Synthesis and Characterization of Group 4 Organometal Oxide Complexes

Babcock, Laura Mae

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Description

Title

Synthesis and Characterization of Group 4 Organometal Oxide Complexes

Author(s)

Babcock, Laura Mae

Issue Date

1988

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 organometallic substituted Keggin polyoxoanions ($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) MPW$\sb $O$\sb{39}$((n-C$\sb4$H$\sb9$)$\sb4$N) $\sb4$, M = Ti(1), Zr(2), or Hf(3), were prepared by reaction of ($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) MCl$\sb3$ with the lacunary Keggin heteropolyanion $\alpha$-H$\sb3$PW$\sb $O$\sb{39}$((n-C$\sb4$H$\sb9$)$\sb4$N) $\sb4$. Infrared data indicated that complexes 2 and 3 have a normal Keggin structure however complex 1 has a distorted structure. The $\sp{183}$W NMR chemical shift of the resonances due to both tungsten atoms adjacent to the substituted site moved to higher frequency when the metal was changed from titanium to zirconium and to hafnium.
• Base-assisted hydrolysis of ($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) MCl$\sb3$, M = Zr or Hf in THF solution gave $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) MCl$\}\sb3$O(OH)$\sb3$Cl, M = Zr(4) or Hf(5), and $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) MCl$\}\sb3$O(OH)$\sb4$, M = Zr(6) or Hf(7). The crystal structure of 6, determined by Dr. Victor Day at Crystalytics Company in Lincoln, NB, revealed a trimer of metals capped on one side by an oxygen atom and on the other side by a hydroxyl ligand with the three edges bridged by hydroxyl ligands. The hafnium complex 7 has a solution $\sp1$H NMR spectrum consistent with the structure for 6. Compounds 4 and 5 have a structure similar to 6 where the ($\mu\sb3$-OH) ligand is missing and one edge is doubly bridged by a ($\mu$-OH) and a ($\mu$-Cl) ligand. Complexes 4 and 5 were converted to 6 and 7 by reaction with one equivalent each of base and water.
• The hydrolysis of ($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) TiCl$\sb3$ resulted in the formation of a six membered titanium oxygen ring $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) TiClO$\}\sb3$, 8. Hydrolysis in the presence of base has produced a tetrameric ligand stabilized titanoxane complex, $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) Ti$\}\sb4$O$\sb6$, 9. The structure of 9, determined by Dr. Victor Day, consisted of an adamantane-like core which was completely surrounded by the ($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) ligands. Reaction of the cage with 0.5 eq. TiCl$\sb4$ resulted in the formation of $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) Ti$\}\sb4$O$\sb5$Cl$\sb2$, 10, where one edge bridged oxygen atom has been replaced by two chloride ligands. Reaction with additional TiCl$\sb4$ results in the formation of a mixture of 8, 10, $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) TiClO$\}\sb4$ (11), and $\{$($\eta\sp5$-C$\sb5$(CH$\sb3$)$\sb5$) TiCl$\sb2\}\sb2$O (12).

Graduation Semester

1988

Type of Resource

text

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