Chains, ladders and sheets of d10 metal-organic polymers generated from the flexible bipyridyl ligands

By use of the three-layer diffusion method, reactions of flexible bipyridyl ligands (4,4'-bpp or 3,3'-bpp) with M(II) salts (M = Zn, Cd) and multi-carboxylate ligands resulted in the formation of four interesting d(10) metal-organic coordination polymers: [Zn(mu-4,4'-bpp)Br-2](n) (1), [Zn(mu-4,4'-bpp)(l,2-bdc)](n) center dot nH(2)O (2), [Zn(mu-3,3'-bpp)(1,3-bdc)](n) center dot nCH(3)OH center dot 2nH(2)O (3) and [Cd(mu-3,3'-bpp)(C4H2O4)](n) center dot 3nH(2)O (4) (4,4'-bpp = 2,2'-bis(4-pyridylmethyleneoxy)- 1,1'-biphenylene; 3,3'-bpp = 2,2 '-bis(3-pyridylmethyleneoxy)-1,1'-biphenylene; bdc=benzenedicarboxylate, C4H4O4 = fumaric acid). Complex 1 has a 2D sheet structure consisting of two unusual zigzag Zn(II) chains which are nearly perpendicular to each other. Complex 2 is comprised of two-leg ladders, in which [Zn(4,4'-bpp)] chains serve as the side rails and 1,2-bdc ligands serve as the cross rungs. In complex 3, every two 1,3-bdc ligands connect the neighbouring Zn(II)-3,3'-bpp dimetallic rings in eta(1) coordination modes into an interesting chain structure. Complex 4 consists of an anionic macrocycle-containing cadmium dicarboxylate sheets that are separated by 3,3'-bpp. These d(10) metal complexes exhibit high thermal stabilities and strong luminescence efficiencies. (c) 2007 Elsevier Ltd. All rights reserved.