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A new family of isostructural 3d-4f heterometallic metal--organic frameworks (HMOFs), [Zn3EuxTb2-x(TZI)4(DMA)5(H2O)3]·4DMA [x = 0 (1), 0.3 (2), 0.6 (3), 0.9 (4), 1 (5), 1.2 (6), 1.5 (7), 1.8 (8), 2 (9)], has been synthesized using the 5-(4-(tetrazol-5-yl) phenyl)isophthalic acid (H3TZI) ligand, LnIII ions and ZnII ions under solvothermal conditions. All HMOFs exhibit a (3,3,4,5,5)-connected 6³·6³(4²·6²·8²)(4·65·8) (4·66·83) topology, which features three different types of motifs: one is a mononuclear ZnII ion and the other two motifs are binuclear [Zn(COO)3Ln] clusters. The adsorption experiments indicate that Zn3Tb2 (1) could efficiently remove almost all I2 from cyclohexane solution after 12 h and also showed better adsorption towards neutral red (NR) dye (adsorption: only the Zn3Tb2 (1) was taken as one representative). Simultaneously, the luminescence sensing showed that Zn3Tb2 (1) and Zn3Eu2 (9) have excellent response and sensitivity towards pollutants such as Fe3+ ions and 2,4,6-trinitrophenol (TNP) with high selectivity and a fairly low limit of detection through luminescence quenching effect. Moreover, seven trimetallic-doped HMOFs 2-8 analogues of Zn3Ln2 (single) HMOFs were designed and prepared, showing different changes of luminescent color. More interestingly, Zn3Eu1.5Tb0.5 (7) with white-light emission was fabricated by doping relative concentrations of Eu3+ and Tb3+ ions. To the best of our knowledge, Zn3Eu1.5Tb0.5 (7) represents a novel kind of heterometallic Zn3Ln2 HMOFs with white-light emission. It could be deduced that the excellent characteristics, namely strong typical luminescence emission of ZnII and LnIII ions, microporous channels, active open metal sites (tetra-coordinated ZnII--metal sites), and uncoordinated carboxylate O atoms and uncoordinated tetrazolate N atoms, made the above HMOFs an ideal platform for adsorption, luminescence sensing, and white-light emission. More significantly, these HMOFs are the first reported Zn-Ln heterometallic materials with the H3TZI ligand. [ABSTRACT FROM AUTHOR]

Novel azobenzene-derived β-diketonates (4,4,5,5,6,6,6-heptafluoro-1-azobenzene-1,3-hexanedione (LA), 4,4,5,5,6,6,6-heptafluoro-1-(4-dimethylamino)azobenzene-1,3-hexanedione (LB)) were designed and their complexes with lanthanide cations (La3+, Eu3+, Gd3+, Yb3+) were prepared and characterized by 1H NMR, FT-IR, and elemental analysis. Three of the complexes were crystallized successfully and identified by X-ray diffraction. It was significant to find that LA showed remarkably reversible trans-to-cis isomerization properties, however, LB, bearing an electron donor compared with LA, slowed down the isomerization to an extent. The presence of Ln(iii) enhanced the reversible trans-to-cis isomerization properties of both LA and LB a little upon photoirradiation in organic solvents, and amazingly increased the fatigue resistance. In addition, the complexes doped in polymethyl methacrylate (PMMA) films produced a similar phenomenon as well as when in solution. Theoretical calculations based on time dependent density functional theory (TD-DFT) were performed for geometry optimization and to determine the excitation energies of LA and LB to gain further insight into the electronic structure of the complexes, and the data were consistent with the experimental results. The excellent reversible photoisomerization properties of the newly designed Ln(iii) complexes can offer important advantages that will help with the further study of these materials to reach their full potential in applications such as molecular switching devices. [ABSTRACT FROM AUTHOR]

A novel 3D Co(ii) coordination polymer, [Co6(4-ptz)6(N3)6]n (1) (4-ptz = 4-(pyridinyl)tetrazole), was synthesized by in situ hydrothermal reaction and characterized magnetically. Compound 1 consists of ferrimagnetic-like Co(ii) layers with the title heterobridges and exhibits the spin-glass slow dynamics. The study on spin-glass behavior in mixed azide and tetrazolate bridged compounds is the first example. [ABSTRACT FROM AUTHOR]

A number of half-zirconocene anilide complexes of the type Cp*ZrCl2[N(2,6-R12C6H3)R2] [R1= iPr (1, 3), Me (2); R2= Me (1, 2), Bn (3)] and Cp*ZrCl[N(2,6-Me2C6H3)Me]2(4) (Cp* = pentamethylcyclopentadienyl) were synthesized from the reactions of Cp*ZrCl3with the lithium salts of the corresponding anilide in diethyl ether at room temperature. All new zirconium complexes were characterized by 1H and 13C NMR and elemental analysis. Molecular structures of complexes 1, 2and 4were determined by single crystal X-ray diffraction analysis. Upon activation with AliBu3and Ph3CB(C6F5)4, complexes 1–4exhibit good catalytic activity for ethylene polymerization, and produce polyethylene with a moderate molecular weight. Among these zirconium complexes, complex 1shows the highest catalytic activity while complex 4shows the lowest catalytic activity for ethylene polymerization. Complexes 1–3also exhibit moderate catalytic activity for copolymerization of ethylene with 1-hexene, and produce copolymers with relatively high molecular weight and reasonable 1-hexene incorporation. In addition, the activation procedure of these catalyst systems were studied by 1H NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Four bimetallic Al or Zn complexes supported by anilido-aldimine ligands (o-C6H4(NHAr)–CHN)2CH2CH2 (Ar = 2,6-Me2C6H3, L1H2; Ar = 2,6-iPr2C6H3, L2H2) have been synthesized and characterized. Treatment of L1H2 or L2H2 with two equiv. of AlMe3 gives bimetallic complex L1(AlMe2)21 or L2(AlMe2)22, respectively. Reaction of L1H2 or L2H2 with two equiv. of ZnEt2 leads to bimetallic complex L1(ZnEt)23 or L2(ZnEt)24, respectively. All of the complexes 1–4 are efficient catalysts for ring-opening polymerization of ε-caprolactone (CL) in the presence of benzyl alcohol and catalyze the polymerization of CL in living fashion yielding polymers with a narrow polydispersity index. The activity of bimetallic Zn complexes 3 and 4 is higher than bimetallic Al complexes 1 and 2. [ABSTRACT FROM AUTHOR]