Near-infrared (NIR) luminescent hetero-tetranuclear Zn₂Ln₂ (Ln = Nd, Yb or Er) complexes self-assembled from the benzimidazole-based HL and two rigid 4,4¡ä-bipyridine ligands with different spacers

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• 作者：Zhao Zhang ; Weixu Feng ; Peiyang Su ; Han Liu ; Yao Zhang ; Zheng Wang ; Tiezheng Miao ; Xingqiang L¨¹ ; Daidi Fan ; Wai-Kwok Wong ; Richard A. Jones
• 关键词：Hetero-tetranuclear Zn2Ln2-arrayed complexes ; Mixed HL-bipyridine ligands ; Sensitization of NIR luminescence
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2013
• 出版时间：December, 2013
• 年：2013
• 卷：116
• 期：Complete
• 页码：102-110
• 全文大小：1267 K

文摘

Through the self-assembly of the benzimidazole-based ligand HL (HL = 2-(1H-benzo[d]imidazol-2-yl)-6-methoxyphenol) with Zn(OAc)₂¡¤2H₂O, Ln(NO₃)₃¡¤6H₂O (Ln = Nd, Yb, Er or Gd) and 4,4¡ä-bipyridine ligand (bpy, 4,4¡ä-bipyridine or bpe, trans-bis(4-pyridyl)ethylene), two series of Zn₂Ln₂-arrayed complexes [Zn₂Ln₂(L)₄(bpy)(NO₃)₆] (Ln = Nd, 1; Yb, 2; Er, 3 or Gd, 4) and [Zn₂Ln₂(L)₄(bpe)(NO₃)₆] (Ln = Nd, 5; Yb, 6; Er, 7 or Gd, 8) were obtained, respectively. The result of their photophysical properties shows that the characteristic near-infrared (NIR) luminescence of Nd³⁺, Yb³⁺ or Er³⁺ ion has been sensitized from the excited state (both ¹LC and ³LC) of the mixed HL and bipyridyl ligands in both complexes 1-3 and 5-7. Moreover, the change from bpy to bpe bridging for the fine-tuning of whole molecular conjugations, attributing to the different crossings of the two benzimidazole-based L^? ligands, has the important influence on their NIR luminescent properties.