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

Reaction of [(CuL)-L-II subset of(H2O)] (H2L = N,N'-ethylenebis(3-ethoxysalicylaldimine)) with nickel(II) perchlorate in 1:1 ratio in acetone produces the trinuclear compound [((CuL)-L-II)(2)Ni-II(H2O)(2)](ClO4)(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 [((CuL)-L-II)(2)Ni-II(H2O)(2)](ClO4)(2)center dot 2[(CuL)-L-II subset of(H2O)]center dot 2MeOH (2A), which loses solvated methanol molecules immediately after its isolation to form [((CuL)-L-II)(2)Ni-II(H2O)(2)](ClO4)(2)center dot 2[(CuL)-L-II subset of(H2O)] (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 x 1 + 1 x 2] cocrystal. The cryomagnetic profiles of 1 and 2B indicate that the two pairs of copper(II)center dot center dot center dot 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). (C) 2010 Elsevier B.V. All rights reserved.