Platinum heteronuclear cluster

Heteronuclear Clusters Containing Platinum and the Metals of the Iron, Cobalt, and Nickel Triads... 

The 31P H NMR spectra of a number of heteronuclear gold cluster compounds are found to be deceptively simple and NMR studies have been used as a probe of the behavior of these species in solution. This is especially true of the higher nuclearity clusters, which often exhibit spectra that are much simpler than would be predicted on the basis of their solid-state structures. For example, [Pt(H)(PPh3)(AuPPh3)7]2+, which adopts the solid-state structure illustrated in Fig. 9 (137) in which the phosphine ligands occupy several different chemical environments within the molecule, shows only two resonances in the 31P 1H NMR spectrum. These are in a ratio of 7 1 and exhibit satellites due to coupling to the central platinum nucleus as Fig. 10 illustrates. 

The relative intensities of all subspectra of the different isotopomers reflect the molar fraction of the different isotopomers, as predicted from the natural abundance of the metal isotopes. The observed spectrum is then the sum of the spectra of each isotopomer weighted by its own relative intensity. Formulae and programs have been proposed to calculate these normalized probabilities for platinum [22,23] and for tin [24,25]. Such calculations can be extended to heteronuclear clusters [25]. Though the number of isotopomers increases rapidly with the size of the cluster, only a small number of them provides subspectra with significant intensities. 

Table 20 Pt chemical shifts (S = 21.4 MHz) for some heteronuclear platinum clusters...

Figure 8 Structures of heteronuclear platinum clusters for Tables 21, 22 and 23...

Figure 14. Structure of the inner core of the heteronuclear gold platinum cluster [Pt(CO)(AuPPh3)6]2+.

In our own work there have been two main strands - the determination of solution-phase structures of heteronuclear clusters and the study of cluster reactions in which the metal framework is assembled or rearranges. In this work we have sought to obtain enhanced structural data as a result of the presence of more than one X-ray absorbing element (metal) in the cluster framework. Furthermore the presence of platinum or palladium in many of these systems leads to much structural variability. 

Polyhedral rearrangements of heteronuclear group 8-platinum clusters... 

F.7 Heteronuclear clusters containing platinum and the metals of the iron, cobalt and nickel triads... 

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