Metal–phenoxyalkanoic acid interactions. Part 13. Copper(II)–(2-chlorophenoxy)ethanoic acid complexes. Crystal and molecular structures of catena-tetra-µ-[(2-chlorophenoxy)ethanoato-O,O′]-dicopper(II), catena-(2-aminopyrimidine-N,N′)-tetra-µ-[(2-chlorophenoxy)ethanoato-O,O′]-dicopper(II), and 1,2,2,2,2-penta-aqua-tetra-µ-[(2-chlorophenoxy)-ethanoato-O,O′]-copper(II)calcium(II)

Abstract

The crystal structures of three copper(II) complexes of (2-chlorophenoxy)ethanoic acid have been determined by X-ray diffraction. Anhydrous [{Cu2(O2CCH2OC6H4Cl-2)4}n](1) is monoclinic, a= 11.587(3), b= 5.084(2), c= 29.600(6)Å, β= 103.76(2)°, Z= 2, space group P21/c. The adduct [{Cu2(O2CCH2OC6H4Cl-2)4(ampym)}n](ampym = 2-aminopyrimidine)(2) is triclinic, a= 17.543(5), b= 13.344(5), c= 8.459(3)Å, α= 77.89(3), β= 81.43(3)°, γ= 87.61(3)°, Z= 2, space group P. [CaCu(O2CCH2OC6H4Cl-2)4(H2O)5](3) is orthorhombic, a= 13.800(4), b= 8.426(3), c= 32.558(10)Å, Z= 4, space group C2221. (1), (2), and (3) were refined to residuals of 0.051, 0.060, and 0.046 for 1 752, 3 399, and 1 042 observed reflections respectively. All three complexes have tetracarboxylate bridged dimer systems [Cu–Cu, 2.583(2)Å(1); 2.700(3), 2.730(3)Å(2); and Ca–Cu, 3.480(3)Å(3)]. In both (1) and (2), the centrosymmetric dimer units are extended into polymer structures via axial groups which in (1) are carboxyl oxygens from adjacent dimer units while in (2) they are the meta-related nitrogens of the pyrimidine rings. Complex (3) is monomeric with ‘half’ the dimer comprising a conventional CuO4(OH2) unit, the other ‘half’ being an eight-co-ordinate CaO4(OH2)4 unit, with two-fold rotational symmetry.