Fluorescent Nitric Oxide Detection by Copper Complexes Bearing Anthracenyl and Dansyl Fluorophore Ligands

Anthrancenyl and dansyl fluorophore ligands [AnCH2pipCS2K (1), Ds-Hen (2), Ds-HAMP (3), Ds-HAQ (4), and
Ds-HAPP (5)] were prepared for coordination to CuII. Five Cu complexes, [Cu(AnCH2pipCS2)2] (6), [Cu(Ds-en)2]
(7), [Cu(Ds-AMP)2] (8), [Cu(Ds-AQ)2] (9), and [Cu(Ds-APP)(OTf)] (10), were synthesized as candidates for detecting
nitric oxide (NO) by fluorescence and characterized by X-ray crystallography. A decrease in fluorescence compared
to that of the free ligands (1−5) was measured following the formation of the corresponding five CuII complexes
6−10. Fluorescence was restored in the presence of NO in CH3OH/CH2Cl2 solutions of the compounds. Complexes
7, 8, and 10 exhibited a fluorescence response to NO in pH 7.0 or 9.0 buffered aqueous solutions. Spectroscopic
studies revealed that NO-induced fluorescence enhancement in these CuII complexes occurs by reduction to CuI.
The present studies demonstrate that CuII complexes are effective as fluorescent probes for detecting NO in both
organic and aqueous environments.

蒽基（Anthrancenyl）与丹磺酰（dansyl）荧光团配体[AnCH2pipCS2K (1)、Ds-Hen (2)、Ds-HAMP (3)、Ds-HAQ (4)及Ds-HAPP (5)]被制备，用于与二价铜（CuII）配位。五种铜配合物：[Cu(AnCH2pipCS2)2] (6)、[Cu(Ds-en)2] (7)、[Cu(Ds-AMP)2] (8)、[Cu(Ds-AQ)2] (9)与[Cu(Ds-APP)(OTf)] (10)，被合成为荧光法检测一氧化氮（NO）的候选探针，并经X射线晶体衍射表征。相较于游离配体（1~5），所形成的对应五种二价铜（CuII）配合物（6~10）的荧光强度均出现降低。在该类化合物的CH3OH/CH2Cl2混合溶液中加入NO后，荧光得以恢复。配合物7、8和10在pH 7.0或9.0的缓冲水溶液中，对NO表现出荧光响应。光谱学研究表明，此类二价铜（CuII）配合物中NO诱导的荧光增强，是通过将二价铜还原为一价铜（CuI）实现的。本研究证实，二价铜（CuII）配合物可作为有效的荧光探针，在有机相和水相环境中实现NO的检测。