Synthesis, Characterization, and Reactivity of Alkylphosphomolybdates: Oxidation, Dehydration, and Isomerization

The alkyl and silyl phosphomolybdates (P$\sb3$O$\sb9$)MoO$\sb2$OR((n-C$\sb4$H$\sb9)\sb4$N) $\sb2$ $\{$R = CH$\sb3$, CH$\sb2$CH$\sb3$, 1, CH(CH$\sb3)\sb2$, CH$\sb2$CH=CH$\sb2$, CH$\sb2$CH$\sb2$C$\sb6$H$\sb5$, and Si(CH$\sb3)\sb3\}$ have been prepared and characterized. A single crystal X-ray diffraction study reveals that in 1, the P$\sb3$O$\sb9\sp{3-}$ ligand acts as a tridentate ligand coordinated to MoO$\sb2$OCH$\sb2$CH$\sb3\sp+$ unit. Two short intramolecular CH$\cdots$OMo contacts between the methylene hydrogens and the oxygens of P-O and Mo=O are found in anion 1. Based on $\sp{31}$P, $\sp $O, and $\sp1$H NMR studies, hydrolysis of (P$\sb3$O$\sb9$)MoO$\sb2$OCH$\sb3\sp{2-}$ produces the anhydride ((P$\sb3$O$\sb9$)MoO$\sb2$) $\sb2$O$\sp{4-}$ and the acid (P$\sb3$O$\sb9$)MoO$\sb3$H$\sp{2-}$. In the presence of excess methanol, the methyl ester (P$\sb3$O$\sb9$)MoO$\sb2$OCH$\sb3\sp{2-}$ can be regenerated from the anhydride and the acid. The acid slowly dimerizes to form the dimer, (P$\sb3$O$\sb $HMoO$\sb2)\sb2\sp{4-}$, which has been isolated in crystalline form. An X-ray crystal structural analysis of this dimer reveals the presence of a tetradentate linear triphosphate ligand. The hydrogens in this anion were located by $\sp{31}$P NMR study.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Wang, Ren-Chain

Contributors dc:contributor

• Klemperer, Walter G.

• Chemistry, Inorganic

Identifier

(UMI)AAI8815439

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70405