Dendrons superstructures

Size and shape Certain steric effects can be achieved using characteristically wedge-shaped dendrons. Thus, self-assembling dendrons have been connected to supramolecular aggregates with defined dimeric or hexameric structures. Such aggregates can form columnar superstructures which reveal liquid-crystalline properties. Spherical superstructures arise from the self-assembly process when conical dendrons are used14 14,161 Similar... 

Supramolecular organization of dendrons can lead to columnar or spherical superstructures, depending on directional and attractive interactions between such wedge-shaped molecules as well as size and shape. For instance, hydrogen-bonding... 

Scheme 2. Shape-directed self-assembly of cone- and wedge-like dendrons to hexagonal-columnar and cubic superstructures according to Percec et al. [15a].

In contrast, recent kinetic investigation of the polymerization of spacerless G2 dendron-substi-tuted styrene and methylmethacrylate, respectively, in solution lead to the unexpected conclusion that above a certain critical monomer concentration a strong increase in the rate of the free radical polymerization is observed [21]. The results can be explained by self-organization of the growing polymer chain to a spherical or columnar superstructure in solution, depending on the degree of polymerization (DP, Fig. 2). The rate constants and low initiator efficiency lead one to conclude that the self-assembled... 

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