A New Quartz-like Metal–Organic Framework Constructed from a Versatile Pyrazole-Based Spacer

Two new coordination polymers, ¹_∞[Cu₂(L)₄­(MeOH)]­·MeOH (<b>1</b>) and ³_∞[Cu­(L)₂]­·5H₂O (<b>2</b>), have been obtained exploring the potential of 5-amino-1-phenyl-1<i>H</i>-pyrazole-4-carboxylate (L^–) to act as a spacer. The different architectures of these compounds arise from the versatility of this organic ligand. In compound <b>1</b>, the carboxylato groups (syn-syn bridging mode) and the copper ions generate a binuclear paddle-wheel motif. Each binuclear entity coordinates to another one, through one out of the four pyrazole rings, resulting in double chains. In crystal <b>2</b>, the organic ligand is coordinated to a copper ion through the carboxylato group (asymmetric chelating) and to another copper ion through the pyrazole nitrogen atom. Compound <b>2</b> crystallizes in the hexagonal system with the chiral space group <i>P</i>6₁22, featuring a quartz-like topology. The magnetic properties of both compounds have been investigated