在这项研究中,配体23,24-二羟基-3,6,9,12-四氮杂三环[17.3.1.1(14,18)]二十碳酸-1(23),14,16,18(24),19,21-己烯,L1,和26,27-二羟基-3,6,9,12,15-五氮杂三环[20.3.1.1(17,21)]艾科萨埃普塔-1(26),17,19,21(27),22,24-己烯,合成了L2:它们代表一类新的分子,其中包含插入大环多胺片段中的联苯酚单元。先前合成的L2在本文中以更有利的程序获得。通过电位法研究了L1和L2的酸碱和Zn(II)结合性能,UV-Vis,和荧光研究,揭示了它们可能用作H+和Zn(II)的化学传感器。L1和L2的新独特设计在水溶液中形成了稳定的Zn(II)单(L1和L2分别为LogK12.14和12.98)和双核(L2为LogK10.16)络合物,它又可以被用作金属受体来结合外部客体,例如流行的除草剂草甘膦(N-(膦酰基甲基)甘氨酸,PMG)及其主要代谢产物,氨甲基膦酸(AMPA)。电位研究表明,PMG与L1-和L2-Zn(II)配合物比AMPA形成更稳定的配合物,此外,PMG对L2的亲和力高于L1。荧光研究表明,L1-Zn(II)络合物可以通过荧光发射的部分猝灭来表示AMPA的存在。因此,这些研究揭示了多氨基-酚配体在设计用于难以捉摸的环境靶标的有希望的金属受体中的实用性。
In this
study, the ligands 23,24-dihydroxy-3,6,9,12-tetraazatricyclo[17.3.1.1(14,18)]eicosatetra-1(23),14,16,18(24),19,21-hexaene, L1, and 26,27-dihidroxy-3,6,9,12,15-pentaazatricyclo[20.3.1.1(17,21)]eicosaepta-1(26),17,19,21(27),22,24-hexaene, L2, were synthesized: they represent a new class of molecules containing a biphenol unit inserted into a macrocyclic polyamine fragment. The previously synthesized L2 is obtained herein with a more advantageous procedure. The acid-base and Zn(II)-binding properties of L1 and L2 were investigated through potentiometric, UV-Vis, and fluorescence studies, revealing their possible use as chemosensors of H+ and Zn(II). The new peculiar design of L1 and L2 afforded the formation in an aqueous solution of stable Zn(II) mono (LogK 12.14 and 12.98 for L1 and L2, respectively) and dinuclear (LogK 10.16 for L2) complexes, which can be in turn exploited as metallo-receptors for the binding of external guests, such as the popular herbicide glyphosate (N-(phosphonomethyl)glycine, PMG) and its primary metabolite, the aminomethylphosphonic acid (
AMPA). Potentiometric studies revealed that PMG forms more stable complexes than
AMPA with both L1- and L2-Zn(II) complexes, moreover PMG showed higher affinity for L2 than for L1. Fluorescence studies showed instead that the L1-Zn(II) complex could signal the presence of
AMPA through a partial quenching of the fluorescence emission. These studies unveiled therefore the utility of polyamino-phenolic ligands in the design of promising metallo-receptors for elusive environmental targets.