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Metallocorroles with Formally Tetravalent Iron.

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Metallocorroles with Formally Tetravalent Iron
Emanuel Vogel,* Stefan Will, Andreas Schulze Tilling,
L u d g e r N e u m a n n , J o h a n n Lex, E c k h a r d Bill,
Alfred X Trautwein, and Karl Wieghardt
Dtw'ilctrtecl t o Piofcrc.or E i m t Otto F i ~ t h e r
017
the> olc
ci\ioi?
of h r ~75th birt~7da1
The coordination chemistry of metals in unusual oxidation
states is a fascinating aspect of research in the field ofmetalloporphyrins. Of particular significance in this respect are oxoiron
porphyrins containing tetravalent iron, since complexes of this
sort occur as reactive intermediates in numerous biological and
biomimetic oxidation processes."] Iron(iv) porphyrins, in which
the metal is not present as part of a [Fe=O] unit, are likewise
known, but are rare species. To the best of our knowledge cationic
and dimetho-phenyliron(1v) porphyrins (type 1 in Scheme
oxyiron(rv) p ~ r p h y r i n s . ' ~both
]
of which are only stable at low
temperatures, as well as some p-nitrido- and p-carbidoiron(1v)
complexesr41are the only representatives of this class of compounds so Far characterized. A route to iron(iv) porphycenes
(type 3 ) . constituting analogues of 1, has very recently been
opened up.[51
phyrinoids corrole["-the
aromatic parent substance of corrin.
the ring system of vitamin B,, --and iso~orrole['~
may enable
the preparation of the corresponding neutral complexes, that is.
types 2 and 4, respectively. This supposition appeared to be
substantiated all the more so. as it was recently shown that
stable iron(iv) complexes with ligands based on pentane-2,4dione-bis(S-alky1isothiosemicarbazides)-which are also trianionic- could be synthesized.18,9] We have now found that octaethylcorrole 5 can be readily converted into the triad of stable
complexes 7-9, all of which contain formally tetravalent
iron."'] Furthermore, the existence of the iron corrole 10 (bearing an axial pyridine ligand) with a formal oxidation state o f the
metal of + 111 was corroborated.
Iron(ir1) corroles. which might serve as starting materials for
the synthesis of iron(1v) corroles. have already been described in
the literature several times.["' However, it is only recently that
they have been thoroughly characterized spectroscopically, in
work by T. Boschi et al.[l'".dlAccording to these investigations
octamethylcorrole undergoes smooth metalation with iron
trichloride or iron pentacarhonyl to give the neutral iron(r11)
corrole, which, on the basis of 'H N M R spectroscopic findings.
has a pronounced tendency to bind ligands in the axial position.
Indications of a possible oxidation of iron(rrr) to iron(iv) corroles cannot be found in any of the published work. Two reasons
led us to use the octaethyl compound 5[12] rather than the
2
1
R
5
L
3
4
Schcme I Models of the iron(iv) complexes of porphyrm ( I j . corrole (2). porphyceiie ( 3 ) .atid isocorrolc (4) with axial ligands ( R = aryl. alkyl. and other suhstituents)
The existence of cationic iron(rv) complexes of types 1 and 3
suggested the possibility that the potentially trianionic por[*I
6
Prof. I k . E Vogel. DipLChem. S. Will, Dip.-Chem. A. Schulde Tilling.
Dr. L. Neumann. Dr. J. Lex
lnstitut fur Organische Chemie der Unrversitiit
Grein\ti-;isw 4. D-50939 Kiiln (FRG)
TeMix Int. code (221) 470-5102
+
Prof. Dr A X. Trautuein. Dr. E. Bill
Instittit fui- Phlsik der Universitit Luheck (FRG)
Prof. D - . K . Wieehardt
Lehrstiihl fur Anorgsnische Chemie I der Universitit Bochuin (FRG)
731
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octamethyl compound as corrole ligand: first, the substantially
better solubility of 5 and its metal complexes; second, a planned
parallel study in the isocorrole series. for which the octaethyl
compound corresponding to 5 was at our
The choice of 5 proved to be fortunate. As it turned out, treatment of 5 with nonacarbonyldiiron in toluene at 100-110°C
(2 h) under an argon atmosphere, followed by a workup with
admission of air (causing a change in the color of the solution
from brown to red), yielded as the only defined product the
oxygen-bridged binuclear iron(rv) complex 7, p-0x0-bis[ (octaethylcorrolato)iron(rv)]. This must have arisen from the spontaneous air oxidation of the iron(nr) octaethylcorrole 6 , the assumed primary product. The new iron(rv) complex 7 can be
easily isolated and is stable. After crystallization from hexane, it
is obtained as black rhombohedra (m.p. > 300 T, yield 58 YO,
see Experimental Procedure).
