{Ti} Cluster-Added Poly(polyoxometalate) Containing Mixed Trivacant Keggin and Dawson Fragments.

A new high-nuclear Ti-oxo-cluster-added poly(polyoxometalate) CsNaH[(Cs@TiO)@{(-α-SiWO) (PWO)}]·29HO () has been made by reacting two types of trivacant precursors with TiOSO under hydrothermal conditions. The polyoxoanion of contains one Keggin-type [-α-SiWO] and three Dawson-type [PWO] fragments that synergistically induce the Ti ions to aggregate at vacant sites, resulting in a large {Ti}-oxo-cluster cavity sealing a Cs ion. It is worth noting that the {Ti} cluster is built by three edge-shared TiO ({Ti}) cores and one corner-shared TiO ({Ti}) core bridged via 6 μ-O, which has never been seen before in polyoxometalate chemistry. Significantly, represents the first example of [-α-SiWO] and [PWO] simultaneously participating in making poly(polyoxometalate).