Exploration of a simple universal route to the myriad of open-framework metal phosphates

Abstract

The reaction of a single amine phosphate, piperazine phosphate, with Zn^II ions is shown to yield a variety of open-framework metal phosphate structures. It is noteworthy that the reaction of this amine phosphate with Zn^II ions yields a hierarchy of structures, including the linear chain, layer and 3-dimensional systems. Of particular interest is the isolation of the linear chain structure consisting of corner-shared four-membered rings, which has been considered to be the primary building block. By the reaction of piperazine phosphate with Co^II ions, we obtained a new strip and a layer structure. Reaction of piperazine phosphate with Sn^II yields a layer structure. The significant role of the amine phosphates in the formation of open-framework metal phosphate structures is also supported by the isolation of a monomeric four-membered zinc phosphate, which on heating transforms to an open-framework structure.