Two silver(I)–lanthanide(III) heterometallic-organic frameworks (HMOFs) {[Ln3Ag3(BPDC)5(OX)(H2O)7]·7H2O}n (Ln = Tb (1), Gd (2)) have been synthesized via a mixed ligand approach using 2,2′-bipyridine-3,3′-dicarboxylic acid (H2BPDC) and oxalic acid (H2OX) under hydrothermal conditions. Single crystal X-ray diffraction studies showed a (3,4,5)-connected new topology of {3·42·5·62}{3·43·52·63·7}{3·5·62·9·10}{42·5·63}{42·5}{42·6}{43·5·62}{43·63}{43·64·82·10}. Luminescence studies showed that the characteristic emissions of Tb3+ ions are observed in HMOF 1 which can be capable of sensing organic small-molecule pollutants and metal ions. In addition, it can also discriminate the isomers of pentanol as well as quantitatively distinguish benzendiamines which are carcinogenic but used for hair coloring.

•A new luminescent Cd-MOF has been obtained.•The obtained MOF possesses selective turn-on luminescent sensing function towards Al3 + and Ca2 + ions in aqueous solutions.•It shows high stability in aqueous solution.A new metal-organic framework (MOF), [Cd2(bptc)(HCOO)]·NH2(CH3)2·3H2O (1), where H4bptc = 3,3′,5,5′-biphenyltetracarboxylic acid, was obtained by solvothermal reaction. The topology of MOF 1 is a (5,8)-connected net with {416 · 58 · 64}{44 · 56}2 point symbol. MOF 1 shows high stability in aqueous solution. Luminescence study indicates that MOF 1 possesses selective turn-on luminescent sensing functions towards Al3 + and Ca2 + ions in aqueous solutions.A new Cd(II) MOF with 3,3′,5,5′-biphenyltetracarboxylic acid was synthesized by solvothermal reaction, which possesses selective turn-on luminescent sensing function towards Ca2 + and Al3 + ions in aqueous solutions.Download high-res image (241KB)Download full-size image

NiO nanoparticles were in situ formed in a new metal–organic framework (MOF), [Ni3(pyip)2(HCOO)2(H2O)2]n [1; H2pyip = 5-(pyridine-4-yl)isophthalic acid], which was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, transmission electron microscopy, and powder and single-crystal X-ray diffraction. The MOF 1 shows a 3,6-connected three-dimensional rtl topology network with a topological symbol of (4.62)2(42.610.83). Magnetic property studies showed that the combination of NiO nanoparticles within the magnetic MOF leads to the occurrence of long-range magnetic ordering below a critical temperature of 18 K.

•A new luminescent Zn-MOF has been synthesized.•This MOF exhibits high thermal stability and water stability.•It can be used as a luminescent sensor to detect p-xylene in xylene isomers.A new Zn(II) metal-organic framework was synthesized with 5-nitro-1,2,3-benzenetricarboxylic acid and auxiliary triazole ligand via hydrothermal method, namely, {[Zn2.5(nbta)(trz)2(H2O)]·3H2O}n (1), where H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid and Htrz = 1H-1,2,4-triazole. 1 shows high thermal stability up to 150 °C under air atmosphere and water stability with the pH range from 1 to 12. Luminescent study shows that 1 displays a high-sensitivity sensing function for p-xylene in the three kinds of xylene isomers.A new luminescent Zn MOF based on mixed ligands approach has been synthesized, which exhibits high-selective luminescent sensing behavior for p-xylene in three kinds of xylene isomers.

Two 2D layered coordination networks with formulas of {[Co(TPA)Cl](H2O)2.5}n (1) and {[Co(TPA)(μ2-OH)](H2O)2}n (2) (HTPA = 4-(1,2,4-triazol-4-yl)phenylacetic acid) were solvothermally synthesized and fully characterized. Interesting 1D Co2+-Cl or Co2+-μ2-OH chain structures were observed. By carefully adjusting the reaction conditions, a new 3D metal–organic framework (MOF) with a formula of {[Co7(TPA)6(μ3-OH)4(μ2-OH)2(H2O)4](TPA)2(DMF)3(H2O)3}n (3) was obtained. MOF 3 is built from Co7 clusters and fully deprotonated TPA ligands, which display a cubic pcu topology. Factors that influence the structures of the three TPA-based complexes, as well as their magnetic properties, were investigated in detail. The heptanuclear-Co(II)-cluster-based MOF 3 shows interesting magnetization dynamics at low temperature.

A framework approach was successfully performed to give a three-dimensional heterometallic compound exhibiting single-ion magnet (SIM) behavior. Enhanced SIM behavior was obtained by continuous application of diamagnetic-ion dilution and an external dc field.

