Driven evolution of a constitutional dynamic library of molecular helices toward the selective generation of [2 x 2] gridlike arrays under the pressure of metal ion coordination

Constitutional dynamics, self-assembly, and helical-folding control are brought together in the efficient Sc(OTf)(3)/microwave-catalyzed transimination of helical oligohydrazone strands, yielding highly diverse dynamic libraries of interconverting constituents through assembly, dissociation, and exchange of components. The transimination-type mechanism of the Sc-III-promoted exchange, as well as its regio-selectivity, occurring only at the extremities of the helical strands, allow one to perform directional terminal polymerization/depolymerization processes when starting with dissymmetric strands. A particular library is subsequently brought to express quantitatively [2 x 2] gridlike metallosupramolecular arrays in the presence of Zn-II ions by component recombination generating the correct ligand from the dynamic set of interconverting strands. This behavior represents a process of driven evolution of a constitutional dynamic chemical system under the pressure (coordination interaction) of an external effector (metal ions).