The effect of transient photoproducts in benzophenone-hydrogen donor systems

Chilton, Jonathan; Giering, Linda P.; Steel, Colin

doi:10.1021/ja00423a036

Cited by 71 publications

(26 citation statements)

References 7 publications

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“…Lesser amounts (<0.5%, estimated) of 12 were also detected in silica gel reaction mixtures at 20 and -55°C. ' The observation of both ortho and para rearranged starting material is consistent with the earlier observation of both ortho and para products in the photo-Fries rearrangement on dry silica gel (5) and with the suggestion that both ortho and para LATs are formed in the photoreduction of benzophenone (29).…”

Section: Photolysis Of Dibenzyl Ketonesupporting

confidence: 91%

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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Section: Photolysis Of Dibenzyl Ketonesupporting

confidence: 91%

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

Frederick¹,

Johnston²,

Mayo³

et al. 1984

Can. J. Chem.

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“…Whether the explanation for this effect is that ketyls are not formed, that the radical-pair loses its triplet character quite rapidly, or that new decay paths become of importance in micellar solution, remains to be resolved. Preliminary results indicate that the so called "light absorbing transients" (24)(25)(26) are formed more efficiently than in homogeneous solution.…”

Section: Discussionmentioning

confidence: 97%

Dynamic aspects of the behavior of aromatic ketone triplets in anionic micelles. A laser flash photolysis study

Scaiano¹,

Selwyn²

1981

Can. J. Chem.

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The behavior of several aromatic ketone triplets has been examined in sodium dodecyl sulfate micelles using laser flash photolysis techniques. The molecules examined, acetophenone, propiophenone, isobutyrophenone, p-methoxyacetophenone, benzophenone, and xanthone are mainly resident in the micellar phase. Phenyl alkyl ketones show considerable self-quenching, a process that is rather sensitive to steric factors. All the molecules examined seem to reside near the Stern layer. Typical rate constants for triplet state entry into the micelle are around 1.8 × 1010 M−1 s−1.

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“…In this case, the increase of absorbance in the longer wavelength region is attributable to the formation of ortho-and para-coupling products of the isomerized ketyl radicals. 18 For the copolymer (NSt/DMAEMA), as shown in Figure 8, decreasing the absorption around 330 nm due to the naphthophenone group and increasing the absorbance in the region above 350 nm were also observed; this suggests that the phenone was photo-reduced and ketyl radicals were formed. 8 …”

Section: Photocross/inkingmentioning

confidence: 89%

Photochemical Reaction of Polymers Having Arylketone and Tertiary Amine as Pendant Groups

Tsubakiyama¹,

Kuzuba²,

Yoshimura³

et al. 1991

Polym J

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ABSTRACT:Binary (M,/M2) and ternary (M,(M 2IM 3) copolymer having aryl ketone and tertiary amine as pendant groups were prepared by radical polymerization, where M 1 is 4-vinylbenzophenone (VBP) or 4-(2-naphthoyl)styrene (NSt), M 2 is 2-N,N-dimethylaminoethyl methacrylate (DMAEMA) or 4-N,N-dimethylaminostyrene (DMASt), and M 3 is methyl methacrylate. The polymer film was irradiated with a high-pressure mercury lamp (A> 300 nm), and photocrosslinking was followed by measuring the gel fraction. Crosslinking of the VBP(n, n*)-polymer was greatly accelerated by the amines, whereas that of the NSt(n, n*)-polymer could be induced only in their presence. The effects of the aliphatic amine (DMAEMA) were larger than those of the aromatic amine (DMASt). Absorption and emission spectra showed that the arylketones interact more strongly with aromatic amine than aliphatic amine. Laser photolysis experiments confirmed that the ketyl radicals were formed in the copolymers.

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The effect of transient photoproducts in benzophenone-hydrogen donor systems

Cited by 71 publications

References 7 publications

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

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

Dynamic aspects of the behavior of aromatic ketone triplets in anionic micelles. A laser flash photolysis study

Photochemical Reaction of Polymers Having Arylketone and Tertiary Amine as Pendant Groups

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