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首页> 外文期刊>Chemistry: A European journal >A cyclam core dendrimer containing dansyl and oligoethylene glycol chains in the branches: Protonation and metal coordination
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A cyclam core dendrimer containing dansyl and oligoethylene glycol chains in the branches: Protonation and metal coordination

机译：支链中含有丹磺酰基和低聚乙二醇链的cyclam核心树状聚合物：质子化和金属配位

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摘要

We have synthesized a dendrimer (1) consisting of a 1,4,8,11-tetraazacyclotetradecane (cyclam) core, appended with four benzyl substituents that carry, in the 3- and 5-positions, a dansyl amide derivative (of type 2), in which the amide hydrogen is replaced by a benzyl unit that carries an oligoethylene glycol chain in the 3- and 5-positions. All together, the dendrimer contains 16 potentially luminescent moieties (eight dansyl- and eight dimethoxybenzene-type units) and three distinct types of multivalent sites that, in principle, can be protonated or coordinated to metal ions (the cyclam nitrogen atoms, the amine moieties of the eight dansyl units, and the 16 oligoethylene glycol chains). We have studied the absorption and luminescence properties of 1, 2, and 3 in acetonitrile and the changes taking place upon titration with acid and a variety of divalent (CO2+, Ni2+, Cu2+, Zn2+), and trivalent (Nd3+, Eu3+, Gd3+) metal ions as triflate and/or nitrate salts. The results obtained show that: 1) double protonation of the cyclam ring takes place before protonation of the dansyl units; 2) the oligoethylene glycol chains do not interfere with protonation of the cyclam core and the dansyl units in the ground state, but affect the luminescence of the protonated dansyl units; 3) the first equivalent of metal ion is coordinated by the cyclam core; 4) the interaction of the resulting cyclam complex with the appended dansyl units depends on the nature of the metal ion; 5) coordination of metal ions by the dansyl units follows at high metal-ion concentrations; 6) the effect of the metal ion depends on the nature of the counterion. This example demonstrates that dendrimers may exhibit complete functionality resulting from the integration of the specific properties of their component units.
机译：我们合成了由1,4,8,11-四氮杂环十四烷（cyclam）核组成的树枝状聚合物（1），该树枝状聚合物带有四个在3和5位带有丹磺酰胺衍生物（2型）的苄基取代基），其中酰胺氢被苄基单元取代，该苄基单元在3和5位带有一个低聚乙二醇链。树枝状聚合物总共包含16个潜在的发光部分（8个丹磺酰基和8个二甲氧基苯类型的单元）和3种不同类型的多价位点，这些位点原则上可以质子化或与金属离子配位（环己酰胺氮原子，胺基） 8个dansyl单元和16个低聚乙二醇链中的一个）。我们研究了1、2和3在乙腈中的吸收和发光特性，以及用酸和各种二价（CO2 +，Ni2 +，Cu2 +，Zn2 +）和三价（Nd3 +，Eu3 +，Gd3 +）滴定时的变化。金属离子为三氟甲磺酸盐和/或硝酸盐。得到的结果表明：1）Cyclam环的双质子化在丹磺酰基单元的质子化之前发生; 2）低聚乙二醇链在基态下不干扰环己酰胺核心和丹磺酰基单元的质子化，但影响质子化丹磺酰基单元的发光; 3）金属离子的第一当量由仙客来核配位; 4）所得的环蛋白络合物与附加的丹磺酰基单元的相互作用取决于金属离子的性质; 5）在高金属离子浓度下，丹磺酰基单元对金属离子的配位作用; 6）金属离子的作用取决于抗衡离子的性质。该实施例证明树枝状聚合物可以表现出由于其组成单元的特定性质的整合而产生的完整功能。

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