An Organic-Inorganic Hybrid Exhibiting Electrical Conduction and Single-Ion Magnetism

The first three-dimensional (3D) conductive single-ion magnet (SIM), (TTF)₂ [Co(pdms)₂ ] (TTF=tetrathiafulvalene and H₂ pdms=1,2-bis(methanesulfonamido)benzene), was electrochemically synthesised and investigated structurally, physically, and theoretically. The similar oxidation potentials of neutral TTF and the molecular precursor [HNEt₃ ]₂ [M(pdms)₂ ] (M=Co, Zn) allow for multiple charge transfers (CTs) between the SIM donor [M(pdms)₂ ]^n- and the TTF^.+ acceptor, as well as an intradonor CT from the pdms ligand to Co ion upon electrocrystallisation. Usually TTF functions as a donor, whereas in our system TTF is both a donor and an accepter because of the similar oxidation potentials. Furthermore, the [M(pdms)₂ ]^n- donor and TTF^.+ acceptor are not segregated but strongly interact with each other, contrary to reported layered donor-acceptor electrical conductors. The strong intermolecular and intramolecular interactions, combined with CT, allow for relatively high electrical conductivity even down to very low temperatures. Furthermore, SIM behaviour with slow magnetic relaxation and opening of hysteresis loops was observed. (TTF)₂ [Co(pdms)₂ ] (2-Co) is an excellent building block for preparing new conductive SIMs.