Neutral and Cationic NCN Pincer Platinum(II) Complexes with 1,3-Bis(benzimidazol-2鈥?yl)benzene Ligands: Synthesis, Structures, and Their Photophysical Properties

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• 作者：Zhao Wang ; Zheming Sun ; Xin-Qi Hao ; Jun-Long Niu ; Donghui Wei ; Tao Tu ; Jun-Fang Gong ; Mao-Ping Song
• 刊名：Organometallics
• 出版年：2014
• 出版时间：April 14, 2014
• 年：2014
• 卷：33
• 期：7
• 页码：1563-1573
• 全文大小：475K
• 年卷期：v.33,no.7(April 14, 2014)
• ISSN：1520-6041

文摘

A series of neutral pincer Pt(II) chloride complexes 3鈥?b>7 were first synthesized via the reaction of 1,3-bis(N-substituted benzimidazol-2鈥?yl) benzene (bzimb) ligands 2a鈥?b>e with K₂PtCl₄ in refluxing HOAc. By treatment of complex 3 with KI and aromatic terminal alkynes in methanolic NaOH, the Pt(II) iodide complex 8 and Pt(II) acetylide complexes 9鈥?b>11 were then obtained. Cationic Pt(II) complexes 12鈥?b>15 were finally produced by the chloro-substitution reaction of complex 3 with AgOTf and several neutral N-donor ligands. With these new compounds in hand, various characterizations including elemental analysis, NMR, and IR were carried out to investigate their properties. On the basis of the X-ray single-crystal structure analysis of complexes 3鈥?b>5, 8, 9, and 12, weak intermolecular interactions including 蟺路路路蟺 stacking and/or hydrogen bonds were found to be responsible for their assembly. After full investigation of the electronic absorption and photoluminescent properties of the Pt(II) complexes 3鈥?b>15, time-dependent density functional theory (TD-DFT) calculations were carried out to elucidate the origins of the UV鈥搗is absorptions. We were delighted to find that the luminescence quantum yields in degassed CH₂Cl₂ solution were around 0.13 in most cases and the emission lifetimes were in the microsecond range, indicating that these complexes could be used as bright phosphorescent materials with various potential applications in the future.