Coordination polymers from mild condition reactions of copper(II) carboxylates with pyrazole (Hpz). Influence of carboxylate basicity on the self-assembly of the [Cu3(μ3-OH)(μ-pz)3]2+ secondary building unit

The reaction of copper carboxylates with pyrazole (Hpz) and water in protic solvents yields trinuclear triangular derivatives based on the Cu3(μ3-OH)(μ-pz)3 moiety only if carboxylate anions are basic enough to deprotonate water and Hpz, yielding OH− and pz− fragments which are needed to generate the trinuclear assembly. In most cases the trinuclear clusters further self-assembly originating coordination polymers.