Wilson Kevin R, Cannon-Smith Desiray J, Burke Benjamin P, Birdsong Orry C, Archibald Stephen J, Hubin Timothy J
Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, Oklahoma 73096, United States.
Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
Polyhedron. 2016 Aug 16;114:118-127. doi: 10.1016/j.poly.2015.11.014.
Two novel pyridine pendant-armed macrocycles structurally reinforced by an ethyl bridge, either between adjacent nitrogens (for side-bridged) or non-adjacent nitrogens (for cross-bridged), have been synthesized and complexed with a range of transition metal ions (Co, Ni, Cu and Zn). X-ray crystal structures of selected cross-bridged complexes were obtained which showed the characteristic cis-V configuration with potential labile cis binding sites. The complexes have been characterized by their electronic spectra and magnetic moments, which show the expected high spin divalent metal complex in most cases. Exceptions are the nickel side-bridged complex, which shows a mixture of high-spin and low spin, and the cobalt cross-bridged complex which has oxidized to cobalt(III). Cyclic voltammetry in acetonitrile was carried out to assess the potential future use of these complexes in oxidation catalysis. Selected complexes offer significant catalytic potential enhanced by the addition of the pyridyl arm to a reinforced cyclen backbone.
合成了两个新型的由乙基桥结构增强的吡啶侧臂大环化合物，该桥分别连接相邻氮原子（用于侧桥型）或不相邻氮原子（用于交叉桥型），并使其与一系列过渡金属离子（钴、镍、铜和锌）形成配合物。获得了所选交叉桥型配合物的X射线晶体结构，其显示出具有潜在不稳定顺式结合位点的特征性顺式-V构型。这些配合物已通过电子光谱和磁矩进行了表征，在大多数情况下显示出预期的高自旋二价金属配合物。例外情况是镍侧桥型配合物，其显示出高自旋和低自旋的混合，以及已氧化为钴(III)的钴交叉桥型配合物。在乙腈中进行循环伏安法以评估这些配合物未来在氧化催化中的潜在用途。所选配合物通过在增强的环醚骨架上添加吡啶基臂而具有显著的催化潜力。
