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.