A Self-Assembled Bicontinuous Cubic Phase with a Single-Diamond Network.

The first single-diamond cubic phase in a liquid crystal is reported. This skeletal structure with the F d 3 ‾ m space group is formed by self-assembly of bolaamphiphiles with swallow-tailed lateral chains. It consists of bundles of π-conjugated p-terphenyl rods fused into an infinite network by hydrogen-bonded spheres at tetrahedral four-way junctions. We also present a quantitative model relating molecular architecture to the space-filling requirements of six possible bicontinuous cubic phases, that is, the single- and double-network versions of gyroid, diamond, and "plumber's nightmare".