Coordination behavior toward copper(II) and zinc(II) ions of three ligands joining 3-hydroxy-2-pyridinone and polyaza fragments
Coordination behavior toward copper(II) and zinc(II) ions of three ligands joining 3-hydroxy-2-pyridinone and polyaza fragments
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DOI：
10.1021/ic0484607
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发表时间：
2005-05-02
影响因子：
4.6
通讯作者：
Zappia, G
中科院分区：
文献类型：
--
作者：
Ambrosi, G;Formica, M;Zappia, G
报道了新的多齿配体2-（N），2 ′-（N ′）-双[2-（3-羟基-2-氧代-2H-吡啶-1-基）乙酰胺基]-1（N ′），2（N），2 ′（N ′）-三甲基-2，2 ′-二氨基二乙胺（L3）的合成与表征。报道了L3和两个类似的大环配体（L1和L2）对Cu（II）和Zn（II）金属离子的配位性质。所有三个配体均显示3-羟基-2（1H）-吡啶酮（HPO）基团作为侧臂连接到多氮杂片段，其在L1和L2的情况下是大环骨架，而在L3的情况下是开链。研究了多氮杂片段在预组织两个侧臂中的作用。L3的碱度和L1-L3的结合性质通过在水溶液（298.1 +/- 0.1 K，f = 0.15 mol dm（-3））中的电位测量来确定。紫外-可见光谱以及H-1和C-13 NMR实验用于理解HPO和多氮杂片段在阳离子稳定化中的作用。虽然L1形成稳定的单核和双核配合物，L2和L3可以形成单核物种与每个金属离子的研究。在L2和L3的主要单核物种中，由于每个HPO的两个氧原子，两个HPO部分使M（I1）稳定在正方形平面几何形状中。通过添加第二配体（例如在Cu（II）系统的情况下的水分子或在Zn（II）系统中的OH-）来完成金属的配位层。这些结果由本文报道的[CuH（-1 L2]（+）和[CuH（-1 L3]（+）物质的晶体结构证实。两种构象的L1可以假设在形成的双核物种，建议由NMR实验上的[ZnH（-2 L1]物种，这表明两个构象缓慢互换的NMR时间尺度上，其中一个被发现是更难溶。
The synthesis and characterization of new polydentate ligand 2-(N),2'-(N')-bis[2-(3-hydroxy-2-oxo-2H-pyridn-1-yl)acetamido]-1(N'),2(N),2'(N')-trimethyl-2,2'-diaminodiethylamine (L3) is reported. The coordination properties of L3 and of two analogous macrocyclic ligands (L1 and L2) toward Cu(II) and Zn(II) metal ions are reported. All three ligands show the 3-hydroxy-2(1H)-pyridinone (HPO) groups attached as sidearms to a polyaza fragment, which is a macrocyclic framework in the case of L1 and L2 while it is an open chain in the case of L3. The role of the polyaza fragments in preorganizing the two sidearms was investigated. The basicity of L3 and the binding properties of L1-L3 were determined by means of potentiometric measurements in aqueous solution (298.1 +/- 0.1 K, / = 0.15 mol dm(-3)). UV-vis spectra as well H-1 and C-13 NMR experiments were used to understand the role of the HPO and of the polyaza fragments in the stabilization of the cations. While L1 forms stable mono- and dinuclear complexes, L2 and L3 can form only mononuclear species with each of the metal ions investigated. In the main mononuclear speces of L2 and L3, the two HPO moieties stabilize the M(I 1) in a square planar geometry due to the two oxygen atoms of each HPO. The coordination sphere of the metal is completed by adding a secondary ligand such as water molecules in the case of Cu(II) systems or OH- in the Zn(II) systems. These results are confirmed by the crystal structures of the [CuH(-1)L2](+) and [CuH(-1)L3](+) species reported herein. Two conformations of L1 can be hypothesized in the formation of the dinuclear species, as suggested by NMR experiments on the [ZnH(-2)L1] species, which shows two conformers slowly interchanging on the NMR time scale, one of which was found to be more insoluble.