A new three-dimensional Zn(II) metal–organic framework (MOF) of {[Zn4(bpydb)3(datz)2(H2O)](DMF)4(EtOH)5(H2O)8}n (1, bpydbH2 = 4,4′-(4,4′-bipyridine-2,6-diyl) dibenzoic acid, Hdatz = 3,5-diamino-1,2,4-triazole) with amino- and pyridine-functionalized pores has been successfully constructed under solvothermal conditions by using the mixed-ligand strategy, which consists of twisty 63 layers pillared by datz– ligands. The adsorption properties of this MOF were studied by CO2, N2, and CH4 sorption measurements. Compared with the analogous 4,4′-bipyridine (bpy) pillared MOF {Zn(bpydb)(bpy)}n (2) we reported earlier, the activated 1 showed enhanced CO2 sorption capacity and good sorption selectivity for CO2 over N2 and CH4 at room temperature.

•The obtained new radical NITThioPh wides the family of NITRs.•Both ferromagnetic NN and antiferromagnetic NNN interactions were observed in 1.•Antiferromagnetic ordering below 1.8 K was detected in complex 2.Based on a new nitronyl nitroxide radical, 2-(benzo[b]thiophen-2-yl)-4,4,5,5-tetramethylimidazolin-1-oxyl-3-oxide (NITThioPh), two new mononuclear tri-spin complexes [Ln(hfac)3(NITThioPh)2] (Ln = Gd (1), Tb (2); hfac = hexafluoroacetylacetonate) are successfully synthesized and fully characterized. Complexes 1 and 2 are isostructural and crystalize in P21/c space group, in which the central metal ions are eight-coordinated in distorted triangular dodecahedron LnO8 coordination geometries (D2d symmetry) finished by three bischelate hfac− ligands and two monodentate radicals. Magnetic studies on 1 suggest the coexistence of ferromagnetic nearest-neighbor (NN) coupling between Gd(III) ions and radical spins and antiferromagnetic next-nearest-neighbor (NNN) interaction between intramolecular radical spins. In addition, antiferromagnetic ordering below 1.8 K was detected in the Tb(III) complex.Two mononuclear tri-spin Ln(III)–NITR complexes were synthesized and fully characterized based on a new nitronyl nitroxide radical. Magnetic studies on 1 suggest the coexistence of ferromagnetic nearest-neighbor (NN) coupling between Gd(III) ions and radical spins and antiferromagnetic next-nearest-neighbor (NNN) interaction between intramolecular radical spins. Antiferromagnetic ordering below 1.8 K was detected in the Tb(III) complex (2).

A series of CuII–LnIII heterometallic metal–organic frameworks (HMOFs), displaying three types of structures with the formulas of {[Ln2Cu(BDPC)4(H2O)6]·9H2O}n (Ln = La, 1; Pr, 2; Nd, 3; BPDC2– = 2,2′-bipyridine-3,3′-dicarboxylate), {[Ln2Cu2(BPDC)5(H2O)6]·9H2O}n (Ln = Pr, 4; Nd, 5; Sm, 6; Eu, 7; Gd, 8; Tb, 9) and [DyCu3(BPDC)4(NO3)(H2O)6]n (10), have been successfully synthesized and well characterized. Single crystals available for X-ray diffraction measurements were carried out for MOFs 3, 7, 9, and 10. Powder X-ray diffraction and Fourier transform infrared analysis demonstrate the isomorphism for MOFs 1–3, as well as MOFs 4–9. The BPDC2– ligand herein exhibits seven different coordination modes to link metal centers for the construction of different three-dimensional structures. The structures of the three types of CuII-LnIII HMOFs can be described topologically with the Schläfli symbol {3·62}{32·66·73·83·9}{62·7}, {4·62}2{42·64·86·103}{6·82}2, and {4·8·9}2{6·8·9}2{6·82·93}{82·9}2, of which the latter two are new topologies. The static magnetic properties of the 10 HMOFs and dynamic magnetic properties of 9-Tb2Cu2 and 10-DyCu3 have been studied.

Reaction of H3TDA with PrIII/NdIII salts resulted in two coordination polymers, [Ln(H2O)4(HTDA)(H2TDA)]·H2O (Ln = Pr(1) and Nd(2), H3TDA = 1H-[1,2,3]-triazole-4,5-dicarboxylic acid), crystallizing in the monoclinic P21/c space group with a one-dimensional zigzag chain structure. The number of ligands and water molecules coordinated to the LnIII ions can be reduced by a hydrothermal method and the products transformed into {[Ln(TDA)(H2O)]·2.5H2O}n (Ln = Pr(3) and Nd(4)), crystallizing in the trigonal P3121 space group with a three-dimensional chiral framework structure. The compounds were characterized by elemental analysis, IR, PXRD, circular dichroism spectra and single crystal X-ray diffraction. The variable temperature magnetic susceptibility studies indicated that there are antiferromagnetic interactions between the LnIII ions in 1–4. Gas sorption and separation were studied as well.

