Photochemical C–C Bond Formation in Luminescent Zirconium Complexes with CNN Pincer Ligands
Photochemical C–C Bond Formation in Luminescent Zirconium Complexes with CNN Pincer Ligands
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DOI：
10.1021/acs.organomet.8b00388
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发表时间：
2018-08
期刊：
影响因子：
2.8
通讯作者：
Yu Zhang;J. L. Petersen;Carsten Milsmann
中科院分区：
文献类型：
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作者：
Yu Zhang;J. L. Petersen;Carsten Milsmann
配合物Zr（HCNN）2和Zr（MeCNN）2通过配体前体2-苯基-6-（5-甲基-3-苯基-1H-吡咯-2-基）吡啶（H2 HCNN）和2-（3，5-二甲基-苯基）-6-（5-甲基-3-苯基-1H-吡咯-2-基）吡啶（H2 MeCNN）与四苄基锆的反应来制备。这两种配合物在可见光激发下都是光致发光的，并且在室温下在溶液中表现出数十至数百微秒的显着长的发射寿命。发射态的性质进行了研究，使用密度泛函理论，这使得分配作为一个主要的配体内的三重态与显着的配体到金属的电荷转移的贡献（3 IL/3LMCT）。电化学研究揭示了两个完全可逆的单电子还原为每个复杂的和一个额外的可逆氧化EC过程的空间保护的复杂Zr（MeCNN）2。在光学和电化学性质的基础上，这两种锆配合物作为光敏剂用于光还原反应的实用性。
The complexes Zr(HCNN)2 and Zr(MeCNN)2 were prepared via reaction of the ligand precursors 2-phenyl-6-(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine, H2HCNN, and 2-(3,5-dimethyl-phenyl)-6-(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine, H2MeCNN, with tetrabenzyl zirconium. Both complexes are photoluminescent upon excitation with visible light and exhibit remarkably long emission lifetimes of tens to hundreds of microseconds in solution at room temperature. The nature of the emissive state was investigated using density functional theory, which allowed the assignment as a predominantly intraligand triplet state with significant ligand-to-metal charge transfer contributions (3IL/3LMCT). Electrochemical studies revealed two fully reversible one-electron reductions for each complex and an additional reversible oxidative EC process for the more sterically protected complex Zr(MeCNN)2. On the basis of the optical and electrochemical properties, the utility of the two zirconium complexes as photosensitizers for photoredo...