Synthesis and Structural Characterization of ... - Jacobs University

Chapter 4
Unpublished Results
The cyclic P 8 W 48 is also known to react with lanthanide cations. Pope et al. reported the only
lanthanide (Ln) derivative of P 8 W 48 known to date. The lanthanide series
[KP 8 W 48 O 184 (H 4 W 4 O 12 ) 2 Ln 2 (H 2 O) 10 ] 25− (Ln = La, Ce, Pr, Nd) was synthesized by the
reaction of P 8 W 48 polyanion with lanthanide cations under hydrothermal and conventional
conditions resulting in 3D networks; with the central cavity of the P 8 W 48 occupied by
lanthanide cations and W 4 O 12 groups. 9
Recently, our group reported the synthesis and structure of the 16-iron(III)-containing P 8 W 48
derivative, [Fe 16 (OH) 28 (H 2 O) 4 (P 8 W 48 O 184 )] 20− (Fe 16 P 8 W 48 ), which was identified
independently in Bremen and Bielefeld. 10 This polyanion contains a cationic
[Fe 16 (OH) 28 (H 2 O) 4 ] 20+ (Fe 16 ) ‘guest’ cluster with 16 edge and corner-sharing FeO 6 octahedra
grafted to the inner surface of the P 8 W 48 ‘host’; therefore exhibiting a highly symmetrical D 4h
geometry (see Figure 4.1). Each of the 16 equivalent Fe 3+ centers in the Fe 16 cluster is bound
to P 8 W 48 via a Fe-O(W) and a Fe-O(P) bond, resulting in a tight anchoring of the 16-ironhydroxo
core, meaning that the eight phosphate groups of P 8 W 48 are involved in the binding
to the cationic Fe 16 cluster guest.
Figure 4.1. Combined polyhedral/ball-and-stick representation of the previously reported
Fe 16 P 8 W 48 . The color code is as follows: WO 6 octahedral (red); PO 4 tetrahedral (green); W
(black); Fe (yellow); O (red).
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