Hydrogen-bonded networks based on cobalt(ii), nickel(ii), and zinc(II) Complexes of N,N'-Diethylurea

Abstract

N,N'-diethylurea (DEU) was employed as a ligand to form the octahedral complexes [ M (DEU)6 ] 2+ (M=Co, Ni and Zn). Compounds [ Co (DEU)6 ] (BF4)2 (1), [ Co (DEU)6 ] (CIO4)2 (2), [ Ni (DEU) 6 ] (CIO 4) 2 (3), and [ Zn (DMU) 6 ] (CIO 4) 2 (4) have been prepared from the reactions of DEU and the appropriate hydrated metal(II) salts in EtOH in the presence of 2,2-dimethoxypropane. Crystal structure determinations demonstrate the existence of [ M (DEU)6 ] 2+ cations and CIO4- (in 2-4) or BF4- (in 1) counterions. The [ M (DEU)6 ] 2+ cations in the solid state are stabilized by a pseudochelate effect due to the existence of six strong intracationic N-H O (DEU) hydrogen bonds. The [ M (DEU) 6 ] 2+ cations and counterions self-assemble to form hydrogen-bonded 2D architectures in 2-4 that conform to the kgd (kagome dual) network, and a 3D hydrogen-bonded rtl (rutile) network in 1. The nature of the resulting supramolecular structures is influenced by the nature of the counter-ion. The complexes were also characterized by vibrational spectroscopy (IR). Copyright © 2010 Labrini Drakopoulou et al.