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Switchable supramolecular polymers from the self-assembly of a small monomer with two orthogonal binding interactions

G. Gröger, W. Meyer-Zaika, C. Böttcher, F. Grohn, C. Ruthard and C. Schmuck – 2011

The low molecular weight heteroditopic monomer 1 forms supramolecular polymers in polar solution as shown, for example, by infrared laser-based dynamic light scattering (DLS), small-angle neutron scattering (SANS), electron microscopy (TEM, cryo-TEM), and viscosity measurements. Self-assembly of 1 is based on two orthogonal binding interactions, the formation of a Fe(II)-terpyridine 1:2 metal-ligand complex and the dimerization of a self-complementary guanidiniocarbonyl pyrrole carboxylate zwitterion. Both binding interactions have a sufficient stability in polar (DMSO) and even aqueous solutions to ensure formation of linear polymers of considerable length (up to 100 nm). The supramolecular polymerization follows a ring-chain mechanism causing a significant increase in the viscosity of the solutions at millimolar concentrations and above. The linear polymers then further aggregate in solution into larger globular aggregates with a densely packed core and a loose shell. Both binding interactions can be furthermore switched on and off either by adding a competing ligand to remove the metal ion and subsequent readdition of Fe(II) or by reversible protonation and deprotonation of the zwitterion upon addition of acid or base. The self-assembly of 1 can therefore be switched back and forth between four different states, the monomer, a metal-complexed dimer or an ion paired dimer, and finally the polymer.

Titel
Switchable supramolecular polymers from the self-assembly of a small monomer with two orthogonal binding interactions
Verfasser
G. Gröger, W. Meyer-Zaika, C. Böttcher, F. Grohn, C. Ruthard and C. Schmuck
Datum
2011
Kennung
DOI: 10.1021/ja200941a
Zitierweise
J. Am. Chem. Soc. 2011, 133, 8961 - 8971
Sprache
eng
Art
Text