Effektivität der photochemischen Co‐C‐Bindungsspaltung in σ‐Alkyl‐Co(III) (salen)‐ und ‐Co(III) (salphen)‐Komplexen
作者:
G. Roewer,
G. Kempe,
B. Kolle,
R. Just,
期刊:
Journal für Praktische Chemie
(WILEY Available online 1982)
卷期:
Volume 324,
issue 1
页码: 53-64
ISSN:0021-8383
年代: 1982
DOI:10.1002/prac.19823240108
出版商: WILEY‐VCH Verlag GmbH
数据来源: WILEY
摘要:
Efficiency of the Photochemical Co‐C‐Bond Cleavage in σ‐Alkyl‐Co(III)(salen)‐and‐Co(III)(salphen)‐Complexes.The photodealkylation rate of RCoIII(chel) X complexes (R = methyl, ethyl; chel = salen, salphen; X = H2O, py, PPh3) depends on the nature of ligands and solvents as well as on the concentration of oxygen and scavengers for alkyl radicals. The rapid recombination of the fragments R. and Co(chel)X is responsible for the low quantum yields of the anaerobic dealkylation. The quantum yields may reflect the H‐donating ability of the solvents used. Lewis bases X in the trans position generally cause a decrease of quantum yields relative to the pentacoordinated species RCo (chel). The anaerobic photolysis can be accelerated by the addition of scavengers for alkyl radicals (e. g. Koelsch radical, nitrosodurene, styrene). The quantum yield also increases in the presence of oxygen, preventing the recombination of the fragments of the cobalt‐carbon bond scission by forming alkyl‐peroxocomplexes ROOCo(chel)X.α‐Hydroxyalkylradicals arising from the decomposition of the ROOCo(chel)X complexes via secondary reactions probably react with the starting σ‐alkyl complexes and cause the dependence of quantum yie
点击下载:
PDF
(618KB)
返 回