Assembly of one-, two-, and three-dimensional Ln(iii) complexes constructed from a novel asymmetric tricarboxylic acid: synthesis, structure, photoluminescence and tunable white-light emission. Issue 20 (3rd May 2016)

• Record Type: Journal Article
• Authors: Zhang, Huijie; Fan, Ruiqing; Dong, Yuwei; Chen, Wei; Du, Xi; Wang, Ping; Yang, Yulin
• Is Part Of: CrystEngComm. Volume 18:Issue 20(2016)
• Page Start: 3711
• Page End: 3724
• Publication Date: 2016-05-03
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c6ce00483k
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : We have successfully synthesized nine luminescent lanthanide complexes from 1D chains to 3D frameworks based on a tricarboxylic acid ligand. Abstract : By reacting an asymmetric semi-rigid V-shaped linker H3 dpob (H3 dpob = 3-(2′3′-dicarboxylphenoxy)benzoic acid) and Ln(NO3 )3 ·6H2 O, nine novel Ln-based luminescent materials, from 1D to 3D, namely {[Eu(dpob)(phen)]·H2 O} n (1 ), {[Ln(Hdpob)(ox)0.5 (H2 O)2 ]} n (Ln = Eu(2 ), Sm(3 ), Gd(4 ), Tb(5 )), {[Eu(dpob)(H2 O)2 ]·0.5H2 O} n (6 ), and {[Ln(dpob)(H2 O)2 ]· m H2 O} n (Ln = Eu(7 ), Gd(8 ), Tb(9 ), m = 0.5 for7 and9 ; m = 1 for8 ) (phen = 1, 10-phenanthroline; H2 ox = oxalic acid) have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, infrared (IR) spectroscopy, elemental analysis, and PXRD. The crystal structures of1–9 indicate that the coordination modes and coordination configuration of the H3 dpob ligand play critical roles in the formation of the lanthanide architectures. Complexes1–5 display multiple structures from double-stranded 1D chains to 4-connected 2D layers, through [Eu2 (CO2 )4 ] or [Eu2 (CO2 )2 ] dinuclear units with different auxiliary ligands. Complexes6 and7 are genuine supramolecular isomers which are induced by the concentration effect.6 possesses a 2Dkgd network with a Schläfli symbol of (4 3 )2 (4 6 ·6 6 ·8 3 ) built from 6-connected [Eu2 (CO2 )2 ] units and 3-connected H3 dpob, which further connects to a (3, 8)-connectedtfz-d topology through O–H⋯O hydrogen bonds.7 displays a 3D (3, 6)-connectedrtl network with the Schläfli symbol (4·6 2 )2 (4 2 ·6 10 ·8 3 ). Eu complexes1, 2, 6, and7 as well as Tb complexes5 and9 could provide intense and bright characteristic 5 D0 → 7 F J / 5 D4 → 7 F J red/green luminescence under UV excitation in the solid state at 298 K and 77 K. The calculated singlet and triplet energies of H3 dpob as well as phen and H2 ox ligands indicate that these ligands act as antenna chromophores that are able to efficiently absorb and transfer energy to Ln(iii ) ions. In complexes1, 2 and5, ligand-to-metal energy transfer processes could occur in mixed ligands. However, these processes occurred in a single H3 dpob ligand in complexes6 and7 . With careful adjustment of the relative concentration of the lanthanide ions and by varying the excitation wavelengths of {[Gd0.92 Eu0.04 Tb0.04 (dpob)(H2 O)2 ]·0.5H2 O} n (10 ), tunable yellow (CIE coordinate: 0.51, 0.40) to white-light (CIE coordinate: 0.33, 0.34) emission has been obtained.