Platinum, - 1,5-cyclooctadiene

A derivative of cyclopentyne has been trapped in a matrix. Although cycloheptyne and cyclohexyne have not been isolated at room temperatures, Pt(0) complexes of these compounds have been prepared and are stable." The smallest cyclic allene" so far isolated is l-/err-butyl-l,2-cyclooctadiene 107." The parent 1,2-cyclooctadiene has not been isolated. It has been shown to exist transiently, but rapidly dimerizes." " The presence of the rert-butyl group apparently prevents this. The transient existence of 1,2-cycloheptadiene has also been shown," and both 1,2-cyclooctadiene and 1,2-cycloheptadiene have been isolated in platinum complexes." 1,2-Cyclohexadiene has been trapped at low temperatures, and its structure has been proved by spectral smdies." Cyclic allenes in general are less strained than their acetylenic isomers." The cyclic cumulene 1,2,3-cyclononatriene has also been synthesized and is reasonably stable in solution at room temperature in the absence of air." ... 

A novel chiral dissymmetric chelating Hgand, the non-stabiUzed phosphonium ylide of (R)-BINAP 44, allowed in presence of [Rh(cod)Cl]2 the synthesis of a new type of eight-membered metallacycle, the stable rhodium(I) complex 45, interesting for its potential catalytic properties (Scheme 19) [81]. In contrast to the reactions of stabihzed ylides with cyclooctadienyl palladium or platinum complexes (see Scheme 20), the cyclooctadiene is not attacked by the carbanionic center. Notice that the reactions of ester-stabilized phosphonium ylides of BINAP with rhodium(I) (and also with palladium(II)) complexes lead to the formation of the corresponding chelated compounds but this time with an equilibrium be-... 

It is worth mentioning that, in a related study, a chiral platinum complex prepared from bis(cyclooctadiene) platinum [Pt(COD)2] (5 mol %) and (f ,f )-Me-DuPhos (6mol%), also catalyzed the reaction of 63 c efficiently to provide the product (R)-65c... 

Bimetallic platinum-ruthenium nanoparticles were synthesized from the reaction of Pt(dba)2 (dba = dibenzyhdeneacetone) with Ru(COD)(COT) (COD = 1,5-cyclooctadiene COT = 1,3,5-cyclooctatriene) in various propor-... 

Significant advances in organonickel chemistry followed the discovery of frtzws,fraws,fraws-(l,5,9-cyclododecatriene)nickel, Ni(cdt), and bis(l,5-cycloocta-diene)nickel Ni(cod)2 by Wilke et. al.1 In these and related compounds, in which only olefinic ligands are bonded to the nickel, the metal is especially reactive both in the synthesis of other compounds and in catalytic behavior. Extension of this chemistry to palladium and to platinum has hitherto been inhibited by the lack of convenient synthetic routes to zero-valent complexes of these metals in which mono- or diolefins are the only ligands. Here we described the synthesis of bis(l,5-cyclooctadiene)platinum, tris(ethylene)-platinum, and bis(ethylene)(tricyclohexylphosphine)platinum. The compound Pt(cod)2 (cod = 1,5-cyclooctadiene) was first reported by Muller and Goser,2 who prepared it by the following reaction sequence ... 

Dichloro(l,5-cyclooctadiene)platinum(II) may be prepared from hexachloro-platinic acid,3 by heating bis(benzonitrile)dichloroplatinum(II)4 in 1,5-cyclo-... 

Other tris(olefin)platinum(0) complexes (where olefin represents a strained olefin such as bicyclo[2.2.1]heptene, dicyclopentadiene, or trans-cyclooctene) may be similarly obtained by direct displacement of 1,5-cyclooctadiene, often in quantitative yield.6... 

Cyclooctenyl and norbomenyl platinum complexes analogous to 14 and 15 have been proposed in the reactions of 1,5-cyclooctadiene and norborna-diene with HPt(N03)(PEt3)2 (57). 

In general, two procedures are most often reported for the preparation of platinacyclopentane compounds. The reaction of the di-Grignard reagent BrMg (CH2)4MgBr with dichloro(l,5-cyclooctadiene)platinum(II) is followed by the... 

Diazido-3-cyanoquinoline, see 2,4-Diazidoquinoline-3-carbonitrile, 3231c Diazido[(l,2,5,6-ri)-l,5-Cyclooctadiene]platinum, 3007... 

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