Synthesis and characterization of mono- and mu(6)-sulfato hexanuclear zinc complexes of a new symmetric dinucleating ligand

摘要

Zinc complexes of a new symmetric dinucleating ligand, N,N'-Bis[2-carboxybenzomethyl]-N,N'-Bis[carboxymethyl]-1,3-diaminopropan-2-ol (H(5)ccdp) with mixed donating groups, have been studied in the solid state as well as in solution. In methanol, the reaction of stoichiometric and substoichiometric amounts of Zn(ClO4)(2)center dot 6H(2)O and the ligand H(5)ccdp, in the presence of K2CO3 or Et3N, afforded a mononuclear zinc complex, [Zn(H2O)(6)][Zn(H(2)ccdp)(H2O)(2)](2)center dot 12H(2)O (1). The solid state structure of 1 contains two units of the zinc-ligand anion, [Zn(H(2)ccdp)(H2O)(2)](-), and one [Zn(H2O)(6)](2+) counter cation. The Zn(II) center of the anion is in a distorted octahedral geometry. However, in methanol, the reaction of ZnSO4 center dot 7H(2)O and the ligand H(5)ccdp, in the presence of NaOH afforded a unique mu(6)-sulfato hexanuclear zinc complex, Na-6[Zn-6(ccdp)(3)(mu(6)-SO4)](OH)center dot 10.5H(2)O (2). The structure of 2 contains a [Zn-6(II)(mu(6)-SO4)] core unit which is held together by three heptadentate bridging ligands, ccdp(5-). Three of the Zn(II) centers are in highly distorted square pyramidal geometry, the other three Zn(II) centers are in a distorted octahedral geometry.