Chapter 4 - Jacobs University

Chapter 4
16-Iron Metal Center Nanocluster
4.4 Results and discussion
4.4.1 Synthesis and structure
Although the P 8 W 48 cluster had been known for more than 20 years, 5 only recently the first
examples of metal-containing derivatives have been reported. Pope’s group prepared the first
lanthanide derivative, {Ln 4 (H 2 O) 28 [KÌP 8 W 48 O 184 (H 4 W 4 O 12 ) 2 Ln 2 (H 2 O) 10 ] 13- } x (Ln = La, Ce, Pr,
Nd), 6 and Kortz and coworkers isolated the first transition metal derivative, the 20-copper(II)
containing [Cu 20 Cl(OH) 24 (H 2 O) 12 (P 8 W 48 O 184 )] 25- 7 (see also the report on the Cu 20 -azide
derivative [P 8 W 48 O 184 Cu 20 (N 3 ) 6 (OH) 18 ] 24- , 8 ), while Müller et al. discovered
[K 8 Ì{P 8 W 48 O 184 }{V V 4V IV 2O 12 (H 2 O) 2 } 2 ] 24- containing two cationic V 6 type mixed-valence clusters
and formed by an unprecedented nucleation process. 9
Very recently Kortz et al. reported
{K(H 2 O)} 3 {Ru(p-cymene)(H 2 O)} 4 P 8 W 49 O 186 (H 2 O) 2 ] 27- which represents the first organometallic
derivative of P 8 W 48 . 10 Here we report on the iron derivative [P 8 W 48 O 184 Fe 16 (OH) 28 (H 2 O) 4 ] 20- (2),
which was identified independently in Bremen 11 and Bielefeld.
Polyanion [P 8 W 48 O 184 Fe 16 (OH) 28 (H 2 O) 4 ] 20- (2) was isolated as the mixed cation salts
Li 4 K 16 [P 8 W 48 O 184 Fe 16 (OH) 28 (H 2 O) 4 ]∙66H 2 O∙2KCl (2a) and
Na 9 K 11 [P 8 W 48 O 184 Fe 16 (OH) 28 (H 2 O) 4 ]∙100H 2 O (2b), see Experimental Section. Polyanion 2
contains an unprecedented {Fe 16 (OH) 28 (H 2 O) 4 } 20+ cluster in the cavity of P 8 W 48 with 16 edgeand
corner-sharing FeO 6 octahedra being grafted to the inner surface of the “host” ( Figures 4.3
and 4.4).
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