Lanthanide coordination frameworks constructed from 1,3-benzenedicarboxylate, oxalate and 1,10-phenanthroline: crystal structure, multicolor luminescence and high-efficiency white light emission

New complexes, [Ln2(1,3-BDC)2(phen)2(ox)(H2O)] (Ln = Eu (1), Tb (2), and Yb (3), 1,3-BDC = 1,3-benzenedicarboxylate, ox = oxalate, and phen = 1,10-phenanthroline), have been obtained under hydrothermal conditions. The isostructural complexes 1–3 have 3D structures with helical chains assembled from tetrameric secondary building units (SBUs) by 1,3-BDC and ox-mixed linkers. Complex 1 shows red luminescence with a high quantum yield (Φ = 63.21%) of Eu(III) (5D4 → 7F0–4) while complex 2 exhibits green luminescence (Φ = 10.13%) of Tb(III) (5D4 → 7F6–2). The Yb:Tb:Eu doped complex reveals significant multicolor luminescence from blue, green, yellow to white regions through tuning of the excitation wavelengths. High-efficiency white light emission (Φ = 20.4%) was achieved and energy transfer from Tb(III) to Eu(III) was observed.