Dicyclopentadiene complexes

AuCl(alkene)] (alkene = m-cyclooctene. norbornene, CHf/o-dicyclopentadiene ) complexes have been obtained by reaction of [AuCl(CO)] with the alkene.2280,2281 The structure of [AuC1(Ci0H12)] shows the ligand //2-bonded to gold via the C=C bond in the norbornene ring and the molecules are associated into dimers through Au Au interactions.2281... 

The anti addition of amines was also observed for norbomadiene and dicyclopentadiene complexes with platinum, palladium and nickel5-8. 

An X-ray analysis 27) of the dicyclopentadiene complex CioHi2PtCl2 (104,182) has shown that the olefin has an endo configuration with both double bonds coordinated to platinum. The platinum-trigonal carbon atom distances are much the same as in the dipentene complex, but no indication is given of the orientation of the double bonds with respect to the platinum coordination plane. 

The first documented example of the living ROMP of a cycloolefin was the polymerization of norbornene using titanacyclobutane complexes such as (207) 510-512 Subsequent studies described the synthesis of di- and tri-block copolymers of norbornenes and dicyclopentadiene.513 However, functionalized monomers are generally incompatible with the highly electrophilic d° metal center. 

By contrast, m/fl-dicyclopentadiene forms a stable crystalline 1 1 complex with AuCl, which is a dimer in the solid state with short aurophilic contacts. The Au-C distances are 2.20(1) and 2.16(1) A (Scheme 77).314... 

Ni° means nickel prepared in situ by reduction of nickel salts, or a Ni° complex containing easily displaceable ligands. 6 Disiamvlborane. Quadricyclane can be employed in place of dicyclopentadiene with which it is in equilibrium. 

Codimerization of butadiene with dicyclopentadiene (example 8, Table II) was shown to proceed via a crotyl-nickel complex (62). Ring contraction of cyclooctadiene (example 10, Table II) appears to be a hydride promoted reaction. The hydride-promoted dimerization of norbomadiene to -toly 1 norbornene (example 9, Table II) appears to be quite different from dimerization via a metallacycle (see Table I, example 16). 

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... 

Dicyclopentadiene reacts with rhenium(III) chloride to give the polymeric complex [ReCl2(CioII,2)2] , and with triphenylphosphinerhe-nium(III) chloride to give the complex [ReCl(CioHi2)2(PPh3)] (49). The structures of these complexes are unknown. 

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). 

The dienes bicyclo[2,2,l]hepta-2,5-diene 1, 7), cyclo-octa-1,5-diene 43), dicyclopentadiene 43, 68), dipentene 48), hexa-1,5-diene 43, 124) and diallyl ether 124) form complexes of the type [Ft X2(diene)J (X = halogen). These complexes are monomeric and nonconducting, and are formulated as chelate complexes of type (XXXI) in which the diene, represented by the symbol (XXXII) functions as a bidentate ligand and occupies two... 

Anhydrous silver-olefin complexes are readily dissociable, low-melting, and variable in composition 92a, 176, 183). Cyclic olefins and polyolefins form stable complexes with silver nitrate or perchlorate, but again the Stoichiometry of the complexes varies considerably, sometimes depending on the conditions of preparation. The following types have been isolated [Ag(un)2]X (un = e.g., cyclohexene, a- and /3-pinene) ISO), [Ag(diene)]X diene = e.g., dicyclopentadiene 220), cyclo-octa-1,5-diene 50, 130), bi-cyclop, 2,1 ]hepta-2,5-diene 207), and cyclo-octa-1,3,5-triene 52), and [Ag2(diene)]X2 (diene = e.g., cyclo-octa-1,3- and -1,4-diene 180), bi-cyclo[2,2,l]hepta-2,5-diene 1) and tricyclo[4,2,2,0]-decatriene 10)). Cyclo-octatetraene (cot) forms three adducts with silver nitrate 52), viz., [Ag(cot)]NOs, [Ag(cot)2]N03, and [Ag3(cot)2](N03)3. On heating, the first two lose cyclo-octatetraene and all three decompose at the same temperature. From the stoichiometry of the above complexes it appears that the... 

Multicoordinated metal complex comprising a multidentate Schiff base ligand with ruthenium, (I) and (II), were prepared by Schaubroeck et al. (1) and Verpoort et al. (2), respectively, and used to prepare poly(dicyclopentadiene). 

Bell, A., Dicyclopentadiene Polymerisation using Well-characterized Tungsten Phenoxide Complexes , in Catalysis in Polymer Synthesis, ACS Symp. Ser. 496, Washington, DC, 1992, pp. 121-133. 

With another change of scene, we note the ability of gold to catalyse transformation of polycyclic hydrocarbons having fascinating structures (Scheme 13.4) 19 the reactions depicted there were catalysed either in the vapour phase using a gold-lined reactor at temperatures between 373 and 543 K and contact times of 10-20 s they were also effected by the complex Au(DCP)2C1 (DCP = dicyclopentadiene) in solution over 1 day at room temperature. 

Arene)(e/ido-dicyclopentadiene)M(0) complexes [M = Ru (211), Os (212)] are prepared by reduction of lc or Id with 2-propanol and Na2C03 in the presence of dicyclopentadiene (Scheme 15). Protonation of derivatives 211 and 212 with HPF6 leads to cations 213 and 214 which are stabilized by an agostic C—H—M bond, as shown by the X-ray structure of the osmium species (214). The cations 213 and 214 react with CN(t-Bu) to give complexes of type 215 in which the agostic C—H—M is no longer observed (102). 

The synthesis and reactivity of arene cyclooctatetraene osmium(O) complexes of type 216 (arene = benzene, mesitylene) (13,132) and arene dicyclopentadiene osmium(O) complexes 212 (arene = mesitylene) (102) have been discussed previously (Section III,A,2). Arene osmium(O) complexes of type Os( 7j6-C6H6)(PR3) (L) (230) have been prepared by reduction... 

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