Sterically-controlled nuclearity in new copper(II) complexes with di-compartmental ligands: Formation of antiferromagnetically coupled angular trimer and mononuclear inclusion complex

Two new copper(II) complexes, [Cu-3(L-1)(2)(H2O)(2)](ClO4)(2) (1) and [CuL2 subset of (H2O)] (2) have been derived from two di-compartmental Schiff base ligands H2L1 and H2L2, respectively. Depending on slight modification of the substituent group of the potentially N2O4 donor ligands, tri- and mononuclear structures are obtained, which have been confirmed by single-crystal X-ray diffraction studies. Both complexes have been characterized by elemental analysis, IR, UV-vis and EPR spectroscopy. Complex 1 consists of an angular trinuclear array of copper ions, while complex 2 consists of a mononuclear copper center. Variable temperature magnetic susceptibility measurements have been performed to investigate the magnetic behaviour of complex 1 and the result indicates a strong antiferromagnetic exchange interaction (J = -120.1(2) cm(-1)) between the adjacent copper(II) centers through two double mu(2)-phenoxo bridges. Complex 2 is a mononuclear inclusion compound encapsulating one water molecule in the vacant external compartment of the ligand through hydrogen-bonding interactions. (C) 2010 Elsevier B.V. All rights reserved.