The dicopper center is the active site of many type III Cu proteins, which play an important role in the transport and activation of oxygen in many biological systems. Among all the different species that occur upon O2 binding in these metalloproteins, the SP motif is the most commonly detectable one. Here we report the synthetic, fully characterized CuII2(µ-η1:η1-O2) complex, featuring an unusual cis-peroxo binding (CP) and weak antiferromagnetic coupling, comparable with that of a theoretically predicted transition state for O2 binding to T3Cu centers, thus supporting the biological relevance of this new compund. UV/vis spectroscopy and DFT computational studies allowed us to demonstrate how the electronic structure of the complex can be tuned by introducing different alkali metal ions (namely Li+, Na+ and K+) which interact with the peroxo moiety. Furthermore, the binding of diverse alkali cations was also found to modulate the magnitude of the antiferromagnetic coupling, by modifying the extent of overlap in copper and oxygen centered orbitals through variations in the coordination environment of the Cu(II) ions and in the Cu-O-O-Cu torsion angle.

Modulation of a weakly coupled peroxo-dicopper(II) complex by interaction with alkali metal ions

253rd National Meeting (2017)

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