A novel polymeric trinuclear-based μ3-phosphato-bridged Cu(II) complex containing two different types of monophosphate. Synthesis, structure and magnetism of {[Cu3(di-2-pyridylamine)3(μ3,η3-HPO4)(μ3,η4-PO4)(H2O)] (PF6)(H2O)3}n

A novel trinuclear-based polymeric Cu(II) complex with uniquely bridged View the MathML sourceHxPO4(3-x)- anions, [Cu3(di-2-pyridylamine)3(μ3,η3-HPO4)(μ3,η4-PO4)(H2O)](PF6)(H2O)3}n1 has been synthesized and characterised. Each Cu(II) ion in the polynuclear unit is linked by hydrogenphosphato and phosphato bridges showing View the MathML sourceμ3,η3-HPO42-and an unprecedented View the MathML sourceμ3,η4-PO43- coordination mode. Two different coordination geometries around the Cu(II) ions are found in the polynuclear unit: an intermediate geometry between square pyramidal and trigonal bipyramidal and a tetrahedrally distorted square-based pyramidal geometry. The Cu ⋯ Cu distances vary from 4.408(3) to 5.942(3) Å. From variable magnetic susceptibility measurements (5–250 K) a weak antiferromagetic interactions between the Cu(II) ions in the trinuclear unit with an exchange parameter of J = −4.98 cm−1 and a very weak antiferromagnetic interaction between neighbouring units with zJ′ = −1.49 cm−1 are observed.