...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>ACS Omega >Synthesis of Bis-β-Diketonate Lanthanide Complexes with an Azobenzene Bridge and Studies of Their Reversible Photo/Thermal Isomerization Properties
【24h】

Synthesis of Bis-β-Diketonate Lanthanide Complexes with an Azobenzene Bridge and Studies of Their Reversible Photo/Thermal Isomerization Properties

机译：带有偶氮苯桥的双-β-二酮酮酸酯镧系配合物的合成及其光/热异构化性质的可逆性研究

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The ligand, bis-β-diketone with an azobenzene bridge (4,4′-(4,4,4-trifluoro-1,3-butanedione)azobenzene, H2L), was prepared for the synthesis of a series of dinuclear lanthanide complexes with the formula [Ln2L3(DMSO)4] (Ln = Eu3+, Gd3+, Tb3+, and DMSO = dimethyl sulfoxide). X-ray crystallographic analysis reveals that the three complexes are triple-stranded dinuclear structures formed by three bis-β-diketonate ligands with two lanthanide ions (Ln3+). The trans-to-cis photoisomerization rates of the azobenzene group of the three [Ln2L3(DMSO)4] complexes in ethanol and acetonitrile solutions are similar to those of the pure H2L ligand and other azobenzene-containing mononuclear lanthanide complexes, but the trans-to-cis quantum yields (Φt→c = 10–3) are 1 order of magnitude smaller. The first-order rate constant for the cis-to-trans thermal isomerization at 50 °C of the H2L ligand is similar to those of azobenzene derivatives, while those for the [Ln2L3(DMSO)4] complexes (kiso = 10–4 s–1) are higher than those of the mononuclear azobenzene-containing lanthanide complexes. Furthermore, as the lanthanide ionic radius becomes smaller from Eu3+ to Gd3+ to Tb3+, the thermal isomerization rate constant decreases and the half-life increases. All these results are proposed to arise from the rigidity at both ends of the azo group by coordination to the dinuclear lanthanide ions and the different isomerization mechanisms. These are the first examples of bis-β-diketonate dinuclear lanthanide complexes with an azobenzene bridge and help illustrate the mechanism of azobenzene isomerization.
机译：制备了具有偶氮苯桥的配体双-β-二酮（4,4'-（4,4,4-三氟-1,3-丁二酮）偶氮苯，H2L），用于合成一系列双核镧系配合物式[Ln2L3（DMSO）4]（Ln = Eu3 +，Gd3 +，Tb3 +，DMSO =二甲基亚砜）。 X射线晶体学分析表明，这三个络合物是由三个带有两个镧系元素离子（Ln3 +）的双-β-二酮酸酯配体形成的三链双核结构。乙醇和乙腈溶液中三种[Ln2L3（DMSO）4]配合物的偶氮苯基的顺式至顺式光异构化速率与纯H2L配体和其他含偶氮苯的单核镧系元素络合物的顺式光异构化速率相似，但反式-顺式量子产率（Φt→c = 10–3）小一个数量级。 H2L配体在50°C时顺式-反式热异构化的一级速率常数与偶氮苯衍生物相似，而[Ln2L3（DMSO）4]络合物的一级速率常数（kiso = 10–4 s –1）高于单核含偶氮苯的镧系元素络合物。此外，随着镧系元素离子半径从Eu3 +到Gd3 +到Tb3 +变小，热异构化速率常数降低，半衰期增加。提出所有这些结果是由于偶氮基团两端的刚性通过与双核镧系离子的配位和不同的异构化机理而产生的。这些是具有偶氮苯桥的双-β-二酮酸双核镧系配合物的第一个实例，有助于说明偶氮苯异构化的机理。

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