Regulating π-Stacked Micelle-Like Assembly via Anion Coordination to Achieve Frank-Kasper C15 Phases

Spherical surfactant micelles, widely used as templates for synthesizing porous inorganic materials, suffer from undeterminable atomic-level structures. Developing structurally precise spherical micelle-like architectures is therefore highly beneficial for understanding template syntheses yet remains challenging. Here, we demonstrate a series of micelle-like π-stacked architectures self-assembled from tripodal synthons ([ML(SO₄)], [ML(SCN)]⁺, or [H₃L(HPO₄)]⁺, where M = Co²⁺ or Zn²⁺ and L = tris(2-benzimidazolylmethyl)amine). These structures form through anion-coordination-regulated π-π stacking. While a honeycomb architecture of oppositely aligned neutral [CoL(SO₄)] forms without the directing of anions, various cationic micelle-like π-stacked architectures of [ML(SCN)]⁺ and [H₃L(HPO₄)]⁺ are successfully constructed via anion coordination-regulated π-π stacking. Within these assemblies, the π-stacked tripodal synthons and the H-bonded anion networks mutually template each other, reminiscent of how surfactant micelles template porous inorganic materials. Remarkably, this approach yields two new Frank-Kasper (FK) C15 phases, representing the first FK C15 complexes formed by small-molecule assembly. These results establish a universal strategy leveraging the interplay between π-π stacking and anion coordination to access complex supramolecular FK structures, potentially enabling new synthetic approaches for porous inorganic materials such as zeolites and porous silicon.