A Microporous Lanthanide–Organic Framework

Stable zeolite-like microporosity , even in the absence of guest molecules, is exhibited by a lanthanide–benzenedicarboxylate (BDC) framework, which was synthesized by the copolymerization of Tb^III and 1,4-benzenedicarboxylic acid. The open Tb–BDC framework adopts an expanded PtS network structure (see diagram; Tb: open circles; C: full circles; lines connecting Tb to C represent O atoms, and those connecting C atoms are benzene rings) and is capable of reversible gas and liquid sorption.     

Definitive Molecular Level Characterization of Defects in UiO‐66 Crystals

The identification and characterization of defects, on the molecular level, in metal‐organic frameworks (MOFs) remain a challenge. With the extensive use of single‐crystal X‐ray diffraction (SXRD), the missing linker defects in the zirconium‐based MOF UiO‐66, Zr₆O₄(OH)₄(C₈H₄O₄)₆, have been identified as water molecules coordinated directly to the zirconium centers. Charge balancing is achieved by hydroxide anions, which are hydrogen bonded within the pores of the framework. Furthermore, the precise nature of the defects and their concentration can be manipulated by altering the starting materials, synthesis conditions, and post‐synthetic modifications.     

One-step synthesis and structure of an oligo(spiro-orthocarbonate)

The reaction of pentaerythritol and tetraethylorthocarbonate at 260 degrees C for 12 h yields a white crystalline material that was characterized by 13C CPMAS NMR, CHN analysis, FT-IR, electron and X-ray powder diffraction, and Rietveld analysis. The white crystalline material was found to have the formula C6H8O4 and a crystal structure with a monoclinic cell [a = 9.167 A, b = 5.681 A, c = 5.880 A, beta = 90.0 degrees , space group I2] of hexagonally arranged spiro-oligomeric chains.     

Cu(2)[o-Br-C(6)H(3)(CO(2))(2)](2)(H(2)O)(2).(DMF)(8)(H(2)O)(2): a framework deliberately designed to have the NbO structure type.

The synthesis of an NbO-type metal-organic framework was achieved by design: o-Br-BDC (BDC = benzenedicarboxylate) was used to direct the formation of Cu2(CO2)4 paddle wheel units at 90 degrees to each other and thus yield the target network. The compound was formulated as Cu2[o-Br-BDC]2(H2O)2.(DMF)8(H2O)2 (MOF-101) and characterized by single-crystal X-ray diffraction [cubic, space group Imm (No. 229) with a = 21.607(3) A, V = 10088(2) A3, Z = 6], which fully confirmed the presence of the expected structure. Despite having very large apertures and voids, MOF-101 has a noninterpenetrated structure, an intriguing observation that is discussed in the context of dual structures.