259868-91-2Relevant academic research and scientific papers
Coaggregation of paramagnetic d- and f-block metal ions with a podand-framework amine phenol ligand
Xu, Zhiqiang,Read, Paul W.,Hibbs, David E.,Hursthouse, Michael B.,Malik, K. M. Abdul,Patrick, Brian O.,Rettig, Steven J.,Seid, Mehran,Summers, David A.,Pink, Maren,Thompson, Robert C.,Orvig, Chris
, p. 508 - 516 (2000)
This report covers initial studies in the coaggregation of nickel (Ni2+) and lanthanide (Ln3+) metal ions to form complexes with interesting structural and magnetic properties. The tripodal amine phenol ligand H3tam (1,1,1-tris(((2-hydroxybenzyl)amino)methyl)ethane) is shown to be particularly accommodating with respect to the geometric constraints of both transition and lanthanide metal ions, forming isolable complexes with both of these ion types. In the solid-state structure of [Ni(H2tam)(CH3CN)]PF6·2.5CH3CN·0.5CH3OH (1), the Ni(II) center has a distorted octahedral geometry, with an N3O2 donor set from the [H2tam]- ligand and a coordinated solvent (acetonitrile) occupying the sixth site. The reaction of stoichiometric amounts of H3tam with the Ni(II) ion in the presence of lanthanide(III) ions provides [LnNi2(tam)2]+ cationic complexes which contain coaggregated metal ions. These complexes are isolable and have been characterized by a variety of analytical techniques, with mass spectrometry proving to be particularly diagnostic. The solid-state structures of [LaNi2(tam)2(CH3OH)( 1/2 )-(CH3CH2OH)( 1/2 )(H2O)]Cl04·0.5CH3OH·0.5CH3CH 2OH·4H2O (2), [DyNi2(tam)2(CH3OH)(H2O)]ClO4·CH3H·H2O (6), and [YbNi2(tam)2(H2O)]ClO4·2.58H2O (9) have been determined. Each complex contains two octahedral Ni(II) ions, each of which is encapsulated by the ligand tam3- in an N3O3 coordination sphere; each [Ni(tam)]- unit caps the lanthanide(III) ion via bridging phenoxy oxygen donor atoms. In 2, La3+ is eight-coordinated, while in 6, Dy(III) is seven- (to 'weakly eight-') coordinated, and Yb(III) in 9 has a six-coordination environment. The complexes are symmetrically different, 2 possessing C2 symmetry and 6 and 9 having C1 symmetry. Magnetic studies of 2, 6, and 9 indicate that antiferromagnetic exchange coupling between the Ni(II) and Ln(III) ions increases with decreasing ionic radius of Ln(III).
