Rational Design of Tightly Closed Coordination Tetrahedra that are Stable in the Solid State, in Solution, and in the Gas Phase

No way out: Small guest cations, such as [Et4N]+ template the formation of stable and tightly closed octaanionic metallosupramolecular tetrahedra (see picture). Since [Et3NH]+ is co-encapsulated with exactly one water molecule, the filling of space seems to be a more pivotal factor for the templation than the symmetry of the cation. X-ray crystallography excellently agrees with NMR spectroscopy and ESI-FT-ICR mass spectrometry data.