title: Excited states of 4-dimethylaminopyridines: magnetic circular dichroism and computational studies.
abstract: The ultraviolet transitions of 4-(dimethylamino)pyridine and its derivatives: 3-methyl-4-(dimethylamino)pyridine and 3,5-dimethyl-4-(dimethylamino)pyridine were investigated by electronic absorption and magnetic circular dichroism (MCD) spectroscopy, and by quantum chemical calculations. The ortho-methylation in the pyridine ring creates a steric hindrance to coplanarity. The resulting changes in the strength of the dimethylamino substitutent are reflected in the MCD spectra. Near-UV experimental data indicate a presence of three low-energy transitions, assigned to 1Lb, 1La and 1(n,pi*) excited states. These results are corroborated by TD-DFT and INDO/S calculations.
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44152, 01-224 Warsaw, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Szydłowska
authors.forename: Alexander
authors.initials: A
authors.lastname: Kyrychenko
authors.forename: Alexander
authors.initials: A
authors.lastname: Gorski
authors.forename: Jacek
authors.initials: J
authors.lastname: Waluk
authors.forename: Jerzy
authors.initials: J
authors.lastname: Herbich