Entangled structures in polyoxometalate-based coordination polymers

Polyoxometalates (POMs) have attracted a lot of interest due to their novel structure characteristics and various connection modes. POM-based coordination polymers with entangled structures, an indispensable branch of entangled networks, take advantage of the features of POMs, and have received increasing attention. Much effort has been devoted over the past few decades toward their preparation and the analysis of their unusual entangled topology. In this review, we will summarize a number of examples of POM-based coordination polymer that have been described according to their different entangled characteristics. Different concepts, such as interpenetration, polycatenation, polyrotaxane, polypseudo-rotaxane and self-penetration, are employed to describe the various types of POM-based coordination polymers with entangled structures. In addition, we further classify POM-based coordination polymers with entangled structures based on the dimensionalities of the individual motifs and the roles of the POMs. Combining the advantages of the attractive potential applications of the POMs and structure diversities of the entangled frameworks, the investigation of POM-based coordination polymers with entangled structures will be a sustainable research field in coordination chemistry. (c) 2014 Elsevier B.V. All rights reserved.