Spectra and Photochemistry of Molecules Adsorbed on Silica Gel. IV

Leermakers, Peter A.; Thomas, Harold T.; Weis, Lawrence D.; James, F. C.

doi:10.1021/ja00974a006

Cited by 101 publications

(43 citation statements)

References 4 publications

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“…One of the earlier investigations of adsorbed radical mobility involved the generation of cyanopropyl radical pairs in a silica gel sluny (2). It was claimed therein, from product analysis, that the adsorbed radicals were not free to rotate on the surface.…”

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Surface photochemistry: generation of benzyl radical pairs on dry silica gel

Frederick¹,

Johnston²,

Mayo³

et al. 1984

Can. J. Chem.

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. 62, 403 (1984).Singlet and triplet benzyl radical pairs have been generated on silica gel by photolysis of a benzyl phenylacetate, a dibenzyl ketone, and a dibenzyl sulfone. The extent of geminate radical recombination has been measured and requires that translational motion of radicals occur on the silica gel surface. This motion was affected by the radical pair multiplicity and the photolysis temperature, but was relatively insensitive to the state of hydration of the silica gel and the presence of coadsorbates. The presence of certain rearranged starting materials, which are not formed in solution, amongst the products from photolysis of both dibenzyl ketone and dibenzyl sulfone on silica gel indicates the restrictions on radical movement on the surface on the shorter tirnescale of the benzyl-phenylacetyl and benzyl -benzyl sulfonyl radical pairs.

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confidence: 99%

Surface photochemistry: generation of benzyl radical pairs on dry silica gel

Frederick¹,

Johnston²,

Mayo³

et al. 1984

Can. J. Chem.

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“…11 Early studies of interaction between PAH and the adsorbent provide the evidence for a redshift in the absorption spectrum of →* transitions whenever PAHs adsorb to a relatively polar surface, such as silica-gel. 12,13 In the case of a pure physical adsorption, the spectrum of the adsorbed molecule is very similar to that of the free molecule.…”

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confidence: 98%

Photoacoustic study of airborne and model aerosols

Alebić-Juretić¹,

Zetzsch

Dóka

et al. 2003

Review of Scientific Instruments

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Airborne particulates of either natural or anthropogenic origin constitute a significant portion of atmospheric pollution. Environmental xenobiotics, among which are polynuclear aromatic hydrocarbons ͑PAHs͒ and pesticides, often adsorb to aerosols and as such are transported through the atmosphere with the physicochemical properties of the aerosols determining the lifetime of these organic compounds. As an example, the resistance of some PAHs against the photolysis is explained by the effect of the aerosol's ''inner filter'' that reduces the intensity of incident light reaching the mineral particles. On the other hand, some constituents of the aerosols can act as catalytic and/or stoichiometric reagents in atmospheric reactions on the solid surfaces. In the study described here the photoacoustic ͑PA͒ spectroscopy in the UV-Vis was used to investigate natural and model aerosols. The PA spectra obtained from coal and wood ashes and of Saharan sand, all three representatives of airborne aerosols, provide the evidence for the existence of the ''inner filter.'' Furthermore, valuable information about the different nature of the interaction between the model aerosols and adsorbed organics ͑e.g., PAH-pyranthrene and silica, alumina, and MgO͒ has been obtained. Finally, the outcome of the study conducted with powdered mixtures of chalk and black carbon suggests that the PA method is a candidate method for determination of carbon content in stack ashes.

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“…The Soret band is broader, red-shifted by 13 nm and drastically weaker compared with TTP-Ni 2+ in chloroform. It is known that organic molecules on oxide-based supports produce strong perturbations in the maximal absorption properties and the molar absorption coefficients [42].…”

Section: Resultsmentioning

confidence: 99%