• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Polyamine Receptors Containing Dipyridine or Phenanthroline Units: Clues for the Design of Fluorescent Chemosensors for Metal Ions
【24h】

Polyamine Receptors Containing Dipyridine or Phenanthroline Units: Clues for the Design of Fluorescent Chemosensors for Metal Ions

机译：含联吡啶或邻菲咯啉单元的多胺受体：用于金属离子荧光化学传感器设计的线索

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The synthesis of the macrocyclic receptor L1, which contains a tetraamine chain linking the 6,6’-positions of a 2,2’-dipyridine moiety, is reported. Its basicity properties and complexation features toward CuII, ZnII,CdII and PbII have been studied in aqueous solutions by means of potentiometric, UV/Vis spectroscopy and fluorescence emission measurements and compared with those of ligand L2, in which a 1,10-phenanthroline moiety replaces the dipyridine unit of L1. In metal coordination, L1 shows a marked selectivity toward CdII over Zn~(II) and Pb~(II). The crystal structures of its metal complexes shows that L1 possesses a preferential tetradentate binding site for metal cations, composed of the dipyridine unit and the two adjacent benzylic amine groups. This binding site has the proper dimension and conformation to selectively coordinate the Cd~(II) ion, as confirmed by DFT calculations carried out on the complexes. This coordinative zone is lost in L2. The rigidity of phenanthroline does not allow the simultaneous binding of both the benzylic amine groups to Zn~(II) and Cd~(II) and, in fact, one benzylic amine is not coordinated to these metal cations. The fluorescence emission properties of the L1 and L2 complexes are strongly pH dependent. Only the Zn~(II) and Cd~(II) complexes with L1 display fluorescence emission at neutral pH. This feature is related to the formation in solution at pH 7 of emissive protonated complexes of the type [M(H_xL)]~((2+x)+) (x=1–3), in which all the nitrogen donors are involved in metal or proton binding. The emissive characteristics of these protonated complexes are confirmed by the fluorescence emission spectra collected on the [Zn(HL1)Br]- [ClO_4]_2 and [Cd(HL1)Br][ClO_4]_2 solid compounds dissolved in CH_3CN. Conversely, the Zn~(II) and Cd~(II) complexes with L2 are not emissive; in fact, they contain a benzylic amine group not involved in metal or proton binding that can quench the fluorescence emission of the fluorophore, thanks to a photoinduced electron-transfer process.
机译：据报道，大环受体L1的合成，它含有连接2，2′-二吡啶部分的6，6′-位的四胺链。通过电位，UV / Vis光谱和荧光发射法研究了其在水溶液中对CuII，ZnII，CdII和PbII的碱性和络合特性，并将其与配体L2（其中有1,10-菲咯啉部分）进行了比较。取代L1的二吡啶单元。在金属配位中，L1对Zn〜（II）和Pb〜（II）具有明显的CdII选择性。其金属配合物的晶体结构表明，L1具有金属阳离子的优先四齿结合位点，由二吡啶单元和两个相邻的苄基胺基组成。如对复合物进行的DFT计算所证实的，该结合位点具有适当的尺寸和构象，以选择性地配位Cd〜（II）离子。该协调区域在L2中丢失。菲咯啉的刚性不允许苄基胺基团同时与Zn〜（II）和Cd〜（II）结合，实际上，一种苄基胺不与这些金属阳离子配位。 L1和L2配合物的荧光发射特性强烈依赖于pH。只有具有L1的Zn〜（II）和Cd〜（II）配合物在中性pH下显示荧光发射。此特征与[M（H_xL）]〜（（2 + x）+）（x = 1–3）类型的质子化质子配合物在pH 7时在溶液中的形成有关，其中涉及所有氮供体在金属或质子结合中。这些质子化配合物的发射特性通过在溶解于CH_3CN的[Zn（HL1）Br]-[ClO_4] _2和[Cd（HL1Br）] [ClO_4] _2固体化合物上收集的荧光发射光谱证实。相反，具有L2的Zn〜（II）和Cd〜（II）配合物不发光。实际上，由于光诱导的电子转移过程，它们含有不参与金属或质子结合的苄胺基团，该苄基胺基团可以猝灭荧光团的荧光发射。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号