Magnetic differentiation of pyrogallol[4]arene tubular and capsular frameworks.

The differences in magnetic properties of metal-based nanometric assemblies are due to distinct contributions from host-guest interactions, structural integrity, and magnetic interactions. To disentangle these contributions, it is necessary to control the self-assembly process that forms these entities. Herein we study the effect of host-to-guest ratios to identify remarkably different structural-magnetic contributions of C-methylpyrogallol[4]arene⊂ferrocene/(PgC1)2⊂Fc dimers vs (PgC1)3⊂Fc nanotubes. At low temperature, a weak anti-ferromagnetic alignment is observed, suggesting a weak dipolar interaction between Fc guest moieties within adjacent dimers or tubes. Also, differences are observed between magnetic atom occupancy as a function of guest (PgC1⊂Fc tube/dimer) versus magnetic atom occupancy within the framework wall (PgC3Ni hexamer/dimer). Identification of the role of the framework shape and metal-metal distances in the crystal lattice opens up unparalleled prospects for materials engineering.