A unique 1D ribbon coordination polymer containing 2 + 1 trimeric copper(II) linked by in situ generated polynitrogen heterocyclic ligand as bridges: Synthesis, crystal structure and magnetism

A one-dimensional ribbon copper(II) complex, {CuII3(L)2(OH)2(NO3)2(H2O)4}n (1, HL = 1-methyl-2-(3H-[1–3]triazol-4-yl)-1H-benzimidazole), has been hydrothermally synthesized from in situ generated HL at 160 °C. Its structure is very unusual that all ligands and Cu(II) ion are distributed in the same horizontal plane in each chain. Two ligands chelate and bridge two Cu(II) ions to form a planar metalloligand which is then connected to each other through coordination to another Cu(II) to give the 2 + 1 infinite chain structure. Axial coordination sites of the Cu(II) are taken up by nitrate and water. Hydrogen bonding and π–π stacking interactions between chains intensify the stability of 3D supramolecular architecture. This particular structure is the result of a cooperative effect associated with the Jahn–Teller distortion of the copper(II) ion, the hydrogen bonding and π–π stacking interactions. Its magnetic properties indicate antiferromagnetic interactions between copper(II) within the chain.