Room-Temperature Magnetic Liquid Complexes of 2-Hexyldecanoato Ligand with Cu(II), Ni(II) and Co(II) Ions

Three new complexes [Cu-2(L)(4)(LH)(2)] (1), [Ni-2(L)(4)(EtOH)(2)(H2O)(2)]center dot H2O center dot CHCl3 (2) and [Co-2(L)(4)(H2O)(4)]center dot 3H(2)O (3), were obtained as coloured viscous liquids at room temperature (30 degrees C) and in good yields from the reaction of sodium 2-hexyldecanoate (NaL) with the corresponding MCl2 (M = Cu, Ni or Co). The structural formulae of these complexes were indirectly deduced by a combination of analytical results and additionally for 1, inferred from that of [Cu-2(CH3(CH2)(5)COO)(4)] (4) obtained as single crystals under similar synthetic conditions. Complexes 1-3 were paramagnetic with weak antiferromagnetic interactions between the two M(II) centres, while 4 has a significantly stronger antiferromagnetic interaction. Complex 3 was also high spin. These complexes were thermally stable: 1 and 2 decomposed at 200 degrees C, 3 at 150 degrees C and 4 at 280 degrees C. However, they were redox inactive in the potential range -1.5 V to +1.5 V, while only 1 was mesogenic with a hexagonal columnar mesophase (Colh) at -23.2 degrees C.