Synthesis and characterisation of two double EE azido and thiocyanato bridged dimeric Cu(II) complexes with tridentate Schiff bases as blocking ligands

Two new double end-to-end azido and thiocyanato bridged copper(II) dimers [Cu-2(L-1)(2)(N-3)(2)(CIO4)(2)] (1) and [Cu-2(L-2)(2)(NCS)(2)](CIO4)(2) (2), where L-1 (N,N-dimethyl-N'-(1-pyridin-2-yl-ethylidene)-ethane-1,2-diamine) and L-2 (N,N-diethyl-N'-(1-pyridin-2-yl-ethylidene)-ethane-1,2-diamine) are tridentate Schiff bases, have been synthesized and their molecular structures have been determined by X-ray crystallography. Copper(II) shows octahedral geometry in 1 and square-pyramidal in 2. The copper(II) in both the compounds are bonded to three nitrogen atoms of the tridentate ligands in met orientations and the forth coordination sites of basal planes are occupied by the nitrogen atom of azide (in 1) or thiocyanate (in 2). The fifth coordination sites of central copper(II) are occupied by a symmetry related N or S of azide or thiocyanate respectively, thereby creating centrosymmetric dimers. Perchlorate oxygen occupies the sixth coordination site of copper(II) in 1. The octahedral geometry of copper(II) in 1 is facilitated by less steric crowding. (C) 2012 Elsevier Ltd. All rights reserved.