Guest-Induced Irreversible Sliding in a Flexible 2D Rectangular Grid with Selective Sorption Characteristics

Design and synthesis of new luminescent coordination networks of topology showing the highest degrees of interpenetration

The highest degree of interpenetration reported so far of 7- and 8-fold is realized in two luminescent sql 2D networks by self-assembly of a new nanometric-sized ligand with Ag(i) salts.

Simultaneous interlayer and intralayer space control in two-dimensional metal-organic frameworks for acetylene/ethylene separation

Three-dimensional metal−organic frameworks (MOFs) are cutting-edge materials in the adsorptive removal of trace gases due to the availability of abundant pores with specific chemistry. However, the development of ideal adsorbents combining high adsorption capacity with high selectivity and stability remains challenging. Here we demonstrate a strategy to design adsorbents that utilizes the tunability of interlayer and intralayer space of two-dimensional fluorinated MOFs for capturing acetylene from ethylene. Validated by X-ray diffraction and modeling, a systematic variation of linker atom oxidation state enables fine regulation of layer stacking pattern and linker conformation, which affords a strong interlayer trapping of molecules along with cooperative intralayer binding. The resultant robust materials (ZUL-100 and ZUL-200) exhibit benchmark capacity in the pressure range of 0.001–0.05 bar with high selectivity. Their efficiency in acetylene/ethylene separation is confirmed by breakthrough experiments, giving excellent ethylene productivities (121 mmol/g from 1/99 mixture, 99.9999%), even when cycled under moist conditions.

Designing efficient adsorbents for trace gas removal remains a serious challenge. Here, the authors show promise in layered 2D metal−organic frameworks, often overlooked in favor of 3D frameworks, for separating trace acetylene from ethylene with enhanced performance and high stability.

From lamellar net to bilayered-lamella and to porous pillared-bilayer: reversible crystal-to-crystal transformation, CO2 adsorption, and fluorescence detection of Fe3+, Al3+, Cr3+, MnO4−, and Cr2O72− in water

Layered coordination polymers of different network topologies have showed reversible structural transformations and fluorescence detection toward Fe³⁺, Al³⁺, Cr³⁺, MnO₄^–, and Cr₂O₇^2– in water.

(113)Cd Nuclear Magnetic Resonance as a Probe of Structural Dynamics in a Flexible Porous Framework Showing Selective O2/N2 and CO2/N2 Adsorption

Two new isomorphous three-dimensional porous coordination polymers, {[Cd(bpe)0.5(bdc)(H2O)]·EtOH}n (1) and {[Cd(bpe)0.5(bdc)(H2O)]·2H2O}n (2) [bpe = 1,2-bis(4-pyridyl)ethane, and H2bdc = 1,4-benzenedicarboxylic acid], have been synthesized by altering the solvent media. Both structures contain one-dimensional channels filled with metal-bound water and guest solvent molecules, and desolvated frameworks show significant changes in structure. However, exposure to the solvent vapors (water and methanol) reverts the structure back to the as-synthesized structure, and thus, the reversible flexible nature of the structure was elucidated. The flexibility and permanent porosity were further reinforced from the CO2 adsorption profiles (195 and 273 K) that show stepwise uptake. Moreover, a high selectivity for O2 over N2 at 77 K was realized. The framework exhibits interesting solvent vapor adsorption behavior with dynamic structural transformation depending upon the size, polarity, and coordination ability of the solvent molecules. Further investigation was conducted by solid state (113)Cd nuclear magnetic resonance (NMR) spectroscopy that unambiguously advocates the reversible transformation "pentagonal-bipyramidal CdO6N → octahedral CdO5N" geometry in the desolvated state. For the first time, (113)Cd NMR has been used as a probe of structural flexibility in a porous coordination polymer system.

The dynamic response of a flexible indium based metal–organic framework to gas sorption

This work presents a flexible indium based MOF which exhibits a novel dynamic response to N₂, Ar and CO₂ sorption.

Construction of 2D interwoven and 3D metal–organic frameworks (MOFs) of Cd(ii): the effect of ancillary ligands on the structure and the catalytic performance for the Knoevenagel reaction

The effect of ancillary ligands on structure and catalytic activity for Knoevenagel reaction of three new metal–organic coordination networks of Cd(ii) constructed from a rigid dicarboxylate ligand and various bipyridine spacers has been presented.

