R. Bakshi et al. / Catalysis Communications 17 (2012) 140–145
145
this can be correlated to the binding energy and bond lengths of the
optimized structures. The binding energy of the OAP bound species
suggests larger stabilization relative to the [Fe(L1)(NO3)3] complex.
Further it is interesting to observe that the Fe(III)-OAP bond length
for the species [FeIII(L1)(NO3)OAP] is found to be 2.37 Å, while it is
3.38 Å for the analogous [FeIII(L1)(Cl)OAP] species. This suggests
that OAP is relatively strongly bound to [FeIII(L)(NO3)] rather than
[FeIII(L)(Cl)]. This may account for the slow release of oxidized OAP
from the coordination sphere of [FeIII(L)(NO3)], implying low rates
of oxidation reaction as found from experimental results.
dependent on an optimal concentration of substrate beyond which
the rates are found to be lower. This suggests that the presence of ex-
cess of substrate retards the reaction of formation of phenoxazine by
some secondary side reaction. It is also found that the rate of reaction
tends to decrease as the concentration of catalyst is increased.
Acknowledgment
We gratefully acknowledge financial support from the Council of
Scientific and Industrial Research and University of Delhi, Delhi,
India for special grant.
Mechanism of oxidation of 2-aminophenol:
Appendix A. Supplementary data
Supplementary data to this article can be found online at doi:10.
1016/j.catcom.2011.10.017.
References
[1] E. Katz, Antibiotics; D. Gottlieb, P.D. Shaw, Eds. Springer Verlag: New York, Vol. 2
(1967) 276.
[2] U. Hollstein, Chemical Reviews 74 (1974) 625.
[3] G. Jones, D. Hopwood, Journal of Biological Chemistry 259 (1984) 14151.
[4] A. Messerschmidt (Ed.), Multicopper Oxidases, World Scientific, Singapore, 1997.
[5] H.T. Nagasawa, H.R. Butmann, M.A. Morgan, Journal of Biological Chemistry 234
(1959) 1600.
[6] A. Tomoda, J. Yamaguchi, H. Kojima, H. Amemiya, Y. Yoneyama, FEBS Letters 196
(1986) 44.
[7] L.I. Simandi, T. Barna, S. Nemeth, Journal of the Chemical Society Dalton Transac-
tions (1996) 473.
[8] C.E. Barry, P.G. Nayar, T.P. Begley, Biochemistry 28 (1989) 6323.
[9] Y. Yano, M. Ikuta, Y. Amamiya, T. Nabeshima, Chemistry Letters (1991) 461.
[10] L.I. Simandi, S. Nemeth, N. Rumelis, Journal of Molecular Catalysis 42 (1987) 357.
[11] Z. Szeverenyi, E.R. Milaeva, L.I. Simandi, Dioxgen activation and homogenous cat-
alytic oxidation, in: L.I. Simandi (Ed.), Studies in Surface Science and Catalysis,
vol. 66, Elsevier, Amsterdam, 1991, p. 171.
[12] L.I. Simandi, T.M. Barna, L. Korecz, A. Rockenbauer, Tetrahedron Letters 34 (1993)
717.
[13] K. Maruyama, T. Moriguchi, T. Mashino, A. Nishinaga, Chemistry Letters (1996)
819.
[14] C. Mukherjee, T. Weyhermuller, E. Bothe, E. Rentschler, P. Chaudhuri, Inorganic
Chemistry 46 (2007) 9895.
[15] M.R. Maurya, S. Sweta, T. Joseph, S.B. Halligudi, Journal of Molecular Catalysis 236
(2005) 132.
[16] L. Que Jr., in: J. Reejik, E. Bouwman (Eds.), Bioinorganic Catalysis, 2nd edition,
Marcal Dekker, New York, 1999.
[17] G.M. Sheldrick, SHELX 97, Program for crystal structure solution and refinement,
University of Gottingen, 1997.
[18] R. Bakshi, M. Rossi, F. Caruso, P. Mathur, Inorg. Chim. Acta 376 (2011) 175.
[19] L.I. Simandi, T.M. Simandi, Z. May, G. Besenyei, Coordination Chemistry Reviews
245 (2003) 85.
[20] J. Kaizer, G. Barath, R. Csonka, G. Speier, L. Korecz, A. Rockenbauer, L. Parkanyi,
Journal of Inorganic Biochemistry 102 (2008) 773.
4. Conclusion
This study has demonstrated that the present series of non-heme
type Fe(III) complexes are efficient catalyst for the oxidation of 2-
aminophenol and serve as functional models for phenoxazinone
synthase enzyme. The rates of reaction are much higher for chloride
bound complexes than their nitrate bound analogs that have more
anodic E1/2 values. The rates are thus not dependent on the E1/2 values
that are quite similar for chlorides and different from nitrates. From
the kinetic measurements, it is found that the rate of reaction is
[21] S.C. Mohapatra, R. Bakshi, M.S. Hundal, P. Mathur, Indian Journal of Chemistry
Section A 49 (A) (2010) 159.
[22] M. Rapta, P. Kamaras, Polyhedron 15 (1996) 1943.
[23] M. Pascaly, M. Duda, F. Schweppe, K. Zurlinden, F.K. Müller, B. Krebs, Journal of
the Chemical Society Dalton Transactions (2001) 828.
[24] E. Safaei, T. Weyhermüller, E. Bothe, K. Wieghardt, P. Chaudhuri, European Jour-
nal of Inorganic Chemistry (2007) 2334.
[25] T. Horvath, J. Kaizer, G. Speier, Journal of Molecular Catalysis 215 (2004) 9.
[26] A.B. Zaki, M.Y. El-Sheikh, J. Evans, S.A. El-Safty, Polyhedron 19 (2000) 1317.