In the reaction of octamethylcorrole with iron transfer agents,
the poor solubility of the intermediate Fe"' corrole complex
slows down the air oxidation, and thus the Fe"'/Fe'" conversion,
which under Suitable conditions is also observed in this system,
was not detected.
A crystal structure analysis[13] of complex 7 (Fig. 1 and
Table 1) confirms its molecular structure. The iron atoms in 7
Q
B
are coordinated in an approximately square-pyramidal fashion.
The corrole ligands have-mainly because of steric interactions
between the ethyl groups in the top and bottom halves of the
Table 1. Selected bond lengths and distances A (in A) in the iron corrole complexes
7 10. L = axial ligand a t the iron center.
7
ligand I [a]
hgdnd 2
1.904(2)
1.705(2)
0.406(1)
0.436(1)
0.164(2)
1.904(2)
1.706(2)
0.400(1)
0 418(1)
0.193(2)
8
9
10
1.906(2j
2.256(3)
0.422(1)
0.533(1)
0.139(3)
l.X71(3)
1.984(3)
0.272(1)
0.318(1)
0.077(3)
1.893(2)
2.188(2)
0.273(1)
0.425(1)
0.219~j
I indicates the upper corrole unit of 7 in Fig. I . [b] Average values. [c]
Distance of the iron atom from the mean plane of the four pyrrole nitrogen atoms.
[dl Distance of the iron atom from the mean plane of the ring framework (core). [el
Maximum distance of the carbon and nitrogen atoms from the average plane o f the
ring framework.
[a] &and
-
-
Table 2. Selected ' H N M R data (room temperature, 300 M H r ) of ligaiid 5 and iron
corroles 7 - 10.
H-5.15
H-10
CH,
CH,
Fig. 1 . Structure of the p-oxodiiron(ivj corrole complex 7 in the crystal. Perspective
view (without hydrogen atoms).
Fe-N [b]
Fe-L
A"
[cl
A(core) [d]
Amax[el
molecule-ring frameworks that are twisted to varying degrees.
However, in comparison to the free corrole, in which the spatial
requirement of the imino hydrogen atoms causes a considerable
deviation of the framework from planarity,[l4I the corrole ligands in 7 have experienced a certain degree of flattening. The
iron atoms are situated 0.403 8, (average value) above the planes
formed by the N-donor atoms. The Fe-N bond lengths, which
are within the range of those of known iron(iv) compounds,['. 91
are significantly shorter than those in iron(Ir1) porphyrins (1.962.09A).[151The F e - 0 bonds in 7 are also noticeably short
[I ,706 vs. 1.757 8, in the poxodiiron(rr1)
derived
from octaethylporphyrin] . The Fe-0-Fe angle is 170.0", even
though one would expect from theoretical arguments that a
complex such as 7. which has a (d4-d4) electronic configuration
[as compared to poxodiiron(rr1) porphyrins which have a (d5
d') configuration], would exhibit a linear Fe-0-Fe unit." 'I
The magnetic susceptibility (measured in the range of 81
293 K)[''l and the ' H N M R spectrum of 7 (Tables 2 and 3),
which displays well-defined signals with small linewidth. indicate that the compound is effectively diamagnetic. The protons
938
9.21
3.9-4.1
1.7 2.0
6.66
6.62
2.6-2.8
1.1 1.3
~
177
189
-5.7-29.9
-0.3-2.5
54.5
49.3
-84-98.1
3.0-7.3
-15.9
-62.2
1.9-67.7
3.2- 3.8
of the perimeter give rise to sharp singlets at 6 = 6.66 (H-5,15)
and 6.62 (H-lo), while those from the ethyl substituents appear
as multiplets in the range 6 = 2.82-2.56 and as triplets at 6 =
1.25, 1.17, 1.15, and 1.14. The shift of the resonances of the
perimeter protons to higher field by no less than 2.7 ppm as
compared to those of free octaethylcorrole, tantamount to substantial loss of the diamagnetic ring current of the ligand, demands interpretation by theory.["] The 13C N M R spectrum of
7 shows the expected 18 signals- again in the range in which
diamagnetic compounds resonate. That the resonances of the
meso-carbon atoms C-5,15 and C-10 have undergone a pronounced low-field shift of 17 and 21 ppm, respectively, compared with those in the uncomplexed 5 seems noteworthy. The
singlet ground state ( S = 0) observed for 7 at room temperature
is caused by a very strong intramolecular antiferromagnetic
coupling of the two iron(rv) ions with S = 1 ground states. It is
interesting that in the analoguous poxodiiron(rI1) porphyrins
this coupling is considerably weaker,["] since in these cases the
ground state ( S = O), due to antiferromagnetic coupling of the
two high-spin iron(rrr) ions ( S = 5 / 2 ) , is only observed at low
temperatures ( T < 50 K) .
