LanguageTerm (authority = ISO 639-3:2007); (type = text)
English
Abstract
A series of novel molecular lanthanide and actinide chalcogenolate compounds have been prepared with different neutral donor ligands. Three lanthanide fluorinated selenolate monomers (DME)2Ln(SeC6F5)3 (Ln = Nd, Er, Tm, DME = 1,2-Dimethoxyethane) were synthesized in high yields by reductive cleavage of the Se-Se bond in (SeC6F5)2 with elemental Ln in DME. Their structural and optical properties are discussed. Emission measurements indicate that these compounds are bright NIR sources. A number of dimeric thorium disulfide and diselenide compounds have been prepared with sterically undemanding ancillary chalcogenolate ligands. Five complexes, (py)6Th2I4(S2)2 (py)6Th2Br2(SC6F5)2(S2)2, (py)6Th2I4(Se2)2, (py)6Th2I2(SC6F5)2(Se2)2, and (py)6Th2Br2(SC6F5)2(Se2)2 (py = pyridine) were isolated in high yields by first reducing mixtures of metal Th, chalcogenolate ligands and halide sources (I2 or PhSeBr) in py, followed by in-situ ligand based redox reactions with elemental sulfur or selenium. These are the first examples of thorium compounds with bridging dichalcogenide ligands. Attempts to prepare chloride derivatives gave mixtures of (py)4ThCl4 and either (py)6Th2Cl2(SC6F5)2(S2)2 or (py)8Th4Se4(SePh)4(SC6F5)4. A computational analysis of experimental 77Se NMR chemical shifts reveals that the dimeric structures with two bridging dichalcogenides are maintained in solution. Thermolysis of (py)6Th2I4(Se2)2 leads to the formation of solid-state ThSe2 and I2. The identities of chalcogenolate ligands and neutral donor ligands have been found to influence the structures of thorium compounds. Three Th monomers, (bipy)2Th(SC6F5)4, (Hpz)4(pz)Th(SC6F5)3 (Hdmpz)2(dmpz)2Th(SC6F5)2 and three Th dimers, (pzn)4Th2(SC6F5)8, (Hpz)4(pz)2Th2(SePh)6 (Hdmpz)4(dmpz)2Th2(SC6F5)6 (bipy=2,2’-bipyridine, pzn = pyrazine; Hpz = pyrazole, Hdmpz= 3,5 dimethylpyrazole) have been prepared and characterized. Reaction of Th, (SeC6F5)2 and Hpz in toluene also results in a thorium cluster (Hpz)8Th4Se4(SeC6F5)8 with Th4Se4 cubane core. Several thorium and uranium oxo- and fluoro- compounds were also synthesized. Oxo compounds (py)6Th2O(Se2)I4, (py)6U2O(Se2)I4, and (py)10Th6O3(Se2)8(SC6F5)2 were prepared by adding elemental Se and SeO2 into the mixture of metal Th or U, chalcogenolate ligands and halide sources in py. Two fluoride complexes have also been prepared. Coming from the reactions of metal Th or U, (SC6F5)2 and I2 in py, (py)4ThI3F contains fluoride from the original (SC6F5)2; while the uranium derivative, (py)3UI3(SC6F5) follows stoichiometry of the starting materials.
Subject (authority = RUETD)
Topic
Chemistry and Chemical Biology
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TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
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