were validated and shown to inhibit CBS activity with IC50 values ranging from 83 to 187 μM. The majority of hits came from a series of synthetic polyandrocarpamine derivatives. In addition, a modified fluorogenic probe for H2S detection with improved solubility in aqueous solutions is reported.

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Dr. Megan K Youmans chemistry publications

Inhibition of the Lymphoid Tyrosine Phosphatase: The Effect of Zinc(II) Ions and Chelating Ligand Fragments on Enzymatic Activity

Bioorganic & Medicinal Chemistry Letters, Volume 24, Issue 16, 2014

A 96-member chelator fragment library (CFL-1.1) was screened to identify inhibitors of the lymphoid tyrosine phosphatase in the absence and presence of zinc acetate. Fragments that inhibit LYP activity more potently in the presence of zinc, fragments that rescue LYP activity in the presence of inhibitory concentrations of zinc, and fragments that inhibit LYP activity independent of zinc concentration were identified. Of these, 1,2-dihydroxynaphthalene was the most potent inhibitor with an IC50 value of 2.52 ± 0.06 μM after 2 h of incubation. LYP inhibition by 1,2-dihydroxynaphthalene was very similar to inhibition by 1,2-naphthoquinone (IC50 = 1.10 ± 0.03 µM), indicating that the oxidized quinone species is likely the active inhibitor. The inhibition was time-dependent, consistent with covalent modification of the enzyme.

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Dr. Megan K Youmans chemistry publications

Identification of Cystathionine Beta- Synthase Inhibitors Using a Hydrogen Sulfide Selective Probe

Angewandte Chemie, International Edition, Volume 52, Issue 17, 2013

Buzzing with activity: A hydrogen sulfide selective fluorogenic probe, 7-azido-4-methylcoumarin (AzMC), serves as a highly sensitive assay for cystathionine β-synthase activity, and is suitable for the high-throughput discovery of novel enzyme inhibitors.

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Dr. Megan K Youmans chemistry publications

Catalytic Nitrene Transfer by a Zirconium(IV) Redox-Active Ligand Complex

Chemical Science, Issue 1, 2011

Nitrene transfer catalyzed by a d0zirconium(IV) complex with a redox-active ligand is reported. The redox-active ligand, bis(2-isopropylamido-4-methoxyphenyl)amide ([NNNcat]3−), afforded zirconium(IV) complexes, [NNNcat]ZrClL2 (1a, L = THF; 1b, L = CNtBu; 1c, L = py), upon reaction with ZrCl4(THF)2. Complex 1a was oxidized by one and two electrons using PhICl2, affording [NNNsq•]ZrCl2(THF) (2) and [NNNq]ZrCl3 (3), respectively. Aryl azides reacted with 1a to afford zirconium imide dimers, including the crystallographically characterized species {[NNNq]ZrCl(μ2-p-NC6H4tBu)}2 (4). The formation of 4 is the result of the addition of an aryl nitrene to the zirconium(IV) metal center. When 1b was reacted with organoazides, the dimer was not observed, but rather the nitrene group was transferred to the isonitrile to form a carbodiimide. In the presence of excess organoazide and isonitrile, catalytic carbodiimide formation occurred, showing that a redox-active ligand and a d0 metal center can work in concert to effect nitrene group transfer reactivity.

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Dr. Megan K Youmans chemistry publications

Mechanism of Hydride Abstraction Catalyst by Cyclopentadienone-Ligated Carbonylmetal Complexes (M= Ru, Fe)

European Journal of Inorganic Chemistry, Issue 2, 2009

Cyclopentadienone-ligated ruthenium complexes, such as Shvo's catalyst, are known to oxidize reversibly alcohols to the corresponding carbonyl compounds. The mechanism of this reaction has been the subject of some controversy, but it is generally believed to proceed through concerted transfer of proton and hydride, respectively, to the cyclopentadienone ligand and the ruthenium center. In this paper we further study the hydride transfer process as an example of a coordinatively directed hydride abstraction by adding quantitative understanding to some features of this mechanism that are not well understood. We find that an oxidant as weak as acetone can be used to re-oxidize the intermediate ruthenium hydride without catalyst re-oxidation becoming rate-limiting. Furthermore, C–H cleavage is a significantly electrophilic event, as demonstrated by a Hammett reaction parameter of ρ = –0.89. We then describe how the application of our mechanistic insights obtained from the study have enabled us to extend the ligand-directed hydride abstraction strategy to include a rare example of an iron(0) oxidation catalyst.

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Teaching.

Contact.

  • 84 W South Street
  • Department of Chemistry and Biochemistry
  • Wilkes University