R. Dabestani, J. Higgin, D. Stephenson
Oct 19, 2000
Citations
0
Influential Citations
15
Citations
Journal
The Journal of Physical Chemistry
Abstract
The photophysics and photochemistry of 2-methylanthracene (2MA), 2-ethylanthracene (2EA), and 2-tert-butylanthracene (2TBA) adsorbed on silica was studied at a silica/air interface to determine the substituent effect on the above processes. In contrast to anthracene (AN), which forms ground state stable pairs at surface coverages as low as 1% of a monolayer, 2MA, 2EA, and 2TBA show no evidence of any ground state pairing even at high surface coverages. Diffuse reflectance and fluorescence data indicate that 2MA, 2EA, and 2TBA crystallize on the surface at higher surface coverages. Photolysis of 2MA, 2EA, and 2TBA at a silica/air interface proceeds more efficiently than photolysis of AN to produce the corresponding 9,10-endoperoxides formed by the addition of singlet molecular oxygen (type II) to the ground state molecules. Thermally unstable endoperoxides slowly decompose on silica surface to give the corresponding 9,10-quinones and other hydroxylated products of 2MA, 2EA, and 2TBA. Although photolyzed AN...