Trinuclear copper(II) pyrazolate compounds: a long story of serendipitous discoveries and rational design
In the past decade great effort has been put into the development of synthetic strategies to produce trinuclear triangular CuII (TTC) arrays, which may be synthetic analogues of the trinuclear site in ascorbate oxidase and blue oxidase. A large number of scientific contributions have been dedicated to the synthesis and spectroscopic characterization of TTC arrays. In contrast, only a small number of studies deal with their possible applications. As a consequence, systematic studies describing their reactivity are very rare and the few existing models can only partially explain how structural and molecular parameters influence their reactivity and their possible uses and applications. This contribution reports a summary of all experimental results related to the Cu3(μ3-OH)(μ-pz)3 core (pz = unsubstituted pyrazolate). We describe here all species, distinguishing them according to whether they are neutral, cationic or anionic, as well as their main structural features, the synthetic procedures employed for their production, their reactivity toward nucleophiles and strong acids and, finally, their possible and perspective applications.