Sensitive and selective sensor based on porphyrin porous organic cage fluorescence towards copper ion

In present work, a fluorescent porphyrin organic cage sensor PTC-1(2H) for sensitively and selectively detecting divalent copper ion has been introduced. PTC-1(2H) contains the three metal-free units connected by chiral cyclohexanediamine, exhibiting a red-light emission with a broad band at the maximum 641 nm. Among the addition of various metal ions, the emission of PTC-1(2H) has been exclusively and seriously quenched by the addition of divalent copper ions, exhibiting a low limit of detection value of 6.3 nM. A crystal structure of cage with copper ion confirms the complexation of porphyrin N4 cavity and metal ions, revealing the optimized bind position. The special cage structure exhibits the better sensing property than monomeric compound. In addition, a photothermal conversion performance of PTC-1(Cu) has been discovered. These results further enrich the chemistry of porous organic cages.