This review focuses on the recent advances in double metal cyanide complex (DMCC) catalyst and its catalysis for epoxides-involved polymerizations. DMCC is an inorganic coordinated polymer with three- dimensional network, in which the inner metal M^Ⅱ is linked with the external metal M^Ⅰ by several cyano-bridges (M^Ⅱ—C≡N—M^Ⅰ[JG)], generally, M^Ⅰ=divalent metal ions such as Zn²⁺, Fe²⁺, Co²⁺, Ni²⁺, et al., M^Ⅱ=transition metal ions such as Fe²⁺, Fe³⁺, Co²⁺, Co³⁺, Ni²⁺, et al). The external metal M^Ⅰ on the surface of the catalyst is generally considered to be the active site for the polymerizations due to its unsaturated coordinated structure. DMCC catalyst was initially applied to the catalysis of the ring-opening polymerization (ROP) of epoxides, and then modified and used as a highly active catalyst for making polyether-polyols with both moderate or high molecular weights and low unsaturation degrees. Later, this catalyst was utilized to catalyze the alternating copolymerization of epoxides and CO₂ for producing aliphatic polycarbonates. The productivity of DMCC-catalyzed epoxides/CO₂ copolymerization is clearly higher than those of other heterogeneous catalysts, while the polycarbonate selectivity of this catalyst is unsatisfied, e.g.: for propylene oxide (PO)/CO₂ copolymerization, the maximum alternating degree of the resultant copolymer was up to ~74%. That is, the copolymer is a poly (ether-carbonate) with random chain structure. However, Zn-Co^Ⅲ DMCC exhibits high activity (TOF: 3 815h^-1) for cyclohexene oxide (CHO)/CO₂ copolymerization with high alternating degree of >90%. Furthermore, this catalyst can also be applied to catalyze epoxide/cyclic anhydrides for producing polyesters, epoxide/CS₂ copolymerization for producing polythiocarbonates, as well as epoxide/cyclic anhydride/CO₂ terpolymerization for producing poly (carbonate-ester)s with high productivity. Based on the research work of our group in recent ten years, this review will discuss the possible structure of the active sites of DMCC and related catalytic mechanism, as well as some common problems for DMCC and DMCC catalyzed polymerizations and possible solutions. Content 1 Introduction
2 Preparation and structure of DMCC
3 Ring-opening polymerization of epoxides catalyzed by DMCC
4 Copolymerization of CO₂/epoxides catalyzed by DMCC
5 Copolymerization of epoxides/cyclic anhydride and terpolymerization of CO₂/epoxide/cyclic anhydride catalyzed by DMCC
6 Copolymerization of CS₂/epoxides catalyzed by DMCC
7 Conclusions and outlook