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The synthesis and characterization of various 3D porous cobalt-organic frameworks are studied. These compounds are shown to exhibit spin-canted antiferromagnetism and field-induced spin-flop transition.

Systematic syntheses, structures, visible luminescence and magnetic properties of a series of new lanthanide hybrids are described. The structures contain trigonal dodecahedral chains and clustered lanthanide oxide ring tunnels and 3D Ln-O-Ln connectivity.

By employment of a tripodal phosphoric carboxylate ligand, tris(4-carboxyl phenyl )phosphin e oxide (H,TPO), two novel porous metal--organic frameworks, namely, [Zn4(μ3OH)2(TPO)2(H2O)2] (l) and [Zn6(μ6-O)(TPO)2] (NO3)4-3H2O (2), have been synthesized by solvothermal methods. Complexes 1 and 2 exhibit three-dimensional microporous frameworks with flu and pyr topologies and possess rare butterfly-shaped Zn4(μ3-OH)2(CO2)6 and octahedral Zn6(μ6-O)(CO2)6 secondary building units, respectively. Large cavities and one-dimensional channels are observed in these two frameworks. Gas-sorption measurements indicate that complex 2 has a good H2 uptake capacity of 171.9 cm g-1 (1.53 wt %) at 77 K and 1.08 bar, and its ideal adsorbed solution theory calculation predicts highly selective adsorption of CO2 over N2 and CH4. Furthermore, complexes 1 and 2 exhibit excellent blue emission at room temperature. [ABSTRACT FROM AUTHOR]

Reaction of europium sulfate octahydrate with p-terphenyl-3,3'',5,5''-tetracarboxylic acid (H4ptptc) in a mixed solvent system has afforded three new coordination polymers formulated as {[Eu(ptptc)0.75(H2O)2]·0.5DMF·1.5H2O}n (1), {[Me2H2N] 2 [Eu2(ptptc)2(H2O)(DMF)]·1.5DMF·7H2O}n (2), and {[Eu(Hptptc)(H2O)4]·0.5DMF·H2O}n (3). Complex 1 exhibits a three-dimensional (3D) metal--organic framework based on {Eu2(μ 2-COO)2 (COO)4}n chains, complex 2 shows a 3D metal--organic framework constructed by [Eu2(μ 2-COO) 2(COO)6]2- dimetallic subunits, and complex 3 features a 2D layer architecture assembling to 3D framework through π···π interactions. All complexes exhibit the characteristic red luminescence of Eu(III) ion. The triplet state of ligand H4ptptc matches well with the emission level of Eu(III) ion, which allows the preparation of new optical materials with enhanced luminescence properties. The luminescence properties of these complexes are further studied in terms of their emission quantum yields, emission lifetimes, and the radiative/nonradiative rates. [ABSTRACT FROM AUTHOR]

Reactions of a tripodal ligand, N,N′,N″-tris(3-pyridinyl)phosphoric triamide (TPPA), and a series of transition-metal ions result in the assembly of five discrete M6L8 coordination cages [M6(TPPA)8(H2O)12](ClO4)12·57H2O [M = Ni2+ (1), Co2+ (2), Zn2+ (3), Cd2+ (4)] and [Pd6(TPPA)8]Cl12·22H2O (5). X-ray structural analyses reveal that the cages have large internal cavities and flexible windows. The flexible ligand TPPA adopts the syn conformation in cages 1-4, but it transforms to the anti conformation in cage 5. Because of the conformational transformation, the sizes of the windows and the volume of the internal cavity of cage 5 are increased. 1H NMR and electrospray mass spectrometric studies show that cage 5 maintains its structural integrity in solution. Additionally, compounds 3 and 4 exhibit strong blue fluorescent emissions, which are 1 order of magnitude higher than that of the free ligand. [ABSTRACT FROM AUTHOR]

Four nickel(II)-5-aminodiacetic isophthalate coordination polymers with different auxiliary ligands are synthesized by the solvothermal method. {[Ni4(adip)2(H2O)10]·6H2O}n(1) (H4adip = 5-aminodiacetic isophthalic acid) is a supermolecular structure assembled by two-dimensional (2D) layers, and it can be viewed as a novel binodal (3,4)-connected topological net with a Schläfli symbol of (4.6.8)4(62.82.102) which has not been reported in the literature. When dipyridyl auxiliary ligands with different spacers are engaged in the reactions to pillar the 2D layers of 1, the 3D frameworks of complexes 2–4are obtained. {[Ni3(Hadip)2(bpy)2(H2O)4]·9H2O}n(2) (bpy = 4,4′-bipyridine) was crystallographically characterized to be a three-dimensional (3D) coordination network with SPC519 type topology. {[Ni8(adip)4(bpy)(H2O)18]·10H2O}n(3) as a 3D framework exhibits a scarcely reported (3,5)-connected topology with a Schläfli symbol of (4.6.8)4(62.86.102). {[Ni2(adip)(bpp)(H2O)2]·2H2O}n(4) (bpp = 1,3-bis (4-pyridyl)propane) features a 3D chiral framework composed of the achiral reagents adip4–and bpp, resulting a new (4.52)(4.53.72.84) topology. Meanwhile, the influences of configuration and length of the auxiliary ligands on the structures are investigated. The magnetic studies indicate antiferromagnetic behaviors for complexes 1and 3, and as their metal–metal distances in the dinulcear units increase the antiferromagnetic interactions become stronger. [ABSTRACT FROM AUTHOR]

