Reaction of methylphenylacetylene with bis(benzonitrile)palladium chloride (1) in chloroform gave 1,2,4-trimethy 1-3,5,6-triphenylbenzene (2, 58%), l,3,5-trimethyl-2,4,6-triphenylbenzene (3, 39%), and 1,2,3-trimethyl-4,5,6-triphenylbenzene (4, 3%). In benzene, a complex [(PhC2Me)3PdCl2]2 was isolated which readily decomposed to palladium chloride, 2, and 3. 2-Butyne reacted with 1 in benzene to give a complex [Cl(MeC2Me)3-PdCl]2 (6) and in chloroform to give [Cl(MeC2Me)3PdClPdCl2]" (7) and some complex 6. On spectroscopic evidence, both 6 and 7 are assigned structures involving a 2-chloro-3,4,5,6-tetramethyl-2-ira/u,4-cw,6-ira/w-octa-2,4,6triene -bonded at C7 and -bonded at C2,3 to palladium(II). The ligand can take up two positions with respect to the metal, with the coordinated double bond parallel or perpendicular to the coordination plane. Both complexes 6 and 7 decomposed readily to palladium chloride and hexamethylbenzene. A new mechanism for the trimerization of acetylenes is proposed.In 1962 one of us reported3 4a reinvestigation of the reaction, originally described by Malatesta, et al.,* in which diphenylacetylene was dimerized to an ethoxytetraphenylcyclobutenylpalladium chloride complex in the presence of palladium chloride in ethanol. Under slightly different conditions (aprotic solvents) from those used by Malatesta, et al., we observed that diphenylacetylene could also be catalytically trimerized to hexaphenylbenzene. In addition, a tetraphenylcyclobutadienepalladium chloride complex ([Ph4C4( PdCl2)"]z) was formed which eventually deactivated the catalyst.5 These results have been confirmed by a number of workers.6-8These reactions of diphenylacetylene and closely related acetylenes did not readily lend themselves to a more detailed investigation and, since the generality of the reaction was of considerable interest particularly as a very easy route to cyclobutadiene-metal complexes, we began an investigation of the reactions of some other acetylenes with palladium chloride.Our first attempts, using acetylene, propyne, and monophenylacetylene, did not lead to characterizable products. Reactions always proceeded very easily to give mixtures of metal complexes. However, the latter were polymeric and nonstoichiometric in nature and not easily handled. It is probable that the ligands in these complexes are linear polyenes; however, hydrogen-transfer and cyclization reactions are by no means excluded.9

Pure cyclopentadienyl-metal compounds involving elements of the first sub-group have not been described hitherto. Only (triethylphosphine)cyclopentadienylcopper(I) is known 121.We have now synthesized cyclopentadienylgold(r). The success of the method depends on preparing solutions of AuCl in organic solvents in which it is normally insoluble. This may be accomplished by means of a loose addition of a cyclic olefin. Dicyclopentadienylgold(1) chloride [31 and truns,trans, cis-1,5,9-cyclododecatrienegold(1) chloride [31 are soluble in tetrahydrofuran (THF) and on treatment with cyclopentadienylsodium afford the desired C5H5Au.About 1 g of the olefin-gold(1) chloride is dissolved in 100 ml of THF/ether (1 :4) and treated at -60 "C under nitrogen with a solution of CSHSNa (3 molar equiv.) in THF. A yellow precipitate is a t once formed but dissolves in the excess of CsHsNa solution to give a colorless solution. The yellow substance separates again on addition of dry ice. After centrifugation at -30 "C the precipitate is washed three times with 96 % alcohol and twice with ether and then taken up in n-pentane. All solvents are precooled to -70 "C. On evaporation of the pentane under vacuum at -3O'C there remains a powdery, yellow insoluble substance whose elemental composition corresponds to the formula CsHsAu.The substance is sensitive to heat and friction. It is stable for about an hour at room temperature but often deflagrates on gentle warming.The same compound was obtained by treating the olefingold(1) chloride with cyclopentadiene (Cp) and triethylamine but was then not analytically pure.Since the insolhbility and instability of CsHsAu prevent its closer study, the soluble and more stable cyclopentadienyl-(triphenylphosphine)gold(r) was prepared.About 1 g of (triphenylphosphine)gold(I) chloride [41 was made into a slurry in 20 mi of ether and treated at -3OOC under nitrogen with an excess of CsH5Na solution in ether (5x 10-3 mole/liter). The temperature was slowly raised to 0 "C and the mixture was stirred for an hour. The whole was poured into 200 ml of ice-water with vigorous stirring and then filtered.Theresidue was washed first withwater,then with cold acetone, and finally with ether. For purification it was dissolved in THF/acetone at 0°C and treated dropwise with ice-water. Colorless rhombohedra1 crystals of the composition C23H20A~P were obtained; they decompose above 100 OC.The same compound was detected by N M R spectroscopy in the products of the following reactions:CsHsAu + triphenylphosphine (TPP) TPP.AuCl+ Cp + triethylamine TPP.AuC1f Cp + KOH TPP.AuCI + Cp + NaOCH3.The IR spectrum (KBr disc) of cyclopentadienyl(tripheny1-phosphine)gold(I) (TPP.AuCsH5) contains the following bands in addition to those that occur in the spectrum of TPP.AuCI: An ionic cyclopentadienyl-metal bond is excluded because there are two bands in the region around 1000 cm-1161; it is questionable whether a n bond of the ferrocene type is present because the intense bands at about 1100 cm-1 are missing [GI. The only remaining p...

