Metal-phenoxyalkanoic acid interactions. Part 3. Crystal and molecular structures of tetra-μ-(2,4-dichlorophenoxyacetato)bis[aquacopper(II)] dihydrate and tetra-μ-(2,4,5-trichlorophenoxyacetato)bis[pyridinecopper(II)]

The crystal structures of tetra-μ-(2,4-dichloropehonxyacetato)bis[aquacopper(II)] dihydrate (1) and tetra-μ-(2,4,5-trichlorophenoxyacetato)bis[pyridinecopper(II)] (2) have been determined by X-ray diffraction from diffractometer data and refined by leasi-squares to R 0.11 (2218 reflections) and 0.0068 (2268 reflections) for (1) and (2) respectively. For (1), crystals are monoclinic, space group C2/c with Z = 4 in a cell of dimensions a = 36-98(3), b = 7.582(2), c = 14.972(5) Å, β = 105.52(5)° while for (2) the space group si P1 with Z = 1 with a cell of dimensions a = 12.184(8), b = 13.719(7), c = 8.687(6) Å, α = 99.69(5), β = 99.15(5), γ = 114.01(4)°. Both compounds (1) and (2) consist of centrosymmetric tetra-carboxylate birdged dimer units of copper acetate type, with CuCu separations of 2.639(5) Å (1) and 2.716(7) Å (2). The copper and carboxylate oxygens lie approximately in the smae plane in both (1) and (2) with a mean CuO distance of 1.972(10) Å and 1.973(12) Å respectively while the co-ordination sphere is completed in the axial positions by water oxygens [2.120(10) Å] in (1) and pyridine nitrogens [2.142(12) Å] in (2)