Synthesis, crystal structure, magnetic properties and electrochemical behaviour of the mixed valence compound [CuI(CN)3CuII(C3H10N2)2]

The binuclear mixed valence copper(I/II) compound [CuI(CN)3CuII(tn)2] (1) (tn = propane-1,3-diamine) and its acetonitrile adduct [CuI(CN)3CuII(tn)2] · 2MeCN (2) have been synthesized. Complex 1 crystallizes triclinic, space group View the MathML sourceP1¯, a = 8.117(2) Å, b = 8.389(2) Å, c = 11.920(2) Å, α = 108.728(3)°, β = 100.024(3)°, γ = 104.888(4)°, Z = 2, and compound 2 monoclinic, space group P21/m, a = 8.752(2) Å, b = 13.243(3) Å, c = 9.549(2) Å, β = 114.678(4)°, Z = 2. In both crystal structures, the binuclear [CuI(CN)3CuII(tn)2] complex with slightly different bonding geometries is formed. One of the three nitrogen atoms of a CuI(CN)3 moiety is coordinated to Cu(II) at the apex of a square-pyramid with two chelating ligands tn on its base. The shortest intramolecular CuII⋯CuII distance in 1 is 5.640(7) Å. The EPR behaviour of 1 has been investigated at room temperature and at 77 K. The magnetic properties were measured in the temperature range 1.8–300 K.