Platinum carbonyl complexes

This section on platinum carbonyl complexes should be read in conjunction with the comparable chapter by Hartley in Comprehensive Organometallic Chemistry , Volume 6, Chapter 39. This section will emphasize very recent work and will omit compounds which are completely organometallic in nature. 

Heterometallic metallomesogens, liquid crystals, 12, 223—224 Heterometallic polynuclear platinum carbonyl complexes heterodinuclear clusters, 8, 415 triangular clusters, 8, 417... 

Carbomethoxylation of olefins toa, -unsaturated esters or (3 -methoxy-esters (Eq. (127) can be achieved if the electrolysis in CH3OH/NaOCH3 at platinum electrodes is conducted under CO pressure. A platinum carbonyl-complex Ptx (CO)y is assumed to be the reactive intermediate in this synthetically interesting reaction 289 ... 

Since the publication of COMC (1995), there have been many new reports of platinum carbonyl complexes. In general, however, the work reported has been incremental and has built on the earlier work. The structure of this section will largely follow that of the previous editions, but with all polynuclear carbonyls considered together. 

New platinum carbonyl complexes 16 have been prepared by the decarbonylation of a phosphaketene, though it is unlikely this will be of general utility (Equation (5)). ... 

Bifunctional platinum carbonyl complexes such as 17 have been synthesized with a view to producing platina-ester polymers 18 (Equation (6)) however, the steric bulk of the ancillary phosphine ligands prevented the formation of the polymer. ... 

In the early work on the thermolysis of metal complexes for the synthesis of metal nanoparticles, the precursor carbonyl complex of transition metals, e.g., Co2(CO)8, in organic solvent functions as a metal source of nanoparticles and thermally decomposes in the presence of various polymers to afford polymer-protected metal nanoparticles under relatively mild conditions [1-3]. Particle sizes depend on the kind of polymers, ranging from 5 to >100 nm. The particle size distribution sometimes became wide. Other cobalt, iron [4], nickel [5], rhodium, iridium, rutheniuim, osmium, palladium, and platinum nanoparticles stabilized by polymers have been prepared by similar thermolysis procedures. Besides carbonyl complexes, palladium acetate, palladium acetylacetonate, and platinum acetylac-etonate were also used as a precursor complex in organic solvents like methyl-wo-butylketone [6-9]. These results proposed facile preparative method of metal nanoparticles. However, it may be considered that the size-regulated preparation of metal nanoparticles by thermolysis procedure should be conducted under the limited condition. 

Platinum(II) Complexes with Carbonyl and Silicon-donor Ligands 688... 

The great majority of platinum(I) complexes are binuclear with monofunctional or bifunctional bridging groups. However, there is also a series of unsupported dimers with the general structure shown in (12). These are generally stabilized by phosphine, carbonyl, and isocyanide ligands.17 Dimeric hydride complexes can have terminal or bridging hydrides and these are discussed above in Section 6.5.2.1.4. 

The first homoleptic, dinuclear platinum(I) carbonyl complex [Pt2(CO)6]2+ has been prepared by dissolving Pt02 in concentrated sulfuric acid under a CO atmosphere.92,93 The structure is rigid on the NMR time scale at room temperature. DFT studies suggested a staggered structure for the dimer.92,93... 

An excess of ligand, including CO, will often inhibit isomerisation. HCo(CO)4, an unstable hydrido-carbonyl complex, belongs to the examples of catalysts also active in an atmosphere of CO. This is the only homogeneous catalyst being commercially applied, albeit primarily for its hydroformylation activity. Higher alkenes are available as their terminal isomers or as mixtures of internal isomers and the latter, the cheaper product, is mainly converted to aldehydes/alcohols by hydroformylation technology. Later we will see that the isomerisation reaction also plays a pivotal role in this system. Since 1990 several catalysts based on rhodium, platinum and palladium have been discovered that will also hydroformylate internal products to terminal aldehydes. 

In a three-component reaction, a cationic platinum isocyanide complex [(Ph3P)2Pt(CNR)Cl][BF4] is reacted with a /3-bromoamine and butyl lithium to give an imidazoldin-2-ylidene complex.This transformation can be a two-component reaction if the isocyanide ligand contains already the necessary amine functionality. This was shown for chromium, molybdenum, tungsten, and rhenium carbonyls. 

The treatment of cyclopentadienyI-metal-2-alkenyl carbonyl complexes, such as 274 and 275, with SO2 leads to the formation of thietane 1,1-dioxide as ligand (Eqs. 73 and 74). Thietane and platinum(II) have also been found... 

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