Perylene diimide based ‘turn-on’ fluorescence sensor for detection of Pd in mixed aqueous media

A perylene diimide (PDI) based fluorescence chemosensor (PDI-1) for Pd²⁺ was prepared. PDI-1 showed a remarkable fluorescence enhancement (over 120-fold) in the presence of Pd²⁺ in mixed aqueous media with high selectivity and sensitivity. Moreover, the dramatically ‘off–on’ fluorescence response concomitantly induced the obvious color change from dark purple to brilliant pink, which could also be identified by naked eyes easily. The low limit for Pd²⁺ detection was found to be as small as 10⁻⁹ mol/L. Hence, PDI-1 is a highly promising fluorescent chemosensor for the direct determination of residual Pd²⁺ in chemical medicines and environment samples.