Exploration of unconventional π–hole and C–H⋯H–C types of supramolecular interactions in a trinuclear Cd(ii) and a heteronuclear Cd(ii)–Ni(ii) complex and experimental evidence for preferential site selection of the ligand by 3d and 4d metal ions

We report the synthesis of a trinuclear cadmium(ii) (1) and a di(phenoxido)-bridged dinuclear cadmium(ii)–nickel(ii) (2) complex derived from a bicompartmental (N₂O₄) Schiff base ligand.

Double-step CO2 sorption and guest-induced single-crystal-to-single-crystal transformation in a flexible porous framework

A new 2D highly flexible and breathing porous framework [CuL(Me2NH)]·DMF·H2O () (H3L = 5-(4'-carboxylphenoxy)nicotinic acid) has been synthesized using a tritopic linker with a flexible joint. The desolvated framework, [CuL(Me2NH)] (), undergoes structural contraction, and exhibits selective and double-step hysteretic adsorption for CO2. Furthermore, on exposure to CH2Cl2 at room temperature, a unique single-crystal-to-single-crystal transformation occurred between and [Cu2L2(Me2NH)2(H2O)2]·5H2O ().

A two-dimensional flexible porous coordination polymer based on Co(ii) and terpyridyl phosphine oxide

A 2D framework with –P(O)Ph₂ phenyl groups on the layer surface has been obtained, which shows remarkable dynamic sorption behaviours.

1D chains, 2D networks and 3D interdigitated frameworks of isoorotic acid or 4,4′-bipyridyl and isoorotic acid: syntheses, structures, and sorption properties

Five new coordination polymers, from 1D chains to a 2D sheet and finally 3D porous frameworks, have been synthesized with different transition metals. The 3D interdigitated framework of Ni(ii) is explored further for stepwise CO₂ and C₂H₂ storage.

Two porous metal–organic frameworks containing zinc–calcium clusters and calcium cluster chains

Two noble Ca-based metal–organic frameworks exhibit the largest surface areas and the highest CO₂ adsorption capacity at 298 K and 1 bar among the Ca-based MOFs reported so far.

A copper based pillared-bilayer metal organic framework: its synthesis, sorption properties and catalytic performance

A copper based metal organic framework with selective, hysteretic sorption, which can act as a heterogeneous catalyst for Glaser type homo-coupling reactions.

A cyclic tetranuclear cuboid type copper(ii) complex doubly supported by cyclohexane-1,4-dicarboxylate: molecular and supramolecular structure and cyclohexane oxidation activity

A rare isolated tetranuclear 3d complex with a single metal CDC cuboid cage. It catalyzes cyclohexane peroxidative oxidation without any promoter.

A family of three magnetic metal organic frameworks: their synthesis, structural, magnetic and vapour adsorption study

Three flexible magnetic metal–organic frameworks (MOFs) have been synthesized and their magnetic and adsorption properties were investigated.

2-D lanthanide–organic complexes constructed from 6,7-dihydropyrido(2,3-d)pyridazine-5,8-dione: synthesis, characterization and photoluminescence for sensing small molecules

The 2-D lanthanide–organic complex [(EuHPDH)(ox)(H₂O)]_n, synthesized under hydrothermal conditions, shows high potential for sensing small molecules by its luminescence properties in different emulsions.

From molecules to materials: molecular paddle-wheel synthons of macromolecules, cage compounds and metal-organic frameworks

Metal-organic frameworks (MOF) are becoming a more and more important class of functional materials. Yet, very often, the synthesis of MOFs is not easy to control and requires a profound knowledge and experience in solid state chemistry. One of the most frequently used metal connectors is the so-called 'paddle-wheel' (PW) unit, which is a well-known molecular compound type in inorganic coordination chemistry. Depending on the ligands, the geometry of PWs strictly directs the assembly of ordered networks. This review focuses on the question, to what extent ordered network structures can be accessed by typical molecular syntheses in solution, starting from molecular PW complexes to ordered macromolecules, finite cage compounds and finally, three-dimensional superstructures.