Efficient CO₂ capture at concentrations between 400–2000 ppm is essential for maintaining air quality in a habitable environment and advancing carbon capture technologies. This study introduces NICS‐24 (National Institute of Chemistry Structures No. 24), a Zn‐oxalate 3,5‐diamino‐1,2,4‐triazolate framework with two distinct square‐shaped channels, designed to enhance CO₂ capture at indoor‐relevant concentrations. NICS‐24 exhibits a CO₂ uptake of 0.7 mmol/g at 2 mbar and 25 °C, significantly outperforming the compositionally related Zn‐oxalate 1,2,4‐triazolate – CALF‐20 (0.17 mmol/g). Improved performance is attributed to amino‐functions that enhance CO₂ binding and enable superior selectivity over N₂ and O₂, achieving 8‐fold and 30‐fold improvements, respectively, in simulated CO₂/N₂ and CO₂/O₂ atmospheric ratios. In humid environments, NICS‐24 retained structural integrity but exhibited an 85 % reduction in CO₂ capacity due to competitive water adsorption. Breakthrough sorption experiments, atomistic NMR analysis, and DFT calculations revealed that water preferentially adsorbs over CO₂ due to strong hydrogen‐bonding interactions within the framework. Gained understanding of the interaction between CO₂ and H₂O within the MOF framework could guide the modification via rational design with improved performance under real‐world conditions.

A twofold (black, red) interpenetrated network of a Zn(Gly-l-Phe)₂coordination polymer, with hydrogen bonds (green) between neighboring layers.

We demonstrate a systematic application of the mechanochemical liquid-assisted grinding (LAG) methodology to screen for forms of zinc imidazolate (ZnIm₂), of fundamental importance as the simplest member of the zeolitic imidazolate framework materials family. The exploration of 45 different liquid additives, selected based on their molecular structure and physicochemical properties has resulted in eight different ZnIm₂ topological forms, appearing in 13 crystallographically distinct solid forms (including two previously unknown forms of the crb (BCT) topology), amorphous phases, and the interrupted moc-Zn₄Im₈HIm. All prepared topological forms were also explored computationally, using dispersion-corrected periodic density functional theory (DFT) calculations, enabling the rationalization of screening outcomes, and setting the stage for future prediction of additive-directed metal-organic framework (MOF) synthesis. This first systematic exploration of LAG in screening for three-dimensional MOFs demonstrates the potential of the liquid additive to not only accelerate materials synthesis, but also to direct it toward topologically different MOFs. The discovery of novel forms of a material that already exhibits at least 21 crystallographically and functionally different forms provides a strong testimony on the power of mechanochemistry in metal-organic materials discovery.

Newly synthesized amino acid hydrazide ligands (L1 = N,N′-di-L-leucine hydrazide; L2 = N,N′-di-L-phenylalanine hydrazide) have shown excellent reactivity and stability, as well as extraordinary coordination ability. Reactions of L1/L2 with copper(II) ions and 4,4′-bipyridine (4,4′-bpy) as a secondary spacer yielded new coordination polymers {Cu(L1)_0.5(4,4′-bpy)(H₂O)(NO₃)}_n·1.5nH₂O (1) and {Cu₃(L2)₂(4,4′-bpy)(H₂O)₂}_n(NO₃)_2n·3nH₂O (2). UV/vis spectroscopy together with structural analysis showed that the deprotonated ligands L1²⁻/L2²⁻ with six available donor atoms per ligand have the ability for strong chelation to copper(II) ions, acting as bis-bidentate (L1²⁻) and bridging bi + tridentate (L2²⁻) ligands. Compound 1 contains copper(II) ions simultaneously bridged with short hydrazide bridges (4.725 Å) and long 4,4′-bpy spacers (11.144 Å) forming a two-dimensional coordination network. In compound 2, a pair of L2²⁻ molecules bridges three copper(II) ions, which are further interconnected with 4,4′-bpy into an overall one-dimensional chain-like structure. Although bulkier, the phenylalanine ligand (L2) was found to be more flexible compared to the leucine ligand (L1), exhibiting additional intramolecular contact: cation–π interaction. In both compounds, the hydrazide (–N–N–) bridge mediates the antiferromagnetic interaction between copper(II) ions. Hydrogen bonds have a strong influence on the crystal packing and physical (magnetic) properties. The reported compounds are first examples of hydrazide-bridged metal centres featuring amino acid-based ligands.

The number and the strength of acid sites in catalysts have paramount importance on their efficiency. In zeolites chemistry, increased content of framework Al in zeolites gives a higher number of strong acid sites. Their strength can be a disadvantage in catalytic reactions (e.g., methanol to olefins conversion) due to undesired secondary reactions of coke formation. Here, the Faujasite type of zeolite with higher content of Al has been used for investigating the role of defects in structure and inserted (wet impregnation and thermal treatment) metal cations (Mg, Co, Ni, Zn) on the strength of OH acid sites. Desorption of deuterated acetonitrile, as a probe molecule, was used for OH groups acid strength measurements at different temperatures (150, 200, and 300 °C).

Efficient CO₂ capture at concentrations between 400–2000 ppm is essential for maintaining air quality in a habitable environment and advancing carbon capture technologies. This study introduces NICS‐24 (National Institute of Chemistry Structures No. 24), a Zn‐oxalate 3,5‐diamino‐1,2,4‐triazolate framework with two distinct square‐shaped channels, designed to enhance CO₂ capture at indoor‐relevant concentrations. NICS‐24 exhibits a CO₂ uptake of 0.7 mmol/g at 2 mbar and 25 °C, significantly outperforming the compositionally related Zn‐oxalate 1,2,4‐triazolate – CALF‐20 (0.17 mmol/g). Improved performance is attributed to amino‐functions that enhance CO₂ binding and enable superior selectivity over N₂ and O₂, achieving 8‐fold and 30‐fold improvements, respectively, in simulated CO₂/N₂ and CO₂/O₂ atmospheric ratios. In humid environments, NICS‐24 retained structural integrity but exhibited an 85 % reduction in CO₂ capacity due to competitive water adsorption. Breakthrough sorption experiments, atomistic NMR analysis, and DFT calculations revealed that water preferentially adsorbs over CO₂ due to strong hydrogen‐bonding interactions within the framework. Gained understanding of the interaction between CO₂ and H₂O within the MOF framework could guide the modification via rational design with improved performance under real‐world conditions.