A sole organic hybrid europium(Ⅲ) chloride as a luminescent sensor for Cu2+ ion

The exploration of an outstanding sensor for selectively and sensitively detecting ion is of great significance, because its deficiency or excess from the normal amount has pernicious effect on the human body. Herein, the optically active 2,4,6-tri(2-pyridyl)− 1,3,5-triazine (TPTZ) was utilized for the construction of a new type of organic hybrid europium(Ⅲ) chloride [Eu2(TPTZ)2(pica)Cl5]·2H2O (1, Hpica = pyridine-2-carboxylic acid), which shows a characteristic red-light emission. The quantum efficiency of 1 diluted in anhydrous acetonitrile is 67.28% at room temperature, and obviously higher than that of solid‐state sample (only 19.41%), suggesting that acetonitrile instead of H2O molecule with –OH oscillator may reduce non‐radiative de‐excitation. Owing to the existence of free triazinyl and pyridyl sites serving as the receptors, 1 displays a remarkable sensing property towards Cu2+ ion in acetonitrile solution with a higher Ksv value of 1.85 × 105 M−1 and lower detection limit of 0.97 ppm. Although some luminescent hybrid europium(Ⅲ) chlorides are emerged to date, they have been not served as a luminescent sensor for monitoring Cu2+ ion. Therefore, 1 presents the sole case of hybrid europium(Ⅲ) chloride as a luminescent sensor for the detection of Cu2+ ion.