Madeleine Gonley
Pronouns: She/Her
Research Mentor(s): Nathaniel Szymczak
Research Mentor School/College/Department: Chemistry / LSA
Program: UROPF
Session: Session 5 (2:40pm – 3:30pm)
Authors: Madeleine Gonley, Andrew LaDuca, Nathaniel Szymczak
Abstract
Perchlorate (ClO4-) is a common wastewater pollutant with a high activation energy associated with its reduction to water and chloride(Cl-), making it challenging to break down. Nature is full of appended hydrogen bonds, which are used to guide pollutants such as ClO4-, to enzymes like perchlorate reductase. This enzyme can then break down ClO4- into less hazardous chemicals. Previous experiments in our lab have shown that a non-heme iron complex with secondary sphere (appended) hydrogen bonds, (6-(phenylamino))-pyridylmethylamine (LH) Fe(OTf)2, spontaneously reduces ClO4- to produce an Fe(III)OH complex. This study investigates the reactivity of other transition metals on LH for the catalytic reduction of ClO4. We have metalated LH with copper, cobalt, manganese, chromium, and molybdenum, then introduced ClO4- to examine the reactivity of each complex. NMR spectroscopy and electrochemistry revealed that LHCu1+ and LHCo2+ complexes do not possess the capacity to spontaneously reduce ClO-, even in the presence of exogenous reductants. LHMn(OTf)2 shows the ability to react with ClO3- , but not with ClO4- . This suggests that manganese has reductive potential, but may be impeded by experimental conditions. Future plans involve investigating a coordinatively unsaturated manganese complex to provide more kinetically favorable conditions for ClO4 reduction. Investigations with Cr2+ and Mo2+ are currently underway.
