Cyclopentadiene complexes with platinum

These studies were extended to hydrosilation of cyclopentadiene with trichlorosilane (52). This is most difficult with platinum catalysts. Palladium complexes favored production of 1 1 adducts as a mixture of 3- and 4-trichlorosilylcyclopentene. Nickel complexes produced substantial amounts of 1 2 adducts as trichlorosilyl-substituted 4,7-methylene-4,7,-8,9-tetrahydroindanes, with the exception of nickel tetracarbonyl, which was very active and selectively formed almost exclusively 3-trichlorosi-lylcyclopentene with no 1 2 adduct. 

The hydroxo complexes behave as strong bases in aqueous organic solvents and react with weak acids, including carbon acids such as nitromethane, methyl ketones, acetylacetone, acetonitrile, phenylacetylene and cyclopentadiene this provides a useful synthesis under mild conditions of platinum(II)-carbon a-bonded complexes, as exemplified in Equation 6 (18) ... 

A palladium complex of tropyne (230) has been prepared by the same method used for 223.86 Interestingly, in contrast to all of the platinum tropyne complexes (223, 226, 235), which are stable at room temperature, the palladium complex is thermally labile, decomposing at -35°C with a half-life of about 3 h. Reactions of 230 with KBEt3H, LiAl(0-f-Bu)3H, HBr, or cyclopentadiene gave only intractable mixtures. 

The [Ir(C6H6)2]+ ion, analogous to the [00(05115)2] + and [Rh(05115)2]+ ions, also has been obtained and investigated as was expected, it showed similar properties. The uncharged complex Ir (05115)2, like Rh(C6H6)2, has not yet been prepared. For palladium and platinum only simple olefin complexes are, as yet, known. Among these there is also a complex of platinous chloride with cyclopentadiene, but physical evidence excludes the possibility of a sandwich structure in this compound (29). 

Doherty and coworkers [44] reported asymmetric Diels-Alder reactions of 25 with cyclopentadiene (shown in Scheme 7.11) using platinum complexes of B1 NAP... 

A convenient way of storing and purifying the strained olefin bicyclo[2,2,0]hex-l(4)-ene is by formation of a platinum complex (776), whose structure has been confirmed by 2f-ray analysis. The olefin is readily liberated from (776) by carbon disulphide and undergoes the expected Diels-Alder reaction with cyclopentadiene. Addition of ethanol to (776) is accompanied by opening of the strained internal bond to give the metallocycle (777). ... 

Bis(l,5-cyclopentadiene)platinum(0) reacts with a mixture of the phosphaalkyne Bu C = P and the phosphaalkene Ph2C = P(C6H2Me3-2,4,6) to give the complex " ... 

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