Syntheses, crystal structures and antioxidant properties of four complexes derived from a new Schiff base ligand (N1E,N2E)-N 1,N2-bis(1-(pyrazin-2-yl)ethylidene)ethane-1,2 diamine

Abstract

Four Ag(I), Cd(II) and Cu(II) complexes, [Ag2L 2](ClO4)2 (1), [CdL(NO3) 2] (2), [Cd2L2Cl4] (3) and [Cu 2L2(ClO4)3](ClO4) (4), derived from the new Schiff base ligand (N1E,N2E)-N 1,N2-bis(1-(pyrazin-2-yl)ethylidene)ethane-1,2 diamine (L) have been synthesized and crystallographically characterized. The crystal structural features of 1-4 show that 1 is a ligand-supported dinuclear silver complex, 2 is a mononuclear eight-coordinate complex, 3 is a dinuclear hepta coordinate species and 4, interestingly, discloses two distinctly crystallographically independent groups of mononuclear [Cu(ClO4) 2L] and a 1D [Cu(ClO4)L](ClO4) unit in one asymmetric group. Furthermore, πâ̄π stacking and/or hydrogen bonding interactions seem to be effective in stabilizing these crystal structures. The antioxidant activities of L and complexes 1-4 have also been studied. © 2013 Elsevier Ltd. All rights reserved.