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UBC Theses and Dissertations

Magnetic and medicinal properties of lanthanides Barta, Cheri A.

Abstract

Two distinct projects involving the use of lanthanide metal ions are discussed in this thesis. In the first study, the magnetic interactions in heterometallic d/f complexes were investigated. The most powerful permanent magnet known to date consists of a Nd-Fe core; however, the magnetic exchange between these two metal ions is poorly understood. By purposeful design, new cationic d/f complexes using a multidentate amine phenol ligand were synthesized that selectively coordinate divalent first row d-block transition metal ions (TM) and lanthanides (Ln) in close proximity, a feature desirable for magnetic studies. The synthesis, characterization, and magnetic studies of the d/f cluster complexes with the formula [LnTM₂(bcn)₂]⁺, where H₃bcn = tris-N,N',N" -(2-hydroxybenzyl)-1,4,7-triazocyelononane), TM(II) = Zn, Cu and Ni, and Ln(III)= La, Nd, Gd, Dy and Yb are discussed herein. In addition, the core structure of [TM(Hbcn)], [TM₂(bcn)₃], [La(bcn)], and [La₃(bcn)₂] have been examined. Select magnetic studies were also completed on a similar trimetallic d/f species, [LnNi₂(tam)₂]⁺, where H₃tam = tris-1,1,1-(((2-hydroxybenzyl)amino) methyl)ethane, and Ln(III) = Gd, Dy and Yb, used to compare the magnetic behaviors between geometrically diverse TM(II)-Ln(III) systems. The second study illustrates the usefulness of Ln(III) in metallopharmaceuticals. La(III) ions are known to be functional mimics of Ca(II) ions and have been shown to affect the bone remodeling cycle. Exploiting this disruption to the homeostasis of bone has potential for the treatment of bone density disorders, such as osteoporosis. In an effort to find new orally active agents for these disorders, a series of Ln(III) containing complexes incorporating small, non-toxic, bidentate pyrone and pyridinone ligands have been synthesized and characterized (LnL₃, Ln(III) = La, Eu, Gd, Tb, Yb, L = 3-oxy-2-methyl-4-pyrone (ma-), 3-oxy-2-ethyl-4-pyrone (ema-), 3-oxy-1,2-dimethyl-4-pyridinone (dpp-) and 3-oxy-2-methyl-4(1H)-pyridinone (mpp-)). Preliminary biological analyses undertaken in this thesis include cytotoxicity, cell uptake and bidirectional transport studies in Caco-2 cells and in vitro hydroxyapatite (HA) binding studies analyzed by ICP-MS, fluorescence assays, UV-vis spectrophotometric assays and IR. The LnL₃ species were found to have IC₅₀ values at least 6 times greater than that of cisplatin, ≥98% HA-binding capacity, and permeability coefficients in the moderate range.

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