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Solid State And Solution Dynamics Of Pyridine Based Tetraaza- Macrocyclic Lanthanide Chelates Possessing Phosphonate Ligating Functionality (Ln-Pctmb): Effect On Relaxometry And Optical Properties, Garry Kiefer, Mark Woods

Chemistry Faculty Publications and Presentations

The macrocyclic ligand 3,6,9-tris(methylenebutyl phosphonic acid)-3,6,9−15-tetraazabicyclo [9.3.1]pentadeca-1(15),11,13-triene (PCTMB) was synthesized and complexes of Eu³⁺, Tb³⁺, and Gd³⁺ studied by X-ray crystallography, luminescence, and relaxometry. In the crystal these complexes are dimeric and possess 8-coordinate Ln³⁺ centers that are linked by bridging phosphonates. The rigidity introduced by the pyridyl nucleus forces the EuPCTMB and TbPCTMB to adopt a twisted snub disphenoid (TSD) coordination geometry. Examination of the ⁵D₀ → ⁷F₀ luminescent transition of EuPCTMB in the solid state confirmed the existence of a single distinct Eu³⁺ coordination environment, whereas two …