*2.1. Materials*

4-Phenyl-pyrazole (4-Ph-pzH) was prepared according to a procedure from the literature [14]. All other reagents were purchased from commercial sources and used as received. Solvents were purified using standard techniques [15]. [PPN]2[Cu3(μ3-Cl)2(μ-pz)3Cl3] and [PPN]2[Cu3(μ3-O)(μ-pz)3Cl3] were prepared according to published procedures [12]; PPN<sup>+</sup> = bis(triphenylphosphine)iminium.