In analogy to p-oxodiiron(Ir1) porphyrins and porphycenes,''
7 experiences cleavage by acids to yield mononuclear complexes.["l When, for example, 7 is allowed to react in dichloromethane with 1 M hydrochloric acid at room temperature, chloro(octaethylcorrolato)iron(~v)(8) is formed, which crystallizes from
hexane/dichloromethane as black needles (m.p. > 300 " C , yield
84%). Treatment of solutions of the chloro complex 8 with
aqueous sodium hydroxide leads to the rapid reformation of 7.
Chloro(octaethylcorrolato)iron(Iv) (8) invited attempts to exchange the axial halogen ligand for aryl and alkyl groups by
reaction with Grignard reagents, and thus provide access to the
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organometallic o-aryl- and o-alkyl(octaethylcorrolato)iron(rv)
complexes, respectively. Indeed, 8 could be smoothly transformed into the o-phenyl complex 9 when it was treated with
four equivalents of phenylmagnesium bromide (in ether) in dichloromethane. Crystallization of the product from hexane/dichloromethane afforded 9 as gray rhombohedra with metallic
luster (decomp. > 185 "C, yield 75 Y O ) .
The isolation of complex 9 as a stable compound is surprising,
considering the fact that cationic o-phenyliron(1v) complexes in
the porphyrin series (type 1) rearrange rapidly even at room temperature to N-phenylated iron(r1) complexes.[21Whether a similar phenyl migration is possible in 9 at higher temperatures or by
electrochemical means is currently under investigation. Insertion of oxygen into the iron-carbon bond, a reaction typical for
o-phenyliron(II1) porphyrins,["] has not been observed for 9,
since complex 9 is relatively air-stable in solution.
X-ray crystal structure analyses allowed an insight into the
molecular structure of complexes 8 and 9 (Figs. 2 and 3, respectively. and Table 1),[131In the chloroiron(1v) complex 8 the co-
n
B
ti
Fig. 2. Structure of the chloroiron(iv) corrole complex 8 in the crystal. Perspective
view (without hydrogen atoms).
ring framework. Additionally, it is worth noting that 9, in contrast to 8, exists in the crystal as a Z-z dimer with laterally
shifted ring frameworks (intermolecular distance between the
ring frameworks: 3.5-3.6 A; Fe. - .Fe distance 5.437
The 'H NMR spectra of complexes 8 and 9 are -in striking
contrast to that of 7V-characteristic for paramagnetic compounds
with broad unstructured signals over a wide range of absorptions (Tables 2 and 3).lz5l In the case of 9 three further signals
Table3. Selected physical data for 7-10. ' H N M R : 300MHz: ' " C N M R :
75.5 MHz; IR: CsI. The isomer shifts 2,. are rclatlve to r-iron at 298 K .
OEC = trianion of octaethylcorrole. py = pyridine
7.M.p. > 300"C(hexane);'HNMR(C6D,):6 = 6.66(~,2H;H-5.15),6.62(s,lH:
H-lo), 2.82 (m. 4 H ; H-2a,lSa). 2.69 (m, 4 H ; H-3a,17a), 2.60 (m, 4 H ; H-Xa.12a).
2.56 (m. 4 H ; H-7a,l3a), 1.25 (t. 6 H ; H-3b. 17b), 1.17 (t, 6 H ; H-2b.lSb). 1.15 (t.
