Hydrolysis of imidazolidine ligands mediated by CuII: Mononuclear, tetranuclear and 1D CuII-amine complexes
作者:Matilde Fondo、Jesús Doejo、Ana M. García-Deibe、Jesús Sanmartín、Concepción González-Bello、Ramón Vicente
DOI:10.1016/j.poly.2015.07.028
日期:2015.11
The potential ability of HL1 [2-(1,3-dimethylimidazolidin-2-yl)phenol] and H3L2 [2,2'-(2-(2-hydroxyphenyl)imidazolidin-1,3-diyl)diethanol] to act as ligands towards copper(II) was tested under different reaction conditions. These essays show that both HL1 and H3L2 are unstable in the presence of Cu-II, suffering total imidazolidine ring hydrolysis and yielding amine complexes. In this way, four different copper(II) complexes could be isolated, depending on the reaction conditions, the ligand itself and the counterions present in the medium. Accordingly, the complexes [Cu(am1)(H2O)(OAc)(2)](n) (1) (am1 = N,N'-dimethylethylenediamine), [Cu(am1)(H2O)(2)(p-O2C-C6H4-CO2)](n) (2), [Cu(am1)(2)(NO3)(2)] (3) and [Cu-4(am2)(2)(OAc)(8)]center dot CH3CN center dot 2H(2)O (4) (am2 = N,N'-bis(2-hydroxyethyl)ethylenediamine) were obtained as the main products of the hydrolytic processes. The crystallographic characterisation of all of them shows great structural diversity. Thus, 1 is a mono-aqua bridged coordination polymer and 2 is a terephthalate bridged zig-zag chain, while 3 and 4 are discrete mononuclear and tetranuclear complexes, respectively. Magnetic characterisation of 1, 2 and 4 reveals different behaviours, with magnetic exchanges varying from weak ferromagnetic (2) to quite strong antiferromagnetic (4). The magnetic study of 1 is remarkable, as it constitutes, as far as we know, the first mono-aqua bridged copper(II) chain magnetically analysed, being an antiferromagnetic system. (C) 2015 Elsevier Ltd. All rights reserved.