Denyce Wicht, PhD

Associate Professor, Chemistry & Biochemistry

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On sabbatical, AY 2019-2020

Education

  • PhD, Dartmouth College, Chemistry
  • BA, University of Vermont, Chemistry

Research Interests

Broadly speaking, my research interests involve understanding the mechanistic processes that cleave methyl group carbon bonds (–CH3) to high-valent main group elements, specifically silicon (Si) and sulfur (S). I’m interested in silicon–carbon bonds (Si–CH3) of the molecule dimethylsilanediol (abbreviated DMSD, structure shown below) because this specific molecule has been detected in environmental matrices. One source of DMSD in the environment is from chemical additives in personal care and other down-the-drain household products. Because no naturally occurring organosilicon compounds have been reported, chemical species containing silicon–carbon bonds, such as DMSD, are anthropogenic. The impacts of organosilicon xenobiotics are not entirely clear, but there is evidence for Si–CH3 catabolism in mammals. The long-term goal of my research is the identification of a catalytic system that can efficiently break the Si–CH3 bonds of DMSD under mild conditions and physiological pH. Neither a chemical nor a biological catalytic system has yet been identified. The identification of a catalyst capable of breaking a Si–CH3 bond would be a significant advancement in the field and applicable to the design of systems engineered to treat environmental pollutants.

The other bond I’m interested in is the sulfur–carbon bond (S–CH3 ) of the molecule dimethylsulfone (abbreviated DMSO2, structure shown below). Unlike DMSD, DMSO2 is a naturally occurring molecule. This compound enters the terrestrial environment through the chemical oxidation of biogenic dimethylsulfide, a compound that plays a major role in the global sulfur cycle. Despite the natural deposition of an estimated 2-8 million tons of DMSO2 annually, DMSO2 has not directly been detected in soil environments. In nature, it is speculated that soil bacteria biodegrade DMSO2 . Perhaps indirect evidence for DMSO2 deposition are reports of microorganisms isolated from soil that can utilize DMSO2 for growth and metabolism, but the complete biochemical reactions that DMSO2 undergoes have only recently been elucidated. An ongoing research interest of mine involves understanding the enzymatic pathways through which DMSO2 is used by microorganisms. Understanding how soil bacteria break the sulfur–carbon bond (S–CH3) in a naturally occurring molecule may provide insight into how to design a catalyst to break other methyl group carbon bonds (–CH3) to high-valent main group elements.

Access the structures of dimethylsilanediol (DSMD) and dimethylsulfone (DMSO2) [PDF].

Employment History

  • Wellesley College, 2003-2005
    Visiting Assistant Professor
  • General Electric Global Research Center, 2000-2002
    Chemist; Polymer and Specialty Chemical Technologies
  • Massachusetts Institute of Technology, 1999-2000
    Postdoctoral Associate

Recent Publications

Muirhead, D. L.; Wicht, D. K.; Stocker, K. M.; Perry, J. L.; Kayatin, M. J. A Simple Model to Estimate the Hydroxyl Radical Concentration and Associated DMSD Production Rates from Volatile Methyl Siloxanes in the ISS Atmosphere, 48th International Conference on Environmental Systems, Albuquerque, NM, July, 2018.

Wicht, D. K. The Reduced Flavin-Dependent Monooxygenase SfnG Converts Dimethylsulfone to Methanesulfinate. Arch. Biochem. Biophys. 2016, 604, 159-166.

O’Brien, K. E.; Wicht, D. K. A greener organic chemistry experiment: Reduction of citronellal to citronellol using poly(methylhydro)siloxane. Green Chem. Lett. Rev. 2008, 1, 149-154.

Wicht, D. K. Green Chemistry Essay: We’re Going to Need a Bigger Earth. In Chemistry for Changing Times, 12th Edition; Hill, J. W.; McCreary, T. W.; Kolb, D. K.; Eds.; Pearson Prentice Hall: Upper Saddle River, NJ, 2010; p 336.

Wicht, D. K. Green Chemistry Essay: Catalysts. In Chemistry for Changing Times, 11th Edition, Hill, J. W.; Kolb, D. K.; Eds.; Pearson Prentice Hall: Upper Saddle River, NJ, 2007; p 320.

Wicht, D. K. Green Chemistry Essay: Antifouling in Rivers of Life; Seas of Sorrow. In Chemistry for Changing Times, 11th Edition; Hill, J. W., Kolb, D. K., Eds.; Pearson Prentice Hall: Upper Saddle River, NJ, 2007; p 378.

Oral Presentations

Wesleyan University, Middletown, CT, Oct., 2019.

255th Meeting of the American Chemical Society, New Orleans, LA, March, 2018.

University of Vermont, Burlington, VT, Nov., 2017.

Worcester Polytechnic Institute, Worcester, MA, Sept., 2015.

250th Meeting of the American Chemical Society, Boston, MA, Aug., 2015.

Bates College, Lewiston, ME, Jan., 2015.

Merrimack College, North Andover, MA, Oct., 2010.

Dartmouth College, Hanover, NH, May, 2010.

Hofstra University, Hempstead, NY, May, 2010.

12th Annual Green Chemistry and Engineering Conference, Washington D.C., June, 2008.

Worcester State University, Worcester, MA, March, 2008.

Grants & Awards

  • NSF Research at Undergraduate Institutions (RUI): Biophysical Characterization of Reduced Flavin-Dependent Two Component Monooxygenase Sulfur Assimilation Enzymes: SfnG, MsuC, and MsuD
  • NASA, International Space Station Water Subsystem, Selective Removal of DMSO2 within the Water Processing Assembly/Oxygen Generation Assembly Water Loop by Enzymatic Processes
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Contact Me

Office Hours

  • T 3:05 p.m. - 4:20 p.m.
  • W 10:00 a.m. - 12:00 p.m. by appointment (please schedule 24 hours in advance)
  • Th 10:50 a.m. - 12:05 p.m.
  • Schedule an Appointment

Courses Taught

  • CHEM 111/L111 - General Chemistry I and Lab
  • CHEM 112/L112 - General Chemistry II and Lab
  • CHEM 211/L211 - Organic Chemistry I and Lab
  • CHEM 212/L212 - Organic Chemistry II and Lab
  • CHEM L355 - Environmental Chemistry Lab
  • CHEM 375 - Transition Metal Chemistry
  • CHEM 390 - Advanced Organic Chemistry
  • CHEM 510 - Independent Study in Chemistry