Dorazio Sarina J, Vogel Anastasia, Dechert Sebastian, Nevonen Dustin E, Nemykin Victor N, Brückner Christian, Meyer Franc
Institute for Inorganic Chemistry, University of Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany.
Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States.
Inorg Chem. 2020 May 18;59(10):7290-7305. doi: 10.1021/acs.inorgchem.0c00714. Epub 2020 May 6.
A series of Pt-based monometallic (), homobimetallic (), and heterobimetallic ( and ) group 10 complexes of the previously established expanded twin porphyrin () were prepared. Structural characterization of the bimetallic Pt series (, , and ) revealed their similar general structures, with slight differences correlated to the ion size. An improvement of the metal-ion insertion process also allowed efficient preparation of the known complex, and the novel heterobimetallic complex was also structurally characterized. UV-vis spectroscopy, NMR spectroscopy, magnetic circular dichroism (MCD), and (spectro)electrochemistry were used to characterize the complexes; the electronic properties followed largely established lines for metal complexes of the twin porphyrin, except that the Pt-based systems exhibited more complex UV-vis spectral signatures. MCD spectra accompanied by density functional theory (DFT)/time-dependent DFT computations (TDDFT) rationalize the origins of the optical features of the twin porphyrin. The presence of the nonplanar, nonaromatic macrocyclic π system with conjugation pathways confined to each half of the molecule could be visualized. Significant pyrazole(π) → pyrrole(π*) charge-transfer character was predicted for several transitions in the visible region. This study adds to our fundamental understanding of the formation, structure, and electronic structure of bimetallic complexes of this class of expanded metalloporphyrins containing nonpyrrolic moieties.
制备了一系列基于铂的单金属（）、同双金属（）和异双金属（和）的第10族配合物，这些配合物由先前已确定的扩展双卟啉（）构成。双金属铂系列（、和）的结构表征揭示了它们相似的总体结构，只是存在与离子大小相关的细微差异。金属离子插入过程的改进也使得已知的配合物能够高效制备，并且对新型异双金属配合物也进行了结构表征。利用紫外可见光谱、核磁共振光谱、磁圆二色性（MCD）和（光谱）电化学对这些配合物进行表征；除了基于铂的体系表现出更复杂的紫外可见光谱特征外，其电子性质在很大程度上遵循了双卟啉金属配合物已确立的规律。MCD光谱结合密度泛函理论（DFT）/含时密度泛函理论计算（TDDFT）阐明了双卟啉光学特征的起源。可以观察到存在非平面、非芳香的大环π体系，其共轭途径局限于分子的每一半。预测在可见光区域的几个跃迁中存在显著的吡唑（π）→吡咯（π*）电荷转移特征。这项研究增进了我们对这类含有非吡咯部分的扩展金属卟啉双金属配合物的形成、结构和电子结构的基本理解。
