Synthesis and Applications of Heteromultimetallic Complexes Containing N-Heterocyclic Carbenes

Due to the strong electronic donor properties and the versatile structures which can be readily modified, as well as the distinct topography, N-heterocyclic carbene (NHC) is a new class of ligands as an alternative to traditional phosphine ones. The catalytic properties of NHC-metal (NHC-M) complexes in homogeneous and asymmetric catalysis have been a focused research field and many successful results have been reported in recent years. The synthesis strategies, physical and chemical properties, as well as applications of heteromultimetallic complexes based on N-heterocyclic carbene ligand have made great development. It is worth noting that the remarkable catalytic activities have been obtained in multi-step catalytic tandem reaction. In this paper, the synthesis and applications of heteromultimetallic complexes containing N-heterocyclic carbene are summarized and reviewed according to the type of N-heterocyclic carbene ligand. The type of N-heterocyclic carbene ligand include; (a) heteromultimetallic complexes based on a triazolyl-di-ylidene ligand; (b) heteromultimetallic complexes based on a bridged bis (imidazol-2-ylidene) ligand; (c) heteromultimetallic complexes based on a functionalized multidentate N-heterocyclic ligand.