Chemistry Letters, Vol.43, No.4, 562-564, 2014
Crystal Structure and Characterization of Trinuclear Cobalt(III) Complex with 2,3,6,7,10,11-Hexahydroxytriphenylene
Trinuclear Co(III) complex [Co-3(III)(tpa)(3)(L)](BF4)(4) (tpa: tris-(2-pyridylmethyl)amine, H6L: 2,3,6,7,10,11-hexahydroxytriphenylene) is prepared from methanol solution. Single-crystal structure analysis revealed that the valency of the three cobalt ions is +3 and that the tris(dioxolene) bridging ligand is formally in the -5 [cat,cat,sq] oxidation state. This complex is stable in the entire temperature range investigated. Various-temperature magnetic susceptibility data for the compound displayed little variation in the range 2-300K, and the reason caused the distinct charge distribution on Co-L (L: bridging ligand) by the natural rigidity of the tripodal ligands. Also, its CH3CN solution exhibits a very strong NIR absorption arising from an internal ligand transition within the triphenylene ligand. Cyclic voltammetry (CV) measurements in CH3CN solution show three reversible cat sq redox waves for the triphenylene ligand.