Kinetics of the reduction of pyridinium ions by 2-hydroxy-2-propyl radicals in aqueous solution

Journal Article · Wed Jan 19 04:00:00 UTC 1983 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00144a026· OSTI ID:6130647

Shimura, M; Espenson, J H

Kinetic measurements were made for the reductions of the pyridinium ions derived from pyridine, 4-methylpyridine, 3-hydroxypyridine, nicotinamide, and isonicotinamide as well as 1-methylpyridinium and 1,4-dimethylpyridinium ions by 2-hydroxy-2-propyl radicals, which were generated by the homolytic cleavage of the chromium-carbon bond in (H/sub 2/O)/sub 5/CrC(CH/sub 3/)/sub 2/OH/sup 2 +/. The rate constants (dm/sup 3/ mol/sup -1/ s/sup -1/) at 25.0/sup 0/C and an ionic strength of 1.0M (LiClO/sub 4/) are as follows: pyridinium ion, 9.6 x 10/sup 5/; 1-methylpyridinium ion, 3.7 x 10/sup 5/; 4-methylpyridinium ion, 7.3 x 10/sup 4/; 1,4-dimethylpyridinium ion, less than or equal to1 x 10/sup 4/; 3-hydroxypyridinium ion, 1.4 x 10/sup 8/; 3-(aminocarbonyl)pyridinium ion, 7.9 x 10/sup 8/; 4-(aminocarbonyl)pyridinium ion, 1.2 x 10/sup 9/. The rate constants are reasonably well correlated by the Hammett p-sigma equation with p = +8.5. The first two compounds show a second kinetic term corresponding to the rate law k'(Cr/sup 2 +/)(pyH/sup +/)(.C-(CH/sub 3/)/sub 2/OH)(H/sup +/)/sup -1/, consistent with reduction of a Cr(II)-pyridine complex by the free radical.

• Research Organization: Iowa State Univ., Ames
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6130647
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 22:2; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
AMINES
AMMONIUM COMPOUNDS
AZINES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM COMPLEXES
COMPLEXES
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
PYRIDINIUM COMPOUNDS
QUATERNARY COMPOUNDS
REACTION KINETICS
REDUCTION
TRANSITION ELEMENT COMPLEXES