Doped Luminescent Lanthanide Coordination Polymers Exhibiting both White-Light Emission and Thermal Sensitivity

Multifunctional lanthanide coordination polymers (CPs) have the advantages of acting in two or more fields simultaneously. Herein, two single lanthanide CPs, formulated as LnL(D/L-Hlac)(H₂O)₂·0.5H₂O (Ln = Eu (1), Tb (2); H₂L = 4,4'-(pyridine-3,5-diyl)dibenzoic acid) and their doped lanthanide analogue Tb_0.9373Eu_0.0627L(D/L-Hlac)(H₂O)₂·0.5H₂O (3) were prepared through hydrothermal methods. Luminescence measurements reveal that 1 displays red photoluminescence and its Commission International ed'Eclairage (CIE) coordinates are almost invariant in the temperature range from 80 to 300 K, while the emission color of 2 changes from yellow to green and its CIE coordinates change from (0.36132, 0.56365) at 80 K to (0.30448, 0.45566) at 300 K. Significantly, 3 not only displays white-light emission with CIE coordinates of (0.32999, 0.33406) but also exhibits a thermal sensitivity of 2.27% K^-1 at 230-300 K. The obviously larger thermal sensitivity in 3 in comparison to that of 1.07% K^-1 for 2 demonstrates that lanthanide CPs with both a heat-sensitive fluorescent thermometer and high-efficiency white-light emission can be expected by doping Eu(III) ions into Tb(III)-based CPs.

Temperature-induced structural diversity of metal-organic frameworks and their applications in selective sensing of nitrobenzene and electrocatalyzing the oxygen evolution reaction

Structural diversities are presented in four new Co-MOFs containing 1,5-bi(imidazolyl)anthracene and different dibenzobarrelene skeletons based on dicarboxylic acid, in which MOFs 1-3 exhibit 2D networks in a 4-connected node sql topology with the point symbol of {44·62}, while MOF 4 forms a 1D chain structure. It is clearly observed that the 2D-1D structural transformation of 2-4 has been realized by temperature modulated hydrothermal synthesis procedures from 120-160 °C, suggesting the key role of temperature for constructing MOFs. In addition, obvious π-π interactions between anthracene rings can be observed in the architectures of 1-3, which may favorably stabilize their 2D supramolecular networks. More importantly, fluorescence behaviors of 1-4 have been investigated in water among various nitro-aromatic compounds (NACs) and the results show that all samples exhibit high selectivity and fine sensitivity to nitrobenzene (NB) with fluorescence quenching, which is confirmed to be the result of electron transfer from the excited state of ligands to that of NB by density functional theory. Furthermore, MOFs 1-4 have been directly employed as electrocatalysts for the oxygen evolution reaction (OER), in which MOF 4 gives the best activity towards the OER among all as-synthesized samples with an overpotential of 398 mV at a current density of 10 mA cm-2 and a low Tafel slope of 59 mV dec-1.

Metal–organic frameworks based on tetraphenylpyrazine-derived tetracarboxylic acid for electrocatalytic hydrogen evolution reaction and NAC sensing

Tetraphenylpyrazine-derived tetracarboxylic acid-based new MOFs and their promising applications in the electrocatalytic hydrogen evolution reaction.

Synthesis, structure and temperature sensing of a lanthanide-organic framework constructed from a pyridine-containing tetracarboxylic acid ligand

A high sensitive, thermostable mixed lanthanide metal–organic framework, Eu_0.19Tb_0.81PDDI, was developed as a self-calibrated thermometer effective in the high temperature range of 313 to 473 K.

Two series of novel 3D potentially porous heterometallic Cu–Ln coordination frameworks assembled by 3,4-pyridinedicarboxylic acid with different topologies and channels: syntheses, structures, luminescence and magnetic properties

Two series of heterometallic Cu–Ln coordination frameworks assembled by 3,4-pyridinedicarboxylic acid with different topologies and channels.

Two- and three-dimensional lanthanide-based coordination polymers assembled by the synergistic effect of various lanthanide radii and flexibility of a new binicotinate-containing ligand: in situ synthesis, structures, and properties

The design and synthesis of ten novel coordination polymers was investigated. They have three structural types from 3D to 2D due to the synergistic effect of lanthanide contraction with diverse coordination modes and conformations of the ligand.

An unusual cobalt(ii)-based single-walled metal–organic nanotube

Self-adaption to the formation of an unusual cobalt(ii)-based single-walled metal–organic nanotube is reported. In addition, a pseudo-merohedral twinning problem encountered in the X-ray diffraction analysis was solved, which significantly improves the crystallographic results.

Solvothermal synthesis, crystal structure, and properties of lanthanide-organic frameworks based on thiophene-2,5-dicarboxylic acid

A series of lanthanide-organic framework coordination polymers, {[La(2)(TDC)(2)(NO(3))(H(2)O)(4)](OH)·5H(2)O}(n) (1) and [Ln(TDC)(NO(3))(H(2)O)](n) (TDC = thiophene- 2, 5- dicarboxylic acid; Ln = Nd(2), Sm(3), Eu(4), Gd(5), Tb(6), Dy(7), Ho(8), Er(9), Yb(10)) have been synthesized by solvothermal reaction and characterized by elemental analysis, FT-IR, TG analysis, single-crystal X-ray diffraction and power X-ray diffraction. The single-crystal X-ray diffraction analysis results show that 1 displays a 3-D porous framework with (3,7)-connected {4(10).6(11)}{4(3)} topology. The compounds 2-10 crystallized in the same P2(1)/c space group and exhibits a (3,6)-connected {4.6(2)}(2){4(2).6(10).8(3)} topology, Right-handed and left-handed helical chains coexist in the 2-D layer structure. The luminescence properties of 2-10 and the magnetic properties of 5,7,8,9 were investigated.