Photochemical generation of alkyl radicals and their reactions with methyl viologen radical cation and with transition-metal complexes in aqueous solution

Journal Article · Wed Oct 04 04:00:00 EDT 1989 · Inorganic Chemistry; (USA)

DOI:https://doi.org/10.1021/ic00319a028· OSTI ID:6985516

Bakac, A; Espenson, J H ^[1]

---

1. Iowa State Univ., Ames (USA)

The irradiation of aqueous solutions of RCo((14)aneN{sub 4})(H{sub 2}O){sup 2+} (R = CH{sub 3}, C{sub 2}H{sub 5}, 1-C{sub 3}H{sub 7}, CH{sub 2}Cl, CH{sub 2}Br, CH{sub 2}OCH{sub 3}) with visible light, {lambda} {le} 400 nm, results in the homolysis of the cobalt-carbon bond. These complexes are quite unreactive toward a variety of dealkylating and redox reagents and thus represent a convenient source of small unstabilized carbon-centered radicals in the presence of potential substrates. The radicals react rapidly with the methyl viologen radical cation, k{sub MB} = (1-2) {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}. The kinetics of the formation of RCr{sup 2+} and RCo((14)aneN{sub 4})(H{sub 2}O){sup 2+} in the reactions of radicals with Cr{sup 2+} and Co((14)aneN{sub 4})(H{sub 2}O){sub 2}{sup 2+}, respectively, were studied by using MV{sup +} as a probe. The respective rate constants have values k{sub Cr} = (1.9-2.4) {times} 10{sup 8} M{sup {minus}1} s{sup {minus}1} and k{sub Co} = (1-2) {times} 10{sup 7} M{sup {minus}1} s{sup {minus}1} for all the radicals examined. 36 refs., 2 figs., 1 tab.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6985516
• Journal Information: Inorganic Chemistry; (USA), Journal Name: Inorganic Chemistry; (USA) Vol. 28:20; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ALKYL RADICALS
AQUEOUS SOLUTIONS
AZINES
BIPYRIDINES
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DATA
DISPERSIONS
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
MIXTURES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMISTRY
PYRIDINES
RADICALS
SOLUTIONS
TRANSITION ELEMENT COMPLEXES