Trigonal Prismatic Cu6l3 Coordination Cage: Encapsulation Of Aromatic Molecules And Tuned Photoluminescence

A trigonal prismatic Cu6L3 coordination cage has been assembled from Cu(I) and semi-rigid bipyrazolyl ligand. The X-ray crystallography demonstrates that the cage has a cavity and can encapsulate the toluene as a guest, exhibiting thermochromism phenomenon. Empty cage can be obtained by expulsion of the guest through single crystal to single crystal transformation. After removed the guest, the empty cage shows a blue-shifted emission (580nm), in comparison to its parent cage (615nm). The empty cage could further serve as a host to encapsulate other aromatic molecules (e.g. mesitylene), which shows new emission band. The trigonal prismatic Cu6L3 coordination cage provides a platform to make advanced luminescent materials.