TY - JOUR
T1 - Synthesis and characterisation of [[µ-(1,7,11,17-tatraaza-2.6.12.16-tetraoxacycloeicosane)][µ-(aquo)bis(acac)(ethanol)Ni(II)]][BPh4]2
AU - Novak, M. A.
AU - Prado, P. F.
AU - Silva, M. V. D. R. E.
AU - Skakle, Janet Mabel Scott
AU - Vaz, M. G. F.
AU - Wardell, J. L.
AU - Wardell, S. M. S. V.
PY - 2005
Y1 - 2005
N2 - The pale blue title compound, 4, was obtained from the reaction between 1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane, Ni(acac)(2) and NaBPh4 in aqueous acetone. X-ray structure determination at 120 K revealed that the dication of the ionic complex, 4, contains two independent octahedral Ni-II centres with trans-Ni2N2O4 chromophores. The macrocyclic ligand and an aqua ligand act as bridges to the two nickel centres: the Ni-O(aquo)-N bond angle is 137.65(17)degrees. Each Ni centre is bonded to two nitrogens of the macrocycle, to a chelating acac unit, to an ethanol molecule as well as the bridging oxygen of the aqua group. The two nickel atoms sit outside the macrocycle cavity, such that the macrocyclic ligand acts as a canopy for the remainder of the dication. While none of the macrocycle oxygens are involved in the coordination to Ni, they are involved in internal hydrogen bonding with the aqua and ethanol ligands. Magnetic measurements show a paramagnetic behaviour down to 2 K, with an effective moment of 2.8 Bohr magnetons at room temperature. (c) 2004 Elsevier B.V. All rights reserved.
AB - The pale blue title compound, 4, was obtained from the reaction between 1,7,11,17-tetraaza-2,6,12,16-tetraoxacycloeicosane, Ni(acac)(2) and NaBPh4 in aqueous acetone. X-ray structure determination at 120 K revealed that the dication of the ionic complex, 4, contains two independent octahedral Ni-II centres with trans-Ni2N2O4 chromophores. The macrocyclic ligand and an aqua ligand act as bridges to the two nickel centres: the Ni-O(aquo)-N bond angle is 137.65(17)degrees. Each Ni centre is bonded to two nitrogens of the macrocycle, to a chelating acac unit, to an ethanol molecule as well as the bridging oxygen of the aqua group. The two nickel atoms sit outside the macrocycle cavity, such that the macrocyclic ligand acts as a canopy for the remainder of the dication. While none of the macrocycle oxygens are involved in the coordination to Ni, they are involved in internal hydrogen bonding with the aqua and ethanol ligands. Magnetic measurements show a paramagnetic behaviour down to 2 K, with an effective moment of 2.8 Bohr magnetons at room temperature. (c) 2004 Elsevier B.V. All rights reserved.
KW - macrocycle ligand
KW - magnetic behaviour
KW - nickel complex
KW - crystallography
KW - CRYSTAL-STRUCTURE
KW - COPPER(II) COMPLEXES
KW - NICKEL(II) COMPLEXES
KW - CHEMISTRY
KW - 1,4,8,11-TETRAAZACYCLOTETRADECANE
KW - MACROCYCLES
KW - CYCLAM
U2 - 10.1016/j.ica.2004.10.023
DO - 10.1016/j.ica.2004.10.023
M3 - Article
VL - 358
SP - 941
EP - 946
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
SN - 0020-1693
ER -