The unique distribution pattern of PFAS in landfill organics.

PFAS from degrading landfill waste partition into organic matter, leachate, and landfill gas. Driven by the limited understanding of PFAS distribution in landfill organics, we analyzed PFAS across various depths and seven spatially distinct locations within a municipal landfill. The measured PFAS concentrations in organics ranged from 6.

Design and Characterization of Metal Nanoparticle Infiltrated Mesoporous Metal-Organic Frameworks.

The infiltration of palladium and platinum nanoparticles (NPs) into the mesoporous metal-organic framework (MOF) CYCU-3 through chemical vapor infiltration (CVI) and incipient wetness infiltration (IWI) processes was systematically explored as a means to design novel NP@MOF composite materials for potential hydrogen storage applications. We employed a traditional CVI process and a new ″green″ IWI process using methanol for precursor infiltration and reduction under mild conditions. Transmission electron microscopy-based direct imaging techniques combined with synchrotron-based powder diffraction (SPD), energy-dispersive X-ray spectroscopy, and physisorption analysis reveal that the resulting NP@MOF composites combine key NP and MOF properties.

Direct Imaging of Isolated Single-Molecule Magnets in Metal-Organic Frameworks.

Practical applications involving the magnetic bistability of single-molecule magnets (SMMs) for next-generation computer technologies require nanostructuring, organization, and protection of nanoscale materials in two- or three-dimensional networks, to enable read-and-write processes. Owing to their porous nature and structural long-range order, metal-organic frameworks (MOFs) have been proposed as hosts to facilitate these efforts. Although probing the channels of MOF composites using indirect methods is well established, the use of direct methods to elucidate fundamental structural information is still lacking.

Design, structural diversity and properties of novel zwitterionic metal-organic frameworks.

Seven new zwitterionic metal-organic frameworks (ZW MOFs) of compositions {[Cd(L1)(OH)]·2HO} (1), {[Mn(L1)(OH)]·HO} (2), {[Cu(HL1)(OH)]·9HO} (3), {[Mn(L2)(OH)]·3HO} (4), [Co(L2)(OH)]·HO (5), [Ni(L2)(OH)] (6), and {[Cd(L2)(OH)]·4HO} (7), where HL1Br = 3-carboxy-1-(3,5-dicarboxybenzyl)pyridinium bromide and HL2Br = 4-carboxy-1-(3,5-dicarboxybenzyl)pyridinium bromide, have been synthesized under hydrothermal conditions. We demonstrate that the diversity of these crystal structures suggests that the tridentate and flexible nature of ZW ligands L1 and L2 make them excellent candidates for the synthesis of new ZW MOFs. A multi-charged anionic nature is a common feature of L1 and L2, and therefore, allows the rational design of ZW MOFs without the presence of additional counterions for charge compensation.

The Importance of Polymorphism in Metal-Organic Framework Studies.

Polymorphic phase transitions remain frequently undetected in routine metal-organic framework (MOF) studies; however, their discovery is of major importance in interpreting structure-property relationships. We herein report a reversible enantiotropic single-crystal to single-crystal polymorphic phase transition of a new microporous MOF [Eu(BDC)(NO3)(DMF)2]n (H2BDC = 1,4-benzenedicarboxylic acid; DMF = dimethylformamide). While modification 1LT at 170 K crystallizes in the monoclinic space group P21/c with unit cell dimensions of a = 17.

A new design strategy to access zwitterionic metal-organic frameworks from anionic viologen derivates.

Two isostructural microporous zwitterionic metal-organic frameworks (ZW MOFs), {[M(bdcbpy)(OH2)4]·4H2O}n with M = Mn (1) and Ni (2), were synthesized by the rational design of the flexible anionic viologen derivate, 1,1'-bis(3,5-dicarboxybenzyl)-4,4'-bipyridinium dibromide dihydrate solvate (H4bdcbpyBr2·2H2O), and its self-assembly with metal(II) acetates in an aqueous medium. Single-crystal structure analyses revealed that both compounds exhibit three-dimensional hydrogen-bonded supramolecular frameworks with one-dimensional channel pores. Significantly, the pore surfaces are lined with charge gradients employed by the ZW ligand bdcbpy(2-) leading to the adsorption of hydrogen attributed to polarization effects.