Narcissistic, Integrative, and Kinetic Self-Sorting within a System of Coordination Cages

Many
useful principles of self-assembly have been elucidated through
studies of systems where multiple components combine to create a single
structure. More complex systems, where multiple product structures
self-assemble in parallel from a shared set of precursors, are also
of great interest, as biological systems exhibit this behavior. The
greater complexity of such systems leads to an increased likelihood
that discrete species will not be formed, however. Here we show how
the kinetics of self-assembly govern the formation of multiple metal–organic
architectures from a mixture of five building blocks, preventing the
formation of a discrete structure of intermediate size. By varying
ligand symmetry, denticity, and orientation, we explore how five distinct
polyhedraa tetrahedron, an octahedron, a cube, a cuboctahedron,
and a triangular prismassemble in concert around CoII template ions. The underlying rules dictating the organization of
assemblies into specific shapes are deciphered, explaining the formation
of only three discrete entities when five could form in principle.