Lingliang Long

A Sensitive and Selective Fluorescent Thiol Probe in Water Based on the Conjugate 1,4‐Addition of Thiols to α,β‐Unsaturated Ketones

Compound 1 was designed and synthesized as a new fluorescent thiol probe. Probe 1 was constructed on the basis of the conjugate 1,4-addition of thiols to alpha,beta-unsaturated ketones. Notably, probe 1 has suitable water solubility, which allows the sensing assay to be performed in water. Probe 1 is highly sensitive for thiols with a 211-fold fluorescence dynamic range and a low detection limit of 9.25x10(-7) M. The major features of probe 1 also include a high selectivity for thiols over other relevant biological species, excitation and emission in the visible region, rapid functioning at pH 7.4, and a good linear relationship between the fluorescence signal and the thiol concentration. Accordingly, these desirable characteristics may render probe 1 as potentially useful for biological applications.

A Ratiometric Fluorescent Probe for Cysteine and Homocysteine Displaying a Large Emission Shift

4-(1H-phenanthro[9,10-d]imidazol-2-yl)benzaldehyde 1 was rationally designed as a novel ratiometric fluorescent probe for cysteine and homocysteine. Upon addition of cysteine or homocysteine, notably, the probe displayed a very large (125 nm) hypsochromic shift in emission due to switching off intramolecular charge transfer. This large emission wavelength shift may allow probe 1 to be employed for quantitatively detecting Cys/Hcy.

A Ratiometric Fluorescent Probe for Hypochlorite Based on a Deoximation Reaction

In this work, we have successfully provided a novel strategy for the rational design and synthesis of a ratiometric fluorescent probe for hypochlorite. The strategy is based on the deoximation reaction, which has not yet been used in the fluorescent hypochlorite probe design. Interestingly, the probe showed a ratiometric fluorescent response to hypochlorite with the emission intensities ratio (I(509)/I(439)) increasing from 0.28 to 2.74. Furthermore, the probe displayed high selectivity for hypochlorite over other species due to the distinct deoximation conditions. The probe developed herein represents the first ratiometric fluorescent probe for hypochlorite.

Construction of Fluorescent Probes Via Protection/Deprotection of Functional Groups: A Ratiometric Fluorescent Probe for Cu2+

Herein a ratiometric fluorescent Cu(2+) probe was rationally constructed in a straightforward manner with the concept of aldehyde group protection/deprotection. The probe showed a ratiometric fluorescent response to Cu(2+) with a large emission wavelength shift (>100 nm) and displayed high selectivity for Cu(2+) over other metal ions due to distinct deprotection conditions. In addition, a Cu(2+)-promoted dethioacetalization mechanism was proposed.

A novel ratiometric fluorescent Fe3+ sensor based on a phenanthroimidazole chromophore.

Phenanthroimidazole derivative 1 has been developed as a rare example of ratiometric fluorescent sensors for Fe(3+). Interestingly, upon treatment with Fe(3+), the sensor displayed a ratiometric fluorescent response with an enhancement of the ratios of emission intensities at 440 and 500 nm from 0.36 to 3.24. The detection range of the sensor for Fe(3+) is in the 1.0x10(-5)-1.5x10(-4) M concentration range and the detection limit is 5.26x10(-6) M. In addition, the sensor showed good selectivity to Fe(3+) with the selectivity coefficients (K(Fe3+) = S(Fe3+)/S(0) of Fe(3+) over other metal ions tested in the range of 5-68.