Luminescent Lanthanide Complex Sensor for Acac and Cd 2 +

In this work, phenylmalonic acid (H 2 pmal) and phenanthroline (phen) are selected to react with Ln(NO 3 ) 3 ·6H 2 O (Ln = Tb, Eu) to form two lanthanide coordination complex [Ln 2 (PAA) 4 (phen) 2 (NO 3 ) 2 ] (Ln = Tb, Tb complex; Eu, Eu complex), PAA = deprotonated phenylacetic acid, phen = 1,10‐phenanthroline). Two lanthanide complexes are stable in neutral, acid (pH = 4) and base (pH = 10) water solutions. Especially, Tb complex is a bifunctional sensor for acac and Cd 2+ , through luminescence “turn on” and “turn off,” respectively. Importantly, the limit of detections (LODs) for acac and Cd 2+ are 90 n m and 0.5 μ m , respectively. Furthermore, the sensing mechanisms are discussed in detail.