Design, synthesis, photoluminescence and electrochemiluminescence properties of naphthalimide derivative and its silver complex

A new D-A (Donor-Accept) type N-(1,2,4-triazolyl)-N′-(2-ethylhexyl) naphthalenediimide (L) was synthesized. AgL2PF6 (1) and AgL2NO3 (2) were obtained through the reactions of L with AgPF6 and AgNO3, respectively. All the compounds were fully characterized. Optical, electrochemical properties and electrogenerated chemiluminescence (ECL) were systematically investigated. Those dual fluorescent emissions for L, short wavelength (SW) and long wavelength (LW) emission bands, are rationally explained by the planar intramolecular charge transfer (PICT) model. All the compounds display anodically shift reduction waves with positive reduction potential, compared to its parent compound, Naphthalene bisimide (NBI). It is very interesting that the ECL intensity of the complexes is successfully increased, which is 20 times larger than that of L, explaining that the radical anions of the complexes are stabilized by coordinating L with Ag(I) ion. The results provide a new approach to study ECL materials.