Hetero-binuclear near-infrared (NIR) luminescent ZnLn (Ln = Nd, Yb or Er) complexes self-assembled from the benzimidazole-based ligand

With the [Zn(HL)2(Py)] compound from the benzimidazole-based ligand H2L (H2L: 2-(1H-benzo[d]imidazol-2-yl)-6-methoxyohenol) as the precursor, the series of four hetero-binuclear ZnLn arrayed complexes [ZnLn(HL)2(Py)(NO3)3] (Ln = Nd, 1; Ln = Yb, 2; Ln = Er, 3; Ln = Gd, 4) have been obtained by the further reaction with Ln(NO3)3·6H2O, respectively. The result of their photophysical properties shows that the strong and characteristic NIR luminescence of Nd3 + or Yb3 + ion with emissive lifetimes in microsecond range, has been sensitized from the excited state (1LC and 3LC) of the benzimidazole-based ligand.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Hetero-binuclear Zn–Ln arrayed complexes assembled from the benzimidazole-based ligand ► Arrangement of energy donors around the Ln3 + ion ► Enhancement of near-infrared luminescent properties