N,N’-bis(salicylidene)-2-(6-(2-aminophenyl)-4-phenylpyridin-2-yl) (3) was synthesized by condensation reaction of 2,6-bis(2-aminophenyl)-4-phenylpyridine and 2-hydroxybenzaldehyde in EtOH and characterized by its melting point, 1H,13C-NMR and molecular mass. The addition of Cr3+ion makes the significant increase of its fluorescent intensity at 537 nm in CH3CN/H2O (95/5%), however, other metal ions have almost no influence on the fluorescence. The reason for this phenomenon might be attributed to the formation of a 1:1 stoichiometric 3-Cr3+ complex which inhibits photo-induced electron transfer (PET) process. The 1:1 binding stoichiometry between 3 and Cr 3+was established using Job’s plot, and the complex structure was proposed by DFT calculation. The association constant (Ka) was determined to be 8.77×104M-1 and the limit of detection (LOD) was calculated to be 2.2×10-7M.
