Synthesis of Tetrahemispheraplexes with Ammonium, Alkylammonium or Alkaline Metal Ions as Exohedral Guests via Self‐Assembly or Guest Exchange

To study the interplay between the steric demand of the guest and the space available at the host, we have prepared the tetraammonium complexes {(NH 4 ) 4 ∩[Mg 4 (L 1/2 ) 6 ]} 1 , tetrakis(methylammonium) complexes {(Me‐NH 3 ) 4 ∩[Mg 4 (L 1/2 ) 6 ]} 2 , tetrakis(ethylammonium) complex {(Et‐NH 3 ) 4 ∩[Mg 4 (L 1 ) 6 ]} 3 , and mixed sodium tris(ethylammonium) complex {Na(Et‐NH 3 ) 3 ∩[Mg 4 (L 2 ) 6 ]} 4 . The tetrahemispheraplexes 1−4 were available in one‐pot syntheses. The tetrakis(alkylammonium) clusters {(R 1 −NH 3 ) 4 ∩[Mg 4 (L 1 ) 6 ]} 5 and the mixed diammonium‐bis( p ‐methoxybenzylammonium) cluster {(NH 4 ) 2 (R 2 −NH 3 ) 2 ∩[Mg 4 (L 1 ) 6 ]} 6 , however, were prepared by exchange of the ammonium ions of 1a by alkylammonium ions. Similarly, exchange of the four ammonium ions of 1b by alkaline metal cations afforded the tetraalkaline metal tetrahemispheraplexes {M 4 ∩[Mg 4 (L 2 ) 6 ]} 7 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)