Synthesis and electronic structure of a mononuclear copper(II) complex supported by tris(2-hydroxyliminopropyl)amine
Synthesis and electronic structure of a mononuclear copper(II) complex supported by tris(2-hydroxyliminopropyl)amine
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DOI：
10.1016/j.poly.2019.114306
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发表时间：
2020-02
期刊：
影响因子：
2.6
通讯作者：
Alexander Roseborough;K. Wheeler;M. Hołyńska;S. Stoian
中科院分区：
文献类型：
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作者：
Alexander Roseborough;K. Wheeler;M. Hołyńska;S. Stoian
通过硝酸铜（II）与L =三（2-羟基亚氨基丙基）胺在甲醇中反应，合成了蓝绿色单核铜配合物[CuL（NO3）]NO3（1）。通过单晶X-射线衍射确定了1的结构，其显示出具有假八面体配位几何形状的铜（II）离子。其中一个硝酸根阴离子以η 2方式配位，而另一个是非配位的，并且参与分子内和分子间氢键。硝酸盐促进的分子间氢键由质子化配体支撑，并导致超分子波状链的形成。利用电子顺磁共振（EPR）测量在低温下对纯粉末和冷冻溶液进行了研究。在固体状态下，我们观察到一个S = 1/2的准轴向信号，描述为gz = 2.256，gy = 2.086，gx = 2.048。使用耦合微扰（CP）密度泛函理论（DFT）和CASSCF/NEVPT 2计算对这些值进行了合理化。1的计算研究表明了一个（x2−y2）型基态和由（xy）→（x2−y2）跃迁控制的ag张量。EPR调查的冷冻溶液样品中发现存在两个类似的光谱成分，表明溶解后的硝酸根阴离子被取代的协调领域和1种成六和五协调的络合物阳离子。1的循环伏安曲线表明，1为准可逆的Cu（I）/Cu（II）氧化还原电对，E1/2=+0.26Vvs.SHE，1是电沉积Cu（0）/Cu 2 O薄膜的前驱体。
The blue-green, mononuclear copper complex [CuL(NO3)]NO3, (1), was synthesized by reacting copper(II) nitrate with L = tris(2-hydroxyliminopropyl)amine in methanol. The structure of1was determined by single-crystal X-ray diffraction, which revealed a copper(II) ion that exhibits a pseudo-octahedral coordination geometry. While one of the nitrate anions is coordinated in anη2fashion, the other is non-coordinated and is involved in intra- and inter-molecular hydrogen bonds. The nitrate-promoted intermolecular hydrogen bonding is supported by the protonated ligand and leads to the formation of supramolecular undulating chains. The electronic structure of1was investigated using Electron Paramagnetic Resonance (EPR) measurements performed at cryogenic temperatures on both neat powders and frozen solutions. In the solid state we observe a quasi-axial S = 1/2 signal described bygz= 2.256,gy= 2.086, andgx= 2.048. These values were rationalized using coupled-perturbed (CP) Density Functional Theory (DFT) and CASSCF/NEVPT2 calculations. The computational investigation of1suggests an (x2−y2)-type ground state and ag-tensor dominated by the (xy) → (x2−y2) transition. EPR investigation of frozen solution samples revealed the presence of two similar spectral components indicating that upon dissolution the nitrate anion is displaced from the coordination sphere and1speciates into six- and five-coordinated complex-cations. The cyclic voltammograms of1revealed a quasi-reversible Cu(I)/Cu(II) redox couple, E1/2= +0.26 V vs. SHE, and that1functions as a precursor for electrodeposited Cu(0)/Cu2O films.