Syntheses, crystal structures and magnetic properties of trinuclear and [3×1+1×2] pentanuclear complexes derived from a compartmental ligand: Role of solvent on nuclearity and number of components

Abstract Reaction of [Cu II L⊂(H 2 O)] (H 2 L =  N , N ′-ethylenebis(3-ethoxysalicylaldimine)) with nickel(II) perchlorate in 1:1 ratio in acetone produces the trinuclear compound [(Cu II L) 2 Ni II (H 2 O) 2 ](ClO 4 ) 2 ( 1 ). On the other hand, on changing the solvent from acetone to methanol, reaction of the same reactants in same ratio produces the pentametallic compound [(Cu II L) 2 Ni II (H 2 O) 2 ](ClO 4 ) 2 ·2[Cu II L⊂(H 2 O)]·2MeOH ( 2A ), which loses solvated methanol molecules immediately after its isolation to form [(Cu II L) 2 Ni II (H 2 O) 2 ](ClO 4 ) 2 ·2[Cu II L⊂(H 2 O)] ( 2B ). Clearly, formation of 1 versus 2A and 2B is solvent dependent. Crystal structures of 1 and 2A have been determined. Interestingly, compound 2A is a [3 × 1 + 1 × 2] cocrystal. The cryomagnetic profiles of 1 and 2B indicate that the two pairs of copper(II)···nickel(II) ions in the trinuclear cores in both the complexes are coupled by almost identical moderate antiferromagnetic interaction ( J  = −22.8 cm −1 for 1 and −26.0 cm −1 for 2B ).