Synthesis and crystal structures of N,N'-bis(5-methylsalicylidene)ethane-1,2-diamine and its bromido-, phenolato-, and dicyanoamido-cobridged polymeric copper(II) complex

Abstract

A bis-Schiff base N,N'-bis(5-methylsalicylidene)ethane-1,2-diamine (H2L) was prepared and characterized by elemental analysis, 1H NMR and 13C NMR spectra, MS, and single crystal X-ray diffraction (CIF file CCDC no. 1022761 (H2L)). Reaction of the Schiff base with copper bromide and sodium dicyanoamide in methanol gave a novel bromido-, phenolato-, and dicyanoamido-cobridged polymeric copper(II) complex, ({Cu2LBr[N(CN)2]}2)n (I). Structure of complex I was characterized by elemental analysis and single crystal X-ray diffraction (CIF file CCDC no. 1022762 (I)). The smallest repeat unit of complex I is a dicyanoamide bridged tetranuclear copper(II) complex moiety, {Cu2LBr[N(CN)2]}2, in which there possesses a crystallographic inversion symmetry. The tetranuclear moieties are further linked through Br atoms, forming a zigzag chain. The chains are further linked by dicyanoamide ligands, forming a 2D network. One Cu atom in complex I is coordinated by two N and two O atoms of the Schiff base ligand and one Br atom, forming square pyramidal geometry. The other Cu atom is coordinated by two N atoms of the Schiff base ligand, two N atoms of dicyanoamide ligands, and one Br atom, forming square pyramidal geometry. The bromido-, phenolato-, and dicyanoamido-cobridged Cu···Cu distances are 4.823(2), 2.955(1), and 7.121(3) A, respectively. The [Cu2L] units are linked by the bridging groups, to form 2D chains along the xy plane.