名称:
Synthetic, structural and spectroscopic studies of complexes derived from the copper(II) perchlorate/fumaric acid/N,N′-chelates tertiary reaction systems
摘要:
The synthetic investigation of the Cu(ClO4)(2)center dot 6H(2)O/fumaric acid (H(2)fum)/N,N'-chelates (1,10-phen, 2.2'-bpy) tertiary reaction systems has yielded mononuclear, dinuclear and tetranuclear complexes, and three coordination polymers. The chemical and structural identity of the products depends on the solvent, the absence or presence of external hydroxides in the reaction mixtures and the N,N'-donor. Three fumarato(-2) complexes, i.e. compounds [Cu-2(fum)(phen)(4)](ClO4)2 center dot 2H(2)O (1 center dot 2H(2)O), [Cu(fum)(phen)(H2O)](n) (3) and [Cu-2(fum)(bpy)(2)(H2O)(2)](n) (ClO4)(2n) (6). were isolated and structurally characterized, and four non-fumarato complexes, i.e. compounds [Cu-4(mu(3)-()II)(2)(mu(2)-()II)(2)(phen)(4)(H2O)(2)](ClO4)(4)center dot 2H(2)O (2 center dot 2H(2)O), [Cu(ClO4) (phen) (MeCN)(2)(H2O)](ClO4) (4), [(Cu(ClO4)(phen)(MeCN)(2)](n) (ClO4)(n) (5) and [Cu(ClO4)(2)(bpy)(MeCN)(2)] (7), were simultaneously obtained from the reaction systems investigated. The coordination versatility of the fumarato(-2) ligand is reflected to the three different coordination modes observed in 1 center dot 2H(2)O, 3 and 6: the monodentate bridging mu(2)-kappa O:kappa O' mode in 3, the asymmetric chelating bridging mu(2)-kappa O:kappa O':kappa O '':kappa O ''' mode in 1 center dot 2H2O and 3, and the syn,syn bridging mu(4)-kappa O:kappa O':kappa O '':kappa O ''' mode in 6. The crystal structures of the complexes are stabilized by intra-and inter-molecular hydrogen bonding and pi-pi stacking interactions leading to interesting supramolecular architectures. Characteristic IR bands of the complexes are discussed in terms of the known structures, and the coordination modes of the fum(2-) ligands. (C) 2009 Elsevier Ltd. All rights reserved.