Tetranuclear clusters platinum

The tetranuclear derivatives are classified as derivatives of the three principal carbonyl cluster units observed, H4M4(CO)12, H2M4(CO)13, and MjCCOlxs, with a final group involving bonding to platinum or gold. 

Ru3(CO)12 with Pt(PBu )2 at room temperature affords 92 as the main product, whereas reaction in refluxing hexane affords small amounts of octanuclear cluster 93 and tetranuclear 94. The capped-pentagonal bipyr-amidal 93 contains 104 cluster electrons, or six fewer than predicted by the Polyhedral Skeletal Electron Pair Theory. Solutions of 93 slowly decompose to give a small amount of 93, together with Pt3(CO)3(PBu3)3. No platinum homologue of 91 has yet been isolated.63... 

Most of the platinum(II) clusters are limited to tetranuclear and trinuclear platinum(II) clusters, although some Pt- M complexes having metal-metal dative bonds are known (57-61). In this article, we... 

Finally, a recent study by Jamali et al. [39] describes the preparation of a tetranuclear butterfly-shaped cluster in which each of two platinum(ll) centers binds to two silver(l) cations that are themselves connected by an argentophilic interaction. The cluster is stabilized by bidentate P,N ligands bridging a Pt-Ag bond each. Solution-phase NMR suggests an equilibrium between the butterfly geometry and a planar arrangement similar to that of [(NN)PtMe2l2Ag2(OTf)2 (see Sect. 3.1.1, Scheme 5). 

Tetranuclear PtsRu cluster 67 is formed when the platinum triangle 20 reacts with [HRu(GO)4] . At low temperature 67 is formed cleanly, and can be identified by NMR and IR spectroscopies however, at room temperature, it isomerizes to 68 in a matter of hours (Scheme 15). Dark purple crystalline samples of 68 can be isolated, and are thermally and air stable. An X-ray structure of 68 shows the metal core to be closer to a butterfly structure than a tetrahedron the unique Pt-Ru distance is a long 2.9951(6) A, whereas the other two are 2.7031(6) and 2.7649(6) A Pt-Pt distances are in the range 2.61-2.73 A. Both 67 and 68 are fluxional in solution, with the NMR spectra of 67 showing fast exchange even at —30 °C. 

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