Treatment of the cyanometalate building unit [Re(CN)7] 3- with [(PY5Me2)M(MeCN)]2+ (M = Co, Ni, Cu) affords a series of pentanuclear clusters of formulas [(PY5Me2) 4M4Re(CN)7]5+ (M = Co, Ni, Cu) and [(PY5Me2)4Cu4Re(CN)7]4+. Single crystal X-ray diffraction analyses of the clusters reveal a star-like structure in which four [(PY5Me2)M]2+ moieties are linked to a central [Re(CN)7]3- unit via bridging cyanide ligands. An intramolecular CoII → ReIV charge-transfer accompanies the formation of the CoII 4ReIV cluster, giving a CoII 3Co IIIReIII species. Spectroelectrochemical methods and irradiation experiments are used to characterize the metal-metal charge-transfer bands of this compound. A rhenium-based thermally induced one-electron reduction is observed for the CuII 4ReIV cluster to give a CuII 4ReIII complex; however, this reduction may be forestalled at low temperature. Finally, magnetic measurements reveal intracluster ferromagnetic exchange coupling, strong uniaxial magnetic anisotropy, and slow magnetic relaxation in the NiII 4ReIV and CuII 4ReIV clusters.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry