Copper(II) bromide and copper(II) acetate complexes of 4,4′-(p- phenylene)bipyridazine

4,4′-(p-Phenyl-ene)bipyridazine, C14H10N4, (I), and the coordination compounds catena-poly[[dibromidocopper(II)] - 4,4′-(p-phenyl-ene) bipyridazine-² N ²:N ^2′], [CuBr2(C14H10N4)] n , (II), and catena-poly[[[tetra-kis(-acetato-² O:O′)-dicopper(II)] - 4,4′-(p-phenyl-ene)bipyridazine-² N ¹:N ^1′] chloro-form disolvate], {[Cu2(C2H3O2)4(C14H10N4)]·2CHCl3}n , (III), contain a new extended bitopic ligand. The combination of the p-phenyl-ene spacer and the electron-deficient pyridazine rings precludes C - H⋯π inter-actions between the lengthy aromatic mol-ecules, which could be suited for the synthesis of open-framework coordination polymers. In (I), the mol-ecules are situated across a center of inversion and display a set of very weak inter-molecular C - H⋯N hydrogen bonds [3.399 (3) and 3.608 (2) Å]. In (II) and (III), the ligand mol-ecules are situated across a center of inversion and act as N ²,N ^2′-bidentate [in (II)] and N ¹,N ^1′-bidentate [in (III)] long-distance bridges between the metal ions, leading to the formation of coordination chains [Cu - N = 2.005 (3) Å in (II) and 2.199 (2) Å in (III)]. In (II), the copper ion lies on a center of inversion and adopts CuN2Br4 (4+2)-coordination involving two long axial Cu - Br bonds [3.2421 (4) Å]. In (III), the copper ion has a tetra-gonal pyramidal CuO4N environment. The uncoordinated pyridazine N atom and two acetate O atoms provide a multiple acceptor site for accommodation of a chloroform solvent mol-ecule by trifurcated hydrogen bonding [C - H⋯O(N) = 3.298 (5)-3.541 (4) Å].