Carbonylation of diamino-ligated methylpalladium(II) methoxide complexes

Kapteijn, Gerardus M.; Verhoef, Michel J.; Broeck, M.A.Frederick H. van den; Grove, David M.; Koten, Gerard van

doi:10.1016/0022-328x(95)05694-k

Cited by 12 publications

(3 citation statements)

References 14 publications

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“…Reported interesting properties of late transition metal alkoxides include CO bond formation, insertion of small molecules into the metal-to-oxygen bond, β-hydrogen elimination of the alkoxide ligand to release aldehydes or ketones, and their ability to associate with alcohols through OH···O hydrogen bonding . In the course of our study concerning palladium alkoxides, we have reported both the synthesis and properties of methylpalladium(II) alkoxides (and their adducts with alcohols) containing bidentate N-donor ligands, as well as the reaction of CO with N-ligated methylpalladium methoxides that affords stable methylpalladium methoxycarbonyl complexes . These studies and the use of P,N-ligating ligands in the palladium methoxide-catalyzed production of methyl methacrylate 3 encouraged us to use bidentate P,N-donor ligands in palladium alkoxide chemistry.…”

Section: Introductionmentioning

confidence: 97%

Chemistry of P,N-Ligated Methylpalladium(II) Alkoxide Complexes: Syntheses, Structural Features in the Solid State and in Solution, and Hydrogen-Bond Formation

et al. 1996

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The reaction of P,N-ligated dimethylpalladium(II) complexes [Pd(Me)2(P∼N)] [P∼N = o-(diphenylphosphino)-N,N-dimethylbenzylamine (PCN), (diphenylphosphino)-N,N-dimethylethyleneamine (PN)] with an equimolar amount of HOCH(CF3)2 or HOC6H4-4-X (X = H, Cl, OMe, Me, CN, NO2, OH) affords methylpalladium(II) alkoxide and aryl oxide complexes [Pd(Me)(OR)(P∼N)] [R = CH(CF3)2, C6H4-4-X; P∼N = PCN, PN], which have been isolated in high yields as white or pale orange solids. NMR spectroscopic data indicate that the complexes have the alkoxide or aryl oxide ligand (OR) positioned trans with respect to the P-atom. Reaction of [Pd(Me)2(PCN)] with 2 equiv of phenol affords the phenol adduct [Pd(Me)(OC6H5)(PCN)]·HOC6H5, which has been isolated as a white solid. The transesterification reaction of [Pd(Me)(OC6H5)(PCN)] with C6H5SC(O)Me affords the arenethiolate complex [Pd(Me)(SC6H5)(PCN)]. Furthermore, the alkoxide complex [Pd(Me)(OCH(CF3)2)(PN)] reacts with phenylacetylene to afford an isolable alkynylpalladium(II) complex [Pd(Me)(C⋮CPh)(PN)]. Thermolysis of the latter complex results in reductive elimination of MeC⋮CPh in 98% yield. When this reductive elimination is performed under a CO atmosphere, MeC⋮CPh (87%) is formed together with small amounts of the insertion product, MeC(O)C⋮CPh (3%). Crystals of [Pd(Me)(OC6H5)(PCN)]·CH2Cl2 and its adduct with HOC6H5 have been subjected to X-ray diffraction studies. The molecular structure of the latter adduct shows an OH···O hydrogen bond between the phenol and the oxygen atom of the phenoxide unit. The 31P NMR chemical shift and 3 J H,P for the PdCH3 group of the complexes [Pd(Me)(OC6H4-4-X)(PN)] have been correlated with various Hammet substituent constants; the best linearity was achieved with parameters that represent the sum of resonance and inductive/field effects of the substituent X.

