Networked Spin Cages: Tunable Magnetism and Lithium Ion Storage via Modulation of Spin-Electron Interactions

A networked spin cage comprising infinite Co<sup>II</sup><sub>6</sub>L<sub>4</sub> cages arrays (where Co = Co­(NCS)<sub>2</sub> and L = 1,3,5-tri-(4-pyridyl)-verdazal radical) is synthesized and found to exhibit tunable magnetic and electrochemical properties via inclusion of guests. SQUID investigation reveals the coexistence of ferromagnetic and anti-ferromagnetic interactions between the Co­(II) ion center and radical ligands. Inclusion of electron-deficient guests (e.g., tetracyanoethylene) dramatically enhances spin concentration and increases anti-ferromagnetic interactions due to the formation of charge-transfer complex between the host and the guest. In addition, introduction of electron-rich guests (e.g., tetrathiafulvalene) into the networked spin cages doubles the capacity for binding the lithium ions.