Options
2010
Journal Article
Titel
Structure and properties of dynamic rigid rod-like metallo-supramolecular polyelectrolytes in solution
Abstract
Metal-ion-induced self-assembly in aqueous solution of the rigid ligand l,4-bis(2,2':6',2"terpyridine-4'-yl)benzene (1) with Fe(OAc)2 and Ni(OAc)2 is investigated with viscosimetry, SANS, and AFM. Ligand 1 forms extended, rigid-rod like metallo-supramolecular coordination polyelectrolytes (MEPEs) with a molar mass of up to 200 000 g mol-1 under the current experimental conditions. The molar mass depends on concentration, stoichiometry, and time. By spin-coating MEPEs on a solid surface, we can image the MEPEs in real space by AFM. Both AFM and SANS confirm the extended rigid-rod-type structure of the MEPEs. As a control experiment, we also studied the flexible ligand l,3-bis[4'-oxa(2,2':6',2"terpyridinyl)] propane (2). Ligand 2 does not form extended macro-assemblies but likely ringlike structures with three to four repeat units. Finally, we present a protocol to control the stoichiometry during selfassembly using conductometry, which is of paramount importance to obtai n meaningful and reproducible results.