Dimeric Complexes of CoIII(cyclam) with a Polyynediyl Bridge

Described in this work are the preparation and characterization of a family of polyynediyl-bridged (μ-C2n) dimers of CoIII(cyclam)Cl (cyclam = 1,4,8,11-tetraazacycloctetradecane) for n = 2–4. The complexes are robust to ambient conditions and are prepared under mild conditions without requiring anaerobic or anhydrous environments. Voltammetric analysis revealed weak Co–Co interaction through the bridge, which is attenuated by polyyne length. The orbital origin of the Co–Co interaction has been rationalized through DFT analysis.