[Ni(L)(MeCN)][BF4]2 {L = 2,5,8-trithia[9],(2,9)-1,10-phenanthrolinophane} as a building block for the synthesis of binuclear nickel(II) complexes: X-ray crystal structure and magnetochemistry of a singly F-bridged nickel(II) dimer

Abstract

The substitution reactions of the coordinated acetonitrile molecule in [Ni(L)(MeCN)][BF4]2 (1) {L = 2,5,8-trithia[9],(2,9)-1,10-phenanthrolinophane} with three potentially bidentate ligands L′ (L′ = N3−, 4,4′-bipyridine and F−) have been studied both in solution and in the solid state with the aim of verifying the potential of 1 as a starting material for the synthesis of [{Ni(L)}2L′]n+ (n = 3, 4) NiII-binuclear compounds. While the mononuclear [Ni(L)(N3)]BF4 complex was isolated in the solid state from the reaction of 1 with N3−, the binuclear [{Ni(L)}2F][BF4]3·MeCN·H2O and [{Ni(L)}2(4,4′-bipy)][BF4]4 compounds have been obtained from the reactions of 1 with F− and 4,4′-bipy, respectively. The first two complexes have been characterised by X-ray diffraction studies. In [Ni(L)(N3)]+, a distorted octahedral geometry is achieved at the NiII, with five sites occupied by the macrocyclic ligand L and the sixth by a monodentate azide group. In [{Ni(L)}2F]3+, two [Ni(L)]2+ units are bridged by a fluoride ligand to give only the second example of a singly F-bridged NiII dimer. The magnetisation of [{Ni(L)}2F][BF4]3·MeCN·H2O and of [{Ni(L)}2(4,4′-bipy)][BF4]4 has been recorded over the temperature range 1.8–300 K and indicates a significant antiferromagnetic exchange in the former.