Selective sensing Ca²⁺ with a spiropyran‐based fluorometric probe

Abstract

Spiropyran (SP) and its derivatives operate between their ring opening and closing forms as a versatile molecular platform for the fluorescence detection of cations and anions, using a colour change for signalling. A functionalized SP fluorescence probe, L, was prepared and characterized. Probe L can detect Ca 2+ with a fluorescence 'turn-on' response in ethanol solution. It selectively binds Ca 2+ to form a 1:1 ligand/metal complex, which produced a new emission band centred at 604 nm. The sensing result was clearly observed by the solution colour change from colourless to pink under visible light, and from blue to red under ultraviolet light. The detection limit was calculated to be 4.53 × 10 −8 M for Ca 2+ . The probe provides another possibility that SP-based derivatives could be used for the development and detection of metal ions in environmental and physiological systems.

Nanostructured and Photochromic Material for Environmental Detection of Metal Ions

“…As an important additional result, some of the metal ions tested presented a fluorescence under UV light irradiation (Figure 7), including Ca 2+ and Mg 2+ . Other researchers have also reported this phenomenon for these ions [35,38]. Zn 2+ appears orange in color, and it was the only one in its set that presented fluorescence.…”

“…In addition, to these results, the PEGSP2 solution was irradiated by cycling UV and visible lights, Figure 5b, demonstrating that PEGSP2 could have a better isomerization efficacy than SPCOOH, after 10 cycles there is a 16.2% decrease in absorbance. Recent literature [35,36,37] also reports SP dyes as sensors, mainly in solution. Based on our data, twenty-five metals ions in aqueous solution were tested on the PEGSP2 nanofibers surface.…”

Noncontact Metal–Spiropyran–Metal Nanostructured Substrates with Ag and Au@SiO2 Nanoparticles Deposited in Nanohole Arrays for Surface-Enhanced Fluorescence and Trace Detection of Metal Ions

“…Through comparison, it is found that the LODs of Zn 2+ , Cu 2+ , and Sn 2+ in our work can reach 0.054, 0.038, and 0.049 μm, respectively, which is the lowest detection concentration reported so far. At present, a lot of references have reported that the introduction of special groups into spiropyran can realize the specific recognition of metal ions. − Combining the innovations of this work with reported references, a metal ion sensor with high fluorescence EF, low LOD, and excellent specific recognition will be fabricated, providing a new idea for the follow-up research in this field.…”

Spiropyran–Merocyanine Based Photochromic Fluorescent Probes: Design, Synthesis, and Applications

“…Wang’s group 52 constructed a spiropyran probe, 15 ( Figure 14 ), to recognize the Ca 2+ ion through a “turn-on” response. An electron-withdrawing cyano group was introduced in the probe to facilitate isomerization by weakening the C–O bond of the closed SP form.…”