Synthesis, structure and catalysis/applications of N-heterocyclic carbene based on macrocycles

It is well-recognized that N-heterocyclic carbenes (NHCs) ligands have provided a new dimension to the design of catalysts. Macrocyclic molecules are a class of material chemistry and have served as the synthetic hosts, and molecular recognition. In recent years, researchers have moved toward fabricating interlocking molecules with specific structures and properties. Therefore, researchers have developed more macrocycles complex based NHCs with multi-complexation modes that provide more diverse host-guest systems. In this account, this review highlights recent advances on synthesis, structure and applications of NHC based on macrocycles. According to the structure of different macrocycles, the complexes can be divided into four parts: (i) complexes of NHC based on crown ether; (ii) complexes of NHC based on porphyrin; (iii) complexes of NHC based on calixarene; (iv) complexes of NHC based on the other macrocycles. The complexes showed good coordination ability with different metal ions and showed excellent catalyst activity and optical ability.