Reaction Of Pentacarbonyl Research Articles

Transfer of heterocyclic carbene ligands from chromium to gold, palladium and platinum

The reaction of pentacarbonyl(pyrazolin-3-ylidene)chromium complexes, ▪ ( 2a– c) (R = Ph ( a), C 6H 4NMe 2-4 ( b); (C 5H 4)FeCp ( c)), with [AuCl(SMe 2)], H[AuCl 4], [PdCl 2(NCPh) 2] and [PtCl 2(NCPh) 2] gives, by transfer of the heterocyclic carbene ligand, new chloro pyrazolin-3-ylidene complexes of gold(I) and gold(III), dichloro bis(pyrazolin-3-ylidene) palladium and dichloro bis(pyrazolin-3-ylidene) platinum in high yield. The chloride ligand in ▪ (Fc = (C 5H 4)FeCp) is readily displaced by trifluoroacetate. The analogous substitution of iodide for the chloride ligands in ▪ (M = Pd, Pt) give the corresponding diiodo complexes although in a much slower reaction. In contrast, the reaction of silver trifluoroacetate with ▪ affords a binuclear Pd–Ag complex containing two pyrazolin-3-ylidene and three trifluoroacetate ligands two of whom occupy bridging positions between Pd and Ag. The reactions of the pyrazolidin-3-ylidene complex ▪ (R = C 6H 4NMe 2-4) with [AuCl(SMe 2)] and [PdCl 2(NCPh) 2] yield chloro pyrazolidin-3-ylidene gold and dichloro bis(pyrazolidin-3-ylidene) palladium complexes. The related dichloro bis(tetrahydropyrimidin-4-ylidene) palladium complex is formed in the reaction of ▪ with the palladium complex [PdCl 2(NCPh) 2]. The solid-state structures of several of these heterocyclic carbene complexes including the structure of the binuclear Pd–Ag complex are established by X-ray structure analyses.

Facile chromium carbene mediated synthesis of functionalised 5- to 7-ring lactones

The reaction of pentacarbonyl[methoxy(2,6-dimethoxyphenyl)methylene]chromium(0) with acetylenic alcohols has been investigated. Reaction protocols have been optimised for rapid and direct access to functionalised γ-, δ-, and ε-lactone products possessing enol ether (i.e. masked carbonyl) functionality.

Organic syntheses via transition metal complexes. LXXXI. Bis(carbene) complex of chromium connected by a conjugated ammonium pentadienide bridge

The reaction of pentacarbonyl(1-ethoxyenthylidene)chromium and tetrachlorocyclopropene in the presence of triethylamine affords a bis(carbene) complex 3, in which the carbene chromium units are connected by a conjugated and planar ammonium pentadienide bridge. According to NMR measurements the compound adopts a fluctional ( Z, E) configuration. The structure of 3 was established by X-ray structure analysis [C 27H 27Ctr 2NO 12 · 2Ch 2Cl 2, triclinic, space group P 1 (No. 2), a = 12.703(1) A ̊ , b = 12.847(1) A ̊ , c = 13.667(2) A ̊ , α = 95.77(1)°, β = 110.15(1)°, γ = 112.81(1)° Z = 2, R = 0.072, wR 2 = 0.201 ].

Reactions of silyl enol ethers with [ethoxy(phenylethynyl)carbene]chromium and -tungsten complexes

The reaction of pentacarbonyl[ethoxy(phenylethynyl)carbene]chromium with silyl enol ethers yields cyclobutenylcarbene complexes in moderate-to-good yield by a process that involves a Michael-type addition of the nucleophilic enol ether to the Fischer carbene complex. An ene-type product and two pyranylidene chromium complexes were also obtained in these reactions. A pyranylidene complex was also obtained in the reaction of the related tungsten complex with ( Z)-1,3-bis(trimethylsilyloxy)-1-ethoxy-1,3-butadiene.

Phosphirane Complexes from Oxiranes via the "Phospha-Wittig" Reaction. The Case of Optically Active Species

Reaction of pentacarbonyl[(diethoxyphosphoryl)phosphine]tungsten complexes with substituted oxiranes gives a new approach to the corresponding pentacarbonyl(phosphirane)tungsten complexes. When optically pure styrene oxide is used, inversion of the carbon configuration is observed in the final products. The synthesis of optically active phosphirane complexes is therefore conceivable.

Reaction of pentacarbonyl(alkoxyalkylcarbene)chromium complexes with N,N-dimethylformamide dialkyl acetals: synthesis of pentacarbonyl-(alkoxyenaminocarbene) and -(dialkoxycarbene)chromium complexes

On treatment of the carbene complexes (1a–f) with N,N-dimethylformamide dialkyl acetals (DMF-DAA)(2a–d) as electrophiles, the nature of the products, (3) or (4), depends on the structure of the starting carbene complexes.

