Probing the structure of Copper(II)-Casiopeina type coordination complexes [Cu(O-O)(N-N)]+ by EPR and ENDOR spectroscopy
Probing the structure of Copper(II)-Casiopeina type coordination complexes [Cu(O-O)(N-N)]+ by EPR and ENDOR spectroscopy
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DOI：
10.1016/j.jcat.2020.07.016
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发表时间：
2021-02-27
影响因子：
7.3
通讯作者：
Murphy, Damien M.
中科院分区：
文献类型：
--
作者：
Folli, Andrea;Ritterskamp, Nadine;Murphy, Damien M.
虽然铜基配合物在均相催化中得到了广泛的应用，但近年来它们作为药物治疗剂引起了人们的极大关注。它们的使用效率中最重要的是它们的结构和电子性质，这可以用先进的EPR技术来彻底探测。本研究合成了一系列含二亚胺N-N配体(包括bipy、phen、Py-bipy和dppz)的[Cu(Acac)(N-N)](+)Casiopeina配合物。所有的配合物都表现出菱形的g张量和(Cu)A张量，尽管菱形的程度取决于N-N配体。对于较小的bipy和phen配体，与较大的Py-bipy和dppz配体相比，CW W带EPR检测到较大的Cu(II)-N_2平面内扭曲，远离正方形平面排列。用CW Q带Endor揭示了配体自旋密度分布(在H-1和N-14核上)的变化。H-1亚胺和N-14超精细偶联的最大组分随着配体尺寸的增加而减少，遵循Bipy>；phen>；Py-bipy>；dppz的趋势。这些结果表明，即使是Casiopeina系列铜(II)配合物中的微小结构和电子(自旋密度)扰动也可以用先进的EPR方法来探测。(C)2020年提交人(S)。由爱思唯尔公司出版。这是一篇基于CC by License(http://creativecommons.org/licenses/by/4.0/).的开放获取文章
Although copper based complexes have been widely used in homogeneous catalysis, more recently they are attracting considerable attention as pharmaceutical therapeutic agents. Of paramount importance in their efficacy of use is their structure and electronic properties, which can be thoroughly probed using advanced EPR techniques. In this study, a series of [Cu(acac)(N-N)](+) Casiopeina type complexes were investigated, bearing a series of diimine N-N ligands (including bipy, phen, Py-bipy and dppz). All complexes displayed rhombic g and (Cu)A tensors, although the extent of rhombicity was dependent on the N-N ligand. Greater Cu(II)-N2 in-plane distortion, away from the square planar arrangement, was detected by CW W-band EPR for the smaller bipy and phen ligands compared to the larger Py-bipy and dppz ligands. Changes in ligand spin density distributions (over the H-1 and N-14 nuclei) were revealed by CW Q-band ENDOR. The largest components of the H-1 imine and N-14 hyperfine coupling decreased as the ligand size increased, following the trend bipy > phen > Py-bipy > dppz. These results indicate how even small structural and electronic (spin density) perturbations within the Casiopeina family of Cu(II) complexes can be probed by advanced EPR methods. (c) 2020 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).