13002-64-7Relevant articles and documents
cis-Octahedral nickel(II) complexes with symmetric and unsymmetric tripodal tetraamine ligands
Ochs, Christian,Hahn, F. Ekkehardt,Lugger, Thomas
, p. 1279 - 1285 (2001)
Nickel(II) complexes with the aliphatic tripodal tetraamine ligands N(CH2CH2NH2)3 (tren, 1), N[(CH2CH2CH2NH2)(CH 2CH2NH2)2] (baep, 2), N[(CH2CH2CH2NH2)2 -(CH2CH2NH2)] (abap, 3), and N(CH2CH2CH2NH2)3 (trpn, 4) are reported. The tripodal tetradentate N4 ligands 1-4 react with Ni(NO3)2·6H2O in acetonitrile or methanol to give the blue nickel(II) complexes [Ni(1)(η1-NO3)2] (5a), [Ni(2)(η1 NO3)2] (5b), [Ni(3)(η2-NO3)]NO3·CH 3CN (5c·CH3CN), and [Ni(4)(η2-NO3)]NO3·CH 3OH (5d·CH3OH). With NiCl2·6H2O, the complexes [Ni(1)Cl(H2O)]Cl·H2O (6a), [Ni(2)(μCl)2Ni(2)]Cl2·2CH3OH (6b·2CH3OH), [Ni(3)Cl(H2O)]Cl (6c), and [Ni(4)(H2O)2]Cl2·H2O (6d·H2O) are obtained. The molecular structures of complexes 5a-d and 6b-d have been determined by X-ray diffraction analysis and they are compared with the molecular structure of the previously characterized complex 6a. Complexes 5a-d and 6b-d exhibit octahedrally coordinated nickel atoms. The tripodal ligands occupy four of the six coordination sites in a pseudo-facial manner. Complexes of the unsymmetrical ligands 2 and 3 possess both five- and six-membered chelate rings. The extension of the ligand arms in 1-4 leads to a systematic variation in the geometric and UV/Vis spectroscopic properties of the complexes depending on the size of the chelate rings formed by the ligands.
