Exploring Lanthanide Luminescence in Metal-Organic Frameworks:  Synthesis, Structure, and Guest-Sensitized Luminescence of a Mixed Europium/Terbium-Adipate Framework and a Terbium-Adipate Framework

Abstract

Two lanthanide-organic frameworks were synthesized via hydrothermal methods. Compound 1 ([(Eu,Tb)(C6H8O4)3(H2O)2].(C10H8N2), orthorhombic, Pbcn, a = 21.925(2) A, b = 7.6493(7) A, c = 19.6691(15) A, alpha = beta = gamma = 90 degrees, Z = 4) takes advantage of the similar ionic radii of the lanthanide elements to induce a mixed-lanthanide composition. Compound 2 ([Tb2(C6H8O4)3(H2O)2].(C10H8N2), orthorhombic, Pbcn, a = 21.866(3) A, b = 7.6101(10) A, c = 19.646(3) A, alpha = beta = gamma = 90 degrees, Z = 8) is the terbium-only analogue of compound 1. Solid-state measurements of their luminescence behavior demonstrate that the neutral guest molecule (4,4'-dipyridyl) residing in the extraframework channels is successful in sensitizing lanthanide ion emission. In compound 1, columinescence occurs, and both lanthanide ions show emission. Additionally, quantum yield and lifetime measurements support the premise that the Tb3+ center is also acting to sensitize the Eu3+, effectively enhancing Eu3+ emission.

Lanthanide‐Based Coordination Polymers Assembled by a Flexible Multidentate Linker: Design, Structure, Photophysical Properties, and Dynamic Solid‐State Behavior

“…[10,14,49] The structure of the coordination polymers prepared in this study shows that the multidentate linker used maintains the distance between the lanthanide centers in the range 8-12 for all the isolated networks. Accordingly, this distance prevents luminescence deactivation through intercenter energy transfer.…”

“…[8] Recently, several lanthanide coordination polymers with interesting photophysical properties, a few of which couple luminescence and porosity, have been reported. [9][10][11][12][13][14][15][16] However, lanthanide systems remain far less studied than frameworks based on d-block transition-metal elements [17][18][19][20] because the typically unspecific coordination properties of the lanthanide ions render the design of lanthanide-based coordination frameworks with specific properties very challenging. By contrast, the coordination flexibility of lanthanide ions can lead to unusual structural topologies and new framework families.…”

Color and Brightness Tuning in Heteronuclear Lanthanide Terephthalate Coordination Polymers

“…[33,34] However, these smart luminescence properties have not been studied in detail, and up to date, only a few reported works deal with heteronuclear lanthanide containing coordination polymers. [29,31,32,[35][36][37] In this paper, the spectroscopic and colorimetric properties of heteronuclear lanthanide terephthalate coordination polymers are deciphered with the aim of gaining easy tuning of the color and brightness of the lanthanide-centered emission by adjusting the intermetallic distances. 4 ] ϱ .…”

Crystal structure of catena-triaqua(5-methoxyisophthalate)- cadmium(II)—water (1:2), [Cd(C9H6O5)(H2O)3] · 2H2O

“…The motivation comes notonly from their application as functional materials but is also due to the intriguing structural architectures [1][2][3][4].Inprinciple, the mosteffective approach for the construction of MOFs is to rationally modify the building blocks and to control the assembled motifs for required products via selecting different organic ligands [5,6]. 5-methoxyisophthalate (CH 3 O-H 2 ip) may serve as as uitable building block to construct novel coordination polymers due to the existence of anoncoordinating CH 3 Ogroup on the aromatic backbone, which will have aprofound impact on the electron density of such aligand and therefore different physical and chemical properties [7][8][9]. The asymmetric unit of the title crystal structure consists of aCd 2+ ion, aCH 3 O-ip ligand, three coordinated water molecules and two free waterm olecules.T he Cd 2+ ion is chelated by four oxygen atomsfrom carboxylate of CH 3 O-ip ligand forming two chelating rings, and the oxygen atomsfrom three coordinated water moleculesc ompletet he seven-fold coordination at the metal center.…”