Sulfate binding in zinc(II) complexes of a monopyridylurea ligand N-(1-naphthyl)-N′-(3-pyridyl)urea

Two zinc(II) complexes of a urea-functionalized pyridyl ligand, [Zn(SO4)L-3]center dot CH3OH (1) and {[Zn((mu(2)-SO4)L-2]center dot 0.5CH(3)OH)(n) (2) (L = N-(1-naphthyl)-N'-(3-pyridyl)urea), have been synthesized by the reaction of L with ZnSO4 center dot 7H(2)O under different conditions. Complex 1 is a hydrogen-bonded 2D grid structure in which the sulfate anion not only coordinates to the Zn-II ion as a monodentate ligand but also forms multiple hydrogen bonds with the urea groups of adjacent molecules. In complex 2 the sulfate ion serves as a mu(2)-bridging ligand, connecting the Zn-II ions to form an infinite 1D organic-inorganic hybrid framework. Meanwhile, the sulfate anion is also bound by neighboring ligands through hydrogen bonds between urea groups and the non-coordinated oxygen atoms. The solid-state emission spectra of 1 and 2 show a red shift of the fluorescence emission of ligand L. (C) 2010 Elsevier B.V. All rights reserved.