Dual-Emission from a Single-Phase Eu–Ag Metal–Organic Framework: An Alternative Way to Get White-Light Phosphor

Abstract

A new bifunctional NTB (tris(benzimidazol-2-ylmethyl)amine)-type ligand incorporating coordination discriminable tripodal benzimidazolyl and monodentate pyridyl groups, tris((pyridin-3-ylmethyl)benzoimidazol-2-ylmethyl)amine (3-TPyMNTB), has been prepared to assemble 4d–4f heterometallic three-dimensional metal–organic frameworks (MOFs) in a stepwise route: (1) direct reaction of 3-TPyMNTB with Ln(ClO4)3 affords monomeric complexes [Eu(3-TPyMNTB)2](ClO4)3·2.5MeCN (1-Eu) and [Gd(3-TPyMNTB)2](ClO4)3·2MeCN·2CHCl3 (1-Gd), and (2) assembly of the precursors 1-Eu and 1- Gd with AgClO4 gives rise to infinite MOFs [EuAg3(3-TPyMNTB)2(H2O)(MeCN)](ClO4)6·4MeCN (2-Eu-Ag) and [GdAg3(3-TPyMNTB)2(H2O)(MeCN)](ClO4)6·4MeCN (2-Gd-Ag), respectively. In monomer 1-Eu, the ligand shows an antenna effect to transfer absorbed energy to Eu3+ center to emit characteristic red luminescence, while in 4d–4f heterometallic MOF 2-Eu-Ag, the ligand centered emission is resensitized by Ag+ ions to generate dual emissions, coming up with the direct white-light emission from a single crystal. The detailed photoluminescent study has been carried out in both solid state and solution to elucidate the emission nature.

Postsynthetic modification of metal–organic framework for hydrogen sulfide detection

“…Metal-organic frameworks (MOFs) are composed of metal ions (or clusters) as nodes and multitopic organic ligands as linkers [37] high, well-defined porosity and intense fluorescence have gathered considerable attention owing to their potential applications in chemical sensors [38][39][40][41], light-emitting devices [42,43], and biomedicine [44][45][46]. However, it still remained a challenge to synthesize functionalized MOFs directly through traditional MOF synthesis.…”

Ln-Ag heterometallic coordination polymers

“…Other solvents were used in solvothermal reaction, for example, compound 2 was synthesized in a mixed solvent of methanol and water (Cai et al 2009b), compounds 172 and 173 were synthesized in acetonitrile (Cui et al 2011), and compound 182 was synthesized in a mixed solvent of acetonitrile and water (Zhou et al 2010). Evaporation and diffusion methods were also used; for example, the first structurally characterized Ln-Ag heterometallic coordination polymer, Ag[Gd(PDA) 2 (H 2 O) 3 ]·3H 2 O (Goodname et al 1992), compound 26 (Brouca-Cabarrecq et al 1999), and compound 169 (Zhang et al 2009) were synthesized by evaporation method, and compound 170 (Terazzi et al 2011), compounds 173-179 (Merkens and Englert 2012), and compound 180 and 181 (Liu et al 2012a) were synthesized by diffusion method.…”

Syntheses, crystal structure, and characterization of two Mn(II) CPs based on 4,4′-sulfonyldicarboxylic acid and length modulated bisimidazole ligands

“…The design and construction of coordination polymers (CPs) based on metal ions and multifunctional organic ligands have attracted interest for multifunctional applications in gas and selective molecule adsorption, luminescence, ion exchange, magnetism and catalysis [1][2][3][4][5][6][7][8][9][10] and for intriguing molecular architectures and topological features [11][12][13]. Self-assembly of CPs mainly depends on combination of several factors, such as the nature of the organic ligands used, versatility of the metal coordination geometry and various experimental conditions (pH, temperature, etc.)…”