Axial additions in nickel(II) complexes of 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane:: syntheses and crystal structures of the octahedral nickel(II) complexes

The complex [NiL]Cl-2 . 2H(2)O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0(1.18),0(7.12)]docosane) undergoes axial additions with monodentate ligands (X = N-3(-), NCS-). The octahedral [NiLX2] complexes have been characterised and structures established by X-ray crystallography. The crystal structures of [NIL(N-3)(2)] 1 and [NiL(NCS)(2)] 2 show that both structures are centrosymmetric and the nickel centre has an axially elongated octahedral geometry with two nitrogen atoms of the axial ligands. Electronic spectra and redox potentials of the complexes also reveal a high-spin octahedral geometry, which is reflected by the nature of the axial ligands. (C) 1998 Elsevier Science Ltd. All rights reserved.