6 H ; H-7b.13b). 1.14 (t, 6 H ; H-8b.12b); I 3 C N M R (C,D,): 6 =146.29, 345.58.
145.34, 140.95.135.76. 135.41, 134.21,130.23.110.13(C-10). 109.78(C-5,15),19.77.
: (100)
18.71. 18.54. 18.37. 17.71, 17.48, 17.04, 16.87; MS (El, 70eV): m': ( Y O ) 575
[ M + - OFe(0EC)I: 1R: i. = 2963.2929.2869. 1469. 1450,1272,1232.1059. 1013.
957, 833, 805 cm-'; U V N I S (n-hexane): d,,, (c) = 310 (53000). 369 (105800).
= 0.69 p"; Moysbauer parameters
537 nm (16500): magnetic moment (293 K): pep<
(77 K): a, = 0.02 m m s - ' . AE, = 2.35 m m s - I .
8 - M.p. > 300'C (hexane/dichloromcthane), ' H N M R (CDCIJ 6 =189 (br. s.
I H ; H-lo), 177 (br. s, 2 H ; H-5,15), 29.9, 27.8, 21.3. 17.7. 15.8. 3.7 (br. s. each 2 H ;
CH,), 2.5. 1.3 (br. s, each 6 H ; CH,), 0.9 (br. s. 2H: CH,), 0.6. - 0 3 (br. s. each 6 H;
CH,), -5.7 (br. s, 2 H ; CH,); MS (EI, 70eV): ,n!z (%) 612/610 {5:9) [ M i ] , 575
(100) [M' - CI]; I R : i= 2964,2930,2869,1466, 1374, 1155,1055. 1011,952.876,
785, 759. 316cm-I (Fe-CI); UV/VIS (CH,CI,): i,,, (8) = 302 (25200) sh. 338
(39200) sh. 371 (57400). 465 (10900) sh. 516 (8000) sh, 602 nm (3000); magnetic
moment (293 K ) : pCtt= 2.97 pH;Mossbauer parameters (77 K): a,, = 0.19 inms- I .
AEq = 2.99mmsc'.
9: Dccomp. > 185 ' C (hexane/dichloromethane); ' H N M R (CDCI,) ii = 98.1.
65.6. 56.5 (br. s. each 2 H ; CH,), 54.5 (br. s. 2 H ; H-5.15), 49.3 (br s. 1 H: H-10).
34.1, 28.2. 13.6 (br. s. each 2 H ; CH,), 7.3 (br. s, 6 H : CH,), 6.4 (br. s. 2 H : CH,).
4.1, 3.7. 3.0 (br. s, each 6 H ; CH,). -4.0 (br. s. 2 H ; phenyl, m-H). - 8.4 (br. s, 2 H ;
CH,) -77.0 (br. s, 1 H ; phenyl, p-H), -153.6 (br. s, 2H: phenyl. o-H). MS (El.
70eV): m:r (YO)652 (8) [ M ' ] , 575 (21) [ M '
Ph], 154 (100) [biphenyl\: I R :
3 = 3044,2964,2930,2869, 1551, 1461, 1056, 1024. 1005,986, 957, 833. 722 c n i - ' ;
U V W S (CH,CI,): I.,, ( 6 ) = 251 (24100) sh, 340 (34300) sh, 380 (66100). 507
(14900). 668 nm (2300): magnetic moment (293 K ) : {left = 2.89 pH: Mossbauer
parameters (77 K): 6,, = 0.11 mms-', A€" = 3.72 m m s - '
10: Decomp. > 160°C (mcthanolipyridine); 'H NMR ([DJpyridine): 4 = 67.7.
37.9, 28.5 (br. s, each 4 H ; CH,). 5.3. 3.8 (br. s, each 6 H ; CH,), 3.2 (br. s. 12H:
CH,), 1.9 (br. s, 4 H ; CH,), -15.9 (br. s. 2 H ; H-5,15), -62.2 (br. h 1 H ; H-10):
' H N M R (CS,, C6H6,",):6 =114 (br. s, 2 H ; py, a-H), 77.1 (br. s. 2 H : py. b-H).
