Platinum cluster compounds

It is interesting to note that the Ni analogue [Ni3(CO)3(p2-CO)3]2 shows a quite different metal architecture.108 Platinum cluster compounds of type [Pt4(CO)5L4] [L = PPh3, PPh2(o-MeC6H4), or PPh(o-MeC6H4)2] have been obtained as purple... 

Table 2.18. Electron counting in platinum cluster compounds...

Phosphine palladium and phosphine platinum carbonyl cluster compounds. N. K. Eremenko, E. G. Mednikov and S. S. Kurasov, Russ. Chem. Rev. (Engl Transl.), 1985, 54, 394 (69). 

Perrhenate and related building blocks are constituents of several cluster compounds where they act as terminal groups in organometallic rhenium oxides such as in [(cp Re)3(//2-0)3(/U3-0)3Re03]+ (49)21 Qj. jjj heterometallic clusters such as the structurally related [(Re)3(//f dppm)3(/u -0)3Re03]+ (dppm = bis(diphenylphosphino)methane) and Pt4 P(C6H 11)3)4 (//-C0)2(Re04)2]. A series of platinum-rhenium and platinum-rhenium-mercury clusters with Pt-Re multiple bonds has been isolated from reactions of Pt3 precursors with Rc207 or perrhenate. " ... 

Heterometal alkoxide precursors, for ceramics, 12, 60-61 Heterometal chalcogenides, synthesis, 12, 62 Heterometal cubanes, as metal-organic precursor, 12, 39 Heterometallic alkenes, with platinum, 8, 639 Heterometallic alkynes, with platinum, models, 8, 650 Heterometallic clusters as heterogeneous catalyst precursors, 12, 767 in homogeneous catalysis, 12, 761 with Ni—M and Ni-C cr-bonded complexes, 8, 115 Heterometallic complexes with arene chromium carbonyls, 5, 259 bridged chromium isonitriles, 5, 274 with cyclopentadienyl hydride niobium moieties, 5, 72 with ruthenium—osmium, overview, 6, 1045—1116 with tungsten carbonyls, 5, 702 Heterometallic dimers, palladium complexes, 8, 210 Heterometallic iron-containing compounds cluster compounds, 6, 331 dinuclear compounds, 6, 319 overview, 6, 319-352... 

Ketenyl complexes, in Ru-Os mixed-metal clusters, 6, 1080 Ketenylidenes, in iron cluster compounds, 6, 301 Ketenylidenetriphenylphosphoranes, with platinum, 8, 632 Ketimines... 

The sole example of a silicon-platinum cluster is the compound in entry 24 its structure has been noted in Section IV,A. It seems very likely that many further cluster systems await discovery, particularly with iridium, platinum, and gold, and that this represents an important future area of research. One obvious application is as precursors to metal silicides with high metal silicon ratios using c.v.d. techniques (compare Section V,A). 

Cluster Compounds.—An interesting new series of platinum carbonyl dianions of formula [Pt3(CO)3(p2-CO)3]2 n = 2—5) have been synthesized by reduction of [PtClg]2" with CO and methanolic NaOH.107 Species with decreasing n were isolated with increasing concentration of reducing agent (equation 18). The X-ray... 

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 heterometallic cluster compounds [Pt(AuPPh3)8](N03)2 and [Pd(AuPPh3)8](N03)2, synthesized by the coreduction of platinum or palladium complexes and Au(PPh3)N03 (117, 123, 124), both adopt a... 

For detailed listings of the many known cluster compounds there are now numerous reviews (12-14). Suffice it to say here, that among the clusters of type (1) formed by rhodium and platinum we now have discrete arrays of thirty, or more, metal atoms and are entering into a fascinating borderline area between metal atom clusters and metals as such. 

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