Structure and efficient luminescence upconversion of Ln(iii) aromatic N-oxide coordination polymers

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 45; no. 30; pp. 12200 - 12205
• Main Authors: Chong, Bowie S K, Moore, Evan G
• Format: Journal Article
• Language: English
• Published: England 2016
• Subjects: Cations; Coordination polymers; Diffraction; Emission; Excitation; Luminescence; Upconversion; X-ray diffraction
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c6dt01828a

A series of lanthanide-based coordination polymers {[Yb1-xErx(4,4'-bpdo)3(H2O)2](CF3SO3)3}∞ were synthesised by solvent diffusion techniques, where 4,4'-bpdo = 4,4'-bipyridine-N,N'-dioxide, and using differing mole fractions of Yb(iii) and Er(iii) which were systematically varied (x = 0, 0.05, 0.20, 0.50 and 1). All of the materials obtained were characterised using elemental analyses, single-crystal X-ray diffraction (SXRD) and solid-state photoluminescence studies. Structurally, the coordination polymers crystallise as an isomorphous series of infinite 2D sheets, which contain two inner sphere water molecules, and are isostructural with a previously characterised homometallic Yb(iii) compound. In addition to the normal Near Infra-Red (NIR) luminescence, these compounds also demonstrate upconversion emission upon 980 nm excitation. Upconversion luminescence measurements reveal visible emission in the red, green, and blue regions corresponding to the (2)H11/2→(4)I15/2, (4)F9/2→(4)I15/2 and (2)H9/2→(4)I15/2 transitions of the Er(iii) cation upon two and three-photon excitation. We also observed weak emission from the Er(iii) cation in the UV region for the first time in a Ln-MOF based material.