Multinuclear transition metal complexes bridged by ligands with extended π‐electronic systems show a variety of complex electronic transitions and electron transfer reactions. While a systematic understanding of the photochemistry and electrochemistry has been attained for binuclear complexes, much less is known about trinuclear complexes such as hexaphenyl‐5,6,11,12,17,18‐hexaazatrinaphthylene‐tristitanocene [(Cp₂Ti)₃HATN(Ph)₆]. The voltammogram of [(Cp₂Ti)₃HATN(Ph)₆] shows six oxidation and three reduction waves. Solution spectra of [(Cp₂Ti)₃HATN(Ph)₆] and of the electrochemically formed oxidation products show electronic transitions in the UV, visible and the NIR ranges. Density functional theory (DFT) and linear response time‐dependent DFT show that the three formally titanium(II) centers transfer an electron to the HATN ligand in the ground state. The optically excited transitions occur exclusively between ligand‐centered orbitals. The charged titanium centers only provide an electrostatic frame to the extended π‐electronic system. Complete active self‐consistent field (CASSCF) calculation on a structurally simplified model compound, which considers the multi‐reference character imposed by the three titanium centers, can provide an interpretation of the experimentally observed temperature‐dependent magnetic behavior of the different redox states of the title compound in full consistency with the interpretation of the electronic spectra.

中文翻译：

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三核5,6,11,12,17,18-六氮杂萘并萘桥接的钛配合物在不同氧化还原态的电子跃迁：光谱电化学和量子化学。

由配体与扩展的π电子系统桥接的多核过渡金属络合物显示出各种复杂的电子跃迁和电子转移反应。尽管已经对双核络合物获得了对光化学和电化学的系统理解，但对三核络合物（如六苯基-5,6,11,12,17,18-六氮杂萘并_三茂锡[（Cp ₂ Ti）₃ HATN ）的了解却很少。 （Ph）₆ ]。[（Cp ₂ Ti）₃ HATN（Ph）₆ ]的伏安图显示六个氧化波和三个还原波。[（Cp ₂ Ti）₃ HATN（Ph）_6的溶液光谱以及电化学形成的氧化产物显示出在UV，可见光和NIR范围内的电子跃迁。密度泛函理论（DFT）和随时间变化的线性响应DFT表明，三个正式的钛（II）中心将电子转移到基态的HATN配体。光激发跃迁仅发生在以配体为中心的轨道之间。带电的钛中心只会为扩展的π电子系统提供静电框架。对结构简化的模型化合物进行完整的主动自洽场（CASSCF）计算，其中考虑了三个钛中心施加的多参考特征，