The approach adopted for the obtention of zeolite-encapsulated FeP led to c
lean syntheses of biomimetical catalyst. The catalysts were obtained throug
h the zeolite synthesis method, where NaX zeolite was synthesised around on
e of the cationic FePs: iron(III) 5,10,15,20-tetrakis(4-N-methylpyridyl)por
phyrin (FeP1) or iron(III) 5-mono(2, 6-dichloro-phenyl)10,15,20-tris(4-N-me
thylpyridyl)porphyrin (FeP2). The syntheses yielded pure FeP1NaX and FeP2Na
X catalysts without any by-products blocking the zeolite nanopores. FeP1NaX
and FeP2NaX efficiently catalysed the epoxidation of (Z)-cyclooctene by io
dosylbenzene (PhIO) in DCE, giving rise to cis-epoxycyclooctane yields of 8
5% and 95%, respectively. Hydroxylation of adamantane shows a preferable al
kane oxidation at the tertiary C-H bond, indicating a hydrogen abstraction
through the Fe-IV(O)P (.+) species in the initial step. The total adamantan
ol yields were 52% and 45% for FeP1NaX and FeP2NaX, respectively. Concernin
g selectivity, FeP1NaX and FeP2NaX gave an 1-adamantanol (Ad-1-ol)/2-adaman
tanol (Ad-2-ol) ratio of 20:1 and 11:1, respectively (after statistical cor
rection). Therefore, these results indicate a free radical activation of th
e C-H bonds of adamantane as expected for P-450 models. In the cyclohexane
oxidation catalysed by FeP1NaX in DCE, a cyclohexanol (C-6-ol) yield of 50%
and an alcohol/ketone ratio of 10 was obtained. The hydroxylation occurs a
ccording to the so-called oxygen rebound mechanism, as expected for a P-450
model system. FeP2NaX is less selective (C-6-ol yield = 25% and alcohol/ke
tone = 1.2). One possible explanation is that a Russell-type mechanism invo
lving O-2 imprisoned within the zeolite cages may be operating parallelly,
generating both C-6-ol and cyclohexanone. (C) 2000 Elsevier Science B.V. Al
l rights reserved.