Fathi-Rasekh Mahtab, Rohde Gregory T, Hart Mason D, Nakakita Toshinori, Zatsikha Yuriy V, Valiev Rashid R, Barybin Mikhail V, Nemykin Victor N
Department of Chemistry and Biochemistry , University of Minnesota Duluth , 1039 University Drive , Duluth , Minnesota 55812 , United States.
Marshall School , Duluth , Minnesota 55811 , United States.
Inorg Chem. 2019 Jul 15;58(14):9316-9325. doi: 10.1021/acs.inorgchem.9b01030. Epub 2019 Jun 26.
Two isomeric ruthenium(II)/5,10,15,20-tetraphenylporphyrin complexes featuring axially coordinated redox-active, low-optical gap 2- or 6-isocyanoazulene ligands have been isolated and characterized by NMR, UV-vis, and magnetic circular dichroism (MCD) spectroscopic methods, high-resolution mass spectrometry, and single-crystal X-ray crystallography. The UV-vis and MCD spectra support the presence of the low-energy, azulene-centered transitions in the Q band region of the porphyrin chromophore. The first coordination sphere in new LRuTPP complexes reflects compressed tetragonal geometry. The redox properties of the new compounds were assessed by electrochemical and spectroelectrochemical means and correlated with the electronic structures predicted by density functional theory and CASSCF calculations. Both experimental and theoretical data are consistent with the first two reduction processes involving the axial azulenic ligands, whereas the oxidation profile (in the direction of increasing potential) is exerted by the ruthenium ion, the porphyrin core, and the axial azulenic moieties.
已分离出两种异构的钌（II）/5,10,15,20-四苯基卟啉配合物，其具有轴向配位的氧化还原活性、低光学能隙的2-或6-异氰基薁配体，并通过核磁共振、紫外可见光谱和磁圆二色性（MCD）光谱法、高分辨率质谱以及单晶X射线晶体学对其进行了表征。紫外可见光谱和MCD光谱证实了在卟啉发色团的Q带区域存在以薁为中心的低能量跃迁。新型LRuTPP配合物中的第一配位层呈现出压缩的四方几何结构。通过电化学和光谱电化学方法评估了新化合物的氧化还原性质，并将其与密度泛函理论和完全活性空间自洽场（CASSCF）计算预测的电子结构相关联。实验数据和理论数据均表明，前两个还原过程涉及轴向薁配体，而氧化过程（在电势增加的方向上）则由钌离子、卟啉核心和轴向薁部分共同作用。
