A Flexible-Robust Copper(II) Metal-Organic Framework Constructed from a Fluorinated Ligand for CO/R22 Capture.

A flexible-robust copper(II) metal-organic framework, denoted as LIFM-100, has been successfully synthesized using a fluorinated linear dicarboxylate to link copper ions. LIFM-100 exhibits a breathing effect, which can transform reversibly between a large form (lp) and a narrow form (np) from single crystal to single crystal. In addition, LIFM-100 shows good thermal and chemical stability.

Self-Generation of Surface Roughness by Low-Surface-Energy Alkyl Chains for Highly Stable Superhydrophobic/Superoleophilic MOFs with Multiple Functionalities.

We transformed the hydrophilic metal-organic framework (MOF) UiO-67 into hydrophobic UiO-67-Rs (R=alkyl) by introducing alkyl chains into organic linkers, which not only protected hydrophilic Zr O clusters to make the MOF interspace superoleophilic, but also led to a rough crystal surface beneficial for superhydrophobicity. The UiO-67-Rs displayed high acid, base, and water stability, and long alkyl chains offered better hydrophobicity. Good hydrophobicity/oleophilicity were also possible with mixed-ligand MOFs containing metal-binding ligands.

Pressure-Induced Multiphoton Excited Fluorochromic Metal-Organic Frameworks for Improving MPEF Properties.

In multiphoton excited fluorescence (MPEF), high-energy upconversion emission is obtained from low-energy excitation by absorbance of two or more photons simultaneously. In a pressure-induced fluorochromic process, the emission energy is switched by outer pressure stimuli. Now, five metal-organic frameworks containing the same ligand with simultaneous multiphoton absorption and pressure-induced fluorochromic attributes were studied.

Catalysis through Dynamic Spacer Installation of Multivariate Functionalities in Metal-Organic Frameworks.

We demonstrate herein a facile strategy to engineer versatile catalytically active coordination interspace in the same primitive metal-organic framework (MOF) for variable heterogeneous catalysis. Different functional ligands can be reversibly inserted into and removed from proto-LIFM-28 individually or successively to bring in single or binary catalytic sites for specific reactions and switch the parent MOF to multipurpose catalysts. Alcohol-oxidation, Knoevenagel-condensation, click, acetal, and Baylis-Hillman reactions are achievable through simple exchange of a single catalytic spacer, while sequential or stepwise reactions are designable via selective combination of two catalytic spacers with different functionalities, thus making proto-LIFM-28 a multivariate MOF for multiuse and economic catalysis.

A Flexible Cu-MOF as Crystalline Sponge for Guests Determination.

A trifluoromethyl functionalized linker and Cu-O chain composed MOF, LIFM-100, was used as "crystalline sponge" to determine eight hardly crystallized liquids' configurations based on its flexibility conformation, suitable pore size, electron-rich channel environment, and low symmetric space group. The H bond interactions between host-guest and guest-guest were well analyzed.

Tunability of fluorescent metal-organic frameworks through dynamic spacer installation with multivariate fluorophores.

Through dynamic spacer installation, five fluorescent metal-organic frameworks (MOFs) have been constructed based on a proto-MOF LIFM-28 and multivariate ligands as fluorophores. The emissions are tunable via insertion of fluorescent ligands, demonstrating a versatile approach for luminescence tuning by virtue of dynamic spacer installation using swing-role MOFs.

Stepwise engineering of pore environments and enhancement of CO/R22 adsorption capacity through dynamic spacer installation and functionality modification.

Through stepwise post-synthetic spacer insertion and click reactions, six Zr-MOFs with different types and amounts of functional groups have been constructed based on proto-MOF PCN-700. Their gas adsorption capacities and selectivities have been greatly improved and finely tuned, demonstrating the combinatorial effect of pore surface modification and pore space partition.

Dynamic Spacer Installation for Multirole Metal-Organic Frameworks: A New Direction toward Multifunctional MOFs Achieving Ultrahigh Methane Storage Working Capacity.

A robust Zr-MOF (LIFM-28) containing replaceable coordination sites for additional spacer installation has been employed to demonstrate a swing- or multirole strategy for multifunctional MOFs. Through reversible installation/uninstallation of two types of spacers with different lengths and variable functional groups, different tasks can be accomplished using the same parent MOF. An orthogonal optimizing method is applied with seven shorter (L) and six longer (L) spacers to tune the functionalities, achieving multipurpose switches among gas separation, catalysis, click reaction, luminescence, and particularly, ultrahigh methane storage working capacity at 5-80 bar and 298 K.