Near-infrared (NIR) luminescent Zn(II)–Ln(III)-containing (Ln = Nd, Yb or Er) Wolf Type II metallopolymer hybrid materials

With series of hetero-binuclear Zn–Ln complexes [Zn(L)(Py) Ln(NO3)3] (H2L = N,N′-bis-(5-(3′-vinylphenyl)-3-methoxy-salicylidene) cyclohexane-1,2-diamine; Py = pyridine; Ln = La, 1; Ln = Nd, 2; Ln = Yb, 3; Ln = Er, 4 or Ln = Gd, 5) as the monomers, three kinds of novel PMMA, PS or PVK-supported Zn2+–Ln3+-containing Wolf Type II metallopolymer hybrid materials are obtained from the further copolymerization with MMA (methyl methacrylate), ST (styrene) or NVK (N-vinyl-carbazole), respectively. Their physical properties results in solid state show that the characteristic Ln3+-based (Ln = Nd, Yb or Er) near-infrared (NIR) luminescent emissions with relatively higher quantum efficiencies than those of the respective Zn–Ln-arrayed complexes in solution, are observed, besides the distinctive increase of thermal and mechanical stabilities. Especially for the Zn2+–Yb3+-containing PMMA-supported metallopolymers, the concentration self-quenching of Yb3+-based hybrid materials could be effectively prevented even at 2.5 mol%, and the replacement of PS or PVK is also helpful for energy transfer.