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(18crown-6)3Ni(dmit)211(H2O)7.33(CH3CN)2 (1) is prepared in the present study, integrating one-dimensional 18crown-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 18crown-6 channels with conducting Ni(dmit)2 layers, establishing a supramolecular route to tune spin-charge coexistence via host design.
Ishikawa et al. (Thu,) studied this question.