Ma Li-Jun, Wu Yuqing
Key Laboratory for Supramolecular Structure and Material of Ministry of Education, Jilin University, Changchun, PR China.
Anal Sci. 2007 Jul;23(7):799-802. doi: 10.2116/analsci.23.799.
A fluoroionophore sensor, N-[4-(1-pyrene)butyroyl]-L-tryptophan (PLT), has been reported. It can distinguish lead ion from other 12 metal ions via forming a pyrene dimer and it exhibits a very high sensitivity (0.15 microM) in aqueous solution (Chem. Commun., 2006, 2702). When the indole moiety in PLT was changed to benzene, in forming a new fluoroionophore of N-[4-(1-pyrene)butyroyl]-L-phenylalanine (PLP), it could not form a pyrene dimer in response to Pb(2+) in water. The present study describes the spectroscopic clarification of the intrinsic differences of the binding model between PLP and PLT in binding with Pb(2+). The model shows identical chelating bidentate coordination between COO(-) and Pb(2+) both in PLP-Pb and PLT-Pb; however, there is no indication of the interaction between the phenyl ring and the metal ion or the hydrogen bonding between amide groups in PLP-Pb. These differences in the binding model between PLP-Pb and PLT-Pb illustrate that the indole ring in PLT appears to play a crucial role in the high selectivity and sensitivity of PLT to lead(II) ion.
一种氟离子载体传感器，N-[4-(1-芘基)丁酰基]-L-色氨酸（PLT），已见报道。它可通过形成芘二聚体来区分铅离子与其他12种金属离子，并且在水溶液中表现出非常高的灵敏度（0.15微摩尔）（《化学通讯》，2006年，2702页）。当PLT中的吲哚部分被苯取代，形成一种新的氟离子载体N-[4-(1-芘基)丁酰基]-L-苯丙氨酸（PLP）时，它在水中对Pb(2+)无响应，无法形成芘二聚体。本研究描述了PLP和PLT与Pb(2+)结合时结合模型内在差异的光谱学阐释。该模型显示在PLP-Pb和PLT-Pb中COO(-)与Pb(2+)之间的螯合双齿配位相同；然而，在PLP-Pb中没有迹象表明苯环与金属离子之间存在相互作用，也没有酰胺基团之间的氢键作用。PLP-Pb和PLT-Pb结合模型的这些差异表明，PLT中的吲哚环似乎在PLT对铅(II)离子的高选择性和高灵敏度中起关键作用。
