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

Two new coordination polymers, (1)(infinity)[Cu-2(L)(4)(-)(MeOH)].MeOH (1) and (3)(infinity)[Cu(L)(2)].5H(2)O (2), have been obtained exploring the potential of 5-amino-1-phenyl-1H-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 1, 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 2, 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 2 crystallizes in the hexagonal system with the chiral space group P6(1)22, featuring a quartz-like topology. The magnetic properties of both compounds have been investigated.