A microporous metal-organic open framework containing uncoordinated carbonyl groups as postsynthetic modification sites for cation exchange and Tb3+ sensing.

A novel 3D microporous compound [Zn3(Httca)2(4,4'-bpy)(H2O)2]n (MOF-COOH) containing uncoordinated carbonyl groups pointing to the pores was prepared. The uncoordinated carbonyl groups in the channels can act as postsynthetic modification sites for cation exchange. The MOF-COOH compound can effectively and selectively serve as an antenna for sensitizing the visible-emitting Tb(3+) cation.