Synthesis and characterization of lanthanide complexes of the lacunary Wells-Dawson heteropolyanions.
Item
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Title
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Synthesis and characterization of lanthanide complexes of the lacunary Wells-Dawson heteropolyanions.
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Identifier
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AAI9807904
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identifier
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9807904
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Creator
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Bartis, Judit.
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Contributor
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Adviser: Lynn C. Francesconi
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Date
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1997
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Inorganic | Chemistry, Analytical
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Abstract
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The preparation of the {dollar}\alpha{dollar}-1 and {dollar}\alpha{dollar}-2 isomers of the lacunary Wells-Dawson heteropolyanions by standard methods is accompanied by a significant proportion of the other isomer present as an impurity. In this study the {dollar}\alpha{dollar}-1 and {dollar}\alpha{dollar}-2 isomers of (ZnP{dollar}\rm\sb2W\sb{17}O\sb{lcub}61{rcub}\rbrack\sp{lcub}8-{rcub}{dollar} and lanthanide complexes of the {dollar}\rm\lbrack P\sb2W\sb{17}O\sb{lcub}61{rcub}\rbrack\sp{lcub}10-{rcub}{dollar} heteropolyoxotungstate have been prepared in {dollar}>{dollar}98% purity, and characterized by multinuclear NMR spectroscopy among the other techniques. The first direct proof of the C{dollar}\sb1{dollar} symmetry of the {dollar}\alpha{dollar}-1 isomer has been obtained by {dollar}\sp{lcub}183{rcub}{dollar}W NMR spectroscopy.;Solution titration data monitored by {dollar}\sp{lcub}31{rcub}{dollar}P NMR spectroscopy show that both the 1:1 and 1:2 Ln: ({dollar}\alpha{dollar}-2 {dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub}\rbrack\sp{lcub}10-{rcub}{dollar} exist in aqueous solution at pH = 4.7 for a variety of Ln ions proceeding across the lanthanide series. The (Ln({dollar}\alpha{dollar}-2 P{dollar}\rm\sb2W\sb{17}O\sb{lcub}61{rcub})\sb2\rbrack\sp{lcub}17-{rcub}{dollar} family of complexes show a nine line pattern in the {dollar}\sp{lcub}183{rcub}{dollar}W NMR spectrum at room temperature for the lanthanum derivative, consistent with a symmetrical structure (C{dollar}\rm\sb{lcub}2h{rcub}{dollar} or C{dollar}\rm\sb{lcub}2v{rcub}{dollar} symmetry), and seventeen, line pattern for the lutetium analog, suggesting a lower symmetry (C{dollar}\sb2).{dollar} High temperature {dollar}\sp{lcub}183{rcub}{dollar}W NMR experiments on the (Lu({dollar}\alpha{dollar}-2 {dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub})\sb2\rbrack\sp{lcub}17-{rcub}{dollar} compound showed reversible broadening and coalescence of the resonances, due to a dynamic effect, possibly rotation of the oxoanion ligand.;The crystal structure of the K{dollar}\sb{17}{dollar}(Lu({dollar}\alpha{dollar}-2 {dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub})\sb2\rbrack{dollar} shows the lutetium ion bound to four oxygen atoms of the ({dollar}\alpha{dollar}-2 {dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub}\rbrack\sp{lcub}10-{rcub}{dollar} in a square antiprismatic coordination environment. {dollar}\sp{lcub}183{rcub}{dollar}W NMR data for the isolated (Ln({dollar}\alpha{dollar}-2 {dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub})\sb2\rbrack\sp{lcub}17-{rcub}{dollar} complexes in aqueous solution are consistent with the crystal structure data.;The solution stoichiometry of the lanthanide complexes of the ({dollar}\alpha{dollar}-1 {dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub}\rbrack\sp{lcub}10-{rcub}{dollar} has been determined using complexometric titration experiments combined with {dollar}\sp{lcub}31{rcub}{dollar}P NMR spectroscopy. The results show that {dollar}\alpha{dollar}-1 ({dollar}\rm P\sb2W\sb{17}O\sb{lcub}61{rcub}\rbrack\sp{lcub}10-{rcub}{dollar} complexes with lanthanides in 1:2 stoichiometric ratio only.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
