Heterospin frustration in a metal-fullerene-bonded semiconductive antiferromagnet.

ABSTRACT: Lithium-ion-encapsulated fullerenes (Li⁺@C₆₀) are 3D superatoms with rich oxidative states. Here we show a conductive and magnetically frustrated metal-fullerene-bonded framework {[Cu₄(Li@C₆₀)(L)(py)₄](NTf₂)(hexane)}_n (1) (L = 1,2,4,5-tetrakis(methanesulfonamido)benzene, py = pyridine, NTf₂^- = bis(trifluoromethane)sulfonamide anion) prepared from redox-active dinuclear metal complex Cu₂(L)(py)₄ and lithium-ion-encapsulated fullerene salt (Li⁺@C₆₀)(NTf₂^-). Electron donor Cu₂(L)(py)₂ bonds to acceptor Li⁺@C₆₀ via eight Cu‒C bonds. Cu-C bond formation stems from spontaneous charge transfer (CT) between Cu₂(L)(py)₄ and (Li⁺@C₆₀)(NTf₂^-) by removing the two-terminal py molecules, yielding triplet ground state [Cu₂(L)(py)₂]⁺(Li⁺@C₆₀^•-), evidenced by absorption and electron paramagnetic resonance (EPR) spectra, magnetic properties and quantum chemical calculations. Moreover, Li⁺@C₆₀^•- radicals (S = ½) and Cu²⁺ ions (S = ½) interact antiferromagnetically in triangular spin lattices in the absence of long-range magnetic ordering to 1.8 K. The low-temperature heat capacity indicated that compound 1 is a potential candidate for an S = ½ quantum spin liquid (QSL).

SUBMITTER: Shen Y 

PROVIDER: S-EPMC8789904 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature