A flexible multidentate Schiff-base ligand having multifarious coordination modes in its copper(II) and cadmium(II) complexes

A mononuclear complex, [CuL2]center dot 2(CH3OH) (1), and two one-dimensional (1D) coordination polymers, {[Cu3L4(CH3OH)(2)]center dot(NO3)(2)}(n) (2) and [Cd(LH)(2)(N-3)(2)](n) (3), having a flexible multidentate Schiff-base ligand, 2-(3-(1H-imidazol-1-yl)propyliminomethyl)phenol (LH), with multifarious coordination modes have been obtained in different solvents and pH values. Another 1D cadmium(II) coordination polymer, [Cd(apimH)(2)Br-3](n) (4) (apim = (3-aminopropyl)imidazole), is also included for comparison. A four-coordinate square-planar Cu(II) center is formed in 1 where L serves as a bidentate N,O-chelating ligand, while two five-coordinate dinuclear Cu(II) centers and one six-coordinate mononuclear Cu(II) center are alternately arranged via two tridentate ligands in 2. In contrast, six-coordinate Cd(II) centers are constructed in 3 and 4, in the absence of a base, and they are bridged by double mu(2) azide anions in an end-to-end way in 3 and alternate mono and triple mu(2) bromine anions in 4. Furthermore, FT-IR, H-1 NMR, UV-Vis and fluorescence spectral comparisons between LH and its metal complexes have been studied. (C) 2013 Elsevier Ltd. All rights reserved.