Three 2D coordination polymers with mixed ligands [M(bpe)(bba)]n (M = Mn for 1, Co for 2 and Ni for 3, bpe = 1,2-bis(4-pyridyl)ethane, H2bba = isophthalic acid) have been synthesized and characterized by single crystal X-ray diffraction, PXRD, TGA and magnetic susceptibility measurements. The central metal ions of each have a distorted octahedral geometry and are bridged by μ2-η1:η1 carboxylate groups to form binuclear units with metal–metal separations of 4.318 Å (1), 4.463 Å (2) and 4.551 Å (3), respectively. The binuclear units are linked by bba2− to form 1D ribbons, which are further assembled through bpe ligands into a 2D grid structure. TGA analysis reveals that 1, 2, and 3 exhibit high thermal stability. The magnetic properties of 1, 2 and 3 were studied in the temperature range of 2–300 K. Analysis of the magnetic data reveals antiferromagnetic interactions in 1 as well as interesting ferromagnetic interactions in 2 and 3 between the anti–syn double carboxylate groups bridging metal ions.Graphical abstractThree 2D coordination polymers with mixed ligands [M(bpe)(bba)]n (M = Mn for 1, Co for 2 and Ni for 3, bpe = 1,2-bis(4-pyridyl)ethane, H2bba = isophthalic acid) have been synthesized and characterized by single crystal X-ray diffraction, PXRD, TGA and magnetic susceptibility measurements. The central metal ions of each have a distorted octahedral geometry and are bridged by μ2-η1:η1 carboxylate groups to form binuclear units with metal–metal separations of 4.318 Å (1), 4.463 Å (2) and 4.551 Å (3), respectively. The binuclear units are linked by bba2− to form 1D ribbons, which are further assembled through bpe ligands into a 2D grid structure. TGA analysis reveals that 1, 2, and 3 exhibit high thermal stability. The magnetic properties of 1, 2 and 3 were studied in the temperature range of 2–300 K. Analysis of the magnetic data reveals antiferromagnetic interactions in 1 as well as interesting ferromagnetic interactions in 2 and 3 between the anti–syn double carboxylate groups bridging metal ions.Highlights► Three 2D coordination polymers with mixed ligand have been synthesized. ► The complexes were structurally characterized by single crystal X-ray diffraction. ► Antiferromagnetic interactions in MnII complex (1). ► Interesting ferromagnetic interactions in CoII (2) and NiII (3) complexes.

The synthesis, structural characterization, and magnetic properties of two new Cu(II) coordination polymers with formula {[Cu(2-nica)(H2O)2]∙H2O}n (1) and [Cu(6-nica)(H2O)2]n (2) (where 2-H2nica = 2-hydroxynicotinic acid and 6-H2nica = 6-hydroxynicotinic acid) are reported. 1 exhibits 1D chain structure formed by the sequence of [Cu(II)OCu(II)]. For 2, nitrogen atoms and μ1,3-COO carboxylic groups of 6-nica2 − bridge Cu(II) ions forming an infinite chain structure. The ESR spectra, as well as the variable temperature magnetic susceptibilities were analyzed, which suggests ferromagnetic coupling in 1 and antiferromagnetic coupling in 2, respectively.Two new 1D Cu(II) coordination polymers constructed from hydroxynicotinic acid were synthesized and structurally characterized. Analysis of the temperature dependence of magnetic susceptibilities suggests ferromagnetic interactions in 1 and antiferromagnetic interactions in 2, respectively.Highlights► Two 1D Cu(II) coordination polymers have been synthesized. ► The complexes were structurally characterized by single crystal X-ray diffraction. ► Interesting ferromagnetic interaction in complex (1). ► Antiferromagnetic interaction in complex (2).

Two silver(I)–lanthanide(III) heterometallic-organic frameworks (HMOFs) {[Ln3Ag3(BPDC)5(OX)(H2O)7]·7H2O}n (Ln = Tb (1), Gd (2)) have been synthesized via a mixed ligand approach using 2,2′-bipyridine-3,3′-dicarboxylic acid (H2BPDC) and oxalic acid (H2OX) under hydrothermal conditions. Single crystal X-ray diffraction studies showed a (3,4,5)-connected new topology of {3·42·5·62}{3·43·52·63·7}{3·5·62·9·10}{42·5·63}{42·5}{42·6}{43·5·62}{43·63}{43·64·82·10}. Luminescence studies showed that the characteristic emissions of Tb3+ ions are observed in HMOF 1 which can be capable of sensing organic small-molecule pollutants and metal ions. In addition, it can also discriminate the isomers of pentanol as well as quantitatively distinguish benzendiamines which are carcinogenic but used for hair coloring.

A framework approach was successfully performed to give a three-dimensional heterometallic compound exhibiting single-ion magnet (SIM) behavior. Enhanced SIM behavior was obtained by continuous application of diamagnetic-ion dilution and an external dc field.