A Copper(II)-Cytidine Complex as a Building Unit for the Construction of an Unusual Three-Dimensional Coordination Polymer

The chiral [Cu(cyd)4]6− anion acts as a multiarmed complex-ligand toward auxiliary copper(II) centers leading to the first example of cytidinate-bridged three-dimensional (3D) coordination polymer of formula [Cu6(H2O)7(ClO4)3Cu(cyd)4](ClO4)3 (1). Single crystal X-ray analysis of 1 shows a unique 3D covalent network supported by the exclusive hypercoordination of the cytidinate ligand that bridges four crystallographically independent copper(II) ions via the N3, O2, O2′, O3′, and O5′ set of atoms. Magnetic susceptibility measurements in the temperature range 1.9−295 K reveal the coexistence of ferro- and antiferromagnetic interactions within the hexacopper(II) core of 1, the exchange pathways being the di-μ-aqua and the single- and double-alkoxo bridges.