Fluorescence signaling of aromatic oxoanion inclusion within metal-ion activated molecular receptor complexes formed from 2-(9-anthracenylmethylamino)ethyl-appended cyclen
作者:Adam J. Bradbury、Stephen F. Lincoln、Kevin P. Wainwright
DOI:10.1007/s10847-011-9924-7
日期:2011.12
Our observations that 1-[2-[(9-anthracenylmethylamino)ethyl)-4,7,10-tris[(2S)-2-hydroxy-3-phenoxypropyl]-1,4,7,10-tetraazacyclododecane, L1, complexes Cd(II) to form fluorescent [CdL1]2+ which undergoes a fluorescence change when it acts as an aromatic anion receptor complex has caused us to explore further the potential development of an interesting sequestration/sensor system. Accordingly, three new, octadentate, fluorescent, macrocyclic ligands, 1-[2-[(9-anthracenylmethyl)((2S)-2-hydroxy-3-phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L2), 1-[2-[(9-anthracenyl-methyl)((2S)-2-hydroxy-3-(4′-methyl)phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-(4′-methyl)phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L3), and 1-[2-[(9-anthracenylmethyl)((2S)-2-hydroxy-3-(4′-t-butyl)phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-(4′-t-butyl)phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L4), have been prepared with a view to using their metal complexes to study aromatic anion sequestration. The eight-coordinate Cd(II) complexes of L2 and L3, [CdL2](ClO4)2·5H2O and [CdL3](ClO4)2·2H2O·2Et2O are both capable of acting as receptors for a range of aromatic oxoanions. This is demonstrated by perturbation of the anthracene derived fluorescence emission intensity as the guest aromatic oxoanion and the receptor complex combine. In 20% aqueous 1,4-dioxane the receptor complex/aromatic oxoanion association constants are in the range of 103.2 M−1 (guest = p-hydroxybenzoate) to 107.3 M−1 (guest = 3,4,5-trihydroxybenzoate).
我们的观察结果是,1-[2-[(9-蒽基甲基氨基)乙基]-4,7,10-三[(2S)-2-羟基-3-苯氧基丙基]-1,4,7,10-四氮杂环十二烷(L1)与Cd(II)络合形成荧光的[CdL1]²⁺,当它作为芳香阴离子受体络合物时会发生荧光变化,这促使我们进一步探索有趣的隔离/传感系统的潜在发展。因此,我们制备了三种新的八齿、荧光、宏环配体:1-[2-[(9-蒽基甲基)((2S)-2-羟基-3-苯氧基丙基)氨基]乙基]-4,7,10-三[(2S)-2-羟基-3-苯氧基丙基]-1,4,7,10-四氮杂环十二烷(L2),1-[2-[(9-蒽基甲基)((2S)-2-羟基-3-(4′-甲基)苯氧基丙基)氨基]乙基]-4,7,10-三[(2S)-2-羟基-3-(4′-甲基)苯氧基丙基]-1,4,7,10-四氮杂环十二烷(L3),以及1-[2-[(9-蒽基甲基)((2S)-2-羟基-3-(4′-t-丁基)苯氧基丙基)氨基]乙基]-4,7,10-三[(2S)-2-羟基-3-(4′-t-丁基)苯氧基丙基]-1,4,7,10-四氮杂环十二烷(L4),目的是利用它们的金属配合物研究芳香阴离子的隔离。L2和L3的八配位Cd(II)络合物[CdL2](ClO4)₂·5H₂O和[CdL3](ClO4)₂·2H₂O·2Et₂O都能够作为一系列芳香氧阴离子的受体。这表明,随着客体芳香氧阴离子与受体络合物结合,蒽基衍生的荧光发射强度发生扰动。在20%水状1,4-二恶烷中,受体络合物/芳香氧阴离子的结合常数范围为103.2 M⁻¹(客体=p-羟基苯甲酸盐)至107.3 M⁻¹(客体=3,4,5-三羟基苯甲酸盐)。