A two-dimensional cationic lattice built from [Zn6(HPO4)2(PO4)2]2+ clusters

Controlling the BET Surface Area of Porous Carbon by Using the Cd/C Ratio of a Cd-MOF Precursor and Enhancing the Capacitance by Activation with KOH

Herein, four new cadmium metal-organic frameworks (Cd-MOFs), [Cd(bib)(bdc)]_∞ (1), [Cd(bbib)(bdc)(H₂ O)]_∞ (2), [Cd(bibp)(bdc)]_∞ (3), and [Cd₂ (bbibp)₂ (bdc)₂ (H₂ O)]_∞ (4), have been constructed from the reaction of Cd(NO₃ )₂ ⋅4 H₂ O with 1,4-benzenedicarboxylate (H₂ bdc) and structure-related bis(imidazole) ligands (1,4-bis(imidazol-1-yl)benzene (bib), 1,4-bis(benzoimidazol-1-yl)benzene (bbib), 4,4'-bis(imidazol-1-yl)biphenyl (bibp), and 4,4'-bis(benzoimidazol-1-yl)biphenyl (bbibp)) under solvothermal conditions. Cd-MOF 1 shows a 2D (4,4) lattice with parallel interpenetration, whereas 2 displays an interesting 3D interpenetrating dia network, 3 exhibits an unusual 3D interpenetrating dmp network, and 4 presents a 3D self-catenated pillar-layered framework with a Schäfli symbol of [4³ ⋅6³ ]₂ ⋅[4⁶ ⋅6¹⁶ ⋅8⁶ ]. The structural diversity indicates that the backbone of the bis(imidazole) ligand (including the terminal group and spacer) plays a crucial role in the assembly of mixed-ligand frameworks. By using the pore-forming effect of cadmium vapor, for the first time we have utilized these Cd-MOFs as precursors to further prepare porous carbon materials (PCs) in a calcination-thermolysis procedure. These PCs show different porous features that correspond to the topological structures of Cd-MOFs. Significantly, it was found that the specific surface area and capacitance of PCs are tuned by the Cd/C ratio of the MOF. Furthermore, the as-synthesized PCs were processed with KOH to obtain activated porous carbon materials (APCs) with higher specific surface area and porosity, which greatly promoted the energy-storage capacity. After full characterization, we found that APC-bib displays the largest specific surface area (1290 m²  g^-1 ) and total pore volume (1.37 cm³  g^-1 ) of this series of carbon materials. Consequently, APC-bib demonstrates the highest specific capacitance of 164 F g^-1 at a current density of 0.5 A g^-1 , and also excellent retention of capacitance (≈89.4 % after 5000 cycles at 1 A g^-1 ). Therefore, APC-bib has great potential as the electrode material in a supercapacitor.

An unprecedented “strongly” self-catenated MOF containing inclined catenated honeycomb-like units

A 3D MOF {[Co(bibp)(1,4-chdc)]·2H₂O}_n (1) (bibp = 4,4′-bis(1-imidazolyl)biphenyl, 1,4-H₂chdc = 1,4-cyclohexanedicarboxylic acid) was hydrothermally synthesized. This framework buries an unprecedented self-catenated net with the highest topological density among the 4-coordinated nets. The photo-catalytic and electrochemical activities were investigated.

A microporous Zn(II)-MOF with open metal sites: structure and selective adsorption properties

A three-dimensional microporous framework, Zn(II)-MOF [Zn(HPyImDC)(DMA)]n (1) (H3PyImDC = 2-(pyridine-4-yl)-1H-4,5-imidazoledicarboxylic, DMA = N,N'-dimethylacetamide), with open metal sites and small-sized pores, exhibits excellent selective capture of CO2 over N2 and CH4 at 273 K, as well as alcohols from water. The excellent CO2 adsorption selectivity of 1 allows its potential use in the capture of CO2 from industrial flue gas or the removal of CO2 from natural gas. More interestingly, compound represents the rare case of porous materials separating propanol isomers, which may be caused by the relative flexibility of the linear n-propanol considering that both n-propanol and i-propanol have similar kinetic diameters.

A series of coordination polymers based on varied polycarboxylates and different imidazole-containing ligands: syntheses, crystal structures and physical properties

To investigate the effect of organic ligands on the coordination frameworks, seven nickel(ii) coordination polymers, based on varied polycarboxylates and different imidazole-containing ligands, are synthesized under hydrothermal method.

1D–3D mixed-ligand frameworks with an unusual dmp topology tuned by intersection angles of isomeric benzenedicarboxylates: magnetic properties, gas-dependent calcination-thermolysis and energy storage performances

Three coordination polymers with isomeric ligands were studied and used to prepare CoO and Co₃O₄ particles.

Structural modulation in two CuII-based MOFs by synergistic assembly involving the mixed-ligand synthetic strategy and the solvent effect

A synergistic assembly involving the mixed-ligand synthetic strategy and the solvent effect was successfully applied to tune two Cu^II-based MOFs. 1 represents a cds topology, while 2 is built by three distinct {Cu₄} clusters as SBUs.