Study on Fluorescence Recognition of Fe 3+ , Cr 2 O 7 2- and p -Nitrophenol by a Cadmium Complex and Related Mechanism.

The effective detection of environmental pollutants is very important to the sustainable development of human health and the environment. A luminescent Cd(II) coordination complex, {[Cd(dbtdb)(1,2,4-H 3 btc)]·0.5H 2 O} n ( 1 ) (dbtdb = 1-(2,3,5,6-tetramethyl-4-((2-(thiazol-4-yl)-2H-benzo[d]imidazol-3(3aH)-yl)methyl)benzyl)-2,7a-dihydro-2-(thiazol-4-yl)-1H-benzo[d]imidazole, 1,2,4-H 3 btc = 1,2,4-benzenetricarboxylic acid), was obtained by hydrothermal reactions. Complex 1 has a chain structure decorated with uncoordinated Lewis basic O and S donors and provides good sensing of Fe 3+ , Cr 2 O 7 2- , and p -nitrophenol with fluorescence quenching through an energy transfer process. The calculated binding constants were 3.3 × 10 3 mol -1 for Fe 3+ , 2.36 × 10 4 mol -1 for Cr 2 O 7 2- , and 9.3 × 10 3 mol -1 for p -nitrophenol, respectively. These results show that 1 is a rare multiresponsive sensory material for efficient detection of Fe 3+ , Cr 2 O 7 2- , and p -nitrophenol.