Our goal is to identifying simple molecular building blocks that predictably self-assemble into well-defined and functional supramolecular structures.  We have focused on macrocyclic building blocks that use ureas or amides to guide the self-assembly of these small donut-shaped building blocks to form straw-like structures.  These macrocycles probe a range of different ring sizes, shapes, and functionality.  They assembled as designed into tubular structures forming porous crystals with guest-accessible channels (Figure 1).  The urea macrocycles form non-covalent assemblies that are robust enough to be used as containers for facilitating photochemical reactions with both high selectivity and conversion.  Other macrocycles contained functional groups that could undergo subsequent reactions and covalent stabilize the straws.  For example, macrocycles that contain diacetylene units within the walls of the straws polymerized to give porous conjugated polydiacetylenes.  These new functionalized supramolecular assemblies may have applications in synthesis, for separations, and in flow and molecular transport. Figure 1.  Bis-urea macrocycles stack into columns through three-centered urea hydrogen bonds to form porous crystals with guest accessible channels.

Self-assembling hosts as functional molecular containers

245th National Meeting (2013)

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