Towards full-color-tunable emission of two component Eu(III)-doped Gd(III) coordination frameworks by the variation of excitation light

Dalton Trans. 2014 Sep 7;43(33):12574-81. doi: 10.1039/c4dt00837e.

Abstract

A series of pyrazine-2,3,5,6-tetracarboxylate alkali-lanthanide coordination frameworks, namely [NaLn(pztc)(H2O)3]·H2O [Ln = Ce (), Sm (), Eu (), Gd () and Tb (); H4pztc = pyrazine-2,3,5,6-tetracarboxylic acid], have been synthesized by reacting Ln(NO3)3·6H2O with H4pztc in the presence of NaOH at room temperature. X-ray crystallographic analysis reveals that complexes are isostructural, featuring three-dimensional (3D) networks with a unique (4(11)·6(8)·8(2))(4(3)·6(2)·8)(4(3)) topology in which the ligand displays a novel μ7-coordination mode. The photoluminescence (PL) spectra in the solid state reveal that complexes , and exhibit the characteristic luminescence of Sm(iii), Eu(iii) and Tb(iii) ions, respectively, while complex displays a broad band in the range of 400-650 nm (λmax = 505 nm) which exhibits about 103 nm red-shift and enhancement compared to the band of the free ligand. Further, the isostructural two-component Eu(iii)-doped Gd(iii) complexes realize color-tunable luminescence from red to yellow, white, green and blue by the variation of excitation wavelengths. They represent the first example of full-color-tunable emission in lanthanide coordination frameworks by the variation of excitation light.