Department of Chemistry, Isfahan University of Technology, Isfahan 8415683111, Iran.
Department of Chemistry, Isfahan University of Technology, Isfahan 8415683111, Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Jan 15;207:6-15. doi: 10.1016/j.saa.2018.08.058. Epub 2018 Aug 31.
A new fluorene based fluorogenic chemosensor, 2-[(9H-Fluoren-2-ylmethylene)-amino]-phenol (L), has been designed, synthesized, and characterized by CHN analyses and different spectroscopic methods. This turn-on fluorogenic chemosensor shows high selectivity and sensitivity toward Cu and CN with low detection limits of 1.54 × 10 M and 1.83 × 10 M, respectively. The stoichiometry ratio of L-Cu in solution is 1:1, by the method of Job's plot and ESI-MS. The microcrystalline solid product of the chemosensor reaction with copper is characterized as CuL. The χT value for CuL is temperature independent at a value of 0.403 cm K mol, which is in agreement with a mononuclear copper(II) complex with an isotropic g-value of 2.075. The fluorescence turn-on recognition process for detection of Cu is attributed to the restricted imine isomerization and blocking of intramolecular charge transfer (ICT) quenching process in the analyte-bound sensor. The selectivity of L for Cu is based on the chelation-enhanced fluorescence effect (CHEF) mechanism. Other interfering ions such as Na, K, Ca, Mg, Ag, Fe, Fe, Co, Ni, Zn, Cd, Hg, Mn, Pb and Al, show no change in the fluorescence intensity of L in the presence of Cu. Furthermore, the compound L can be used as a fluorescence and colorimetric sensor for selective detection of CN over a number of other anions based on the nucleophilic addition to the imine CN bond, with consequent hydrogen bond formation and electrostatic interaction of the resulting product with K. The sensing mechanism for CN was theoretically supported by DFT calculations.
一种新的基于芴的荧光化学传感器，2-[(9H-芴-2-基亚甲基)-氨基]-苯酚（L），已经通过 CHN 分析和不同的光谱方法进行了设计、合成和表征。这种开启型荧光化学传感器对 Cu 和 CN 具有高选择性和灵敏度，检测限分别低至 1.54×10-7 M 和 1.83×10-7 M。通过 Job 图和 ESI-MS 方法，确定溶液中 L-Cu 的化学计量比为 1:1。化学传感器与铜反应的微晶固体产物被表征为 CuL。CuL 的 χT 值在 0.403 cm K mol 的温度独立值，与具有各向同性 g 值为 2.075 的单核铜（II）配合物一致。用于检测 Cu 的荧光开启识别过程归因于受限的亚胺异构化和分析物结合传感器中分子内电荷转移（ICT）猝灭过程的阻断。L 对 Cu 的选择性基于螯合增强荧光效应（CHEF）机制。其他干扰离子，如 Na、K、Ca、Mg、Ag、Fe、Fe、Co、Ni、Zn、Cd、Hg、Mn、Pb 和 Al，在存在 Cu 时，L 的荧光强度没有变化。此外，基于与亚胺 CN 键的亲核加成，化合物 L 可以用作荧光和比色传感器，选择性检测 CN 及其它阴离子，随后形成氢键，并与 K 形成静电相互作用。CN 的传感机制得到了 DFT 计算的理论支持。
