6
7
8
9
O. Brede, H. Orthner, V. Zubarev and R. Hermann, J. Phys.
Chem., 1996, 100, 7097.
R. Hermann, G. R. Dey, S. Naumov and O. Brede, Phys. Chem.
Chem. Phys., 2000, 2, 1213.
O. Brede, R. Hermann, S. Naumov and H. S. Mahal, Chem. Phys.
Lett., 2001, 350, 165.
S. Patai, The Chemistry of Quinoid Compounds, Wiley, N.Y., 1974,
vol. I and II.
Conclusion
By analogy with phenols, thiols and selenols, by free electron
transfer from the bifunctional phenols catechol, resorcinol
and hydroquinone to parent radical cations derived from
non-polar solvents (alkanes, alkyl chlorides), diphenol radical
cations as well as phenoxyl radicals in the ratio 2:3 are formed
as directly observable products. Although the detection time
was limited to q10 ns, we are stating that within the electron
transfer gross process eqn. (17), the electron jump proceeds in
times of p10 fs and, therefore, diffusion only determines the
time scale of transient observation in so far that reactants must
be brought together for reaction. The very rapid electron jump
proceeds in times faster than the molecular oscillations of the
electron donor molecule and, hence, identifies the molecular
situation of at least C–OH bond rotation.
10 G. E. Adams and B. D. Michael, Trans. Faraday Soc., 1967, 63,
171.
1
11
12
13
E. J. Land, J. Chem. Soc., Faraday Trans., 1993, 89, 803.
R. E. Huie and P. Neta, J. Phys. Chem., 1985, 89, 3918.
V. A. Roginsky, L. M. Pisarenko, W. Bors, C. Michael and M.
Saran, J. Chem. Soc., Faraday Trans., 1998, 94, 1835.
14 O. Brede, F. David and S. Steenken, J. Chem. Soc., Perkin Trans.
2, 1995, 23.
15
16
17
M. R. Ganapathi, R. Hermann, S. Naumov and O. Brede, Phys.
Chem. Chem. Phys., 2000, 2, 4947.
R. Mehnert, O. Brede and W. Naumann, Ber. Bunsen-Ges. Phys.
Chem., 1982, 86, 525.
M. Gerhards, C. Unteberg and S. Schumm, J. Chem. Phys., 1999,
111, 7965.
The formed biphenol radical cations are converted in the
00 ns time range into phenoxyl radicals, eqn. (18), but they
5
were found to be more stable than those of the monofunctional
phenols (see Tables 1 and 3). As related to the biologically and
electrochemically interesting stepwise oxidation of hydro-
quinone (catechol) into the corresponding quinones by
subsequent one-electron transfers, here we could observe
the primary biphenol radical cation directly which has
been ignored until now.
18 M. R. Ganapathi, S. Naumov, R. Hermann and O. Brede, Chem.
Phys. Lett., 2001, 337, 335.
1
9
S. L. Murov, I. Carmichael, G.L. Hugh, Handbook of Photochem-
istry, 2nd edition, Marcel Dekker, N.Y. 1993.
H. D. Burrows, D. Greatorex and T. J. Kemp, J. Chem. Phys.,
2
0
1
21 S. Steenken and P. Neta, J. Phys. Chem., 1982, 86, 3661.
966, 44, 2369.
22
23
24
K. B. Patel and R. L. Willson, J. Chem. Soc., Faraday Trans. 1,
973, 69, 814.
M.J. Frisch et al., Gaussian 98, Revision A9, Gaussian Inc., Pitts-
burgh PA, 1998.
A. D. Becke, J. Chem. Phys., 1993, 98, 5648.
1
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