Non-aqueous supramolecular assembly of mesostructured metal germanium sulphides from (Ge4S10)4- clusters

Microporous materials have found extensive application as catalysts, ion-exchange media and sorbents(1,2). The discovery of mesoporous silica(3) has opened the path to selective catalysis and separation of large molecules and to the synthesis of inorganic-organic composite materials, polymer mesofibres and semiconducting quantum dots(4-7). Various oxide-based mesoporous materials, such as TiO2, ZrO2, SnO2, Al2O3, Nb2O5 and GeO2, have been reported(8-13). A challenge for materials research is now to expand the scope of mesoporous materials beyond the oxides. Only a few non-oxide mesostructured composites, such as CdS, SnS2 and CdSe, have been reported; they are usually synthesized by ad hoc hydrothermal methods or from aqueous solutions containing ill-defined species, and are often not well characterized(14-16). Here we report the rational synthesis of a new family of metal germanium sulphide mesostructured materials prepared by a non-aqueous surfactant-templated assembly of adamantanoid [Ge4S10](4-) cluster precursors. In the presence of quaternary alkylammonium surfactants, [Ge4S10](4-) anions in formamide solution self-organize with metal cations (Co2+, Ni2+, Cu+ and Zn2+) to create well ordered hexagonal metal germanium sulphide mesostructures, some having fibre-like morphologies with channels running down the long axis of the fibre. Materials of this genre could prove effective in applications as diverse as detoxification of heavy metals in polluted water streams, sensing of sulphurous vapours, and the formation of semiconductor quantum 'anti-dot' devices.