3-D Silver(I)—Lanthanide(III) Heterometallic-Organic Frameworks Constructed from 2,2′-Bipyridine-3,3′-dicarboxylic Acid: Synthesis, Structure, Photoluminescence, and Their Remarkable Thermostability

Abstract

A new family of silver(I)-lanthanide(III) heterometallic-organic frameworks having the formula [AgLn(bpdc)2] (Ln = Eu (1), Tb (2), Sm (3), Dy (4), Y (5), Yb (6), Er (7), Ho (8); H2bpdc = 2,2'-bipyridine-3,3'-dicarboxylic acid), each of which crystallizes in the monoclinic space group C2/c with Z = 4, has been hydrothermally synthesized. The compounds were characterized by means of IR, elemental analysis, thermogravimetric-differential thermal analysis, and powder X-ray diffraction (XRD), wherein compounds 1, 2, and 4-8 were structurally characterized. The powder XRD and single-crystal structures of the title compounds indicate that all the compounds are isostructural and feature a three-dimensional (3-D) open framework. In the structures of the compounds, bpdc(2-) ligands link Ln(3+) through their carboxylic groups, resulting in the formation of a one-dimensional {Ln(bpdc)2}n infinite chain along the c direction. The adjacent chains are then connected to each other through the coordination interaction between Ag(+) and the pyridyl N atoms of bpdc(2-) ligands from the chains, resulting in a 3-D (2,4,6)-connected open framework with (4(11)·6(4))(4(3)·8(2)·10)(8)2 topology. The compounds show remarkable good thermally stability up to 370 °C because neither aquo ligands nor lattice water molecules exist in the composition of the compounds. The photoluminescent properties of compounds 1 and 2 were studied in detail. The energy level of the triplet states of the ligand H2bpdc 21,505 cm(-1) (465 nm) was determined based on the 77 K emission spectrum of the compound [Gd2(bpdc)3(phen)2(H2O)2]·6H2O 9. The (5)D0 and (5)D4 emission lifetimes (1.58 and 1.76 ms) and the overall quantum yields (21% and 22%) were determined for the compounds 1 and 2, respectively.

Syntheses, Structures, and Properties of Two Coordination Complexes of a Flexible Ligand with Channel Structure

“…[4b] Depending on the size of ligands, inorganic connecting points, and network connectivity, the CPs may have various multi‐dimensional structures with channels and pores with different shapes and sizes. The rigid ligands with multicarboxylate and multi‐diazo groups, trimesic acid, and bipyridine as examples, are the common candidates for preparation of coordination polymers with 3D frameworks because of their ability to reduce orientational freedom. The rigid ligands have been extensively proved to assemble open MOFs, while the flexible ones which possess rotatable components in their skeletons tend to engender entangled networks , .…”

Synthesis, Photoluminescence and Effect of Lanthanide Contraction on Structures of 3D Lanthanide‐Organic Frameworks from 1,4‐Benzenedicarboxylic Acid and Oxalic Acid

“…The luminescent lifetime of compound 1 was performed by monitoring the most intense emission line at 545 nm within the 5 D 4 → 7 F 5 transition at room temperature under the excitation at 275 nm (Figure ). The emission decay curve of compound 1 is well fitted by a single‐exponential function, consistent with the observation of only one independent crystallographic site for Tb 3+ . The determined lifetime values τ obs of compound 1 is 0.54 ms which is in the range of other related Tb(III) compounds…”

Lanthanide Complexes with 2,3-Dimethoxybenzoic Acid and Terpyridine: Crystal Structures, Thermal Properties, and Antibacterial Activities

“…The search of lanthanide aromatic carboxylic acid complexes have aroused great interest for their various and fascinating structures, which exhibit potential applications for extraction and separation, drug delivery, luminescent probes, and so on . These complexes combine central metallic units with organic N‐donor, which may enhance conjugate function, rigidity and stability, and reinforce the luminescent properties of the complexes . Furthermore, aromatic carboxylic acids exhibiting high affinity to central lanthanide atoms are chosen as conjugated organic ligands, since they have strong coordination capability to the lanthanide ions .…”