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 HxPO4(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 μ3,η3-HPO42- and an unprecedented μ3,η4-PO43- coordination mode. Two different coordination geometries around the Cu(II) ions are found in the polynuclear unit: an intermediate 5-coordinate geometry and a tetrahedrally distorted square-based pyramidal geometry. From variable magnetic susceptibility measurements (5-250 K) a weak antiferromagetic interactions between the Cu(II) ions in the trinuclear unit, J = −4.98 cm−1 and a very weak antiferromagnetic interaction between neighbouring units, zJ′ = −1.49 cm−1 are observed.