MOFs are promising heterogeneous catalysts for chemical fixation of CO₂and epoxides into cyclic carbonates.

Metal–organic frameworks (MOFs) have a good designability, a well-defined pore, stimulus responsiveness, a high surface area, and a controllable morphology. Up to now, various MOFs have been widely used as nanocarriers and have attracted lots of attention in the field of drug delivery and release because of their good biocompatibility and high-drug-loading capacity. Herein, we provide a comprehensive summary of MOF-based nanocarriers for drug delivery and release over the last five years. Meanwhile, some representative examples are highlighted in detail according to four categories, including the University of Oslo MOFs, Fe-MOFs, cyclodextrin MOFs, and other MOFs. Moreover, the opportunities and challenges of MOF-based smart delivery vehicles are discussed. We hope that this review will be helpful for researchers to understand the recent developments and challenges of MOF-based drug-delivery systems.

In order to investigate the effect of the substituent group of an organic ligand on the structures of coordination polymers, four new Ni(II) coordination polymers based on 5-position substituted 1,3-benzenedicarboxylate and N-donor auxiliary ligands, namely, [Ni(5-CH₃-ip)(L₁)(H₂O)]_n (1), [Ni(5-NO₂-ip)(L₁)₂(H₂O)]_n (2), [Ni(5-CH₃-ip)(L₂)_1.5]_n (3) and {[Ni₂(5-NO₂-ip)₂(L₂)₂(H₂O)₂]·(H₂O)}_n (4) (5-CH₃-ip = 5-methyl-1,3-benzenedicarboxylic acid, 5-NO₂-ip = 5-nitro-1,3-benzenedicarboxylic acid, L₁ = 1,4-bis(imidazol-1-yl)benzene and L₂ = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene), have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 features a two-dimensional (2D) layer structure. Complex 2 possesses a three-dimensional (3D) 5-connected net giving an interesting 3-fold interpenetrating architecture. Complex 3 shows a 5-connected topological framework with point symbol (4².6⁸). Complex 4 displays a 6-connected 3D self-penetrating topological network with point symbol (4⁸.5².6⁵). Structural diversities indicate that the substituent group of organic ligands play important roles in tuning the structures of these complexes. Furthermore, magnetic properties of complexes 1 and 4 are investigated.

A multi-response Tb-based metal–organic framework with excellent stability is used as a rapid and reversible luminescent sensor for Fe³⁺, Cr₂O₇²⁻, and nitrofurantoin in water.

Three new metal coordination polymers, [Mn(Hdpa)₂(4,4′-bipy)₂] _n (1), [Mn(dpa)(1,10-phen)(H₂O)] _n (2), and [Mn(dpa)(2,2′-bipy)] _n (3) (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, 4,4′-bipy = 4,4′-bipyridine, 1,10-phen = 1,10-phenanthroline, and 2,2′-bipy = 2,2′-bipyridine), have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. Single-crystal X-ray analyses reveal that 2,4′-diphenic acid is a bridging ligand, exhibiting three coordination modes to link metal ions: μ ₁-η ¹: η ¹/μ ₀-η ⁰: η ⁰; μ ₂-η ²: η ⁰/μ ₁-η ¹: η ⁰; and μ ₂-η ¹: η ¹/μ ₂-η ¹: η ¹. Intermolecular hydrogen bonds in 1 lead to a zigzag chain. In 2, the 2-D supramolecular arrays extended along b-axis through π–π interactions between 1,10-phen. The dinuclear paddle-wheel second building units (SBUs) constructed by four dpa²⁻ ligands in 3 are linked by dpa²⁻ into double-strand chains. The fluorescence of H₂dpa and 1–3 are also determined.