Metal–organic frameworks based on infinite secondary building units: recent progress and future outlooks

Abstract

Metal–organic frameworks (MOFs) are a type of inorganic–organic hybrid connected by organic ligands and discrete metal ions/metallic secondary building units (SBUs). Recently, more and more MOF examples based on infinite SBUs (ISBUs) including one-dimensional (1D) rods, two-dimensional (2D) sheets, and even three-dimensional (3D) nets have emerged and exhibited unique physical and chemical properties (e.g., excellent stability, strong light absorption, and fast charge carrier mobility). Hence, rapidly increasing endeavors have been devoted to the structure design, synthesis methodology, property exploration and performance evaluation of novel ISBU MOFs. In this timely review, we will first summarize the established synthesis methods and resolved crystallographic structures of various types of ISBU MOFs. At the same time, the distinct physical and chemical properties resulting from corresponding ISBUs deserve to be highlighted and compared with traditional MOFs consisting of discrete metal ions/SBUs. Moreover, recent progress of those ISBU MOFs achieved in fields of gas adsorption and separation, energy conversion, photocatalysis, etc. is also introduced. We hope it is constructive and attractive for further advancement achieved in this new but intriguing research field.