测定氨基酸浓度和对映体组成的手性荧光探针

Chiral Fluorescent Probes for Determination of Both Concentration and Enantiomeric Composition of Amino Acids

设计并合成了基于1,1'-联二萘酚(BINOL)骨架的新型荧光探针(R)-(E)-2,2'-二羟基-3'-((喹啉-7-亚基氨基)甲基)-[1,1'-联萘]-3-甲醛[(R)-2]及其异构体(R)-(E)-2,2'-二羟基-3'-((喹啉-6-亚氨基)甲基)-[1,1'-联萘]-3-甲醛[(R)-3].在探针分子的3'位引入的喹啉亚胺基团通过N原子与Zn(Ⅱ)的络合作用参与氨基酸的分子识别,协同增强了BINOL手性醛对氨基酸的对映选择性.探针分子对多种氨基酸在438nm表现出与手性无关的荧光增强,而在513nm显示出优异的对映选择性荧光响应.研究了以上两个不同发射峰强度分别与精氨酸浓度和对映体过量(ee)的依赖函数关系,并应用拟合的函数方程测定了多个精氨酸样品的浓度和ee值.利用^(1)HNMR和HRMS研究了在Zn^(2+)存在条件下,探针分子与不同手性构型的精氨酸分子之间的作用机理,并采用高斯16计算了D-或L-精氨酸/探针/Zn(Ⅱ)络合物的热力学稳定性,进一步阐明了探针分子对氨基酸对映选择性的本质原因.本研究实现了单一探针测定7个手性氨基酸(Glu,Arg,Gln,Ser, Thr, Met, Ala)的浓度和对映体组成两个重要参数.

A novel 1,1'-bi-2-naphthol(BINOL)-based fluorescent probe(R)-(E)-2,2'-dihydroxy-3'-((quinolin-7-ylimino)methyl)-[1,1'-binaphthalene]-3-carbaldehyde[(R)-2]and its isomer(R)-(E)-2,2'-dihydroxy-3'-((quinolin-6-ylimino)methyl)-[1,1'-binaphthalene]-3-carbaldehyde[(R)-3]were designed and synthesized.The quinoline imine groups at 3'-position of the probes were involved in the molecular recognition of amino acids through complexation between N atom and Zn(II),which synergically enhanced the enantioselectivity of BINOL-aldehyde to amino acids.The probe molecule exhibited chiral independent fluorescence enhancement for various amino acids at 438 nm,while exhibiting excellent enantioselective fluorescence response at 513 nm.The dependence function of the intensities of the above two emission peaks on arginine concentrations and enantiomeric excess(ee)was studied,and the concentrations and ee values of several arginine samples were measured by the fitted function equation.The interaction mechanism between(R)-2 and D-/L-arginine in the presence of Zn2+was investigated by 1H NMR and HRMS.The thermodynamic stability of the arginine enantiomer/probe/Zn(II)complexes was calculated by Gaussian 16 program to elucidate the origin of the enantioselectivity.This work affords a platform for the determination of the concentration and enantiomeric composition of 7 amino acids(Glu,Arg,Gln,Ser,Thr,Met,Ala)through a single probe.