A series of luminescent lanthanide coordination complexes, [Eu2(hqc)6(H2O)4]·8H2O (1), [Ln2(hqc)6(H2O)2(DMF)2]·2H2O (Ln = Eu (2), Dy (3), Ho (4)), and [Ln2(hqc)6(H2O)4]·2H2O·2DMF (Ln = Ce (5), La (6), Pr (7); Hhqc =2-hydroxyquinoline-4-carboxylic acid), have been synthesized via evaporative crystallization and then characterized by single-crystal X-ray diffraction. Complexes 1−7are nine-coordinated lanthanide(III) complexes with distorted tricapped trigonal prism geometry around each metal center. The dinuclear units in 1−7form the two-dimensional square networks and further extend to three-dimensional supramolecular frameworks through the π−π stacking and strong hydrogen bonding interactions. The optical properties of complexes 1−7in both the solid state and solution state were investigated in detail at room temperature and 10 K. The results show that the Eu3+ions in 1and 2could be highly sensitized by the hqc−ligands and thus emit intense red luminescence with long lifetimes, while complexes 3and 5−7exhibit the characteristic blue luminescence. Furthermore, X-ray diffraction and thermogravimetric analysis of 1−7are also studied, which demonstrate their high purities and good thermal stabilities. [ABSTRACT FROM AUTHOR]

Reactions of 2,2′-dihydroxyl-[1,1′]-binaphthalene-3,3′-dicarboxylate acid (H2bna) with manganese chloride by a solvent or solvothermal method in the presence of pyridine (py) or 4-picoline (pic) give birth to three 1D to 3D frameworks: [Mn(bna)(DMF)2(H2O)2]n·nDMF (1), {(Hpic)2[Mn3(bna)4(C2H5OH)2(H2O)2]·5H2O}n(2), and {(Hpy)2[Mn3(bna)4(py)2(H2O)2]·4H2O}n(3) (DMF = N,N′-dimethylformamide). Crystal structure analyses reveal that 1is a mesomer with equivalent R- and L-helical rectangular tubes constructed from homochiral ligands, which is further assembled into a 3D supramolecular network through hydrogen bonds and C−H···π interactions. Complex 2consists of a (4,4) grid chiral layer structure, while 3features a 3D cubic diamond network with Schläfli symbol 66topology, though they both comprise of [Mn3(μ2-COO)6(COO)2] pinwheel molecular building blocks which act as 4-connected nodes and bna2−as linkers. Magnetic studies indicate that antiferromagnetic couplings exist in both 2and 3. [ABSTRACT FROM AUTHOR]

A porous anionic framework with cubic symmetry and multi-intersecting open channels, H2tmdp3In6(btc)8·40H2On (1) (tmdp 4,4‘-trimethylene dipiperidine, H3btc1,3,5-benzenetricarboxylic acid), is reported. Complex1crystallizes in the cubic space group I3d (abc20.3732(8) Å, V8456.2(6) Å3, and Z2). Its cagelike units, In9(btc)11, constitute a large accessible void with 65.4% of the total volume. The cationic guests located in the channels can be exchanged with inorganic ions, such as K, NH4, Ca2, Sr2, and Ba2. [ABSTRACT FROM AUTHOR]

Two 3D lanthanide frameworks, [Ln7(DPA)5(NA)3(μ3-OH)8(H2O)3]·2.5H2O [H2DPA = diphenic acid; HNA = nicotinic acid; Ln = Gd (1), Dy (2)], were synthesized and structurally characterized. They were rarely seen examples of 3D frameworks constructed from heptanuclear trigonal-antiprismatic lanthanide clusters with mixed H2DPA and HNA ligands. Both 1 and 2 show typical antiferromagnetic interactions. Additionally, complex 1 possesses a large magnetocaloric effect of 34.15 J kg-1 K-1. [ABSTRACT FROM AUTHOR]

A novel three-dimensional (3D) microporous lanthanide−organic framework [Nd(2,5-pydc)(Ac)(H 2O)] n·2 nH 2O ( 1) has been prepared under hydrothermal conditions. The results of an X-ray crystallographic analysis revealed that compound 1has a 3D nanotubular structure. From the topological point of view, the intricate 3D framework of compound 1can be specified by the Schläfli symbol (4 26 38) as a zeolite ABW net. The H 2adsorption isotherm at 77 K shows an uptake of 132 cm 3g −1at 1.0 atm. [ABSTRACT FROM AUTHOR]