Chemistry: Student Scholarship & Creative Works
Student Research Paper
Kristi A. Kneas
Chemistry and Biochemistry
Traditionally, in luminescence-based sensing, a sensor molecule is designed for one specific analyte. A new method of sensing was proposed which combines a non-luminescent sensing matrix and a luminescent reporter molecule that reacts to the change in its environment upon the interaction of the matrix with an analyte. In previous attempts at this method of sensing an environmentally-sensitive fluorophore was embedded into a hydrogel. However, leaching of the reporter molecule occurred with repeated use in aqueous phase sensing. In response to this limitation, two specific reporter molecules are explored: a nitrile derivative of dapoxyl sulfonic acid (compound 1), which can be covalently bonded to the polymer support matrix and [Os(CO)2(sulf-dpp)Cl2], which can be incorporated into a luminescent metal organic framework. The solvent sensitivity of 1 was measured, and it was found that the derivative exhibits solvent-sensitivity, albeit complicated by the presence of two accessible excited states. The fluorophore was polymerized into an analyte-responsive hydrogel, and the sensitivity of the derivative to change in relative humidity was measured. It was found that the derivative lost some sensitivity when incorporated into the gel, though modified analyses of resultant data may allow for the emission responses to changes in polarity to be calibrated. The viability of [Os(CO)2(sulf-dpp)Cl2] as a reporter complex was determined. The quantum yield was found to be 0.00092 ± 0.00006 and the molar extinction coefficient was 410 ± 10 L·mol-1cm-1 indicating that a fair amount of complex may be ii necessary to provide reasonable sensor signal. However, if incorporated into a luminescent metal organic framework, the response might improve due to the increased rigidity of the environment of the complex.
Kramer, Stephanie N., "Photophysical Characterization of Luminophores for Use in Sensing Applications" (2016). Chemistry: Student Scholarship & Creative Works. 2.