CAY10732 is a fluorescent probe for the detection of carbon monoxide. [1] In the presence of palladium (Pd) and carbon monoxide, CAY10732 undergoes the Pd0-mediated Tsuji-Trost reaction to release 2,7-dichlorofluorescein, and its fluorescence can be used to detect carbon monoxide production in vitro and in live cells. 2,7-Dichlorofluorescein displays excitation/emission maxima of 493/527 nm, respectively.

Reference:
[1]. Feng, S., Liu, D., Feng, W., et al. Allyl fluorescein ethers as promising fluorescent probes for carbon monoxide imaging in living cells. Anal. Chem. 89(6), 3754-3760 (2017).