Two- and three-dimensional nickel( ii ) and copper( ii ) metal–organic frameworks based on 1 H -pyrazole-4-carboxylate

2D polymers, [M(pzca) 2 (Hpz) 2 ] n (M = Ni and Cu), and a 3D polymer, [Cu(pzca) 2 ] n , were synthesized using 1 H -pyrazole-4-carboxylic acid (Hpzca) and pyrazole (Hpz). Omission of the capping Hpz ligand promotes the formation of 3D.