Self-Assembly and (Hydro)gelation Triggered by Cooperative π-π and Unconventional C-H•••X Hydrogen Bonding Interactions

Weak C-H center dot center dot center dot X hydrogen bonds are important stabilizing forces in crystal engineering and anion recognition in solution. In contrast, their quantitative influence on the stabilization of supramolecular polymers or gels has thus far remained unexplored. Herein, we report an oligophenylene-ethynylene (OPE)-based amphiphilic PtII complex that forms supramolecular polymeric structures in aqueous and polar media driven by pi-pi and different weak C-H center dot center dot center dot X (X=Cl, O) interactions involving chlorine atoms attached to the PtII centers as well as oxygen atoms and polarized methylene groups belonging to the peripheral glycol chains. A collection of experimental techniques (UV/Vis, 1D and 2D NMR, DLS, AFM, SEM, and X-Ray diffraction) demonstrate that the interplay between different weak noncovalent interactions leads to the cooperative formation of self-assembled structures of high aspect ratio and gels in which the molecular arrangement is maintained in the crystalline state.