Crystal structure of a two-dimensional grid-type iron(II) coordination polymer: poly[[diaquatetra-μ-cyanido-diargentate(I)iron(II)] trans-1,2-bis(pyridin-2-yl)ethylene disolvate]

In the title compound, {[Ag2Fe(CN)4(H2O)2]·2C12H10N2}n, the asymmetric unit contains one FeII cation, two water molecules, two dicyanidoargentate(I) anions and two uncoordinating 1,2-bis(pyridin-2-yl)ethylene (2,2′-bpe) molecules. Each FeII atom is six-coordinated in a nearly regular octahedral geometry by four N atoms from dicyanidoargentate(I) bridges and two coordinating water molecules. The FeII atoms are bridged by dicyanidoargentate(I) units to give a two-dimensional layer with square-grid spaces. The intergrid spaces with interlayer distance of 6.550 (2) Å are occupied by 2,2′-bpe guest molecules which form O—H...N hydrogen bonds to the host layers. This leads to an extended three-dimensional supramolecular architecture. The structure of the title compound is compared with some related compounds containing dicyanidoargentate(I) ligands and N-donor organic co-ligands

Thermally Induced Single-Crystal-to-Single-Crystal Transformation and Heterogeneous Catalysts for Epoxidation Reaction of Co(II) Based Metal–Organic Frameworks Containing 1,4-Phenylenediacetic Acid

Four new metal–organic frameworks (MOFs) based on 1,4-phenylenediacetic acid (1,4-H₂phda), [Co­(1,4-phda)­(4,4′-bpa)] (<b>1</b>), [Co­(1,4-phda)­(4,4′-bpp)] (<b>2</b>), [Co­(1,4-phda)­(4,4′-bpa)­(H₂O)₂] (<b>3</b>), and [Co­(1,4-phda)­(4,4′-bpa)] (<b>3a</b>) (4,4′-bpa = 1,2-bis­(4-pyridyl)­ethane and 4,4′-bpp = 1,3-bis­(4-pyridyl)­propane) were successfully synthesized. The various synthetic methods play an important role in the formation of diverse structural frameworks. Compound <b>1</b> shows a 3D framework, while <b>2</b>, <b>3</b>, and <b>3a</b> exhibit 2D layered MOFs with different architectures. The irreversible thermally induced single-crystal-to-single-crystal transformation with chromotropism from <b>3</b> to <b>3a</b> was observed, which was established by the breakage and reformation of coordination bonds around Co­(II) centers. The orientation of coordinated 4,4′-bpa ligand and conformation of 1,4-phda ligand play a key role on pore opening in <b>3</b> and pore closing in <b>3a</b>. Furthermore, the functional properties as heterogeneous catalysts of these MOFs including epoxidation of alkenes and photocatalytic performance for MB degradation have been investigated. The heterogeneous catalytic properties of <b>1</b>, <b>2</b>, and <b>3a</b> exhibit high catalytic activity with good catalyst stability