Design and synthesis of electro-optical sensors that distinguish between organophosphorus pesticides and chemical warfare agent mimics

ORGN 440

Brigitte J. Engelmann, brigitte.j.engelmann@wmich.edu and Sherine O. Obare, sherine.obare@wmich.edu. Department of Chemistry, Western Michigan University, 1903 W. Michigan Avenue, 3425 Wood Hall, Kalamazoo, MI 49008
The creation of new materials for sensing and actuation requires careful manipulation of the responsive units required to control analyte selectivity. We have developed a series of molecular sensors based on dipyrido-[3,2-a:2'3'-c]phenazine (DPPZ). Rational choice of substituents at the 3 and 6 positions and the back-end phenazine unit of DPPZ allow manipulation of optical, electrochemical and mechanical properties required to selectively distinguish between various toxic organophosphorus-based pesticides and chemical warfare agent mimics. We have demonstrated that 3,6-dialkylbenzo[i]dipyrido-[3,2-a:2'3'-c]phenazine in comparison to benzo[i]dipyrido-[3,2-a:2'3'-c]phenazine show significant differences in the optical and electrochemical signal outputs upon interaction with various organophosphorus compounds including diethyl chlorothiophosphate, diethyl chlorophosphate, dimethyl methylphosphonate, and the pesticides fenthion and paraoxon. The presentation will demonstrate the rational choices in substituent selection for selective discrimination between organophosphorus compounds.