Three chemosensors DN1, DN2 and DN3, incorporating dansyl dye as a fluorophore and various carboxhydrazones as ionophores, are reported. DN1 contains a pyridine-carboxhydrazone tridentate coordination site, forming a 2:1 stoichiometric complexation species with Cr3+, and exhibits selectivity for Cr3+ over alkali and alkaline earth metals and most first-row transition metals in aqueous media. DN1 displays high quantum yield (Φ = 0.86) and fluorescence enhancement following Cr3+ coordination within a wide pH range. DN2 contains a 8-hydroxyquinoline-carboxhydrazone tetradentate metal-binding moiety, forming a 1:1 complex with Cr3+. DN2 also exhibits significantly fluorescence enhancement but a much lower quantum yield following Cr3+ binding in aqueous solution. In contrast, their congener DN3, having a salicyl-carboxhydrazone tridentate binding site, does not exhibit any significant fluorescence variation following Cr3+ binding. These results demonstrate that the hydroxyl group is an important factor influencing the fluorescence response to Cr3+ in aqueous media.
报道了三种
化学传感器DN1、DN2和DN3,均采用dansyl
染料作为荧光团,并采用各种羧
肼酮作为离子载体。DN1包含一个
吡啶-羧
肼酮的三齿配位位点,与Cr3+形成2:1的化合物,具有对Cr3+的选择性,高于碱
金属、碱土
金属和大多数第一过渡族
金属在
水相中的选择性。DN1在宽pH范围内显示出高量子产率(Φ = 0.86)和荧光增强,随着Cr3+的配位而增强。DN2包含一个
8-羟基喹啉-羧
肼酮的四齿
金属结合基团,与Cr3+形成1:1的配合物。DN2在
水溶液中与Cr3+结合后也表现出显著的荧光增强,但量子产率显著较低。相比之下,其同类物DN3,具有
水杨酸-羧
肼酮的三齿结合位点,与Cr3+结合后并未表现出任何显著的荧光变化。这些结果表明,羟基是影响
水相中对Cr3+荧光响应的重要因素。