A Mononuclear and a Mixed-Valence Chain Polymer Arising from Copper(II) Halide Chemistry and the Use of 2,2′-Pyridil

Reactions of 2,2'-pyridil (pyCOCOpy) with CuCl(2) . 2H(2)O and CuBr(2) in EtOH yielded the mononuclear complex [Cu(pyCOOEt)(2)Cl(2)] . H(2)O (1) and the one-dimensional, mixed-valence complex [Cu(2) (I)Cu(II)(pyCOOEt)(2)Br(4)](n) (2), respectively. Both complexes crystallize in the triclinic space group P 1 . The lattice constants are a = 8.382(2), b = 9.778(2), c = 7.814(2), alpha = 101.17(1), beta = 114.55(1), gamma = 94.14(1) degrees for 1 and a = 8.738(1), b = 9.375(2), c = 7.966(1), alpha = 79.09(1), beta = 64.25(1), gamma = 81.78(1) degrees for 2. 2,2'-pyridil undergoes a metal-assisted alcoholysis and oxidation leading to decomposition and yielding the ethyl picolinate (pyCOOEt) ligand. The autoredox process associated with the reduction of copper(II) to copper(I) in the case of complex 2 is discussed in terms of the increased redox activity of the copper(II) bromide system relative to the copper(II) chloride system.