Design of an antenna effect Eu(III)-based metal-organic framework for highly selective sensing of Fe 3 .

Highly selective sensing of Fe 3+ is very important due to its great effect on biological systems. A novel ligand [1,1':4',1'':4'',1''':4''',1''''-quinquephenyl]-2,2'',2'''',5''-tetracarboxylic acid (H 4 qptca) was designed and successfully obtained for the first time via three steps in high total yields according to the absorption spectrum of Fe 3+ . The europium(III)-based metal-organic framework derived from H 4 qptca, {[Eu(qptca) 1/2 (H 2 qptca) 1/2 (H 2 O) 2 ]·DMF} n (referred to as SLX-1), was then synthesized and used as a water-stable and highly selective luminescent sensor for Fe 3+ in aqueous solution with a comparable detection limit using Ln-MOF probes (6.45 μM) through the antenna effect of SLX-1. Furthermore, the luminescence quenching mechanism was also proposed as a competitive absorption mechanism.