Min Zhu

A europium(III) based metal–organic framework: bifunctional properties related to sensing and electronic conductivity

The accessible interspace of [Eu4(BPT)4(DMF)2(H2O)8] (EuL) metal–organic framework (MOF) based host materials can serve as good candidates for loading of a variety of guest molecules. In this regard, two functional properties, sensing and electronic conductivity of EuL MOF were systematically studied in this contribution. The photoluminescent properties reveal that the EuL exhibits characteristic red emission of Eu3+ ion, and presents highly detectable luminescence responses for Cu2+ ions and acetone molecules in DMF solution. For the studies of electrical properties, they were focused on the electronic conductivities of I2-incorporated EuL in anhydrous media and at different temperatures. With the increase of temperature from 25 to 80 °C, the I2-incorporated EuL showed significant changes in conductivities from 8.27 × 10−7 S cm−1 to 2.71 × 10−5 S cm−1. Meanwhile, the activation energy (Ea) was for the first time estimated for iodine-element-incorporated MOF with the help of Arrhenius plots. The successful achievements of the impedance measurements and analyses for I2-incorporated EuL prove for the first time that iodine-element-incorporated MOF can also be used for studies of conductivity under anhydrous conditions and at moderate temperature.

A series of POM/Ag-based hybrids: distinct forms and assembly of [AgxLy] complexes through combinational effects of POM and isomeric ligands

Five POM/Ag-based hybrids were obtained under hydrothermal conditions: (AgLa)2[Ag2La2(SiW12O40)] (1), [(AgLb)2-Ag2Lb2][(SiW12O40)] (2) Na2[AgLa(HLa)]2[Ag5La4(H2O)2][H(P2W18O62)2] ·21.6H2O (3), [Ag5Lb5][K2(OH)P2W18O62]·H2O (4) and [Ag2La2][HPW12O40]·7.5H2O (5) (La = 1,2-bis(imidazol-1-ylmethyl)benzene; Lb = 1,3-bis(imidazol-1-ylmethyl)benzene). It is likely that the forms and assembly of [AgxLy] complexes are crucial to the eventual structures, which are quite dependent on the POM and isomeric ligands in combination. Compound 1 shows a “S”-like chain structure with [(AgLa)2]n2n+ templates, while compound 2 features a unique 2D layer constructed by polypseudo-rotoxane motifs and infinite Ag chains. Compound 3 exhibits a 2D layer consisting of {Dawson-Ag5} double chain and [AgLa2] complexes. Compound 4 possesses a 3D poly-threading framework containing {POM-K} chains and interdigitated metal–organic layers. Compound 5 is a 1D chain, formed by Keggin anions and [Ag2La2] circles. Further, the luminescent and electrochemical properties of 1–5 are also investigated.

Three unprecedented open frameworks based on a pyridyl-carboxylate: synthesis, structures and properties

Three open frameworks, [Ni(pnta)2]·1.3DMF (1), [Zn2(pnta)3(OH)]·2DMF (2), and [Cd(pnta)2]·3.8DMF (3), were obtained by solvothermal reactions between 6-(pyridin-4-yl)nicotinic acid (Hpnta) and nickel(II), zinc(II) and cadmium(II) nitrate, respectively. Compound 1 is a chiral framework with a fourfold interpenetrated diamondoid network structure and two types of chiral channels. Compound 2 also possesses the fourfold interpenetrated adamantanoid architecture with helical rhombic nanotube-like channels, each of which has two sides of double-layer walls and two other sides of single-layer walls. Compound 3 is a rarely reported double-walled framework with bcu topology. The luminescent properties of compounds 2 and 3 have been studied in the solid state at room temperature.