Platinum complexes cyclo-octa-1,5-diene

Chelate complexes of the type [PdX2(diene)] (X = Cl, Br) are readily formed by the dienes hexa-1,5-diene (124), bicyclo 2,2,lJhepta-2,5-diene (1, 7) tricyclo[4,2,2,0]-deca-triene and -diene derivatives (10), cyclo-octa-1,5-diene and dicyclopentadiene, but not dipentene (43). These may be converted to complexes of the types [Pd2X2(dieneOR)2] and [PdCl(dieneOR)-(amine)] (R = alkyl) (43), and their properties indicate that they have similar structures to the platinum complexes (XXXI) and (XXXIII). 

M. Green, J. A. K. Howard, J. L. Spencer, and F. G. A. Stone, Synthesis of Ethylene, Cyclo-octa- 1,5-diene, Bicyclo [2.2.1]heptene, and trans-Cyclo-octene Complexes of Palladium ) and Platinum(O) Crystal and Molecular Structure of Tris(bicyclo2.2.1]hepte-ne)platinum, J. Chem. Soc., Dalton Trans. 1977, 271-277. 

Bis(trifluoromethyl)platinum complexes may conveniently be prepared by the reaction of dimethyl(cyclo-octa-l,5-diene)platinum with trifluoro-iodomethane in methylene chloride, followed by displacement of the cydo-octadiene with the required ligand L (L = AsMcs, PMeaPh, pyridine, RNC, etc.) Oxidative addition of iodine thence gives the platinum(iv) compounds ... 

Hexaduoroazomethane reacts at -70°C with bis(cyclo-octa-l,5-diene)-nickel to give a low yield of an unstable solid which is formulated, on the basis of micro-analysis and mass spectrometric results, as the three-mem-bered ring complex (130), analogous to known unfluorinated compounds. " Phosphine-substituted zerovalent-nickel and -platinum complexes fail to give analogous complexes with hexafluoroazomethane under the conditions investigated. 

The radical trap Bu NO has little effect on overall reaction rates and mechanism (a) therefore predominates. However, the radical BuKMe)NO can be detected so mechanism (b) must be operative to some extent. Attack of PhS- at the metal centre is considered to be the rate-determining step. Homolytic cleavage of platinum-(ii)-alkyl bonds also results when the complexes [PtRgl (R = CH3, CD3, or QH5 L = 2,2 -bipy R = Me, Lj = 1,10-phen or cyclo-octa-1,5-diene) are treated with diethyl fumarate, free alkyl radicals being detected by the radical trap Bu N==0. The reactions proceed according to the equations in Scheme 12. 

Platinum(o) complexes of cyclohepta-, cyclo-octa-, and cyclonona-1,2-dienes have been observed complexing ability increases with decrease in ring size. ... 

Hetorogenized Catalysts.—Reaction of [Ru(NH3)60H] + with a Faujasite-type zeolite gives a supported Ru complex, which effects hydroformylation of ethylene the catalytic species may be ruthenium clusters that are trapped in the zeolite cages. The effect of reaction conditions upon the selectivity of the hydroformylation of methyl methacrylate with [RhH(CO)(PPh3)3] or its polymer-anchored analogue has been investigated and hydroformylation of hex-l-ene and cyclo-octa-1,5-diene has been carried out with cobalt, rhodium, and platinum-tin complexes anchored to an ion-exchange resin via quaternary amino-phosphines. ... 

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