On the magnetic circular dichroism of aromatic carbonyl compounds

摘要

The magnetic circular dichroism of the singlehyphen;ring aromatic compounds benzaldehyde, acetophenone, and phthalaldehyde and of the twohyphen;ring compounds benzophenone, anthrone, 9,10hyphen;anthraquinone, and 10hyphen;methylene anthrone is reported. In each case the molecular symmetry is so low that onlyBterms contribute to the magnetic ellipticity. The magnitude of the magnetic ellipticity in thenpgr;*absorption region is discussed in terms of vibronic and electronic intensification mechanisms. The MCD of the pgr;pgr;* transition region of the singlehyphen;ring compounds is discussed in terms of a model which considers magnetic field mixing of the1Lband1Labenzene states alone. The MCD of the twohyphen;ring compounds, other than benzophenone, reveal pgr;pgr;* transitions which are not observed in either absorption or polarized phosphorescence excitation spectra.