Sensitive molecular optical material for signaling primary amine vapors

Given their adverse effects on human health and environment, sensitive recognition of amine vapors is highly desirable. To this endeavor, a new method has been developed which integrates a tailored approach using a reaction based fluorescent turn-on probe for the selective recognition of primary amine vapors in the solid state at trace level (ppm). The present chemodosimetric probe has been successfully utilized for the detection of primary amines with high sensitivity and selectivity. The utility of probe 1 in selective discrimination of primary amines over other relevant reactive nucleophiles such as secondary amines, tertiary amines, thiols and alcohols has been established using fluorescence spectroscopy as one of the most efficient and sensitive optical techniques. Moreover, the changes in absorption spectra of probe 1 and the result of ‘dip-coating’ method with primary amines support further its high specificity and selectivity. The generation of optical signal upon interaction of probe 1 and primary amine vapor was mainly due to a fast chemical reaction between the probe and the primary amine resulting in the formation of pyrene amine. The formation of different new species was confirmed by various advanced spectroscopic techniques such as NMR and mass spectroscopy. To the best of our knowledge, this is the first example of a turn-on chemodosimeter that detects primary amines selectively through in situ molecular structure engineering leading to the generation of a new turn-on optical signal.

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