Dr. Gayan B. Wijeratne joined UAB in 2018, and is currently an Assistant Professor of Chemistry. He was born in Kandy, Sri Lanka, and received his B.Sc. (Honors) degree in chemistry from the University of Colombo, Sri Lanka, where his research on transition metal complexes of Sri Lankan natural products was recognized by the Professor R. S. Ramakrishna Memorial Gold Medal in inorganic chemistry in 2009.
He moved to the United States in 2010 and carried out his graduate research in the laboratory of Professor Timothy A. Jackson at the University of Kansas, working on bioinspired manganese complexes that bind dioxygen and its reduced derivatives, as well as on thermodynamic and kinetic studies of proton-coupled electron transfer reactivity of manganese-based oxidants. There he won the Higuchi Doctoral Progress Award in 2015, the highest graduate distinction at the University of Kansas. He carried out his postdoctoral research in the laboratory of Professor Kenneth D. Karlin at Johns Hopkins University from 2015 to 2018, where his research interests were focused on understanding heme and/or copper interactions with nitrogen oxides, primarily the mechanistic aspects involved with the reductive coupling of nitric oxide to nitrous oxide. He was also involved in dioxygen reduction and substrate oxidation reactivity studies of heme/copper assemblies.
Dr. Wijeratne’s research program at UAB is geared toward interrogating key mechanistic details pertaining to various crucial biologically and/or industrially relevant inorganic processes utilizing small-molecule, synthetic model compounds. This research interface between synthetic inorganic/organic chemistry, structural, spectroscopic, and theoretical characterization methodologies, and detailed thermodynamic and kinetic investigations of reactivity patterns. This research program is designed to produce all-rounded researchers with multidisciplinary chemical proficiencies, that range from traditional fundamental topics to state-of-the-art inorganic chemistry applications. The ultimate goal is aimed at comprehending the implications and significance of inorganic transformations/mechanisms of interest in human health and therapeutics, future sustainable catalysis, and next generation alternative energy applications.
Nature has evolutionarily integrated metal centers in some of its most crucial/efficient functional proteins, most of which successfully mediate catalytic chemical transformations under entirely environmentally benign, ambient conditions. The pivotal nature of these metalloenzyme biochemistries often implicate them in human disease and diagnostics, whereupon a clear comprehension of their mechanistic details may lead to effective therapeutics against some of the most challenging pathological conditions humans face in present day, such as cancer, Alzheimer’s or Huntington’s. The efficiency in which nature utilizes these greener, cheaper metal systems in enzymatic catalytic turnovers also offers invaluable chemistry lessons to humans on how to move away from toxic, expensive catalytic metals that are currently in use for industrial-scale bulk transformations.
Wijeratne Research Laboratory utilizes synthetic organic and inorganic chemical tools to generate inorganic model complexes that resemble metalloprotein active sites, and then studies their reactivity profiles with small molecule biological substrates such as dioxygen (O2), its reduced derivatives such as superoxide (O2–•), peroxide (OO2–) etc., and/or nitrogen oxides (NOx’s; e.g., NO, N2O, NO2–, NO3–) under inert laboratory conditions (i.e., utilizing glovebox/Schlenk techniques). One of the primary goals of this work is to identify biologically relevant intermediates/active species using synthetic model systems. Such reaction intermediates often display impaired thermal/chemical stabilities, and thus require specialized low-temperature techniques for unequivocal characterization. An array of spectroscopic and structural characterization strategies will be applied, such as electronic absorption (UV-Vis), electronic paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), Infrared (IR), resonance Raman (rR), and X-ray absorption (XANES & EXAFS) spectroscopies, mass spectrometry, and X-ray diffraction (XRD) along with electrochemical analysis (e.g., cyclic voltammetry (CV)). Careful thermodynamic and kinetic analyses (i.e., Eyring-, Arrhenius-, Polanyi-, and Hamett-type, kinetic isotope effects (KIE), and bond dissociation (free) energy (BD(F)E) calculations) of substrate and/or self reactivities of these species will lead into crucial insights that relate to key unknowns pertaining to the corresponding metalloprotein systems. Complementary Density Functional Theory (DFT) computations will also be employed as warranted. Comprehensive understanding of the bio-related chemistry will pave the way into novel, more effective therapeutics, as well as greener (nature-inspired) methodologies for industrial scale catalytic applications. The undergraduate, graduate and postdoctoral researchers engaged in these research attempts will progress to adepts in synthetic, spectroscopic and structural approaches for tackling mechanistic ambiguities, with sound knowledge of biological, inorganic, organic and physical chemistries, and their potential roles in industrial applications. Wijeratne Research Group actively collaborates with multiple on-campus, local and international research groups and national labs/facilities, including the UAB Center for Free Radical Biology (CFRB).
Dr. Wijeratne is also the organizer of a seminar series themed “Pathways to Chemistry Careers”, which strives to provide a broader perspective on career opportunities that are available for future chemistry graduates. Both academic and industrial professionals will be invited on-campus for seminars/discussions.
My lectures will routinely relate chemical principles to “real–life” situations, to which students can easily relate to, and thus, readily comprehend. I will also transform the classroom experience into a memorable one by delivering most of the material on the chalk-board, as well as by means of effective problem–solving methodologies, such as in–lecture demos, group activities, and related in-class presentations. I will take the opportunity to design take-home examinations for graduate level courses where possible, since it is my belief that they benefit the students in a unique pattern, familiarizing them with the valuable practice of exploring scientific literature in search of chemical solutions. To supplement topics covered in lecture as well as further develop problem–solving and critical thinking skills, weekly problem sets will be assigned, and will be graded and returned promptly to render sound self-evaluation. As well, I intend to hold office hours as needed, during which, students are free to stop by my office to discuss related matters (chemistry or otherwise), and will also be available to meet by appointment anytime outside the office hours. I have found such flexibility of teaching professors to be of incredible benefit during my student days. My teaching style also involves directing students toward suitable resources for further reading/understanding, which will mold my students to be capable of tackling unforeseen challenges both inside and outside the classroom. Nonjudgmental, impartial aspects have always dominated my inclusive teaching style, which I believe creates a healthy classroom environment in which all students are equally treated and appreciated.
Teaching Interests: Inorganic and Bioinorganic Chemistry, Inorganic Structure and Spectroscopy, Metalloenzymes – Structure and Function, Bio-inspired Model Chemistry, Environmentally Benign (Green) Catalysis, and Pathways to Careers in Chemistry