New Network Structures from Cu(II) Complexes of Chelating Ligands with Appended Hydrogen Bonding Sites

Complexes [Cu(phenpyzda)Cl2(H2O)]·H2O (1) and [Cu(phenpyzda)Br2(H2O)]·2H2O (2), where phenpyzda = pyrazino[2,3-f][1,10]phenanthroline-2,3-diamide, show similar molecular structures with square planar Cu(II). Each complex has a complicated three-dimensional (3D) hydrogen bonding network with 1 having an unusual 3,9-connectivity. Use of the corresponding carboxylic acid, pyrazino[2,3-f][1,10]phenanthroline-2,3-dicarboxylic acid, results in the unexpected conversion of the ligand to 1H,3H-imidazol[2,3-f][1,10]phenanthroline (= imiphen) in the complex [CuCl3(imiphenH)]·2H2O, which has a 3D hydrogen bonded network structure of 3,6-connectivity. The more extended phenanthroline-based ligand 1,10-phenanthroline-5,6-[pteridine-2,4-diamine] was also synthesized, but no crystalline complexes of it were isolated. [Cu(bpy4diol)2](NO3)2·H2O (4), where bpy4diol = 2,2′-bipyridine-4,4′-diol, shows a two-dimensional (2D) hydrogen bonded network with hexagonal topology. [Cu(bpy4da)(NO3)2] (5) where bpy4da = 2,2′-bipyridine-4,4′-diamine has a 3D 2-fold interpenetrating α-Po related hydrogen bonded structure. Complexes [Cu(bpy4da)Cl2] (6) and [Cu(bpy5dmol)Cl2] (7) where bpy5dmol = 2,2′-bipyridine-5,5′-bis(hydroxymethyl) have similar chloro bridged coordination chains that hydrogen bond together into 3D and 2D networks, respectively. Despite their different hydrogen bonding patterns, complexes 6 and 7 are isomorphic.