Trapped radicals in titania gels

ABSTRACT Free radicals are in general very reactive entities capable only of transient existence. Nevertheless, several methods have been devised for their detection and identification,

including stabilization by matrix isolation procedures1 and detection by spectroscopic methods. Radicals can be readily produced by oxidation–reduction processes where electrons are

transferred from the solute to the matrix or conversely. Here we report the first production of trapped O−2 free radicals generated in a titania-gel matrix by the initial reaction of Ti(III)

ions with H2O2 and the subsequent precipitation with NH4OH. We also have indications that the detected paramagnetic species may be complexed to the Ti(IV) ions. A striking feature in our

results is the very high 2-year stability of these trapped O−2 radicals. We are able to confirm unequivocally the mechanism proposed by Haber and Weiss to explain the Fenton reagent

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CYCLOHEXYLAMMONIUM HEXAISOTHIOCYANATOFERRATE(III) 2.5H2O Article Open access 15 April 2025 REFERENCES * Symons, M. C. R. & McLauchlan, K. A. _Faraday Discuss, chem. Soc._ 78, 7–17

(1984). Article  CAS  Google Scholar  * Uri, N. _Chem. Rev._ 50, 375–454 (1952). Article  CAS  Google Scholar  * Pryor, W. A. in _Free Radicals_, 136–137 (McGraw-Hill, London, 1966). Google

Scholar  * Takakura, K. & Ranby, B. _J. phys. Chem._ 11, 164–168 (1968). Article  Google Scholar  * Nixon, W. T. & Norman, R. O. C. _Nature_ 196, 891–892 (1962). Article  ADS  Google

Scholar  * Chiang, Y. S., Craddock, J., Mickewich, D. & Turkevich, J. _J. chem. Phys._ 70, 3509–3515 (1966). Article  CAS  Google Scholar  * Lunford, J. H. & Jayne, J. P. _J. chem.

Phys._ 44, 1487–1492 (1966). Article  ADS  Google Scholar  * Naccache, C., Meriaudeau, P., Che, M. & Tench, A. _J. Trans. Faraday Soc._ 67, 506–512 (1971). Article  CAS  Google Scholar 

* Dufaux, M., Che, M. & Naccache, C. _C.r. hebd. Séanc. Acad. Sci., Paris_ 258, 2255–2267 (1969). Google Scholar  * Iyengar, R. D. & Kellermann, R. K. _J. Colloid Sci._ 35, 424–433

(1971). Article  ADS  CAS  Google Scholar  * Ragai, J. & Sing, K. S. W. _J. Colloid Sci._ 101, 369–376 (1984). Article  ADS  CAS  Google Scholar  * Ragai, J. & Selim, S. I. _J.

Colloid Sci._ (in the press). * Gundrizer, G. A. _Mater. Konf. Molodykh Uch. Tomsk. gos. Univ._ 2, 166–168 (1974). CAS  Google Scholar  * Milligan, D F. & Jacox, M. E. _J. chem. Phys._

38, 2627–2631 (1963). Article  ADS  CAS  Google Scholar  * Nakamoto, K. in _Infrared and Raman Spectra of Inorganic and Coordination Compounds_, 229–230 (Wiley, New York, 1978). Google

Scholar  * Bahnemann, D., Henglein, A. & Lubomir, S. _Faraday Discuss, chem. Soc._ 78, 151–163 (1984). Article  CAS  Google Scholar  Download references AUTHOR INFORMATION AUTHORS AND

AFFILIATIONS * Department of Science, The American University of Cairo, Cairo, 113 Kasr el Eini Street, Egypt Jehane Ragai Authors * Jehane Ragai View author publications You can also search

for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Ragai, J. Trapped radicals in titania gels. _Nature_ 325,

703–705 (1987). https://doi.org/10.1038/325703a0 Download citation * Received: 25 September 1986 * Accepted: 19 November 1986 * Issue Date: 19 February 1987 * DOI:

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