70.2,38.7,28.3(br.s,each4H;CH,),5.6,4.0(br.s,each6H;CH,),3.4(br.s,12H;
C H 3 ) , 2 . 0 ( b r . s , 4 H ; C H , ) , - 3 . 3 ( b r . s . l H , p y , y - H ) , -14.6(br s,ZH,H-5,15),
-59.1 (br. s. 1 H ; H-10); MS (FAB): m / z ( % ) :575 (lOO)[Mt py]: IR: i.= 2962.
2930. 2868, 1596, 1482, 1445, 1155, 1056, 1024, 1009, 959, 807. 754. 6 9 4 c m - ' ,
UViVIS(pyridine):E.,,,(~) = 397(67200),482(8850), 547(15200).640(3200).670
(2900) sh, 720 nm (2000): magnetic moment (293 K): hierr = 3.80 p"; Mossbauer
parameters (77 K). a, = 0.09 mms-', AEq = 3.88 m m s - '
-
-
-
-
are observed at 6 = - 4.0, -77.0, and - 153.6, which can be
attributed to the protons at the meta, para, and ortho positions,
respectively, of the axially bound phenyl ligand.[261The paramagnetism in 8 and 9 was confirmed by measurement of their
ordinative environment of the iron center corresponds to that
magnetic susceptibility, from which it is evident that both comfound in the p-0x0 compound 7, but the nitrogen atoms are
plexes, similar to other iron(1v) compounds, exist in a spin triplet
better orientated towards the metal, allowing the ligand to
ground state ( S = 1 ) (perf= 2.97 and 2.89 pB, respectively, at
adopt a more symmetric conformation. Otherwise 8 is charac293 K).["I The Mossbauer spectra of 7-9, measured at 4.2 and
terized by a relatively long iron-chlorine bond [2.256 vs.
77K,["] are in agreement with the formulation of these com2.23 1 8, in high-spin chloro(octaethylporphyrinato)iron(rr~)[~~~]. pounds as iron(1v) complexes. Small isomer shifts in the range
The phenyliron complex 9 is distinguished from 7 and 8 in so far
a, = - 0.11-0.19 mms-' and relatively large quadrupole
as the distance between the metal and the N, plane is reduced to
splittings AE, = 2.35-3.72 mms-' were observed (Table 3).
0.272 8, (compared with 0.403 8, and 0.422 8, in 7 and 8, respecSimilar Mossbauer parameters have been reported for comtively). Consequences of this are not only the shortening of the
pounds I and I1 of heme peroxidases and related porphyrin model
Fe-N distances, but also the almost complete flattening of the
complexe~.[~''
Fig. 3. Structure of the o-phenyliron(~v)corrole complex 9 in the crystal. Perspective view (without hydrogen atoms).
Aiigcw. Cliiwi. Int. Ed. Engl. 1994, 33, N o . 7
C VCH ~ ~ r l r r ~ . ~ j i ~ . ~m~h ~H l, l0s- 6~9h4u5 1f fU.i,inhein?. 1994
0570-0833194t0707-0733,X /O.OO+ . 2 : 0
733
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The possibility of stabilizing iron(in) corrole complexes by an
axial pyridine ligand was demonstrated some time ago by Y
Murakami et al. with the exampie of 7,8.12.13-tetraethyl2,3,17.18-tetramethylcorrole. but no details were given about
the characterization of the complex." I b l In parallel to this we
have established that the product obtained from the metalation
of 5 with nonacarbonyldiiron and subsequent removal of the
solvent under vacuum yields the monopyridine complex 10
when treated with pyridine prior to the admission of air.
The ' H NMR spectrum of 10 (in [DJpyridine) corresponds in
its kind to that expected for pentacoordinated paramagnetic highspin iron(rrr) porphyrins :[251 the mcso protons absorb at high
field, the protons of the ethyl groups. on the other hand, at low
field (Tables 2 and 3). On measuring the spectrum in carbon
disulfide, three additional signals appear at 6 = 114. 77.1, and
-3.3. which correspond to the protons in the s(, /j, and 7 positions. respectively. of the axially coordinated pyridine ligand.['"l
The positions of the resonances of the ligand protons change
only slightly on altering the solvent from [DJpyridine to carbon
disulfide: a tendency for 10 to form a six-coordinate dipyridine
complex is thus not evident. Susceptibility measurements'i81
indicate that 10 has a S = 3:2 ground state due to the observed
temperature-independent magnetic moment of 3.80 pH (81
293 K). To our surprise, the Mossbauer spectrum of 10 exhibits
parameters (d,+ = - 0.09 m m s - ' and AEq = 3.88 mms- I at
77 K ) which are difficult to reconcile with the assumption of an
iron(ri1) complex with a S = 312 ground state.[291The observed
isomer shifts and quadrupole splittings correspond rather a s
has also been established for the F e + N bond lengths-to those
in complexes 7-9. We must therefore entertain the possibility
that the formal Fe"' complex 10 should actually be considered
as an Fe'" corrole anion radical complex, whose magnetic properties (S = 3i2) come about as a result of ferromagnetic spin
coupling of an iron(rv) metal center (S = t ) with a corrole anion
radical (S = 1 i 2 ) . Theoretical studies should shed further light
on the electron distribution in 10.
