Isomerism as a remarkable tool for the design of new potentially bridging macrocycle ligands: Synthesis and characterization of the [Cu(4-L1)](NO3)2·2H2O polymeric chain (4-L1=mono-N (4-picolyl)cyclen)

A new coordination complex [Cu(4-L1)](NO3)2·2H2O (1) based on the functionalized cyclen mono-N (4-picolyl)cyclen (4-L1) has been prepared and characterized by X-ray diffraction. The structure of 1 can be described as a monodimensional coordination polymer in which the macrocycle ligand acts as bridging ligand. Examination of the inter-chain distances revealed the presence of hydrogen bonds between oxygen atoms of the nitrate anions and the hydrogen atoms of two secondary amines of the macrocycle ligands, affording isolated “double-chain” units. The overall structure of 1 consists of alternating succession of cationic layers of infinite “double-chain” units and anionic nitrate-water H-bonded layers.