Self-Optimizing Charge-Transfer Energy Phenomena in Metallosupramolecular Complexes by Dynamic Constitutional Self-Sorting

In this paper we report an extended series of 2,6-(iminoarene)pyridine-type ZnII complexes [(Lii)2Zn]II, which were
surveyed for their ability to self-exchange both their ligands and their aromatic arms and to form different homoduplex
and heteroduplex complexes in solution. The self-sorting of heteroduplex complexes is likely to be the result of
geometric constraints. Whereas the imine-exchange process occurs quantitatively in 1:1 mixtures of [(Lii)2Zn]II
complexes, the octahedral coordination process around the metal ion defines spatial-frustrated exchanges that
involve the selective formation of heterocomplexes of two, by two different substituents; the bulkiest ones (pyrene
in principle) specifically interact with the pseudoterpyridine core, sterically hindering the least bulky ones, which are
intermolecularly stacked with similar ligands of neighboring molecules. Such a self-sorting process defined by the
specific self-constitution of the ligands exchanging their aromatic substituents is self-optimized by a specific control
over their spatial orientation around a metal center within the complex. They ultimately show an improved charge-transfer energy function by virtue of the dynamic amplification of self-optimized heteroduplex architectures. These
systems therefor illustrate the convergence of the combinatorial self-sorting of the dynamic combinatorial libraries
(DCLs) strategy and the constitutional self-optimized function.