1,1′ Ferrocenylenediol as chelating ligand for cobalt in fivefold and sixfold coordination geometry: Synthesis, Electrochemistry and X-ray crystal structure of [{((1,1′ O2(η5-C5H5)2Fe)2}Co(OEt2){(η5-Me5C5)Co}2] and [{((1,1′ O2(η5-C5H5)2Fe)3}Co((η5-EtMe4C5

The title compounds 3 and 4 were synthesized by reaction of 1,1′ ferrocenylenediol with the Co triple decker compounds [{(η5-Me5C5)Co}2(η6:η6-toluene)] and [{(η5-EtMe4C5)Co}2(η6:η6-toluene)], respectively. The central Co atom of 3 is coordinated by five O atoms in a square-pyramidal manner. The remaining two Co atoms of 3 are coordinated to a Me5C5 ligand in a η5-fashion and by the two O atoms of two 1,1′ ferrocenylenediolato ligands which serve as chelating ligands. In 4, the central Co atom is coordinated to all six O atoms of three ferrocenylenediolato ligands in a trigonal-prismatic manner, whereas the two other Co atoms are coordinated by an EtMe4C5 ligand in a η5-fashion and by three O atoms of three ferrocenylenediolato ligands resulting in an overall tripoidal structure for 4.