The Kinetics of Growth of Metallo-supramolecular Polyelectrolytes in Solution

Several transition metal ions, like Fe²⁺ , Co²⁺ , Ni²⁺ , and Zn²⁺ complex to the ditopic ligand 1,4-bis(2,2':6',2''-terpyridin-4'-yl)benzene (L). Due to the high association constant, metal-ion induced self-assembly of Fe²⁺ , Co²⁺ , and Ni²⁺ leads to extended, rigid-rod like metallo-supramolecular coordination polyelectrolytes (MEPEs) even in aqueous solution. Here, we present the kinetics of growth of MEPEs. The species in solutions are analyzed by light scattering, viscometry and cryogenic transmission electron microscopy (cryo-TEM). At near-stoichiometric amounts of the reactants, we obtained high molar masses, which follow the order Ni-MEPE≈Co-MEPE