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Section: Introductionmentioning

confidence: 97%

Chemistry of P,N-Ligated Methylpalladium(II) Alkoxide Complexes: Syntheses, Structural Features in the Solid State and in Solution, and Hydrogen-Bond Formation

et al. 1996

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“…The availability of the N-ligated complexes [Pd(Me)(OR)-(N ~ N)] prompted us to study the reactivity of both the Pd-O and Pd-C bond towards carbon monoxide so that we could compare the reactivity of analogous N-and P-ligated complexes. Some aspects of the carbonylation of these species was communicated earlier [13].…”

Section: Introductionmentioning

confidence: 99%

Chemistry of diamino-ligated methylpalladium(II) alkoxides and aryloxides (Part II): methoxide formation and carbonylation reactions

Kapteijn

Dervisi

Verhoef

et al. 1996

Journal of Organometallic Chemistry

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Reaction of N-ligated methylpalladium(II) alkoxide and aryloxide complexes [Pd(Me)(OR)(N ~ N)] (R = Ph, CH(CF3)2; N ~ N = trneda (N, N,N', N'-tetramethylethylenediamine) or bpy (2,2'-bipyridyl)) with carbon monoxide produces the corresponding methylesters in high yields. The insertion takes place either into the Pd-Me bond (aryloxide complexes) or into the Pd-OR bond (alkoxide complexes). Methylpalladium(II) methoxide complexes [Pd(Me)(OMe)(N ~ N)] (N ~ N = tmeda, bpy) have been generated in situ by aryloxide-or alkoxide-methanol exchange reactions for which the equilibrium constants have been determined. The bpy-ligated methylpalladium methoxide complex undergoes insertion of CO producing either a methylpalladium methoxycarbonyl complex [Pd(Me)(CO2Me)(bpy)] (at -60°C) or an acylpalladium methoxycarbonyl complex [Pd(COMe)(CO2Me)(bpy)] (at -25°C); both carbonylated species could be isolated and characterized at low temperature.

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“…CO insertion into the Pd−OR bond in the palladium alkoxides has been reported by several groups. , For the nitrogen-ligated methylpalladium methoxide,18d CO (1 atm) first inserts into the Pd−OMe bond at −60 °C and then into the Pd−Me bond at −25 °C. On the other hand, the present study shows that CO insertion into the Pd−OAr bond in the TMEDA-ligated palladium diaryloxide requires a higher CO pressure and temperature.…”

Section: Resultsmentioning

confidence: 88%

Reactivity of Diaryloxy Palladium Complex with TMEDA (N,N,N‘,N‘-Tetramethylethylenediamine) Ligand toward Carbon Monoxide and Carbon Dioxide

et al. 2002

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The reactivity of the diaryloxy palladium complex toward carbon monoxide was investigated relevant to the mechanism of the palladium-catalyzed oxidative carbonylation of phenol to produce diphenyl carbonate (DPC). (TMEDA)Pd(OC 6 H 4 -p-t-Bu) 2 (1) reacted at high CO pressures (10-80 atm) at 100 °C to give the di(p-tert-butyl)phenyl carbonate. The yield of the carbonate increased with the increase in the CO pressure and with the addition of triphenylphosphine. The 13 C{ 1 H} NMR and IR spectroscopic studies at room temperature under high CO pressure (50 atm) revealed that CO inserts into one of the Pd-O bonds in 1. Thus, the formation of palladium phenoxide followed by carbonylation and subsequent reductive elimination is considered to be one of the possible DPC formation routes in the oxidative carbonylation of phenol; the reductive elimination is slower than the carbonylation. The reactivity of 1 with carbon dioxide was also examined relating to the DPC synthesis from carbon dioxide and phenol. The reaction of 1 with CO 2 led to the formation of a palladium carbonate complex, (TMEDA)Pd(η 2 -CO 3 ) (2), whose molecular structure was determined by X-ray crystallography.

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Carbonylation of diamino-ligated methylpalladium(II) methoxide complexes

Cited by 12 publications

References 14 publications

Chemistry of P,N-Ligated Methylpalladium(II) Alkoxide Complexes: Syntheses, Structural Features in the Solid State and in Solution, and Hydrogen-Bond Formation

Chemistry of P,N-Ligated Methylpalladium(II) Alkoxide Complexes: Syntheses, Structural Features in the Solid State and in Solution, and Hydrogen-Bond Formation

Chemistry of diamino-ligated methylpalladium(II) alkoxides and aryloxides (Part II): methoxide formation and carbonylation reactions

Reactivity of Diaryloxy Palladium Complex with TMEDA (N,N,N‘,N‘-Tetramethylethylenediamine) Ligand toward Carbon Monoxide and Carbon Dioxide

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