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Titolo:
Synthesis and X-ray structure of the rhenium methyl complex trans-Cp*Re(CO)(2)(Me)I and a study of the products of photolysis of the rhenium alkyl methyl and dimethyl complexes Cp*Re(CO)(2)(Me)R (R = Ph, p-tolyl, Me) under CO
Autore:
Leiva, C; Klahn, AH; Godoy, F; Toro, A; Manriquez, V; Wittke, O; Sutton, D;
Indirizzi:
Simon Fraser Univ, Dept Chem, Burnaby, BC V5A 1S6, Canada Simon Fraser Univ Burnaby BC Canada V5A 1S6 , Burnaby, BC V5A 1S6, Canada Univ Catolica Valparaiso, Inst Quim, Valparaiso, Chile Univ Catolica Valparaiso Valparaiso Chile Inst Quim, Valparaiso, Chile Univ Chile, Fac Ciencias, Dept Quim, Santiago, Chile Univ Chile SantiagoChile ile, Fac Ciencias, Dept Quim, Santiago, Chile
Titolo Testata:
ORGANOMETALLICS
fascicolo: 3, volume: 18, anno: 1999,
pagine: 339 - 347
SICI:
0276-7333(19990201)18:3<339:SAXSOT>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
CIS TRANS ISOMERISM; PHOTOCHEMICAL DECOMPOSITION; CRYSTAL-STRUCTURE; METAL CENTER; MECHANISM; (ETA-5-C5ME5)RE(CO)2BR2; CARBONYLATION; REDUCTION; RADICALS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
31
Recensione:
Indirizzi per estratti:
Indirizzo: Sutton, D Simon Fraser Univ, Dept Chem, Burnaby, BC V5A 1S6, Canada Simon Fraser Univ Burnaby BC Canada V5A 1S6 BC V5A 1S6, Canada
Citazione:
C. Leiva et al., "Synthesis and X-ray structure of the rhenium methyl complex trans-Cp*Re(CO)(2)(Me)I and a study of the products of photolysis of the rhenium alkyl methyl and dimethyl complexes Cp*Re(CO)(2)(Me)R (R = Ph, p-tolyl, Me) under CO", ORGANOMETAL, 18(3), 1999, pp. 339-347

Abstract

Reaction of Cp*Re(CO)(2)I-2 with methylcopper affords cis-Cp*Re(CO)(2)(Me)I, which converts to the trans isomer on prolonged reaction or in the presence of neutral alumina. The X-ray structure of the trans isomer has been determined. The related chloro complexes Cp*Re(CO)(2)(Me)Cl and Cp*Re(CO)(2)(p-tolyl)Cl are formed in the photolyses of compounds 3 and 1 (below) in CCl4. Photolysis of Cp*Re(CO)(2)(Me)R (R p-tolyl (1), Ph (2), Me (3)) in the presence of CO has been carried out in hydrocarbons, CCl4, and benzene-d(6). In hydrocarbons, 1 and 2 produce Cp*Re(CO)(3), CH4, and either toluene or benzene, respectively; 3 produces Cp*Re(CO)(3) and CH4. In benzene-d(6) 1 gave CH3D and toluene-4-d, and 3 gave mainly CH3D. These results are consistent with a general scheme involving successive homolysis of the metal-methyl and metal-aryl bonds to give methyl and aryl radicals that abstract H or D from the solvent and carbonylation of the rhenium dicarbonyl fragment. Products known or expected to arise from further photolysis of Cp*Re(CO)(3) in benzene-d(6), such as Cp*Re-2(2)(CO)(3), Cp*Re-2(2)(CO)(5), and Cp*Re(CO)(2)(eta(2)-C6D6), were also found. Photolysis of 1 in CCl4 in the presence or absence of CO gave CH3Cl and Cp*Re(CO)(2)(p-tolyl)Cl, but no p-chlorotoluene, indicating the preferential homolysis of the Re-Me bond and the rapidscavenging of the subsequent radicals by the chlorinated solvent. Photolysis of the dimethyl complex 3 gave CH3Cl and some evidence of a small amountof Cp*Re(CO)(2)(Me)Cl, but the major rhenium product was Cp*Re(CO)(2)Cl-2,consistent with the more facile homolysis of both Re-Me bonds in 3. Production of small amounts of CH2D2 (in benzene-d(6)) and CH4 and CH2Cl2 (in CCl4) are discussed in terms of a competing pathway. Notably, in none of thesephotolyses were there observed other than trace amounts of products such as p-xylene, which would be expected to be major products if reductive elimination were to occur.

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Documento generato il 29/09/20 alle ore 06:32:42