An unprecedented CuII–Schiff base complex existing as two different trinuclear units with strong antiferromagnetic couplings

A new tetradentate N2O2 donor Schiff base ligand [OHC6H4CHNCH2CH2CH(CH2CH3)NCHC6H4OH = H2L ] was obtained by 1:2 condensation of 1,3-diaminopentane with salicylaldehyde and has been used to synthesise an unusual copper(II) complex whose asymmetric unit presents two structurally different almost linear trinuclear units [Cu3(μ-L)2(ClO4)2] [Cu3(μ-L)2(H2O)(ClO4)2] (1). The ligand and the complex were characterised by elemental analysis, FT-IR, 1H NMR and UV–Vis spectroscopy in addition electrochemical and single crystal X-ray diffraction studies were performed for the complex. The magnetic properties of 1 reveal the presence of strong intra-trimer (J1 = −202(3) cm−1 and J2 = −233(3) cm−1) as well as very weak inter-trimer (zJ′ = −0.11(1) cm−1) antiferromagnetic interactions.

Graphical abstractA new tetradentate N2O2 donor Schiff base ligand was obtained by 1:2 condensation of 1,3-diaminopentane with salicylaldehyde and has been used to synthesise an unusual copper(II) complex (1) whose asymmetric unit presents two structurally different almost linear trinuclear units. The ligand and the complex were characterised by elemental analysis, FT-IR, 1H NMR, UV–Vis, electrochemical and single crystal X-ray diffraction studies. The magnetic properties of 1 reveal the presence of strong intra-trimer and as well as very weak inter-trimer antiferromagnetic interactions.Figure optionsDownload full-size imageDownload as PowerPoint slide