Photoluminescent Honeycomb Structures from Polyoxometalates and an Imidazolium-Based Ionic Liquid Bearing a π-Conjugated Moiety and a Branched Aliphatic Chain.

Honeycomb-structured films represent an intriguing class of two-dimensional porous materials. Specifically, polyoxometalate (POM) macroanions can be introduced into these films by complexing with oppositely charged, double-tailed surfactants. Here highly-ordered honeycomb structures are reported that can be constructed by the complexes between POMs and a room temperature ionic liquid (IL1) having an imidazolium moiety in the middle and a naphthyl unit and a branched aliphatic chain at the ends. The complexes can be produced through phase transfer between an aqueous solution of POMs (typically {Mo72 Fe30 }) and a CS2 (or chloroform) solution of IL1. Based on the intrinsic properties of {Mo72 Fe30 } and the functional groups of the IL1, the honeycomb structures show multiple functions with bright photoluminescence and rich electrochemical properties. This work shows that by simply engineering the organic ligands involved in the POM-based inorganic-organic complexes, supramolecular structures with improved properties and wide applications can be obtained.