11.03.2014 Views

Synthesis and Structural Characterization of ... - Jacobs University

Synthesis and Structural Characterization of ... - Jacobs University

Synthesis and Structural Characterization of ... - Jacobs University

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Amal H. Ismail<br />

Ph.D. Thesis Abstract<br />

presented. Polyanions {YbAs 2 W 19 }, {La 2 As 2 W 19 }, {LnSb 2 W 21 } <strong>and</strong> {Ln 2 Sb 2 W 20 } were<br />

synthesized in simple, one-pot reactions <strong>of</strong> Ln 3+ ions with the lone pair containing polyanion<br />

precursors ([As 2 W 19 O 67 (H 2 O)] 14− , [B-α-AsW 9 O 33 ] 9− , [Sb 2 W 22 O 74 (OH) 2 ] 12− , [B-α-SbW 9 O 33 ] 9− ).<br />

Chapter IV describes the mixed lanthanide/d-transition metal containing POMs, the novel<br />

open-ring shaped polyanions [Fe 16 O 2 (OH) 23 (H 2 O) 9 (P 8 W 49 O 189 )Ln 4 (H 2 O) 20 ] 11−<br />

{Ln 4 Fe 16 P 8 W 49 }(Ln = Eu <strong>and</strong> Gd) which have been synthesized by reaction <strong>of</strong> the known<br />

[H 7 P 8 W 48 O 184 ] 33− {P 8 W 48 } cyclic precursor with Fe 3+ <strong>and</strong> Ln 3+ ions in acidic aqueous medium<br />

in the presence <strong>of</strong> hydrogen peroxide. The unique novel open-ring tungstophosphate(V) unit<br />

{P 8 W 48 O 188 (WO 3 )} 44− exists in the structure <strong>of</strong> the {Ln 4 Fe 16 P 8 W 49 }compounds in addition to<br />

the {Fe 16 O 2 (OH) 20 (H 2 O) 12 } 21+ nanocluster <strong>and</strong> four {Ln(H 2 O) 5 } 3+ grafted units.<br />

Chapter V comprises non-lanthanide-containing POMs, divided into two sections,<br />

tellurium <strong>and</strong> d-transition metal containing POMs. The tungstotellurates(IV)<br />

[H 2 Te 4 W 20 O 80 ] 22− <strong>and</strong> [NaTeW 15 O 54 ] 13− <strong>and</strong> the molybotellurate(IV) [H 2 Te 24 Mo 44 O 198 ] 34− are<br />

described in the first section. In the second section, the s<strong>and</strong>wich-type tungstogermanates<br />

[Cu 3 (H 2 O)(B-β-GeW 9 O 33 (OH))(B-β-GeW 8 O 30 (OH))] 12− ,<br />

[Co(H 2 O) 2 {Co 3 (B-β-<br />

GeW 9 O 33 (OH))(B-β-GeW 8 O 30 (OH))} 2 ] 22− <strong>and</strong> [Mn(H 2 O) 2 {Mn 3 (H 2 O)(B-β-GeW 9 O 33 (OH))(Bβ-GeW<br />

8 O 30 (OH))} 2 ] 22− are presented.<br />

All obtained compounds have been characterized in the solid state by FTIR, single-crystal<br />

XRD, TGA <strong>and</strong> elemental analyses. Furthermore, solution studies <strong>of</strong> the diamagnetic<br />

derivatives (La, Lu <strong>and</strong> Y analogues) by 183 W <strong>and</strong> 89 Y NMR spectroscopy were also<br />

performed, in addition to 13 C NMR <strong>and</strong> 1 H NMR spectroscopy for the acetate containing<br />

POMs.<br />

iii

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!