| Abstrakt: |
The hexanuclear cluster {Pt6}H2(2) contains a sterically hindered and chemically stable {Pt6}=Pt6(μ‐PtBu2)4(CO)4core, with the six metals forming an edge‐bridged tetrahedron. The two hydrides are the reactive sites of the cluster and lie on opposite sides of the cluster, terminally bonded to the two “apical” edge‐bridging platinum centres. Indeed, cluster 2reacts with acids of different acidity (HA=CF3SO3H, HBF4, p‐CH3C6H4SO3H, CF3COOH, PhCOOH and CH3COOH), affording, after evolution of two equivalents of dihydrogen, the corresponding anion‐substituted clusters {Pt6}A2(4). We suggest that the reaction proceeds through a mechanism similar to the one generally accepted for the analogous protonation of mononuclear hydrides, with some of the intermediates partially characterised at low temperature. Interestingly, the reverse reaction, the heterolytic splitting of H2by clusters 4, occurs readily under mild conditions. The anions in clusters 4 aand 4 b(4 a: A=CF3SO3, 4 b: A=BF4) are bonded in the solid state but very easily dissociate in solution and may be substituted under mild conditions by weak ligands, such as CH2Cl2or CH3CN. With dialkyl ethers, the reaction proceeds further with the heterolytic splitting of a CH bond of the ethereal ligand. This process allowed us to isolate the polymer [{Pt6}(CH2OCH2CH2OCH2)]x(8), in which the {Pt6} cluster units are connected by insulating spacers arising from dimethoxyethane. The results of single‐crystal X‐ray diffraction studies on 4 aand 8are also reported. |
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