摘要:
N-Salicylideneglycinatocopper(II) complexes of the composition Cu(salgly) (L(s))(H2O)(x) were synthesized with L(s) = thiourea, N-methylthiourea, N,N,N',N'-tetramethylthiourea, N-ethylthiourea, N,N'-diethylthiourea, N-(2-chlorphenyl)thiourea, N,N'-diphenylthiourea, N,N'-ethylenethiourea, N,N'-phenylenethiourea [equivalent to 1,3-dihydrobenzimidazole-2-thione]; and x = 0 or 1. The EPR spectra gave evidence for square-pyramidal coordination around Cu-II, however, with a different strength of axial interaction originating from an oxygen atom from the adjacent complex molecule. In the case of monohydrates bonding of a water molecule is also possible. In two examples, even square-planar geometry, without any significant axial interaction can be assumed. The great variety of cooperative ordering phenomena in the structure, which is caused mainly by the extraordinary flexibility of the Schiff base ligand, results in coupling patterns ranging from ferrodistortive to antiferrodistortive. These patterns are remarkably influenced by the substitutions on thiourea. Both the global and local symmetry effects are analysed with the aid of EPR spectroscopy.