Zusammenfassung

Double bond, yes or no? That is the poignant question in the case of the complex [Cp*CoCoCp*] prepared by J.J. Schneider et al. The Co-Co distance and the number of electrons suggest a double bond, while the H-1-NMR spectrum and the poor reactivity toward C2H4 and CO would suggest the contrary. Nevertheless, with this unbridged complex, the prerequisite for the synthesis of further such compounds and for studying the properties of these multibond systems was realized.