Self-assembly iterative

A recent iterative approach to pentacene (Scheme 3.3) has yielded the hexacene-quinone derivative 17 (plus several related compounds) [29]. The novel aspect of such compounds lies in the dipole induced by having electron-withdrawing substituents on only one end of the pentacene, and the unique self-assembly opportunities enabled by this functionalization strategy. 

However, there can be limits to this approach because it is not always clear whether the chosen CG mapping scheme can converge to an optimal fit. For liquid mixtures or solutions, the situation is more complex because several RDFs that mutually affect each other need to be simultaneously reproduced. In additicni, for dilute solutions, where we have a low concentration of solute, the solute-solute RDFs converge very slowly in the CG simulations. In this case, the PMF between the solute molecules can be obtained using free-energy calculation methods such as umbrella sampling or constraint dynamics. Recently, these methods have been used in an iterative optimization approach to study self-assembling dipeptides at the CG scale [75, 76]. The PMF between solute molecules in a solvent box, Fpi (r), is calculated by all-atom simulation from n distance constraint simulations ... 

Another type of stimulus-responsive supramolecular polymer was produced using the complementary affinity of a bisporphyrin (Figure 7.20). The bispor-phyrin units were connected with 1,3-butadiyne units to produce homoditopic tet-rakisporphyrin 23. The iterative self-assanbly of 23 gave rise to supramolecular nanometric polymeric assemblies. An electron-deficient aromatic guest can aggressively bind within the bisporphyrin cleft, causing the supramolecular polymeric assemblies to dissociate. 

One of the students enrolled in the class also served as a teaching assistant for the laboratory. She prepared necessary reagents, located and made available the appropriate supphes, and provided support before, during and after the experiments. Importantly, she also worked with the faculty to develop and optimize the organic synthesis and self-assembly modules. Having a stndent TA familiar with one of the modules contributed to the sueeess of the laboratory portion of the SoS class, and is recommended for the first iteration of a similar eonrse. 

---