Self-Assembly of Chiral Metal–Organic Tetartoid

Chiral
coordination cages feature both chirality and defined inner
space, providing advanced molecular materials. A series of chiral
20-nucleus cobalt-imidazolate cages were synthesized by self-assembly
of 72 subcomponents, featuring a novel tetartoid (tetragonal pentagonal
dodecahedron) structure. Spontaneous resolution of racemic tetartoidal
cages (Δ and Λ) into a conglomerate of homochiral crystals
are observed, while both homochiral Δ and Λ tetartoidal
cages can be obtained through chiral induction of (d)- and
(l)-enantiomers of menthol, respectively. The 2-methyl substituent
on imidazolyl is critical to the formation of a tetartoidal cage,
and the absence of such steric effect will switch the final structure
to a cubic cage.