Near-Infrared Luminescence and Inner Filter Effects of Lanthanide Coordination Polymers with 1,2-Di(4-pyridyl)ethylene

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• 作者：Nicole Dannenbauer ; Philipp R. Matthes ; Thomas P. Scheller ; Jörn Nitsch ; Sven H. Zottnick ; Markus S. Gernert ; Andreas Steffen ; Christoph Lambert ; Klaus Müller-Buschbaum
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：August 1, 2016
• 年：2016
• 卷：55
• 期：15
• 页码：7396-7406
• 全文大小：679K
• 年卷期：0
• ISSN：1520-510X

文摘

A series of 12 lanthanide coordination polymers was synthesized from anhydrous LnCl₃ and 1,2-di(4-pyridyl)ethylene (dpe) under solvothermal conditions in either thiazole (thz) or pyridine (py). The reactions yielded _∞¹[Ln₂Cl₆(dpe)₂(thz)₄]·dpe with Ln = Ce (1), Nd (2), _∞¹[LnCl₃ (dpe)(py)₂]·(dpe/py) with Ln = Gd (3), Er (4), and _∞¹[LnCl₃(dpe) (thz)₂](dpe/thz) with Ln = Sm (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10), as well as _∞¹[HoCl₃(dpe)(thz)₂]·thz (11) and _∞²[La₂Cl₆(dpe)₃(py)₂]·dpe (12). One-dimensional coordination polymers (CPs) and a two-dimensional network of five different constitutions are formed by connection of LnCl₃ units via dpe molecules. As free ligand, dpe shows an excimer effect that is reduced in the coordination polymers. In addition, dipyridylethylene proves to be a suitable sensitizer for the photoluminescence of lanthanides in the near-infrared region (NIR) only. Thereby, dpe differs from the related ligand 1,2-di(4-pyridyl)ethane. For the compounds presented, four different luminescence effects were detected: luminescence based on fluorescence of the linker dpe is observed in the visible region, whereas ligand-sensitized 4f–4f NIR emission is dominating for trivalent Nd, Er, and Yb. The Er-containing CPs show an inner-filter effect of Er³⁺, which is based on reabsorption of emission of dpe triggering the erbium NIR emission.