ISSN:
0030-493X
Schlagwort(e):
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The mass spectra of polyenic compounds of the type RC6H4(CH=CH)nCOPh, n=1, R=H,p-NMe2,p-OH,p-OMe,p-Cl,p-Br,p-NO2,m-NO2; n=2, R=H, p-NMe2, p-OMe,p-Cl,p-Br, p-NO2; n = 3, R = H, p-OMe,p-Cl, p-Br,p-No2 have been measured. The ratio of the intensities of the common ion PhCO (m/e 105) to the intensities of the molecular ions for these series is correlated with the Hammett-Brown equation with reaction constants p = 0.73 (when n = 1), 0.25 (when n =2), 0.11 (when n = 3). The transmission coefficients were calculated as π'=0.72,0.25 and 0.11 respectively [assuming p=1.01 for benzophenone series-see M. M. Bursey and F. W. McLafferty, J. Am. Chem. Soc. 89, 1 (1967)]. The contributions of the inductive mesomeric direct polar conjugation and non-additive interaction were calculated in accordance with the equation log Z/Z0= ρIσI + ρc+σc+ + ρI, cσIσc+. It was found that the inductive influence as well as the mesomeric influence of substituents decreases rapidly with the increase in the number of double bonds in the chain. The direct polar effect has a very small value in all series for all substituents with the exeption of NMe2. Non-additive interaction effects are large. They probably express the general influence of RC6H4(CH=CH)n on COPh.
Zusätzliches Material:
3 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/oms.1210050903
Permalink
