Coordination-Driven Self-Assembled Zn-6(II) -Ln(3)(III) Metallocycles Based on a Salicylamide Imine Ligand: Synthesis, Structure, and Selective Luminescence Enhancement Induced by OAc-

Five heterometallic Zn-6(II) -Ln(3)(III) macrocycles based on a salicylamide imine multidentate unsymmetrical ligand H2L [1-(2-hydroxy-3-methoxy-benzamido)-2-(2-hydroxy-3-methoxy-benzylideneamino)-ethane] have been prepared via a coordination-driven self-assembly strategy. Single-crystal X-ray diffraction analysis reveals that the five metallocycles are isomorphic with a formula of [Zn(6)Ln(3)L(6)(OH)(2)(NO3)(4)(H2O)]center dot 3NO(3)center dot nCH(3)CN (ZnLn-1, where Ln = Pr, Nd, Eu, Tb, or Yb; for ZnPr-1, n = 4; for ZnNd-1, ZnEu-1, and ZnTb-1, n = 2; for ZnYb-1, n = 3), where six octadentate ligands L2- and two in situformed mu(2)-OH- ions bridged the alternating Zn-II-Ln(III)-Zn-II subunits into a macrocycle. Along with the structural novelty, ZnNd-1 shows distinctive enhanced emission in the visible and near-infrared range upon addition of OAC(-). On the basis of ultraviolet-visible spectroscopy, H-1 nuclear magnetic resonance, single-crystal X-ray diffraction, and high-resolution electrospray ionization mass spectrometry, we deduced that this emission enhancement could be attributed to the synergistic effect of TICT and the absent nonradiative transition of it mu(2)-OH- induced distinctively by OAc- bridging. Our results demonstrate that the Nd-III-containing heterometallic macrocycle can act as a host for anion exchanging and provide a nice example of heterometallic macrocycles with interesting properties and potential applications.