Size- and shape-adaptable mixed-alkoxide-aggregates: encapsulation of tetrafluoroborate and butadiynediide.

The reaction of sodium tert -butoxide with trimethylsilyl compounds enables the encapsulation of small anions in an icosahedral arrangement of 12 alkoxide units and 13 dynamically moving sodium cations. Advancement of this method in connection with larger anions results in the formation of mixed aggregates involving the tetraflouoroborate anion or the butadiyne-dianion.