Structural diversity and magnetic properties of a series of transition metal complexes based on 1,1′-binaphthalenyl-2,2′-diamine-N,N,N′,N′-tetraacetic acid

Abstract

Five complexes, [Mn2(L)(H2O)5]·3H2O (1), [Fe(L)](Et3N+H) (2), {[Co2(L)(H2O)4]·2.25H2O}n (3), {[Ni2(L)(H2O)4]·2H2O}n (4) and {[CuNa2(L)(H2O)5]·H2O}n (5), have been synthesized by self-assembly of a N-containing polycarboxylic acid ligand H4L and corresponding metal salts, H4L=1,1′-binaphthalenyl-2,2′-diamine-N,N,N′,N′-tetraacetic acid. Interestingly, complexes 1–5 display a structural variation from discrete 0D to 1D coordination polymer and 2D framework, depending on the identity of the metal ion. The structure of 1 is dinuclear, and that of 2 is mononuclear. Complexes 3 and 4 show similar structure in which the metal ions are joined by alternating syn–anti and anti–anti bridging carboxylate groups of L4− into a zigzag chain. Complex 5 is a novel 3s–3d heterometallic 2D polymer constructed from trinuclear units [CuNa2(L)(H2O)5]. The magnetic investigations of 1, 3 and 4 were carried out, which indicates the presence of dominant antiferromagnetic exchanges mediated by the alternating syn–anti and anti–anti bridging carboxylate groups between the metal centers.