Crystallization of High-Generation Carbosilane Dendrimers: From Space Filling to Dense Packing

High-generation carbosilane dendrimers exhibit properties of both macromolecules and particles and are characterized by precise chemical architecture. Because of their highly flexible branching, carbosilane dendrimers are relatively pliable, allowing them to have different shapes and crystal structures. The characteristics of dendrimers as both molecules and particles provide a potential solution to the challenging problem of packing soft quasispherical objects into a well-organized three-dimensional structure, which is a fundamental problem in modern physics. However, crystallization of such dendrimers has yet to be observed. Here, we present a successful approach for directly crystallizing high-generation carbosilane dendrimers using the procedure of solvent vapor annealing. Furthermore, the identification of general features in the mesophases produced by multigeneration dendrimers, including the formation of face-centered cubic (FCC) plastic crystal mesophases and body-centered cubic-FCC transitions, provides insight into and reveals the general properties of the crystallization process resulting from symmetry breaking.