Mixed d−f3 Coordination Complexes Possessing Improved Near-Infrared (NIR) Lanthanide Luminescent Properties in Aqueous Solution

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• 作者：Aline M. Nonat ; Clmence Allain ; Stephen Faulkner ; Thorfinnur Gunnlaugsson
• 刊名：Inorganic Chemistry
• 出版年：2010
• 出版时间：September 20, 2010
• 年：2010
• 卷：49
• 期：18
• 页码：8449-8456
• 全文大小：943K
• 年卷期：v.49,no.18(September 20, 2010)
• ISSN：1520-510X

文摘

The cyclen-based ligand 1, possessing a [1,10]-phenanthroline moiety as a pendant arm, has been used as a ditopic ligand for the complexation of d- and near infrared (NIR) emitting (and) f-metal ions. This ligand forms kinetically stable complexes, 1·Ln, with lanthanide ions such as Ln = ytterbium, neodymium, and lutetium (formed as a non-IR emitting reference compound), the synthesis and photophysical properties of which are described herein in detail. These 1·Ln complexes were then used as building blocks for the formation of mixed d−f heteropolymetallic self-assemblies, where the phen moiety was used to complex a ruthenium (Ru(II)) ion, giving the d−f₃ complexes Ru·Ln₃ (Ln = Nd(III), Yb(III), Lu(III)). The formation of these supramolecular coordination conjugates was studied by using absorption and luminescence spectroscopy, while the solution structure of the Ru·Lu₃ was elucidated by ¹H NMR in D₂O and H₂O. Of these conjugates, both Ru·Nd₃ and Ru·Yb₃ displayed an intense NIR-emission in H₂O at pH 7.4 (with Q_Yb^L = 0.073% and Q_Nd^L = 0.040%) and in D₂O (with Q_Yb^L = 0.23% and Q_Nd^L = 0.10%). By comparison with their monometallic analogues Ln·1 (Ln = Nd(III), Yb(III)), we demonstrate that our new design possesses an enhanced sensitization efficiency for lanthanide metal centered sensitization upon using the [Ru(phen)₃] moiety (d → f energy transfer) as a visibly exciting antenna, and we demonstrate that the intensity of the Ru(II)-based luminescence strictly correlates to the efficiency of the d → f energy transfer processes.