53500-08-6Relevant articles and documents
PHOTOCHEMISTRY AND LUMINESCENCE OF ROTATIONAL ISOMERS OF 1-(n-NAPHTHYL)-2-(3-PYRIDYL)ETHYLENE
Masetti, Fausto,Bartocci, Giampiero,Mazzucato, Ugo,Galiazzo, Guido
, p. 255 - 260 (2007/10/02)
The trans isomers of 1-(n-naphthyl)-2-(3-pyridyl)ethylene (n,3-NPE, with n=1 or 2) exibit some anomalies in their fluorescence behaviour.The fluorescence spectrum and quantum yield of 2,3-NPE at room temperature show a dependence on the excitation wavelength (λex) and the fluorescence decay follows a bi-exponential function.For 1,3-NPE, only the fluorescence spectrum in a rigid matrix depends on λex whilst ΦF changes only slightly and the observed decay is monoexponential.This behaviour, which can be accompained by a λex-dependent photochemistry, is probably due to the existence in solution of distinct rotational isomers involving the quasi-single bonds between the aromatic groups and the ethylenic carbons.The almost isoenergetic naphthyl conformers are probably responsible for the more pronounced λex-effect on 2,3-NPE while the pyridyl conformers could give a greater contribution to the smaller effect observed in the less planar 1,3-NPE.The corresponding cis isomers give azabenzophenanthrenes as photocyclization products.In both cases, two products were isolated.Their very different chemical yields depend on the position of the heteroatom with respect to the photoreactive site.The fluorescent properties of the four cyclized products, including the effect of oxygen, were also determined.
