A fast responsive and highly selective mercury(II) sensor was developed using the fluorescence quenching mechanism of 2,9-dimethyl-1,10-phenanthroline (2,9-DMP) towards mercury(II). Furthermore, two kinds of metal–organic frameworks (MOFs) of 2,9-DMP–Hg(II) have been synthesized and characterized by X-ray diffraction. The probe 2,9-DMP exhibited a fast and highly selective response to mercury(II) ions in aqueous solution, showing a good linear relationship over the concentration range of 0.050–2.0 μM for Hg(II) with R2 = 0.9994. The established procedure was used to monitor the concentration of mercury(II) in drinking water and Zhujiang River water samples with satisfactory recoveries of 85.42–101.5% and 81.72–96.09%, respectively. Furthermore, the fluorescence quenching mechanism of 2,9-DMP by mercury(II) was investigated and clarified by the data of single crystal X-ray diffraction of MOFs and the Job's plot analyses of 2,9-DMP towards Hg(II).
You-Hui Zhao,Hai-Yan Li,David James Young,Xiangqian Cao,Da-Liang Zhu,Zhi-Gang Ren,Hong-Xi Li
Earth-abundant copper(I) coordination complexes of an imine-phosphine and a diimine have been developed as visible-light photocatalysts. Reaction of [Cu(MeCN)4]BF4 with hetero-bidentate phosphinopyrazole (phpz) ligand R1R2C3HN2PPh3 (R1 = R2 = H (1a); R1 = H, R2 = Me (1b); R1 = H, R2 = Ph (1c); R1 = R2 = Me (1d)) and 2,9-dimethyl-1,10-phenanthroline (dmp) gave four heteroleptic bis-chelate Cu(I) complexes [Cu(dmp)(R1R2C3HN2PPh3)]BF4 (R1 = R2 = H (2a); R1 = H, R2 = Me (2b); R1 = H, R2 = Ph (2c); R1 = R2 = Me (2d)) with distorted tetrahedral geometries. Complexes 2a–2d exhibited broad absorption in the visible spectrum and could facilitate photochemical intermolecular atom-transfer radical addition reactions of CBr4, or CCl3Br, CHI3 to styrenes in yields up to 91% and with a broad substrate scope. The absorption, emission, redox potential and photocatalytic activity were dependent on the substituents on the phpz ligand. Mechanistic studies supported an atom-transfer radical addition (ATRA) mechanism.