Short Naphthalene Organophosphonate Linkers to Microporous Frameworks

We report two novel 3D porous metal-organophosphonate metal organic frameworks (MOFs) [{Cu(4, 4’-bpy)0.5(1,4-NDPA-H2)] (1), [{Cu2(4,4’-bpy)0.5}(1,4-NDPA)] (2) and a non-porous [{Cu(4, 4’-bpy)}(2,6-NDPA-H2)] (3) constructed using the structurally rigid 1,4-naphthalenediphosphonic acid (1,4-NDPA-H4) and 2,6-naphthalenediphosphonic acid (2,6-NDPA-H4). 1 and 2 exhibit high surface areas obtained using the structurally rigid and short aromatic organophosphonate linkers with copper. The compound 1 has been further analyzed by TGA and Quantum Design PPMS vibrating sample magnetometer

Direct Simulation of Ternary Mixture Separation in a ZIF‐8 Membrane at Molecular Scale

Separation of H2 in a ZIF‐8 membrane from a syngas mixture composed of CO2, H2, and N2 at 300 K and 35 atm is simulated with the concentration gradient driven molecular dynamics (CGD‐MD) method. Steady‐state fluxes are computed to predict the H2 selectivity of the ZIF‐8 membrane using four different flexible force fields developed for ZIF‐8. The permselectivities predicted by the CGD‐MD method are compared with those obtained from the grand canonical Monte Carlo+equilibrium molecular dynamics (GCMC+EMD) approach, which is based on the solution‐diffusion model and widely used to predict permselectivities for mixture separations. The permselectivities obtained by using the CGD‐MD method accurately predict that ZIF‐8 is H2 selective over CO2 and N2. On the other hand, permselectivities predicted with the GCMC+EMD approach are found to be incorrect, that is, ZIF‐8 not selective for H2. The study suggests that a reliable non‐equilibrium molecular dynamics approach should be employed in order to obtain accurate predictions for the permselectivity of a membrane for a multicomponent mixture separation process which happens at moderate or high pressure conditions

Computer-assisted screening of ordered crystalline nanoporous adsorbents for separation of alkane isomers.

A matter of degree: Separation of di-branched alkanes from their linear and mono-branched isomers is important in producing high-octane gasoline. Using computational techniques to screen a large variety of adsorbent materials, ZIF-77 emerges as the best adsorbent. It has the unique ability to fractionate isomer mixtures according to the degree of branching

Metal-organic framework materials with ultrahigh surface areas: is the sky the limit?

We have synthesized, characterized, and computationally simulated/validated the behavior of two new metal-organic framework (MOF) materials displaying the highest experimental Brunauer-Emmett-Teller (BET) surface areas of any porous materials reported to date (∼7000 m(2)/g). Key to evacuating the initially solvent-filled materials without pore collapse, and thereby accessing the ultrahigh areas, is the use of a supercritical CO(2) activation technique. Additionally, we demonstrate computationally that by shifting from phenyl groups to "space efficient" acetylene moieties as linker expansion units, the hypothetical maximum surface area for a MOF material is substantially greater than previously envisioned (∼14600 m(2)/g (or greater) versus ∼10500 m(2)/g)

Metal-organic framework materials with ultrahigh surface areas: is the sky the limit?

We have synthesized, characterized, and computationally simulated/validated the behavior of two new metal-organic framework (MOF) materials displaying the highest experimental Brunauer-Emmett-Teller (BET) surface areas of any porous materials reported to date (∼7000 m(2)/g). Key to evacuating the initially solvent-filled materials without pore collapse, and thereby accessing the ultrahigh areas, is the use of a supercritical CO(2) activation technique. Additionally, we demonstrate computationally that by shifting from phenyl groups to "space efficient" acetylene moieties as linker expansion units, the hypothetical maximum surface area for a MOF material is substantially greater than previously envisioned (∼14600 m(2)/g (or greater) versus ∼10500 m(2)/g)

Two Large-Pore Metal–Organic Frameworks Derived from a Single Polytopic Strut

Two noninterpenetrated MOFs with strikingly different structures, <b>NU-108-Cu</b> and <b>NU-108-Zn</b>, were prepared from a single hexa-carboxylated ligand. <b>NU-108-Cu</b> contains paddlewheel-coordinated copper ions as nodes and is based on a 3,24 network associated with an inherently noncatenating <i>rht</i>-topology. Modifications introduced in the hexa-carboxylated struts (uniquely placed phenyl spacers) lead to substantial changes in pore sizes, relative to those found in other MOFs based on 3,24 networks and paddlewheel-coordinated copper ions. <b>NU-108-Zn</b> features a new net based on (3,3,6)-connecter and octadehral Zn₄O nodes in which all struts lie in <i>a</i>–<i>b</i> planes

Two Large-Pore Metal–Organic Frameworks Derived from a Single Polytopic Strut

Two noninterpenetrated MOFs with strikingly different structures, <b>NU-108-Cu</b> and <b>NU-108-Zn</b>, were prepared from a single hexa-carboxylated ligand. <b>NU-108-Cu</b> contains paddlewheel-coordinated copper ions as nodes and is based on a 3,24 network associated with an inherently noncatenating <i>rht</i>-topology. Modifications introduced in the hexa-carboxylated struts (uniquely placed phenyl spacers) lead to substantial changes in pore sizes, relative to those found in other MOFs based on 3,24 networks and paddlewheel-coordinated copper ions. <b>NU-108-Zn</b> features a new net based on (3,3,6)-connecter and octadehral Zn₄O nodes in which all struts lie in <i>a</i>–<i>b</i> planes

Two Large-Pore Metal–Organic Frameworks Derived from a Single Polytopic Strut

Two noninterpenetrated MOFs with strikingly different structures, <b>NU-108-Cu</b> and <b>NU-108-Zn</b>, were prepared from a single hexa-carboxylated ligand. <b>NU-108-Cu</b> contains paddlewheel-coordinated copper ions as nodes and is based on a 3,24 network associated with an inherently noncatenating <i>rht</i>-topology. Modifications introduced in the hexa-carboxylated struts (uniquely placed phenyl spacers) lead to substantial changes in pore sizes, relative to those found in other MOFs based on 3,24 networks and paddlewheel-coordinated copper ions. <b>NU-108-Zn</b> features a new net based on (3,3,6)-connecter and octadehral Zn₄O nodes in which all struts lie in <i>a</i>–<i>b</i> planes