Synthesis and crystal structure of three new copper(II) complexes with a tridentate amine and its Schiff bases

Three new mononuclear complexes of copper(II), viz. [Cu(L)(N3)Cl] (1), [Cu(L′)(H2O)]ClO4 (2) and [Cu(L″)] (3) where L = N-(3-aminopropyl)-N-methylpropane-1,3-diamine, L′ = 2-(N-{3-[(3-aminopropyl)(methyl)amino]propyl}ethanimidoyl)phenolate ion and L″ = 2,2′-{(methylimino)bis[propane-3,1-diylnitrilo(1E)eth-1-yl-1-ylidene]}diphenolate ion, have been prepared. The synthesis of complex 1 has been achieved by reacting copper chloride with the triamine (L) and sodium azide in a 1:1:1 M ratio. The other two compounds have been synthesized by the reaction of copper perchlorate with the same triamine, L, plus 2-hydroxyacetophenone in a molar ratio of 1:1:1 (for 2) and 1:1:2 (for 3), so that the respective tetradentate and pentadentate Schiff bases HL′ and H2L″ are formed in situ to bind the copper(II) ions. The complexes have been characterized by microanalytical, spectroscopic and single crystal X-ray diffraction studies. Structural studies reveal that the mononuclear units of all the three complexes adopt a distorted square pyramidal geometry and are held together by either intermolecular H-bonding (in 1 and 2) or C–H⋯π interactions (in 3) to form supramolecular networks in the solid state.

Three mononuclear copper(II) complexes, viz. [CuL(N3)Cl] (1), [Cu(L′)(H2O)]ClO4 (2) and [Cu(L″)] (3) where L = N-(3-aminopropyl)-N-methylpropane-1,3-diamine, L′ = 2-(N-{3-[(3-aminopropyl)(methyl)amino]propyl}ethanimidoyl)phenolate and L″ = 2,2′-{(methylimino)bis[propane-3,1-diylnitrilo(1E)eth-1-yl-1-ylidene]}diphenolate, have been prepared. X-ray diffraction studies reveal that the complex units are five-coordinated and are held together by intermolecular H-bonding or C–H⋯π interactions to form supramolecular networks.Figure optionsDownload as PowerPoint slideHighlights
► New Schiff bases were prepared in situ to bind copper(II) ions.
► Two different copper(II) complexes were obtained from same reactants with varying mole ratios.
► All the complexes are five-coordinated and have a distorted square pyramidal geometry.
► H-bonding or C–H⋯π interactions are operative to build up interesting supramolecular structures.