J. CHEM. RESEARCH (S), 1998 557
reactions. When the green solution of Mn(TPP)OAc in
CH2Cl2, with a Soret band at 478 nm, was treated with an
excess of Bun4NIO4 in the presence of imidazole at either
room or low temperature ( 63 8C) no change in the Soret
band, due to the formation of a high-valent manganese-oxo
species, was noticed. This result contrasts sharply with the
observation of an oxo(tetraphenylporphyrinato)manganese
species, with a characteristic Soret band (at 401 nm),5 when
NaIO4 was reacted with Mn(TPP)OAc in a two-phase
(CH2Cl2±H2O) medium. These experiments imply that the
primary oxidizing species in the ImMn(TPP)OAc±
Bun4NIO4 system is likely to be a complex formed by the co-
References
1 (a) R. A. Sheldon and J. K. Kochi, Metal-Catalyzed Oxidation of
Organic Compounds, Academic Press, New York and London,
1981, 340; (b) C. L. Hill, Activation and Functionalization of
Alkanes, Wiley, New York, 1989; (c) G. W. Parshall and S. D.
Ittel SD, Homogeneous Catalysis, 2nd edn., Wiley-Interscience,
New York, 1992, ch. 10; (d) D. H. R. Barton and D. Doller, Acc.
Chem. Res., 1992, 25, 504; (e) B. A. Arndtsen, R. G. Bergman,
T. Andrew Mobley and T. H. Peterson, Acc. Chem. Res., 1995,
28, 154; ( f ) A. Bottcher, M. W. Grinsta, J. A. Labinger and
H. B. Gray, J. Mol. Catal., 1996, 113, 191.
2 (a) T. J. McMurry and J. T. Groves, Cytochrome P-450,
Structure, Mechanism and Biochemistry, ed. P. R. Ortiz de
Montellano, Plenum Press, New York and London, 1986, ch. 1;
(b) B. Meunier, Bull. Soc. Chim., Fr., 1986, 4, 578;
(c) D. Mansuy, Pure Appl. Chem., 1987, 59, 759; (d) I. Tabushi,
Coord. Chem. Rev., 1988, 86, 1; (e) B. Meunier, Chem. Rev., 1992,
92, 1411; ( f ) D. Mansuy, Coord. Chem. Rev., 1993, 125, 129;
(g) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uelman and J. I.
Brauman, Science, 1993, 261, 1404; (h) P. Bhyrappa, J. K.
Young, J. S. Moore and K. S. Suslick, J. Mol. Catal., 1996, 113,
109; (i) A. M. d'A. R. Gonsalves and M. M. Pereira, J. Mol.
Catal., 1996, 113, 209; ( j) A. Maldotti, A. Molinari, P.
Pergamini, R. Amadelli and D. Mansuy, J. Mol. Catal., 1996,
113, 147; (k) D. Dolphin, T. G. Traylor and L. Y. Xie, Acc.
Chem. Res., 1997, 30, 251.
ordination of periodate and [ImMn(TPP)]. To test this
view, we examined the interaction of a CH2Cl2 solution of
Mn(TPP)F with an excess of Bun4NIO4. A gradual shift of
the Mn(TPP)F Soret band from 454 to 478 nm, which
is close to lmax (Soret) expected for an anionic oxygen
donor ligand, provides acceptable evidence for the replace-
ment of F by periodate species in the solutions.6
In conclusion the simple Mn(TPP)OAc, Mn(TNP)OAc
and Mn(TMP)OAc complexes are eective catalysts for
the oxidation of benzylic C±H bonds and cycloalkanes by
Bun4NIO4 in the presence of imidazole. Mn(TPFPP)OAc
shows a particularly high ecacy for catalytic oxidation of
cyclooctane. Oxidation of benzylic C±H bonds leads to
much higher yields of ketones rather than alcohols, whereas
in the oxidation of cycloalkanes comparable amounts of
ketones and alcohols are obtained.
3 Abbreviations used include Bun4NIO4, tetra-n-butylammonium
periodate; Im, imidazole; TPP, meso-tetraphenylporphyrin
dianion; TNP, meso-tetrakis(1-naphthyl)porphyrin dianion; TMP,
meso-tetramesitylporphyrin dianion; TPFPP, meso-tetrakis(penta-
¯uorophenyl)porphyrin dianion; TDCPP, meso-tetrakis (2,6-
dichlorophenyl)porphyrin dianion.
4 (a) D. Mohajer and S. Tangestaninejad, J. Chem. Soc., Chem.
Commun., 1993, 240; (b) D. Mohajer and S. Tangestaninejad,
Tetrahedron Lett., 1994, 35, 945.
Further work is underway to learn more about the factors
that in¯uence these catalytic systems.
5 (a) J. T. Groves, W. J. Kruper, Jr. and R. C. Hawshatter, J. Am.
Chem. Soc., 1980, 102, 6375; (b) C. L. Hill and B. C. Schardt,
J. Am. Chem. Soc., 1980, 102, 6374; (c) R. D. Arasasingham,
G. X. He and T. C. Bruice, J. Am. Chem. Soc., 1993, 115, 7985.
6 M. F. Powell, E. F. Pai and T. C. Bruice, J. Am. Chem. Soc.,
1984, 106, 3277.
We are thankful to Shiraz University Research Council
for ®nancial support of this work.
Received, 6th January 1998; Accepted, 12th May 1998
Paper E/8/00216I