[Ni(L)(MeCN)][BF4]2 {L=2,5,8-trithia[9],(2,9)-1,10-phenanthro-linophane} 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

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' = N-3(-), 4,4'-bipyridine and F-) have been studied both in solution and in the solid state with the aim of verifying the potential of I as a starting material for the synthesis of [{Ni(L)}(2)L'](n+) (n = 3, 4) Ni-II-binuclear compounds. While the mononuclear [Ni(L)(N-3)]BF4 complex was isolated in the solid state from the reaction of 1 with N-3(-), the binuclear [{Ni(L)}(2)F][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)(N-3)](+), a distorted octahedral geometry is achieved at the Ni-II, with five sites occupied by the macrocyclic ligand L and the sixth by a monodentate azide group. In [{Ni(L)}(2)F](3+), two [Ni(L)](2+) units are bridged by a fluoride ligand to give only the second example of a singly F-bridged N-II dimer. The magnetisation of [{Ni(L)}(2)F][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.