Affiliation:
1. Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, E -15706 Santiago de Compostela, Spain
2. Department of Inorganic Chemistry, Faculty of Pharmacy, University of Granada, E -18071 Granada, Spain
Abstract
Abstract
The stoichiometric reaction of N-(2-hydroxyethyl)-1,2-ethylenediamine-N,N,N′-triacetic acid [H3hedta = (HOCH2CH2)(HO2CCH2)NC2H4N(CH2CO2H)2)] and copper(II) hydroxy-carbonate in water yields crystalline samples of poly-{(N-(2-hydroxyethyl)-N′-carboxymethyl-1,2-ethylenediamine-N,N′-diacetato)copper(II) hydrate}, {[Cu(Hhedta)] · H2O}n (I)-The compound was studied by TG analysis (with FT-IR study of the evolved gases), IR, electronic and ESR spectra, magnetic susceptibility data and single crystal X-ray diffraction methods. It crystallises in the orthorhombic system, space group Fdd2 (a = 21.906(2), b = 36.602(4), c = 6.928(1) Å, Z = 16, and final R1 = 0.029 for 1554 independent reflections). The Cu(II) atom exhibits a very distorted octahedral coordination (type 4+1 + 1). The Hhedta ligand plays a N,N′,O,O′O″-pentadentate chelating role as well as a O,O′-carboxylate bridging one and has a free N-carboxymethyl arm. The bridging carboxylate group of the Hhedta ligand leads to polymeric chains {[Cu(Hhedta)] · H2O}n parallel the c axis. A hydrogen bonding network involves all O-H polar bonds (non-ionised carboxylic and alcoholic hydroxyl groups and water molecules). The structure reveals the preferred formation of a copper(II)-(N-2-hydroxyethyl-amino) or copper(II)-(ethanolamino) versus a copper(II)-(N-carboxymethylamino) chelate ring.