Synthesis and Structural Characterization of ... - Jacobs University

Amal H. Ismail
Ph.D. Thesis
(pink); O (red). In the solid state the “red” oxo ligand links two {W 28 } units via an Ln–O–W’
bridge (see also Figure 3.13). The two types of subunits were colored differently for clarity. 82
Figure 3.13. Representation of polyanions 11 and 12 forming dimers in the solid state. The
color code is as follows: WO 6 octahedra (red and geen); Ln (blue); H 2 O (pink). ................... 83
Figure 3.14. IR spectra of the seven isotructural derivatives of the {Ln 2 W 28 } family with Ln
= La, Ce, Pr, Nd, Sm, Eu and Gd (from top to bottom). .......................................................... 84
Figure 3.15. Scheme of different types of lanthanide-containing isopolytungstates and the pH
of formation. The color code is as follows: W (black); O (red); Ln (blue); H 2 O (pink); Cl
(brown)..................................................................................................................................... 86
Figure 3.16. Representation of the two structures of the {W 11 } units containing lanthanides.
The color code is as follows: WO 6 octahedra (red and green); Ln (blue); H 2 O (pink), O (red).
.................................................................................................................................................. 87
Figure 3.17. Representation of the {W 28 } unit in 11 and 12 which is composed of two {W 11 }
(red) and one {W 6 } (green) fragment. The two subunit types were colored differently for
clarity. ....................................................................................................................................... 89
Figure 3.18. Thermograms of Na-11 and NaEu-12. ............................................................... 91
Figure 3.19. Ball-and-stick representation of the dilacunary polyanion precursor
[As 2 W 19 O 67 (H 2 O)] 14− (As 2 W 19 ). The color code is as follows: W (black), As (yellow), H 2 O
(pink), O (red). ......................................................................................................................... 97
Figure 3.20. Ball-and-stick representation of the monolacunary polyanion precursor
[As 2 W 20 O 68 (H 2 O)] 10− (As 2 W 20 ). The color code is the same as in Figure 3.19. ...................... 98
Figure 3.21. Polyhedral (left) and ball-and-stick (right) representation of
[Yb(H 2 O) 2 K(H 2 O) 2 As 2 W 19 O 67 (H 2 O)] 10− (13). The color code is as follows: WO 6 octahedra
(red), W (black), As (yellow), Yb (blue), K (grey), H 2 O (pink), O (red). ............................. 103
Figure 3.22. IR spectra of KNa-13 (black line) and its four compositional analogues
[Ln(H 2 O) 2 K(H 2 O) 2 As 2 W 19 O 67 (H 2 O)] 10− (from top to bottom Ln = La, Ce, Sm, Eu, Gd). .... 104
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