Copper(I) coordination polymers of 2,2′-dipyridylamine derivatives: syntheses, structures, and luminescence

Reactions of CuX (X = Br-, I- or CN-) with various types of 2,2'-dipyridylamine (dpa) derivatives have been performed via a hydrothermal-solvothermal method and the products have been structurally characterized by X-ray crystallography. Four ligands with different coordination motifs were employed in the reactions, including angular N,N,N',N'-tetra(2-pyridyl)-2,6-pyridinediamine (tppda); linear N,N,N',N'-tetra(2-pyridyl)-1,4-phenylenediamine (tppa) and N,N,N',N'-tetra(2-pyridyl)biphenyl-4,4'-diamine (tpbpa); and star-shaped tris-[4-(2,2'-dipyridylamino)-phenyl]amine (tdpa), which yielded eight copper(I) complexes exhibiting different stoichiometries of Cu-dpa and variable coordination modes of dpa. The compound [Cu-2(tppda)(mu-I)(2)](n) (1) forms a one dimensional (1D) coordination polymer exclusively through double mu(2)-I bridges, which arranges to two dimensional (2D) metal-organic frameworks (MOFs) via the face-to-face pi center dot center dot center dot pi stacking interactions from pyridyl rings. The compound [Cu-6(tppa)(mu(3)-Br)(6)](n) (2) forms a 2D network linked through multiple mu 3-Br bridges. The compound [Cu-2(tppa)(mu-CN)(2)](n) (3) is also a 2D MOF containing 1D (CuCN)n chains. The compounds [Cu(tpbpa)Br](n) (4) and [Cu-4(tpbpa)(2)(mu-I)(4)](n) (5) display two different 1D assemblies: a zig-zag chain for 4 and a linear structure for 5. The compound [Cu-4(tpbpa)(mu-CN)(4)](n) (6) shows a pseudo-4,82 topological net, while the compound [Cu-8(tpbpa)(mu-CN)(8)](n)center dot 2nH(2)O (7) exhibits a three-dimensional (3D) framework containing a center dot center dot center dot PM center dot center dot center dot double helical structure, although both of them contain (CuCN)(n) chains. The compound [Cu-2(tdpa)(mu-I)(2)](n) (8) is a zig-zag chain based on the star-shaped molecule tpda, in which one of three dpa-arms is free of coordination to metal ions. All complexes exhibit luminescence in the solid state.