A Porous Coordination Polymer Assembled from 8-Connected {CoII3(OH)} Clusters and Isonicotinate: Multiple Active Metal Sites, Apical Ligand Substitution, H2 Adsorption, and Magnetism

Combined experimental and theoretical investigation on the magnetic properties derived from the coordination of 6-methyl-2-oxonicotinate to 3d-metal ions

Five new compounds are reported herein starting from 2-hydroxy-6-methylnicotinic acid (H2h6mnic) and first-row transition metal ions, although H2h6mnic shows a prototropy in solution to lead to the 6-methyl-2-oxonicotinate (6m2onic) ligand that is the molecule eventually present in the compounds. The structural and chemical characterization reveals the following chemical formulae: {[MnNa(μ₃-6m2onic)₂(μ-6m2onic)(MeOH)]·H₂O·MeOH}_n (1Mn), {[M₂Na₂(μ₃-6m2onic)₂(μ-6m2onic)₂(μ-H₂O)(H₂O)₆](NO₃)₂}_n [M^II = Co (2Co) and Ni (3Ni)], 2[Cu₂(6m2onic)₃(μ-6m2onic)(MeOH)]·[Cu₂(6m2onic)₂(μ-6m2onic)₂]·2[Cu(6m2onic)₂(MeOH)]·32H₂O (4Cu) and {[Cu(μ-6m2onic)₂]·6H₂O}_n (5Cu) (where 6m2onic = 6-methyl-2-oxonicotinate). An unusual structural diversity is observed for the compounds, ranging from isolated complexes (in 4Cu), 1D arrays (in 1Mn and 5Cu) and 3D frameworks (in 2Co and 3Ni). Magnetic properties have been studied for all compounds. Analysis of the magnetic dc susceptibility and magnetization data for 4Cu and 5Cu suggests the occurrence of ferromagnetic exchange, which is well explained by broken-symmetry and CASSCF calculations. The sizeable easy-plane magnetic anisotropy present in compound 2Co allows for a field-induced magnet behaviour with an experimental effective energy barrier of 16.2 cm^-1, although the slow relaxation seems to be best described through Raman and direct processes in agreement with the results of ab initio calculations.

Experimental and theoretical studies of a pyridylvinyl(benzoate) based coordination polymer structure

The electronic, adsorption and structural properties of a layered coordination polymer formed with 3,4-pvb− and copper(ii) were studied.

A Trinuclear Cobalt-Organic Framework: Solvatochromic Sensor towards CH2 Cl2 , and its Derivative as an Anode of Lithium-Ion Batteries with High Performance

Here, a porous cobalt-organic framework with pillared layer structures, namely [Co₃ OBA₃ PTD(H₂ O)₂ ⋅ 2 DMA⋅H₂ O]_n (1, H₂ OBA=4,4'-oxybis(benzoic acid); PTD=6-(pyridin-4-yl)-1,3,5-triazine-2,4-diamine), was fabricated by using cobalt trinuclear nodes, low-cost carboxylic linker, and accessible nitrogen heterocyclic ligands. This compound exhibited a highly efficient solvatochromism towards CH₂ Cl₂ within one minute and can be used 200 times at least. The corresponding dropper detector was assembled as a practical sensor. Meanwhile, the porous Co₃ O₄ was obtained by a simple but effective annealing treatment. Electrochemical measurements confirm that this Co₃ O₄ material derived from compound 1 shows high and stable lithium storage capabilities (1081.75 mA h g^-1 at 200 mA g^-1 after 115 cycles) and excellent rate properties.

