An optical anion chemosensor based on a europium complex and its molecular logic behavior

In this paper, synthesis and photophysical properties of an organoeuropium complex, Eu(DBM)3DPPZ (DBM = dibenzoylmethane, DPPZ = dipyrido [3,2-a:2′,3′-c]phenazine), are described and discussed. The europium complex sensor can efficiently recognize AcO− ion over other anions by the increase of luminescence intensity, which is applicable to naked eye detection for AcO− ion. The sensing mechanism is ascribed to the replacement of DPPZ by AcO− ion. Moreover, the Eu3+ emission is also found to be sensitive to molecular oxygen through a back-energy transfer mechanism. Based on these characters, this “off–on”-type luminescent sensor could successfully mimic an IMP (IMPLICATION) gate at molecular level with AcO− ion and oxygen as inputs. The output of a sharp characteristic Eu3+ emission is read as “0” only in the absence of AcO− ion under oxygen atmosphere. As far as we know, this is the first example of a logic gate corresponding to a two-input IMP function obtained from a europium complex.