Quenching and radical formation in the reaction of photoexcited benzophenone with thiols and thioethers (sulfides). Nanosecond flash studies
Laser flash measurements have been made of rate constants and primary radical yields in the reactions of triplet benzophenone with aliphatic and aromatic thiols and with dialkyl and aryl alkyl sulfides. Reaction with n-pentylthiol in benzene leads mainly to quenching, with k/sub ir/ = 9 x 10/sup 6/ M/sup -1/ s/sup -1/ and radical yield (ketyl) = 0.14; with mesitylene-2 thiol in benzene k/sub ir/ = 7 x 10/sup 8/ M/sup -1/ s/sup -1/ and hydrogen transfer is efficient, radical yield (ketyl) approx. 1.0. In reactions with both p-chlorophenyl ethyl and diisopropyl sulfides, k/sub ir/ increases and radical yield (ketyl) decreases with increasing solvent polarity. Values of k/sub ir/ are higher and those of radical yield (ketyl) are lower for the dialkyl than for the aryl alkyl sulfide. Results are discussed in terms of rapid interaction of the triplet with S, followed by quenching and/or hydrogen transfer. Quenching without hydrogen transfer occurs to a much greater extent with sulfides and aliphatic thiols than with amines.
- Research Organization:
- Brandeis Univ., Waltham, MA
- OSTI ID:
- 5035107
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 104:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BENZOPHENONE
PHOTOCHEMICAL REACTIONS
QUENCHING
HYDROGEN TRANSFER
EFFICIENCY
RADICALS
CHEMICAL REACTION YIELD
THIOLS
ALKYL RADICALS
BENZENE
DECAY
EQUATIONS
EXPERIMENTAL DATA
IONIZATION
OSCILLOGRAPHS
POTENTIALS
QUANTITY RATIO
REDUCING AGENTS
TRIPLETS
AROMATICS
CHEMICAL REACTIONS
DATA
ELECTRONIC EQUIPMENT
EQUIPMENT
HYDROCARBONS
INFORMATION
KETONES
MULTIPLETS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
YIELDS
400500* - Photochemistry
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)