Puntus Lada, Zhuravlev Konstantin, Lyssenko Konstantin, Antipin Mikhail, Pekareva Irina
Laboratory of Molecular Nanoelectronics, Institute of Radio Engineering & Electronics, Russian Academy of Sciences, 11-7 Mokhovaya, Moscow, 125009, Russia.
Dalton Trans. 2007 Sep 28(36):4079-88. doi: 10.1039/b706020c. Epub 2007 Jul 30.
Lanthanide complexes of Schiff bases (SBs) with 1:1 and 1:2 (M:Lig) stoichiometric ratios were prepared by condensation of pyridoxal (PL) and aspartic acid (Asp) or l-histidine (His), respectively, in the presence of the appropriate metal chloride as a templating agent. These complexes were studied by optical spectroscopy and single crystal X-ray diffraction techniques. Crystallographic studies of 1:1 (Eu(PL-Asp)(H(2)O)(4)) and 1:2 ([Eu(PL-His)(2)(H(2)O)(2)]Cl(H(2)O)(4)) complexes show that Eu(III) is eight-coordinate in both structures, in a distorted square antiprism environment formed by the phenolic oxygen of PL, the nitrogen atom of carbon-nitrogen double bond, oxygen atoms of the carboxylate groups of His or Asp, and oxygen atoms of the water molecules. The main species formed in aqueous solutions containing these SBs have been determined by analysis of the luminescence spectra, lifetimes of Eu(III) excited states and vibronic interaction as well as structural features of the Eu(III) coordination sphere. Possible tetradentate coordination function of SBs in aqueous solutions with relatively high concentrations as well as the potential application of the lanthanide SB complexes as new luminescence materials are discussed.
通过分别在适当的金属氯化物作为模板剂的存在下，使吡哆醛（PL）与天冬氨酸（Asp）或L-组氨酸（His）缩合，制备了化学计量比为1:1和1:2（M:Lig）的席夫碱（SBs）镧系配合物。通过光谱学和单晶X射线衍射技术对这些配合物进行了研究。对1:1（Eu(PL-Asp)(H₂O)₄）和1:2（[Eu(PL-His)₂(H₂O)₂]Cl(H₂O)₄）配合物的晶体学研究表明，在这两种结构中Eu(III)均为八配位，处于由PL的酚氧、碳氮双键的氮原子、His或Asp的羧基的氧原子以及水分子的氧原子形成的扭曲方形反棱柱环境中。通过对发光光谱、Eu(III)激发态寿命和振动相互作用以及Eu(III)配位球的结构特征进行分析，确定了含有这些SBs的水溶液中形成的主要物种。讨论了SBs在相对高浓度水溶液中可能的四齿配位功能以及镧系SB配合物作为新型发光材料的潜在应用。
