Selective vibronic excitation of singlet oxygen--furan reactions in cryogenic matrices

Journal Article · Sat Oct 01 00:00:00 EDT 1983 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.446224· OSTI ID:5833547

Frei, H; Pimentel, G C

The reactions of 2,5-dimethylfuran (DMF), 2-methylfuran (MF), and furan with molecular oxygen to form endoperoxides have been induced in Ar and O/sub 2/ matrices at 12 K with selective vibronic excitation of O/sub 2/ using near infrared light. Reaction was induced through excitation of the /sup 1/..delta../sub g/(v' = 0, v' = 1) and /sup 1/..sigma../sub g//sup +/(v' = 0, v' = 1) O/sub 2/ states near 8000 and 13 100 cm/sup -1/, respectively, as well as by the (/sup 1/..delta../sub g/, /sup 1/..delta../sub g/) simultaneous transitions of (O/sub 2/)/sub 2/ at 15 900 and 17 300 cm/sup -1/. The /sup 1/..delta../sub g/ reverse arrow /sup 3/..sigma../sub g//sup -/ vibronic progression in solid O/sub 2/ was recorded by FTIR spectroscopy, whereas members of the /sup 1/..sigma../sub g//sup +/ reverse arrow /sup 3/..sigma../sub g//sup -/ and (/sup 1/..delta../sub g/, /sup 1/..delta../sub g/) reverse arrow (/sup 3/..sigma../sub g//sup -/, /sup 3/..sigma../sub g//sup -/) progressions in Ar matrices were located by ''reaction excitation'' spectroscopy. The DMF+O/sub 2/ reaction is a single photon process, apparently with unit quantum yield, for all vibronic levels excited. For MF+O/sub 2/(/sup 1/..delta../sub g/, v' = 0) and furan +O/sub 2/(/sup 1/..delta../sub g/, v' = 0), quantum yields were high, approx.0.6 and 0.4, respectively, but the reservoirs of reactive pairs were 10--20 times smaller than for DMF+O/sub 2/. The furan+O/sub 2/ reaction rate showed an /sup 18/O/sub 2/ isotope effect 0.78 +- 0.15, which can be interpreted in terms of quantum mechanical tunneling on the lowest singlet hypersurface.

• Research Organization: Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
• OSTI ID: 5833547
• Journal Information: J. Chem. Phys.; (United States), Vol. 79:7
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
FURANS
CHEMICAL REACTION KINETICS
OXYGEN
ARGON
CHEMICAL REACTIONS
EXCITATION
INFRARED RADIATION
MATRIX ISOLATION
REACTION INTERMEDIATES
ULTRALOW TEMPERATURE
VIBRATIONAL STATES
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
GASES
HETEROCYCLIC COMPOUNDS
KINETICS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
RADIATIONS
RARE GASES
REACTION KINETICS
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)