Characterization of 3-OHFT3-hydroxyflavothione was characterized by 1H NMR, UV-Visible spectroscopy, LCMS and HPLC. This synthetic approach has resulted in efficient conversion and good yield, as reported previously.1

Characterization of Metal ComplexesNi(3-OHFT)2 and Fe(3-OHFT)3 was characterized by UV/Vis spectroscopy.

In this study, we investigate the synthesis and characterization of new flavothiones and their related metal complexes to be used as photodegradable pesticides. Photodegradable pesticides are a promising solution to the problems posed by the use of synthetic chemicals in the environment.The goals for photodegradable pesticides are to be activated by sunlight, pest management and to degrade into products that are environmentally safe.It was reported that the photochemical reaction of 3-hydroxyflavothione (3-OHFT) produced a reactive oxygen species capable of killing bacterial and fungal species, as well as degraded into products that can be removed from the environment over time.Although 3-OHFT corresponds with the characteristics for photopesticidal use, the lifetime is not long enough to be effective for practical use. A recent study was performed to react various metal salts with 3-OHFT to create metal complexes, [M-(OHFT) n].It demonstrated that the addition of a metal compound increased the lifetime versus that of the free ligand..

Characterization

Future WorkOur future research include the thionation of quercetin (2), morin (3) and apeginin (4), along with synthesizing and characterizing their corresponding metal complexes. This will allow us to examine the oxidative properties of flavothiones and their ability to be used as a photodegradable pesticide.

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AcknowledgementsWisconsin Alliance for Minority Participation ProgramUniversity of Wisconsin – Eau Claire Chemistry DepartmentUniversity of Wisconsin – Eau Claire Material Science ProgramStudent Blugold Commitment Differential Tuition funds through the University of Wisconsin - Eau Claire Faculty/Student Research Collaboration Grants program

References

SynthesisSynthesis of 3-OHFTIn a one-step synthesis, thionation of the carbonyl in 3-hydroxyflavone affords 3-hydroxyflavothione following methods found in literature.1,2

Synthesis of Metal ComplexesFlavothionato metal complexes will be synthesized by deprotionation of the hydroxyl group on the flavothione which is achieved through treatment with excess base followed by reaction of metal salt. We explored the metals Ni2+ and Fe3+. We predict a four or six-coordinate complex with two or three bidentate (O,S donor) ligands.

1. Ba L. Tran; Seth M. Cohen. Chem. Comm. 2006, 10, 203-205.2. Curphey, T. J. Org. Chem. 2002, 67, 6461-6473.

UV/VIS Spectrum of 3-OHFT in CH2Cl2

Wavelength (nm)

Abs

orba

nce

356 nm

420 nm

1H NMR Spectrum of 3-OHFT

Chemical Shift (ppm)

Wavelength (nm)

Abs

orba

nce

UV/VIS Spectrum of Fe(3-OHFT)2 in CH2Cl2

Wavelength (nm)

Abs

orba

nce

UV/VIS Spectrum of Ni(3-OHFT)2 in CH2Cl2

Introduction

730 nm

619 nm

417 nm359 nm

385 nm

460 nm

Quercetin

2

Synthesis and Characterization of Flavothiones and Corresponding Metal Complexes for the Use of Photodegradable PesticidesAriel Schuelke and Dr. Roslyn M. Theisen

Department of Chemistry, University of Wisconsin- Eau Claire

Research GoalsTo reproduce results using 3-OHFT from previous studies

To synthesize a thionated quercetin compound and it’s metal analogues.

To test the emissive properties of quercetin and metal analogues, and compare the results to those of 3-OHFT.