INVESTIGATING THE PHOTOPHYSICAL PROPERTIES OF POTENTIAL ORGANIC LEAD SENSORS

<p dir="ltr">LeadGlow (<b>LG</b>) was reported in 2009 for its ability to both sensitively and selectively detect Pb²⁺ in aqueous solutions. Utilizing the synthetic approach of <b>LG</b>, it is possible to generate a class of novel fluorophores. A derivative of first-generation <b>LG </b>was synthesized and reported here for the first time, intuitively named <b>LG2</b>. Both compounds contain interesting photophysical properties that have not been extensively researched prior to this work. Because of this, photophysical properties of both <b>LG</b> and <b>LG2</b> are unveiled here for the first time. These properties were investigated by determinations of quantum yield (QY), average fluorescence lifetime, and DFT calculations. <b>LG</b> was found to have a higher QY (0.057) than <b>LG2</b> (0.011); however, <b>LG2</b> displays an average fluorescence lifetime (3.186 ns) 5x greater than that of <b>LG</b>. Both <b>LG </b>and <b>LG2</b> are synthesized via Hg²⁺-facilitated desulfurization of their respective thiocarbonyls, resulting in a turn-on fluorescence feature. The thiocarbonyl-containing fluorophores (<b>SLG </b>and <b>SLG2</b>) display quenched fluorescence compared to their oxo-derivatives (<b>LG </b>and <b>LG2</b>), this work attempts to investigate the mechanism(s) responsible.<b> </b>A whole class of LeadGlow compounds can be synthesized and could be potentially used as fluorescence-based sensors.</p>