Supramolecular Ion-Channel Engineering of Spin–Charge Coexistence in a [Ni(dmit) ₂ ] Conductor Hosting Mixed-Valence Mn Cations

The interplay between electrical conduction and magnetism offers a powerful means to elucidate emergent mechanisms and control properties; however, realizing this in Ni(dmit)₂ crystals has been challenging due to undesirable reactions among their components. Mn1.83([18]crown-6)₃[Ni(dmit)₂]₁₁(H₂O)7.33(CH₃CN)₂ (1) is prepared in the present study, integrating one-dimensional [18]crown-6 ion channels hosting mixed-valence Mn²⁺/Mn³⁺ with conducting [Ni(dmit)₂] layers. Subsequently, a structure-driven mechanism of conductivity is clarified. In the crystal, [Ni(dmit)₂] forms one-dimensional dimer-dimer-trimer-dimer-dimer stacks; weak interchain contacts generate two-dimensional sheets alternating with supramolecular channel layers. Mn ions occupy two partially populated sites and adopt seven-coordinate environments with two axial aqua ligands and five equatorial crown-ether oxygen. Magnetometry indicates Mn moments are effectively decoupled from the conducting [Ni(dmit)₂] sublattice: the Mn sublattice follows Curie-Weiss behavior with an exceptionally small Weiss temperature, while the [Ni(dmit)₂] stacks form S = 1/2 one-dimensional Heisenberg antiferromagnetic chains. Compound 1 exhibits high conductivity at 300 K and one-dimensional variable-range hopping, attributable to thermal fluctuations of the supramolecular channels that modulate intracolumn transfer integrals and promote carrier localization. To our knowledge, 1 is the first system combining transition-metal-ion [18]crown-6 channels with conducting [Ni(dmit)₂] layers, establishing a supramolecular route to tune spin-charge coexistence via host design.