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

Journal Article · Sat Oct 01 04:00:00 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), Journal Name: J. Chem. Phys.; (United States) Vol. 79:7; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

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