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- Title
Structural studies of PdCl[sub 2] L[sub 2] complexes with fluorinated phosphines, phosphites, and phosphinites as precursors of benzyl bromide carbonylation catalysts, and and X-ray crystal structure of cis-PdCl[sub 2] [PPh[sub 2] (OEt)][sub 2].
- Authors
Trzeciak, Anna M; Bartosz-Bechowski, Hubert; Ciunik, Zbigniew; Niesyty, Katarzyna; Ziólkowski, Józef J
- Abstract
PdCl[sub 2] L[sub 2] -type complexes with phosphines (L = PPh[sub x] (C[sub 6] F[sub 5] )[sub 3-] [sub x] (x = 0-3)), phosphites (L = P(OMe)[sub 3] , P(OPh)[sub 3] , P(OEt)[sub 3] ), and phosphinites (L = PPh[sub 2] (OC[sub 6] F[sub 5] ), PPh[sub 2] (O-3,5-F[sub 2] C[sub 6] H[sub 3] ), PPh[sub 2] (OEt), PPh[sub 2] (O-n-Bu), PPh[sub 2] (O-t-Bu)) were synthesized and characterized by UV-vis and [sup 31] P NMR methods. PdCl[sub 2] L[sub 2] complexes with less sterically demanding phosphines (Θ < 140°) exist as cis isomers, which is confirmed by the X-ray structure of cis-PdCl[sub 2] [PPh[sub 2] (OEt)][sub 2] . These complexes react with CO in the presence of NEt[sub 3] forming Pd(CO)[sub x] L[sub y] (x + y = 4) type carbonyls characterized by IR spectra. All PdCl[sub 2] L[sub 2] complexes studied are active as precursors of benzyl bromide carbonylation catalysts at 40°C and 1 atm CO; however, the activity of the cis isomers is higher than that of the trans isomers. The highest yields of the carbonylation product, phenylacetic acid methyl ester, were obtained using cis-PdCl[sub 2] [P(OMe)[sub 3] ][sub 2] (92%), cis-PdCl[sub 2] [P(OPh)[sub 3] ][sub 2] (89%), and cis-PdCl[sub 2] [PPh[sub 2] (O-n-Bu)][sub 2] (78%) as catalyst precursors.Key words: palladium complexes, fluorinated phosphines, benzyl bromide carbonylation.On a synthétisé des complexes de type PdCl[sub 2] L[sub 2] comprenant des phosphines L = PPh[sub x] (C[sub 6] F[sub 5] )[sub 3-] [sub x] (x = 0-3), des phosphites L = P(OMe)[sub 3] , P(OPh)[sub 3] et P(OEt)[sub 3] et des phosphinites L = PPh[sub 2] (OC[sub 6] F[sub 5] ), PPh[sub 2] (O-3,5-F[sub 2] C[sub 6] H[sub 5] ), PPh[sub 2] (OEt), PPh[sub 2] (OBu) et PPh[sub 2] (O-t-Bu) et on les a caractérisés par spectroscopie UV-vis et par RMN du [sup 31] P. Les complexes PdCl[sub 2] L[sub 2] comportant des phosphines stériquement moins encombrées (Θ < 140°) existent sous la forme d'isomères cis; cette situation a été confirmée par diffraction des rayons du cis-PdCl[sub 2] [PPh[sub 2] (OEt)][sub 2] . Ces complexes réagissent avec le CO en présence de NEt[sub 3] pour former des complexes carbonylés de type Pd(CO)[sub x] L[sub y] (x + y = 4) qui ont été caractérisés par spectroscopie IR. À 40°C et 1 atm de CO, tous les complexes de type PdCl[sub 2] L[sub 2] sont actifs comme précurseurs de catalyseurs pour la carbonylation du bromure de benzyle; toutefois, l'activité des isomères cis est supérieure à celle des isomères trans. Les rendements les plus élevés en produit de carbonylation, le phénylacétate de méthyle, ont été obtenus avec les cis-PdCl[sub 2] [P(OMe)[sub 3] ][sub 2] (92%), cis-PdCl[sub 2] [P(OPh)[sub 3] ][sub 2] (89%) et cis-PdCl[sub 2] [P(OBu)[sub 3] ][sub 2] (78%) comme précurseurs de catalyseur.Mots clés : complexes de palladium, phosphines fluorées, carbonylation du bromure de benzyle.[Traduit par la Rédaction]
- Subjects
PALLADIUM compounds; TRANSITION metal compounds; PHOSPHINE; PHOSPHORUS compounds; BROMINE
- Publication
Canadian Journal of Chemistry, 2001, Vol 79, Issue 5/6, p752
- ISSN
0008-4042
- Publication type
Article
- DOI
10.1139/v01-075