Bivalent metal-based MIL-53 analogues: Synthesis, properties and application

Trivalent metal-based MIL-53 (Al3+, Cr3+, Fe3+, In3+) compounds are interesting metal-organic frameworks (MOFs) with breathing effect and are promising gas sorption materials. Replacing bridging mu(2)-OH group by neutral ligands such as pyridine N-oxide and its derivatives (PNOs), the trivalent metal-based MIL-53 analogous structures could be extended to bivalent metal systems. The introduction of PNOs and bivalent metal elements endows the frameworks with new structural features and physical and chemical properties. This minireview summarizes the recent development of bivalent metal-based MIL-53 analogues (Mn2+, Co2+, Ni2+), typically, focusing on the synthetic strategies and potential applications based on our own works and literatures. We present the synthetic strategy to achieve structures evolution from single-ligand-walled to double-ligand-walled channel. Properties and application of these new materials in a wide range of potential areas are discussed including thermal stability, gas adsorption, magnetism and liquid-phase separation. Promising directions of this research field are also highlighted. (C) 2014 Elsevier Inc. All rights reserved.