Co-existence of heterometallic Zn2Er and ZnEr arrayed chromophores for the sensitization of near-infrared (NIR) luminescence

With the Zn-Schiff-base [ZnL(Py)] from the simple Salen-type Schiff-base ligand H2L(H2L = N,N'-bis(salicylidene)ethylene-1,2-diamine) as the precursor, two co-crystallized heterometallic (Zn(2)Ln and ZnLn array) complexes [Zn(2)Ln(L)(2)(Py)(2)(NO3)(2)]center dot[ZnLn(L)(Py)(NO3)(3)(H2O)]center dot NO3 center dot mMeOH center dot nS (Ln = Er(1), S = CH3CN, m = 2, n = 1 or Gd(2), S = H2O, m = 1, n = 3) were obtained by the further reaction with Ln(NO3)(3)center dot 6H(2)O, respectively. The result of their photophysical properties shows the intramolecular effective energy transfer has been demonstrated in the Zn2Er and ZnEr arrayed complex 1, and the co-existence of different chromophores should be a potentially new way to the fine-tuning properties of NIR luminescence from Er3+ ions. (C) 2009 Elsevier B.V. All rights reserved.