Gold(ll1)-chlorid und Tetrachlorogold(II1)-saure setzen sich mit Olefinen unter Chloraddition urn. Dabei wird das Gold(lI1) stufenweise iiber Au2C14 und AuCl bis zum Metal1 reduziert. Unter geeigneten Bedingungen lassen sich diese Zwischenstufen in Form ihrer Olefinkomplexe isolieren. Die auch aus Olefin und Gold([)-chlorid erhaltlichen AuC1-Olefin-Komplexe sind schon fruher beschrieben worden. Die vorliegende Arbeit befaBt sich hauptsachlich mit der Darstellung und den Eigenschaften der Au2CI4-Komplexe, fur die ein Strukturvorschlag entwickelt wird.

Darstellung und Eigenschaften der Gold(1)-chlorid-Komplexe von Cyclopenten, Cyclohexen, Cyclohepten, cis-Cycloocten, trans-Cyclodecen, Cyclooctadien-( I S ) , cis.trans-Cyclodecadien-(1 S), Norbornadien, Dicyclopentadien, cis.cis.trans-und truns.trans.truns-Cyclododecatriem(l.5.9) werden beschrieben. Tab. 2. NMR-Spektren vonCyclenen mit 6 bis 10 Ringgliedern und ihren Au(1)-Komplexen (60 MHz, Losungsmittel CDC13, chemische Verschiebung in T, TMS als innerer Standard) Olefin Cyclohexeng) 4.32 S (2) 8.15 M (4) 8.37 M (4) Cyclohepten 4.19 M (2) 7.90 M (4) 8.38 M (6) cis-Cycloocten 4.38 M (2) 7.84 M (4) 8.50 M (8) trans-Cy clodecen 4.52 M (2) 7.95 M (4) 8.62 M (12) Komplex 4.02 S (2) 7.65 M (4) 8.30 M (4) 4.08 M (2) 7.55 M (4) 8.30 M (6) 4.44 M (2) 7.61 M (4) 8.47 M (8) 4.75 M (2) 7.64 M (4) 8.57 M (12)

1‐Olefine bilden mit Gold(I)‐chlorid lockere Additionsverbindungen, von denen nur die höheren Glieder (ab C12) isoliert und untersucht werden können. Auch Olefine mit innenständiger Doppelbindung scheinen Gold(I)‐chlorid‐Komplexe bilden zu können, wenn auch nicht in allen Fällen. Hexadien‐(1.4), Hexadien‐(1.5) und Decatrien‐(1.4.9) vereinigen sich mit Gold(I)‐chlorid zu relativ beständigen Komplexen der Zusammensetzung Oligoolefin·(AuCl)2.