The synthesis of the iron(1v) corrole complexes 7 - 9 makes it
conceivable that corroles might allow also the stabilization of
unusual oxidation states of metals other than iron.[301This possibility is directed. in particular, to the already well-known corrole complexes of copper and nickel, which. on the basis of
chemical. UV;'VIS, and ESR spectroscopic studies. have long
been assumed to contain the metal in a divalent state.[6. The
conjecture that these complexes are actually Ni"' and Cu"' compounds is presently under investigation.
We are confident that research efforts in the field of metallocorroles, which have long stood in the shadow of metalloporphyrins. will now receive renewed impetus as a result of the
access to iron(1v) complexes.
-
<
I
10
Alternatively, 10 can be obtained by reduction of 7 with hydrazine in the presence of pyridine. Complex 10 is stable in the
solid state; however. in solution devoid of pyridine slow oxidation
occurs to yield 7. Treatment of a solution of 10 in dichloromethane with dilute hydrochloric acid leads to the immediate formation of the chloro complex 8.
An X-ray crystal structure a n a l y ~ i s " ~could
'
also be carried
out on complex 10 (Fig. 4 and Table 1). The distance between the
iron atom and the N, plane (0.273
is small and is similar to
that in the phenyl compound 9. Although all the nitrogen atoms
A)
E.x-perinicnicrl Procc&rc
Fig. 4. Structure of the pyridine iron(iii) corrole complex 10 in the crystal. Pcrspective vicu (without hydrogen atoms)
are in good alignment with the metal, the ring framework in 10
deviates from planarity more pronouncedly (the maximum distance of the C and N atoms from the mean plane of the ring is
0.21 9
than is the case in the mononuclear complexes 8 and 9.
The F e + N bond lengths in 10 are virtually the same as those
found in the iron(rv) complexes 7-9. This is unexpected, since
one would have predicted an elongation towards the distances
found in iron(ri1) porphyrins. The Fe-N distance between the
iron atom and the pyridine ligand (2.188 A) is similar to that in
complex of octaethylporthe cationic (3-~hloropyridine)iron(111)
phyrin (2.126 A).[281Finally. it should be noted that 7c-n dimer
formation in crystals of 10 is encountered by analogy to the
situation in 9 (iptermolecular separation of the ring frameworks: 3.6-3.7 A ; Fe ' ' ' Fe distance: 6.221
A)
7 . Octaethylcorrole ( 5 ) (523 mg. 1 mmol) and nonacnrbonyldiiron (1.8 g, 5 mmol)
were heated together in toluene (25 mL) for t w o hours at 100-1 10 C under r\u
atmospherc ofitrgon. Subsequently. the solution wasconcciitrated iiiider \"iicuu~iit o
5 mL and air \ \ a s introduced over 20 min. causing a change in color from brown to
red. After filtration, the solution was stirred intensively for a further two hours
under 8 current of ail- to coinplete ilic oxidation. The solvcnt was remo\ed and the
i-eaidue wms subjected twicc to chroiniitographic filtration (nluminum oxide. Woelm
activity I. 10 x 2 cm, eluent diethyl ether). The p o x o complex 7 was eluted as iiu
intenrely red fraction. from which black rhombohedra Mere obtained after crystallization fi-om heuaiie. iii.p. >300 C: yield 336 ing (5X0,b).
