Synthesis, spectroscopy, and crystal structure of a thiocyanato-bridged mixed-valence copper(I)–copper(II) compound with the ligand 1,6-bis(5′-methylimidazol-4′-yl)-2,5-dithiahexane
Abstract
The synthesis, crystal structure, electronic, and e.s.r. spectra are reported for the complex catena-[1,6-bis(5′-methylimidazol-4′-yl)-2,5-dithiahexane]tri-µ-thiocyanato-dicopper(I,II). The complex crystallizes as dark brown octahedra in the space group P21/c, with a= 13.684(4), b= 9.537(2), c= 18.531(3)Å, β= 108.91(2)°, Z= 4, R= 0.036, R′= 0.039 for 2 936 reflections with l > 2σ(l). Each copper(II) ion is surrounded by four nitrogens at 1.968(3), 1.972(3), 2.002(4), and 2.395(4)Å, and two sulphurs at 2.426(1) and 2.814(1)Å. The co-ordination geometry of the copper(II) ion is intermediate between elongated octahedral and square pyramidal. The copper(I) ion is surrounded by three sulphurs and one nitrogen from the bridging thiocyanates in a distorted tetrahedral geometry. Two of the thiocyanate anions bridge to another copper(I) ion and the other two bridge to two different copper(II) ions, resulting in a three-dimensional network.