The supramolecular tenants that govern the self-assembly of biologically important macromolecules into their native tertiary and quaternary superstructures have long been employed by the synthetic chemist to develop increasingly complex architectures. At the heart of these self-assembly processes are a clutch of non-covalent bonding interactions that are responsible for aiding and abetting the molecular components in their journey to achieving higher ordered superstructures. By incorporating the concepts of structural preorganization, and complementarity in concert with [p���p], [C�H���p], and [C�H���O] non-covalent bonding interactions, a duo of p-electron deficient bipyridinium-based amphiphiles when mixed with the p-electron rich triethyleneglycol-disubstituted 1,5-diaminonapthalene (DAN-TEG) results in programmed template-directed micellization in H2O by way of donor-acceptor p-stacking interactions. The binding of DAN-TEG to the bipyridinium-based aggregate superstructure can be actuated �ON� and �OFF� like a switch by the addition of acid and base. Upon the addition of acid, protonation of DAN-TEG to the dication causes disassembly by Coulombic repulsion with the charged head groups of the micellar aggregate. This process is completely reversible upon the addition of base, whereby the DAN-TEG guest reintercalates into the superstructure �again forming polar donor-acceptor stacks at the micellar-solvent interface amongst contiguous surfactant head groups. The reversible self-assembly process was monitored by 1H-NMR spectroscopy, variable temperature UV-VIS spectroscopy, conductivity, dynamic surface tension, and dynamic light scattering (DLS) measurements. Snapshots of the donor-acceptor superstructure stacks were modeled and elucidated in the solid-state by X-ray crystallography using methyl viologen and DAN-TEG. Additionally a phase separation model was employed to calculate the thermodynamic Gibb's free energy of micellization (?G�) at 298K for each of the templated processes. The templated micellization also proceeds with a net decrease in the diffusion coefficient (Do) and consequently measureable increases in the hydrodynamic diameter (Dh) at the nanometer scale.

Reversible docking at the micellar-solvent interface

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.