Two Metal-Organic Frameworks Based on Hexanuclear Cobalt-Hydroxyl Clusters or a Manganese-Hydroxyl Chain from Triangular [MII3(μ3-OH)] (M = Co and Mn) Units: Antiferromagnetic and Spin-Canting Antiferromagnetic Ordering with Soft-Magnetic Behavior

Three-dimensional highly connected isonicotinic acid-base metal-organic frameworks (MOFs), [Co^II₆(μ₃-OH)₂(in)₇(HCOO)₃H₂O]·4DMF (1) and [Mn^II₃(μ₃-OH)(in)₃(CH₃COO)₂] (2) (Hin = isonicotinic acid), have been successfully prepared. Compounds 1 and 2 were constructed from planar Co₆ cluster SBUs or rare 1D manganese-hydroxyl chain SBUs, respectively. Both SBUs contain triangular M^II₃(OH) (M = Co and Mn) central units, which are connected by rare syn,anti,syn,anti- and syn,syn,anti-coordinated formic acid or acetic acid. Both compounds 1 and 2 have good thermal stability, while compound 2 also exhibits an extraordinarily high moisture stability. Magnetic studies demonstrate that 1 shows antiferromagnetic behavior, and 2 exhibits spin-canting antiferromagnetic ordering with soft-magnetic behavior.

Novel 3D anionic heterometallic frameworks based on trinuclear CoII and trinuclear LnIII motifs displaying slow magnetic relaxation and selective adsorption of methylene blue

3D CoLn heterometallic frameworks have been synthesized. CoDy and CoHo show slow magnetic relaxation behavior. CoTb exhibits excellent adsorption capacity for methylene blue.

Tetranuclear cobalt(ii)-isonicotinic acid frameworks: selective CO2 capture, magnetic properties, and derived "Co3O4" exhibiting high performance in lithium ion batteries

Two new 3D cobalt metal-organic frameworks (MOFs), [Co4(CH3COO)(in)5(μ3-OH)2]·2H2O (1) and [Co4(SO4)2(in)4(DMF)2]·3DMF (2) (Hin = isonicotinic acid), have been prepared through the anion template method. Compound 1 consists of rare odd-number connected (9-connected) cubane-like SBUs, while compound 2 consists of 8-connected high-symmetry square-planar clusters. Magnetic studies indicate that compound 1 exhibits spin-canting antiferromagnetic ordering, while compound 2 shows antiferromagnetic behavior. At 273 K and 1 bar, compound 1 exhibits a high CO2 selectivity over CH4 and a significant CO2 uptake of 13.6 wt%, which is higher than that of 2 (8.5 wt%). Furthermore, compound 1 was then transformed into ultrasmall Co3O4 nanoparticles via simple but effective annealing treatment. Electrochemical measurements show that the Co3O4 nanospheres derived from compound 1 exhibited high and stable lithium storage properties (1100 mA h g-1 after 100 cycles at 200 mA g-1) and excellent rate capabilities.

Charge control of the formation of two neutral/cationic metal–organic frameworks based on neutral/cationic triangular clusters and isonicotinic acid: structure, gas adsorption and magnetism

Two neutral/cationic frameworks based on triangular MnII3/CoII3 clusters are constructed using an SBU charge controlling strategy, and their gas adsorption performances are investigated.

Liquid-free single-crystal to single-crystal transformations in coordination polymers

Single-crystal to single-crystal (SCSC) transformations not only can create new materials, but also provide an opportunity to explore the process of forming a chemical bond. SCSC transformations discussed in this paper are confined to transformationsviaan absolutely liquid-free mode and involve the breakage and formation of new chemical bonds.

Separation of C2/C1 hydrocarbons through a gate-opening effect in a microporous metal–organic framework

Here we report highly selective C2 separation from methane in a porous metal–organic framework.

Metal organic frameworks with uni-, di-, and tri-nuclear Cd(ii) SBU prepared from 1,3-bis(4-pyridyl)propane and different dicarboxylate ligands: syntheses, structures and luminescent properties

Systematic variation of co-dicarboxylate ligands leads to three new MOFs based on uni-, di-, and tri-nuclear Cd(ii) SBUs.

A porous metal-organic framework with a unique hendecahedron-shaped cage: structure and controlled drug release

A porous MOF constructed from a [Cu2(COO)4] secondary building unit, H3L (H3L = [1,1';3',1'']terphenyl-4,5',4''-tricarboxylic acid), and pyrazine ligands features a unique hendecahedron cage-like cavity with good stability and a high BET surface area of 3235 m(2) g(-1), showing good controlled drug release property of ibuprofen over those of anethole and guaiacol.

