Responsive Four‐Coordinate Iron(II) Nodes in FePd(CN)₄

Abstract

Metal node design is crucial for obtaining structurally diverse coordination polymers (CPs) and metal-organic frameworks with desirable properties;h owever,F e II ions are exclusively six-coordinated. Herein, we present ac yanidebridged three-dimensional (3D) CP,F ePd(CN) 4 ,bearing fourcoordinate Fe II ions,which is synthesized by thermal treatment of at wo-dimensional (2D) six-coordinate Fe II CP,F e-(H 2 O) 2 Pd(CN) 4 •4 H 2 O, to remove water molecules.A tomicresolution transmission electron microscopyand powder X-ray and neutron diffraction measurements revealed that the FePd-(CN) 4 structure is composed of atwo-fold interpenetrated PtS topology network, where the Fe II center demonstrates an intermediate geometry between tetrahedral and square-planar coordination. This four-coordinate Fe II center with the distorted geometry can act as athermo-responsive flexible node in the PtS network.

Atomically isolated Sb(CN) 3 on sp 2 -c-COFs with balanced hydrophilic and oleophilic sites for photocatalytic C-H activation

“…Note that the saturated coordination number of Sb is 6. Such a large coordination number (~10) of Sb in Sb5-sp 2 -c-COFs could be attributed to water adsorption over the Sb(CN) 3 species, similar to water adsorption via lattice change in Ni(CN) 4 ) (24,26).…”

“…On the contrary, the appearance of a broad peak at 3500 cm −1 over amorphous Sb(CN) 3 (fig. S4B) indicates a strong affinity of Sb(CN) 3 to water molecules (24,26). The peak intensity gradually increased in the FTIR spectra of Sb(CN) 3 -modified sp 2c-COFs with increasing Sb(CN) 3 content, indicating that H 2 O could be captured by Sb(CN) 3 .…”

“…Cyanide-bridged amorphous metal-organic frameworks exhibit excellent water adsorption behavior with reversible amorphous/ crystalline transitions (24)(25)(26)(27). The metal cyanides in the framework can effectively capture H 2 O molecules by changing the local 1 coordination geometry of the metal center.…”

New family of Hofmann-like coordination polymers constructed with imidazole ligands and associated with spin crossover and anisotropic thermal expansions

“…5b and see Table S4, ESI †). Such an anisotropic TE for a Hofmannlike layer is well known for the fence effect, 10 which is derived from a motion between shrinking and expanding in a rhombus.…”

“…NTE behaviour has been investigated fairly extensively for cyanobridged CPs without any other organic ligands, with examples of such CPs including Prussian blue 3D [29][30][31][32][33][34][35][36] and Hofmann-like 2D 10 CPs. But NTE behaviour has been investigated much less extensively for Hofmann-like 2D compounds with organic ligands.…”