Nucleophilic addition of. cap alpha. -hydroxyalkyl radicals to polypyridyl complexes of chromium(III), cobalt(III), rhodium(III), and ruthenium(II) in aqueous solution
- Instituto di fotochimica e radiazioni d'Alta Energia del C.N.R., Bologna, Italy
The reactions of radiolytically generated ..cap alpha..-hydroxyalkyl radicals of the form R/sub 1/R/sub 2/COH, where R = H and CH/sub 3/ with M(NN)/sub 3//sup n+/ complexes, where M = Cr(III), Co(III), Rh(III), and Ru(II) and NN = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen), proceed via electron transfer and/or addition of the radicals to the complex. The distribution of the products is controlled by the relative rate constants of electron transfer and addition which, in turn, are affected by the redox potential of the radical-complex couple and by the nature of the ligand. The overall rate constants for the radicals increase always in the order .CH/sub 2/OH < CH/sub 3/CHOH < (CH/sub 3/)/sub 2/COH. The radical adducts show lambda/sub max/ 475 nm and are discussed in terms of the known nucleophilic character of the ..cap alpha..-hydroxyalkyl radicals and the electron-deficient nature of these nitrogen heteroaromatic ligands. The limitations to the utilization of methanol, ethanol, and 2-propanol as H and OH radical scavengers and as sources of reducing radicals in the presence of polypyridyl complexes is discussed.
- OSTI ID:
- 5018406
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 84:17
- Country of Publication:
- United States
- Language:
- English
Similar Records
Synthesis, spectroscopy, and photophysical behavior of mixed-ligand mono- and bis(polypyridyl)chromium(III) complexes. Examples of efficient, thermally activated excited-state relaxation without back intersystem crossing
Concurrent electrophilic and oxidative pathways for reactions of. cap alpha. -hydroxyalkyl and. cap alpha. -alkoxyalkyl complexes of chromium(III) with mercury(II) ions
Related Subjects
08 HYDROGEN
14 SOLAR ENERGY
BIPYRIDINES
RADIOLYSIS
CHROMIUM COMPLEXES
COBALT COMPLEXES
PHENANTHROLINES
RADICALS
CHEMICAL REACTIONS
RHODIUM COMPLEXES
RUTHENIUM COMPLEXES
AQUEOUS SOLUTIONS
COMPARATIVE EVALUATIONS
ETHANOL
HYDROGEN PRODUCTION
METHANOL
PHOTOLYSIS
PROPANOLS
PULSES
SOLAR ENERGY CONVERSION
ALCOHOLS
AZINES
CHEMICAL RADIATION EFFECTS
CHEMISTRY
COMPLEXES
CONVERSION
DECOMPOSITION
DISPERSIONS
ENERGY CONVERSION
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
MIXTURES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PYRIDINES
RADIATION CHEMISTRY
RADIATION EFFECTS
SOLUTIONS
TRANSITION ELEMENT COMPLEXES
400600* - Radiation Chemistry
080106 - Hydrogen- Production- Biosynthesis & Photochemical Processes
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)