Four cobalt(ii) complexes based on a new tricarboxylate with a naphthalene ring and different N-containing ligands: synthesis, crystal structures and magnetic properties

Four cobalt(ii) coordination polymers have been synthesized under hydrothermal conditions, and their magnetic behaviors have been discussed in detail.

Biphenyl-2,4,6,3',5'-pentacarboxylic acid as a tecton for six new Co(II) coordination polymers: pH and N-donor ligand-dependent assemblies, structure diversities and magnetic properties

Six new Co(ii)-based mixed-ligand coordination polymers, namely, [Co2(H3bppc)2(2,2'-bpy)4]·H2O (), [Co2(Hbppc)(2,2'-bpy)2(H2O)]·H2O (), [Co(H2bppc)(H-bpp)]·2H2O (), [Co3(μ3-OH)(bppc)(dps)(CH3CH2OH)]·4H2O (), [Co2(bppc)(bib)(H2O)4]·(H2-bib)0.5·(H2O)3 (), and [Co2(Hbppc)(bix)2]·2H2O (), (H5bppc = biphenyl-2,4,6,3',5'-pentacarboxylic acid, 2,2'-bpy = 2,2'-bipyridine, bpp = 1,3-bis(4-pyridyl)propane, dps = 4,4'-sulfanediyldipyridine, bib = 1,4-bis(imidazol-1-yl)benzene, bix = 1,4-bis(imidazol-1-ylmethyl)benzene), have been obtained under solvothermal conditions. exhibits a 3D supramolecular framework based on a [Co2(H3bppc)2(2,2'-bpy)4] unit. has a (3,4)-connected dmc net with a (4·8(2))(4·8(5)) topology containing alternate binuclear metal clusters and single metal centres. shows a 3D supramolecular architecture constructed from ladder-like arrays decorated with H-bpp. exhibits a binodal (5,7)-connected 3D network based on trinuclear [Co3(μ3-OH)](5+) units with an unusual (3·4(6)·5(2)·6)(3(2)·4(6)·5(7)·6(5)·7) topology. features a (4,6)-connected 3D fsc open framework with binuclear [Co2(H2O)(COO)](3+) units as nodes, and H2-bib and water molecules located in the voids of its framework by hydrogen bonds. possesses a 3D net containing unusual 2D polyrotaxane sheets. Topological analysis reveals that has a (3,4,4)-connected 3D network with a (4·6·7(4))(4·6·7)(6·7(2)·10(2)·11) topology. The structural difference of and is due to the different pH values of the reaction system. Though complexes were synthesised under similar reaction conditions, the carboxylic groups of H5bppc were partially deprotonated in , and and fully deprotonated in and . Complexes display diverse structures depending on different N-donor ligands and the coordination modes of the multicarboxylate ligand. Variable-temperature magnetic susceptibility measurements reveal that complexes show antiferromagnetic interactions.

Template controlled synthesis of cluster-based porous coordination polymers: crystal structure, magnetism and adsorption

By utilizing the template agent, pentaerythritol, a porous framework with dual tetra-nuclear codes has been successfully constructed, which also exhibits interesting magnetism and sorption properties.

The concept of mixed organic ligands in metal–organic frameworks: design, tuning and functions

The mixed organic ligand strategy is significant for the rational construction of MOFs, and furthermore for their functionality and tunability.

Self-assembly, crystal structures and properties of metal–3,4,5-tris(carboxymethoxy)benzoic acid frameworks based on polynuclear metal-hydroxyl clusters (M = Zn, Co)

Three new inorganic–organic frameworks based on 3,4,5-tris(carboxymethoxy)benzoic acid and polynuclear metal-hydroxyl clusters were assembled. Photoluminescent and magnetic properties are investigated.

Two robust metal–organic frameworks with uncoordinated N atoms for CO2adsorption

Two highly porous metal–organic frameworks are successfully constructed through the assembling of Co/Ni ions and mixed ligands. From the contribution of the uncoordinated tetrazolate N atoms of the ligand the two complexes show high CO₂adsorption capacities, serving as potential CO₂adsorption materials.