Supramolecular Features of Polyoxometalate-Supported Transition-Metal Complexes

Detailed discussions on supramolecular structures of giant polyoxometalate clusters have been reported by Muller and co-workers. The number of ionic lattices formed from anionic POM clusters and organic cations-coordination complex cations resulting in supramolecular structures is substantial and literally more than hundreds of new compounds in this class appear annuallyIn this overview, the supramolecular features of POM-based systems will be discussed mainly under three headings (a) supramolecular features of polyoxometalate supported transition metal complexes, (b) polyoxometalate-crown ether complexes with supramolecular cations, and (c) supramolecular water clusters associated with polyoxometalates. 

SUPRAMOLECULAR FEATURES OF POLYOXOMETALATE-SUPPORTED TRANSITION-METAL COMPLEXES 

FIGURE 1. (a) POM-supported cobalt coordination complexes in the polyoxocation, [PMo Mo2 V 044 Co(2,2 -bipy)2(H20) 4f, showing the tetra-capping and tetra-sup-porting connection mode and disordered P tetrahedron, (b) The same is shown in the polyhedral representation of the polyoxocation. (Reprinted with permission from ref. 27.). 

Other examples of Keggin heteropolyanion-supported transition metal complexes that are structurally characterized, include [Cu (phen)2]4PMo V  

Octamolybdate, [Mog026] , a common isopolyanion, is now well established for supporting transition-metal complexes that exhibit diversity in supramolecular structures. In this isopolyanion, eight isomeric forms are known based on different types of polyhedral and oxo-groups present in these isomers (Table 1).  

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II. SUPRAMOLECULAR FEATURES OF POLYOXOMETALATE-SUPPORTED TRANSITION-METAL COMPLEXES... 

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