Porous MOF Featuring 2D Intersecting Channels Based on a Pentanuclear Mn5(COO)10CO3 Cluster with Upgrading of Pipeline Natural Gas

Natural gas plays a crucial role in daily and industrial production, but the impurities contained in natural gas limit its further use. It is very important to develop adsorbents that can separate CH4 from multicomponent mixtures, but there are still many challenges and problems. Herein, a novel porous MOF {[Mn5(pbdia)2(CO3)(H2O)2] ↔ 5H2O ↔ 2DMF}n (pbdia = 2,2'-(5-carboxy-1,3-phenylene)bis(oxy) diterephthalic acid) was successfully synthesized based on a flexible pentacarboxylic acid ligand and a unique pentanuclear Mn5(COO)10CO3 cluster. The MOF reveals a 3D porous structure with 2D intersecting channels, which shows high C3H8, C2H6, and CO2 adsorption capacities and affinities over CH4. Moreover, the ideal adsorption solution theory selectivities of C3H8/CH4, C2H6/CH4, and CO2/CH4 can reach 263.0, 27.0, and 7.7, respectively, suggesting a potential for removing the low content of C3H8, C2H6, and CO2 from pipeline natural gas, which was further confirmed by breakthrough curves and GCMC simulations.

Toward Universal Substituent Constants: Relating QTAIM Functional Group Descriptors to Substituent Effect Proxies

Substituents modulate reactions, but their effects are commonly described by using proxies to their functional group properties. Substituent descriptors from the quantum theory of atoms in molecules, which are true functional group properties, are related here to these proxies, which have historically had chemically relevant meaning. Due to the large number of descriptors, multivariate analysis is used to intuit their significance. Multiple linear regression, principal component, and partial least squares regression analyses highlight that these substituent descriptors contain similar information to the proxies while being intrinsic, predictable substituent properties. Sources of error limiting quantitative reproduction of the proxy data include transferability, experimental accuracy, and solvation issues.

Two Structurally Similar Co5 Cluster-Based Metal-Organic Frameworks Containing Open Metal Sites for Efficient C2H2/CO2 Separation

To reasonably design and synthesize metal-organic frameworks (MOFs) with high stability and excellent adsorption/separation performance, the pore configuration and functional sites are very important. Here, we report two structurally similar cluster-based MOFs using a pyridine-modified low-symmetry ligand [H₄L = 2,6-bis(2',5'-dicarboxyphenyl)pyridine], [(NH₂Me₂)₂][Co₅(L)₂(OCH₃)₂(μ₃-OH)₂·2DMF]·2DMF·2H₂O (1) and [Co₅(L)₂(μ₃-OH)₂(H₂O)₂]·2H₂O·4DMF (2). The structures of 1 and 2 are built from Co₅ clusters, which have one-dimensional open channels, but their microporous environments are different due to the different ways in which ligands bind to the metals. Both MOFs have extremely high chemical stabilities over a wide pH range (2-12). The two MOFs have similar adsorption capacities of C₂H₂ (144.0 cm³ g^-1 for 1 and 141.3 cm³ g^-1 for 2), but 1 has a higher C₂H₂/CO₂ selectivity of 3.5 under ambient conditions. The difference in gas adsorption and separation between the two MOFs has been compared by a breakthrough experiment and theoretical calculation, and the influence of the microporous environment on the gas adsorption and separation performance of MOFs has been further studied.

The anionic Zn-MOF composed of 1D columnar SBUs for highly C2H2/CH4 selective adsorption, dye adsorption and fluorescence sensing

An anionic three-dimensional framework {(Me2NH2)2[Zn8(L)6(ad)4(μ4-O)]·10DMF·11H2O}(Zn-MOF, L2-=4,4'-(3-aminopyridine-2,5-diyl)dibenzoic acid, ad-=adeninate) with a column-layered structure was synthesized. Structural studies show that the Zn-MOF has octahedral cages [Zn8(ad)4(μ4-O)], adjacent cages are connected by O...

Construction of three new Co(ii)-organic frameworks based on diverse metal clusters: highly selective C2H2 and CO2 capture and magnetic properties

Three Co(ii)-MOFs have been synthesized. The desolvated frameworks of 2 and 3 exhibit good adsorption selectivity for C₂H₂ and CO₂ over CH₄ at 273 and 298 K. Moreover, 1–3 show that there exist antiferromagnetic interactions between metal ions.

A lactam-functionalized copper bent diisophthalate framework displaying significantly enhanced adsorption of CO2 and C2H2 over CH4

The first lactam-functionalized MOF based on a bent diisophthalate ligand was constructed, displaying significantly enhanced uptake and selectivity for C₂H₂ and CO₂ over CH₄.

Rational construction and remarkable gas adsorption properties of a HKUST-1-like tbo-type MOF based on a tetraisophthalate linker

A condensed version of tetraisophthalate MOF MFM-181 was rationally designed and synthesized based on ligand contraction and conformation preorganization strategy, exhibiting the promising potential for the separation of C₂H₂ and CO₂ from CH₄.

Effect of arrangement of functional groups on stability and gas adsorption properties in two regioisomeric copper bent diisophthalate frameworks

The substituent's arrangement was found to have a significant effect on the structural stabilities and thus gas adsorption properties of the resultant MOFs.

A heterometallic metal–organic framework based on multi-nuclear clusters exhibiting high stability and selective gas adsorption

Porous In/Tb-CBDA has been successfully synthesized in the light of the heterometallic cooperative crystallization (HCC) approach. In/Tb-CBDA with high thermal and chemical stability exhibited high performance for gas storage and separation.

Tailoring the structures and gas adsorption properties of copper–bent diisophthalate frameworks by a substituent-driven ligand conformation regulation strategy

A substituent-induced ligand conformation regulation strategy was employed to tailor the structures and gas adsorption properties of copper-bent diisophthalate frameworks.

A ligand conformation preorganization approach to construct a copper–hexacarboxylate framework with a novel topology for selective gas adsorption

A ligand conformation preorganization strategy was employed to design a hexacarboxylate ligand, and its corresponding copper-based MOF was constructed, exhibiting a novel topological structure and the potential for the separation and purification of acetylene and natural gas.

Highly selective C2H2 and CO2 capture and magnetic properties of a robust Co-chain based metal–organic framework

A robust Co-MOF based on uncommon 1D alternate Co₄ chain units was synthesized, which efficiently takes up C₂H₂ and CO₂ with significant selectivity for C₂H₂ and CO₂ over CH₄, as well as shows a slow freezing process of magnetic behavior.

A NbO-type MOF based on an aromatic-rich and N-functionalized diisophthalate ligand for high-performance acetylene storage and purification

A NbO-type MOF based on an aromatic-rich and N-functionalized diisophthalate ligand exhibits promising potential for acetylene storage and purification.

Two NbO-type MOFs based on linear and zigzag diisophthalate ligands: exploring the effect of ligand-originated MOF isomerization on gas adsorption properties

Two NbO-type MOFs were constructed as a platform to reveal the effect of ligand-originated MOF isomerization on selective C₂H₂/CH₄ and CO₂/CH₄ adsorption properties.