Synthesis and Reactivity of Iso- and Hetero-Polyoxotungstates Containing Organic Subunits

Hur, Nam Hwi

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Description

Title

Synthesis and Reactivity of Iso- and Hetero-Polyoxotungstates Containing Organic Subunits

Author(s)

Hur, Nam Hwi

Issue Date

1987

Doctoral Committee Chair(s)

Klemperer, Walter G.

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Chemistry, Inorganic

Abstract

• The RCHMo$\sb4$O$\sb $H$\sp{3-}$(R = H, CH$\sb3$, CH$\sb2$CH) anions were prepared by reaction of Mo$\sb2$O$\sb7\sp{2-}$ with the appropriate aldehyde RCHO. The tungstate analogues RCHW$\sb4$O$\sb $H$\sp{3-}$ (R = H, CH$\sb3$, CH$\sb2$CH) were prepared by treatment of WO$\sb4\sp{2-}$ with the aldehyde in the presence of an equimolar amount of acids (e.g. HCl), and were isolated as pure crystalline solids. The spectroscopic data is consistent with all these anions being isostructural. The relative thermal stabilities of these compounds in CD$\sb3$CN solution were examined by measuring their $\sp1$H NMR spectra under several different conditions.
• The OHCCHMo$\sb4$O$\sb $H$\sp{3-}$ anion was prepared by reaction of 2,3-dihydroxy-1,4-dioxane with Mo$\sb2$O$\sb7\sp{2-}$ in the presence of a stoichiomeric amount of acid. Similarly, the tungstate OHCCHW$\sb4$O$\sb $H$\sp{3-}$ was obtained by treatment of 2,3-dihydroxy-1,4-dioxane with WO$\sb4\sp{2-}$ plus equimolar HCl. These compounds are also assumed to be isostructural with the RCHM$\sb4$O$\sb $H$\sp{3-}$ anions on the basis of the spectroscopic data. Reaction of OHCCHMo$\sb4$O$\sb $H$\sp{3-}$ with acids such as formic acid and hydrofluoric acid gave the diacetal adducts HCCHMo$\sb4$O$\sb $X$\sp{3-}$(X = HCOO, F). The tungstates HCCHW$\sb4$O$\sb $X$\sp{3-}$(X = HCOO, F) were prepared by a method similar to that used to prepare HCCHMo$\sb4$O$\sb $X$\sp{3-}$. All of these compounds were characterized spectroscopically. The spectroscopic results suggest that all of the anions have a common structure. The relative thermal stabilities of the diacetal adducts were also examined in CD$\sb3$CN solution.
• The (P$\sb3$O$\sb9$)WO$\sb2$Cl$\sp{2-}$ anion was obtained by treatment of WO$\sb2$Cl$\sb2$ with P$\sb3$O$\sb9\sp{3-}$. Reaction of (P$\sb3$O$\sb9$)WO$\sb2$Cl$\sp{2-}$ with (n-C$\sb4$H$\sb9$)$\sb4$NOH in methanol yielded the methyl ester, (P$\sb3$O$\sb9$)WO$\sb2$OCH$\sb3\sp{2-}$. The ethyl, isopropyl, and allyl esters (P$\sb3$O$\sb9$)WO$\sb2$OR$\sp{2-}$(R = C$\sb2$H$\sb5$, CH(CH$\sb3$)$\sb2$, CH$\sb2$CHCH$\sb2$) were obtained by reaction of (P$\sb3$O$\sb9$)WO$\sb2$OCH$\sb3\sp{2-}$ with excess ROH. Hydrolysis of the esters resulted in the formation of the anhydride, ((P$\sb3$O$\sb9$)WO$\sb2$) $\sb2$O$\sp{4-}$. All of these compounds were isolated as pure crystalline solids and characterized spectroscopically. The acid (P$\sb3$O$\sb9$)WO$\sb2$OH$\sp{2-}$ anion was not isolated but identified in solution by $\sp{31}$P NMR spectroscopy.

Graduation Semester

1987

Type of Resource

text

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