A chemosensor 1 with a long hydrocarbon chain and polar end group is synthesized by the simple condensation reaction of a long chain amine with salicylaldehyde. A long chain hydrocarbon with a polar end group is used because of its solubility in an aqueous surfactant solution, which ensures that it can be used in a neutral water medium. The rationale for choosing an aryl aldehyde with –OH functionality is based upon the fact that a chelate ring consisting of an –OH group and an sp2 nitrogen donor is always better for the selective recognition of Zn2+. The sensor shows selective binding to Zn2+ in 1% Triton-X-100 solution. Binding of Zn2+ by sensor 3 leads to an approximately 300% enhancement in the fluorescence intensity of the sensor, due to the combined effects of excited state intramolecular proton transfer (ESIPT) and the inhibition of the photo-induced electron transfer (PET) process by the –OH group. The fluorescence emission profiles of sensor 1 show some changes in the low and high pH ranges, however the sensor remains stable in the pH range 4–9, which makes it appropriate for use in biological fluids.
通过长链胺与
水杨醛的简单缩合反应,可以合成具有长碳氢链和极性端基的
化学传感器1。之所以使用具有极性端基的长链烃,是因为它在
水表面活性剂溶液中具有可溶性,从而确保它可以在中性
水介质中使用。选择具有-OH官能团的芳基醛的理由是,由-OH基团和sp2氮供体组成的螯合环对于Zn2+的选择性识别总是更好的。该传感器在1% Triton-X-100溶液中显示出对Zn2+的选择性结合。由于激发态分子内质子转移(ESI
PT)和-OH基团对光诱导电子转移(PET)过程的抑制的共同作用,传感器3对Zn2+的结合导致传感器的荧光强度提高了约300%。传感器1的荧光发射曲线在低pH值和高pH值范围内有一些变化,但在pH值4-9范围内保持稳定,这使其适用于
生物液体。