A case of cyclodextrin-catalyzed self-assembly of an amphiphile into microspheres

Abstract

One of the recent challenges in nanotechnology is the development of ‘catalyzed self-assembly’. So far successful cases are still scarce. In this work we report the delicate case of a cyclodextrin (CD) catalyzed self-assembly of the terthiophene-containing amphiphile TTC4L into microspheres. TT4CL can form precipitates when CDs are not present, whereas it self-assembles into microspheres in the presence of CDs. The CDs were not involved into the microspheres, but they stayed in the supernate in the form of the TTC4L@CD inclusion complex. This complex may further transform into microspheres in the presence of a competitive guest. ITC and 1H NMR measurements suggest that part of the terthiophene group binds weakly with CDs. We expect that this weak binding interferes with the quick stacking of TTC4L, so that a ‘slow’ arrangement of the terthiophene moiety becomes possible which finally leads to the formation of microspheres. Our results not only provide a new solid example of a catalyzed molecular self-assembly, but also envisage a new paradigm for the possible role of CDs in supramolecular chemistry.