Description
TitleFinding new equilibria
Date Created2013
Other Date2013-05 (degree)
Extentxviii, 129 p. : ill.
DescriptionThis dissertation covers the synthesis and characterization of three unique classes of lanthanide materials produced exclusively by the addition of sodium azide (NaN3) into solution based lanthanide reactions. The products were achieved through transmetallation and redox reactions between rare earth chalcogenolate reagents (Lnx(EPh)y), NaN3 and elemental chalcogenides (E = O, S, Se, Te). The products displayed atypical structural and physical properties including; unique coordination geometries, high nuclearities, tunable detonation/deflagration, strong NIR emissions, and unexpected magnetic ordering behaviors. The introduction of NaN3, Na2O, Cd, elemental Se and Te into Ln (EPh)2 and Ln(EPh)3 pyridine (py) solutions led to the production of (py) 2Na2(EPh)2 and 5 structurally distinct azide encapsulated rare earth clusters; (Py)10Sm6O2(N3)16Na2, (py)8Ln6O2(N3)12(SePh)2, (py)10Ln6O2(Se2) 2(N3)10 (Ln=Er, Ho), and (py)16Sm8Se(O2)Na2(Te2)6(N3)8. Each system was encapsulated by a variety of azide bridging moieties, while exhibiting a [Ln]/[N3] dependent correlation with detonation and deflagration temperatures. ! The inclusion of NaN3 in Ln(SePh)3 pyridine solutions with elemental Se, led to the discovery of the (py)16Ln17NaSe18(SePh)16; (Ln= Ce, Pr, and Nd). Emission studies of the Nd17 analogue, revealed a 35% quantum efficiency for the 4F3/2 - 4I11/2 transition (1070 nm emission), and a near solid state emission intensity for the 4F3/2 → 4I15/2 transition (1822 nm emission). The novel Eu(EPh)4Na2•2DME; (E=S,Se), specimens were synthesized by the combination of Eu(EPh)2 with NaN3 in dimethoxyethane (DME). The europium coordination sphere was solvent free and resembles the coordinations of europium monochalcogenides (EuE). Comparative structural analysis and magnetic susceptibility studies of the Eu3+ product, ((py)6Eu2(μ4-S2)2(OC6F5)2) revealed paramagnetic ordering at low temperature for Eu(EPh)4Na2•2DME; (E=S,Se), while ferrimagnetic ordering was found for ((py)6Eu2(μ4-S2)2(OC6F5)2). All materials exhibited antiferromagnetic ordering above 50 K, while a Curie temperature of 18.0 K was determined for ((py)6Eu2(μ2-S2)2-(OC6F5)2).
NotePh.D.
NoteIncludes bibliographical references
NoteIncludes vita
Noteby Brian Freeman Moore
Genretheses, ETD doctoral
Languageeng
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.