Exotic Functions of Flexible Coordination Polymer Crystals

摘要

Porous materials with infinite number of nanometer-sized pores are ubiquitous materials in our daily life as functional substances that efficiently separate or remove small molecules such as gas molecules. Recently, a new porous material called“porous coordination polymer (PCP)” or “metal–organic framework (MOF)” has been developed and actively studied because of their prominent functions for storage, separation, catalysis, etc. The advantage for the synthesis of PCP/MOF is its designable framework obtained by combinations of metal ions and organic ligands for various sizes, shapes and chemical properties of pores at the molecular level. One of the unique features of PCP/MOF compared with other conventional porous materials is that it is crystalline, but it can flexibly change its structure and provide exotic porous properties. In this review, we will present the synthesis, functions and mechanisms of unique porous functional materials in which “rigidity” and “flexibility” act in concert with each other. Especially, we will focus on the PCPs/MOFs showing (1) guest-responsive and (2) photo-responsive properties.