Kinetische und mechanistische untersuchungen von übergangsmetall-komplex-reaktionen XXII. Konkurrenz zwischen dissoziativem und assoziativem mechanismus bei der reaktion von pentacarbonyl(diphenylcarben)wolfram mit nitrilen

The reaction of pentacarbonyl(diphenylcarbene)tungsten, (CO) 5WCPh 2 (I), with organyl nitriles, RCN (II) (R = C 6H 4NMe 2- p (b), Ph (c), Me (d), Bu t (e)), yields the insertion product (CO) 5W[C(R)NCPh 2] (III), the nitrile complexes (CO) 5WNCR (IV) and cis-(CO) 4W(NCR) 2 (V) and diphenyl ketene, Ph 2CC). The product distribution depends on the type and the concentration of the organyl nitrile II. At contant temperature, the yield of III increases and that of IV as well as that of diphenyl ketene decreases with increasing concentration of II and in the order IId, IIc, IIb, IIa. When I reacts with IIb in the presence of 13CO, 13CO is incorporated almost exclusively into IVb. At 50.6°C in 1,1,2-trichloroethane, the reaction of I with IIa–d follows an additive rate law: −d[I]/d t = k 2[I] + k 2[I][II]. The rate constant k 1 is independent of the type of II and agrees well with the rate contant for the dissociative thermolysis of I in 1,1,2-trichloroethane, however, k 2 clearly increases in the series IId–a. A reaction scheme is proposed consisting of an associative pathway (giving III) and a dissociative pathway leading to the compounds IV, V and diphenyl ketene.

ChemInform Abstract: KINETIC AND MECHANISTIC STUDIES OF TRANSITION METAL COMPLEX REACTIONS, XV. TRANSITION METAL SULFUR YLIDE COMPLEXES, XX. KINETIC EVIDENCE OF ((CO)5CR:CH2) IN THE REACTION OF PENTACARBONYL((DIMETHYLOXOSULFONIO)METHANIDE)CHROMIUM(0) WITH TERTIARY PHOSPHINES

Chemischer InformationsdienstVolume 16, Issue 22 Organoelement Compounds ChemInform Abstract: KINETIC AND MECHANISTIC STUDIES OF TRANSITION METAL COMPLEX REACTIONS, XV. TRANSITION METAL SULFUR YLIDE COMPLEXES, XX. KINETIC EVIDENCE OF ((CO)5CR:CH2) IN THE REACTION OF PENTACARBONYL((DIMETHYLOXOSULFONIO)METHANIDE)CHROMIUM(0) WITH TERTIARY PHOSPHINES H. FISCHER, H. FISCHERSearch for more papers by this authorL. WEBER, L. WEBERSearch for more papers by this author H. FISCHER, H. FISCHERSearch for more papers by this authorL. WEBER, L. WEBERSearch for more papers by this author First published: June 4, 1985 https://doi.org/10.1002/chin.198522298AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume16, Issue22June 4, 1985 RelatedInformation

Transition metal complexes of unstable ylides. 6. Synthesis of five- and six-membered ylide-chelate complexes by the reaction of pentacarbonyl(dimethyloxosulfonium methylide)chromium(0) with bis(arsines) of the type (R2As)2X (X = C:PPh3, NMe, O, S) and 1,2-ethylenebis(phosphines) and -bis(arsines)

Transition metal complexes of unstable ylides. 6. Synthesis of five- and six-membered ylide-chelate complexes by the reaction of pentacarbonyl(dimethyloxosulfonium methylide)chromium(0) with bis(arsines) of the type (R2As)2X (X = C:PPh3, NMe, O, S) and 1,2-ethylenebis(phosphines) and -bis(arsines)

Gekkopelte einschiebung von “NC” in die metall-carbenkohlenstoff-bindung und von “C(R′)Ph” in die RCN-bindung bei der reaktion von (CO) 5M[C(R′)Ph] mit RCN

The pentacarbonyl[methoxy(phenyl)carbene]complexes (CO) 5M[C(OMe)Ph][M = Cr (Ia), Mo (Ib), W (Ic) react with [(Ph 3P) 2N][NCBH 3] to give the new nitrile complexes [(Ph 3P) 2N] + {(CO) 5M[NCC(OMe)(Ph)BH) 3]} −. The reaction of Ic with NCSiMe 3 yields (CO) 5W[NCC(OMe)(Ph)SiMe 3]; however, in the presence of silica gel (CO) 5W[NCC(OMe)(Ph)H] is obtained. From the reaction of pentacarbonyl(diphenylcarbene)tungsten, (CO) 5W[CPh 2], with NCSnBu n 3 in diethyl ether, (CO) 5W[NCCHPh 2] was isolated. Formally, the new nitrile complexes correspond to the products of a coupled insertion: (a) of NC from RCN into the MC(R′)Ph bond of (CO) 5M[C(R′)Ph] and (b) of C(R′)Ph into the CR bond of RCN. For RSiMe 3 and SnBu n 3, subsequent hydrolysis of the initially formed complexes affords the R/H substitution products.

Kinetische und mechanistische untersuchungen von Übergangsmetall-komplex-reaktionen : III. Abhängigkeit des gleichgewichts der addition von tributylphosphan an pentacarbonyl(arylmethoxycarben)wolfram vom substituenten am ring

The reaction of pentacarbonyl(arylmethoxycarbene)tungsten, (CO) 5W[C(OCH 3( p-C 6H 4R)] [R = OCH 3 (a), CH 3 (b), H (c), Br (d), CF 3 (e)], with tributylphosphane at low temperatures results in a reversible addition of the phosphane to the carbene carbon atom. The addition—dissoziation equilibrium is not only dependent on the temperature but also to a strong degree on the nature of the substituent R. Δ G, Δ H and the equilibrium constant K increase in the series from R = OCH 3 to R = CF 3. With the exception of R = OCH 3 the substituents b to e form an isentropic class. For all substituents (a to e) a linear dependency from Jaffés σ-constants was observed for Δ H. Good linear correlation for the substituents b to e was also found for log K and σ as well as for log K and the CO-force constants k cis and k trans .