Abstract：
A series of new charge transfer (CT) chromophores of \"α-diimine-MII-catecholate\" type (where M is 3d-row transition metals-Cu, Ni, Co) were derived from 4,4\'-di-tert-butyl-2,2\'-bipyridyl and 3,6-di-tert-butyl-o-benzoquinone (3,6-DTBQ) in accordance with three modified synthetic approaches, which provide high yields of products. A square-planar molecular structure is inherent for monomeric [CuII(3,6-Cat)(bipytBu)]∙THF (1) and NiII(3,6-Cat)(bipytBu) (2) chromophores, while dimeric complex [CoII(3,6-Cat)(bipytBu)]2∙toluene (3) units two substantially distorted heteroleptic D-MII-A (where D, M, A are donor, metal and acceptor, respectively) parts through a donation of oxygen atoms from catecholate dianions. Chromophores 1-3 undergo an effective photoinduced intramolecular charge transfer (λ = 500-715 nm, extinction coefficient up to 104 M-1·cm-1) with a concomitant generation of a less polar excited species, the energy of which is a finely sensitive towards solvent polarity, ensuring a pronounced negative solvatochromic effect. Special attention was paid to energetic characteristics for CT and interacting HOMO/LUMO orbitals that were explored by a synergy of UV-vis-NIR spectroscopy, cyclic voltammetry, and DFT study. The current work sheds light on the dependence of CT peculiarities on the nature of metal centers from various groups of the periodic law. Moreover, the \"α-diimine-MII-catecholate\" CT chromophores on the base of \"late\" transition elements with differences in d-level\'s electronic structure were compared for the first time.
摘要：
一系列“α-二亚胺-MII-儿茶酚酸盐”型的新电荷转移（CT）发色团（其中M是3d行过渡金属-Cu，Ni,Co）根据三种改进的合成方法，衍生自4,4'-二叔丁基-2,2'-联吡啶和3,6-二叔丁基-邻苯醌（3,6-DTBQ），提供高产量的产品。单体[CuII（3,6-Cat）（bipytBu）]·THF（1）和NiII（3,6-Cat）（bipytBu）（2）发色团固有的方形平面分子结构，而二聚复合物[CoII(3,6-Cat)(bipytBu)]2*甲苯(3)单位两个实质上扭曲的杂配D-MII-A(其中D,M,A是捐赠者,金属和受体，分别）通过从儿茶酚酸二阴离子中捐赠氧原子而形成的部分。发色团1-3经历有效的光诱导分子内电荷转移（λ=500-715nm，消光系数高达104M-1·cm-1），伴随着极性较小的受激物种的产生，其能量对溶剂极性非常敏感，确保明显的负溶剂化作用。特别注意通过UV-vis-NIR光谱的协同作用探索的CT和相互作用的HOMO/LUMO轨道的能量特征，循环伏安法,和DFT研究。当前的工作揭示了CT特性对周期律各个组的金属中心性质的依赖性。此外，首次比较了基于“晚期”过渡元素的“α-二亚胺-MII-儿茶酚盐”CT发色团，其d级电子结构存在差异。
