Cd2+-triggered amide tautomerization produces a highly Cd2+-selective fluorescent sensor across a wide pH range

•Cd2+ can trigger amide tautomerization in the amide-DPA receptor.•The probe is extremely sensitive to Cd2+ with 65-fold emission enhancement.•The probe has an excellent selectivity for Cd2+.•The probe can recognize Cd2+ across a wide pH range from 4.5 to 11.5.•The probe can image Cd2+ in living cells.

An NBD-derived fluorescent sensor termed CdTS was reported to sense Cd2+ with very high binding selectivity and significant fluorescence turn-on signal selectivity (65 fold enhancement). The amide/di-2-picolylamine receptor binds Cd2+ in an imidic acid tautomeric form, but binds most of other metal ions in an amide tautomeric form. The transformable ability makes CdTS have the specific selectivity for Cd2+. Additionally, CdTS can fluoresently and colorimetricly recognize Cd2+ across a wide pH range from 4.5 to 11.5. Finally, we applied CdTS to detect Cd2+ in living cells.

Graphical abstractCdTS can fluoresently recognize Cd2+ across a wide pH range.Figure optionsDownload full-size imageDownload as PowerPoint slide