ISSN:
0947-6539
Schlagwort(e):
cumulenes
;
heterocumulenes
;
ketenimines
;
matrix isolation
;
thermolysis
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Flash vacuum thermolysis (FVT) of suitably substituted isoxazol-5(4H)-ones 7-9 leads to three different types of ketenimines, namely, the isoxazolonoketenimines 2, the novel bisiminopropadienes RN=C=C=C=NR (5), and the C-cyanoketenimines 14, all characterized by a combination of FVT/matrix isolation/IR spectroscopy and FVT/MS. An unusual, linear C=C=N-C backbone in ketenimines 2g and 2h is revealed by their exceptional spectroscopic properties as well as an X-ray crystal structure of 2g, and confirmed by density functional calculations (B3LYP/6-31 G*); these compounds are best described as resonance hybrids of ketenimines and isonitrile ylides R2C-C≡N-R'. The identification of the highly reactive bisiminopropadienes 5 is supported by the observed shifts in the IR bands of the 15N and 13C isotopomers as well as theoretical calculations, tert-Butyl-substituted isoxazolones 7e and 7f, and 8i form the expected ketenimines 2, which then undergo elimination of isobutene and CO2 to generate C-cyanoketenimines 14 and 14i. N-Phenyl-dicyanoketenimine 32 is also described.
Zusätzliches Material:
8 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/chem.19960021020
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