The structure of metallo-supramolecular polyelectrolytes in solution and on surfaces

Abstract

Metal ion induced self-assembly of the rigid ligand 1,4-bis(2,2':6',2 ''-terpyridine-4'-yl) benzene (1) with Fe(II), Co(II), Ni(II) and Zn(II) acetate in aqueous solution results in extended, rigid-rod like metallosupramolecular coordination polyelectrolytes (MEPE-1). Under the current experimental conditions the molar masses range from 1000 g mol(-1) up to 500 000 g mol(-1). The molar mass depends on concentration, stoichiometry, metal-ion and time. In addition, we present viscosity measurements, small angle neutron scattering and AFM data. We introduce a protocol to precisely control the stoichiometry during self-assembly using conductometry. The protocol can be used with different terpyridine ligands and the above-mentioned metal ions and is of paramount importance to obtain meaningful and reproducible results. As a control experiment we studied the mononuclear 4'-(phenyl)2,2':6',2 ''-terpyridine (3) complex with Ni(II) and Zn(II) and the flexible ligand 1,3-bis[4'-oxa(2,2': 6',2 ''-terpyridinyl)] propane (2) with Ni(II) acetate (Ni-MEPE-2). This ligand does not form extended macroassemblies but likely ring-like structures with 3 to 4 repeat units. Through spin-coating of Ni-MEPE-1 on a solid surface we can image the MEPEs in real space by AFM. SANS measurements of Fe-MEPE-1 verify the extended rigid-rod type structure of the MEPEs in aqueous solution

Fluorescence quenching in Zn2+-bis-terpyridine coordination polymers: a single molecule study

“…Hydrodynamic and atomic force microscopy experiments on related bis-terpyridine coordination polymers, containing transition metals like Ni 2+ , Fe 2+ , Ru 2+ or Zn 2+ , identified a linear conformation for all of these polymers. 4,16,25,47,48 Thus, these experiments are in agreement with the herein presented results and further corroborate the linear rod-like structure of the investigated Zn 2+ -bis-terpyridine coordination polymer. Fig.…”

Growth and Differentiation of Myoblastic Precursor Cells on Thin Films of Metallo‐Supramolecular Coordination Polyelectrolyte (MEPE)

“…[61,62] Surface Modification-Layer by Layer: Layer-by-layer coating was carried out using the method described earlier [63][64][65] and under the conditions described as follows: Glass slides with a diameter of 18 mm consisted of pure white borosilicate glass. Ligand and MEPE syntheses were performed according to the procedure described elsewhere.…”

Controlling supramolecular polymerization through multicomponent self‐assembly

“…17). This has been recognized by many in the area, and methods that allow the adjustment of the stoichiometry with high accuracy, straight forward and in situ characterization are for example conductivity measurements 245 or viscometry. 246,247 We refer the interested reader to recent reviews that highlight fundamental self-assembly mechanisms, as well as magnetic, electronic, optical, and catalytic applications for metal containing supramolecular polymers.…”