8 : A solution of thc 11-oxocomplcx 7 ( 2 3 3 nip. 0.2 mmol) in dichloroinetliane
(20 inL) w a s thoroughly stirred with hydrochloric acid ( I M. 20 m L ) for 5 min. Thc
orgmic phase was dried ovcr sodium sulfate. and the residue obtained after removal
ofthe solvent \\as chromatographically filtered (silica gel. 4 x 2 cni. eluent dichloromethane). The chloro complex 8 waa eluted as the only fraction. which. after crybtollization from hcxane'dichloroinethane (9: 1). \\\as obtained a s small black
needles. m.p >300 C : yield 704 mg (X4%)
9 : The cliloi-ocomplex 8 (122 mg. 0.2 mmol) in dichloromethane (10 mL) w a s treated x i t h four equivalents ofphenylmagnesium bromide (solution in dielhyl ether. cii.
0.5 \I) ovel 5 min. Aftcr zddition of watcr. the organic phasc wis separated. dried
over sodium sulfate. a n d the solvent removed under vdcuum. A chromatogimphie
filtration (aluminum oxide. Woclm activity 1. 10 x 2 cm, eluent diethql ether) of the
residue gave ii rcd-orange eluate This contained [he phenyl complex 9. v,hich, after
crystalliration froin liexane dichloromethme (9,I ) , was reco\ered as grny rhonibohedru with mcrahc lu\tcr: decoinp z I85 C : yield 98 mg ( 7 5 " h ) .
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10: A solution of the /I-0x0 complex 7 (233 mg, 0.2 mmol) in pyridine ( 5 mL) was
treatcd \rith hydi-arine hydrate (0 2 inL) and thereafter stirred for 5 min. After the
,iddition 01' methanol (SO mL). the pyridine complex 10 was allowed to crystallize
out iit -:(I
C Subsequent crystallization from methano1,'pyridine( 5 : l ) gave LO as
grab I-hoiiihohedr;i \+ith metallic luster; decomp. > 160 C ; yield 210 mg ( 8 0 % ) . All
compouiidi g i v e correct elemental analyses (C. H. N, CI).
Rcceived: July 29. 1993 [Z62441E]
Publication delayed at authors' request
German version : Aii,qcii,. Cheiti. 1994. 106, 711
P.R. Ortiz de Montellano.
C'i.lochroinc P-450; S ~ r i i i t u r ecMe1hirnisni
,
u i t d BioPlenuin. New! York. 1986: R.H. Holm. C / w m Rri,. 1987. 87. 1401 :
B. Meunirr. / h i d . 1992. 92. 141 I : D. Ostovic. T. Bruice. ,4w. C l i ~ w R. e x 1992.
2.5. 314,
D. I.aiicon. P. Cocolios. R. Guilard, ti M. Kadish. Orguiiomrtrillir.~1984. 3.
1163. ./ .4iit C/iiwi. S i r . 1984. 106,4472; A. L. Balch. M . W, Reniiei-, rhid 1986,
/OX. 2603: ii stable (at room temperature: in solution) cr-phenyliron(iv) porphyrin 1i:is i n the meantime been reported: K. M. Kadish. E. Van Caemelbecke.
t. D'Sot17~i.C'. J. Medforth. ti. M. Smith. A. Tabard. R. Guilard. Orguitoiitc>ru// i 1 \ 1993. 12. 241 I
J. T C;ro\es. R Quitin, T. J. McMurry. M. Nakamura. G. Lang. B. Boso. J.
4 t i t . C ' h w SO,. 1985, 107. 354: J. T. Groves, J. A . Gilbert. Inorfi. C h o ~ t 1986,
.
25. 131
D. M t i n w y . J.-P. Lecointe. J.-C. Chottard. J.-F. Bartoli. Iiior,q. (%eiti. 1981. 20,
i l IY, ti. M . Ktidish. R. K. Rhodes. L. A Bottomley. H . M . Goff. i6id. 1981,
20. 3195. V. L. (ioedken. M. R. Deakin. L. A. Bottoniley. J. Chcnt. Soi.. Chem.
( ' o n i i i u u i . 1982. 607; D. R English. D. N. Hendrickson. K. S . Suslick, Inorg
C % l w i 1983. 22. 367. h c l . 1985. 24. 121
R . C i u i l d r d University of Burgundy. Dijon. personal communication.
4.\V Johnson, I.T Kay, J, ('Iient. S i x . 1965. 1620; A W. Johnson in Porp / i i w t ! mi/ I l ~ ~ / a / l o ~ ~ ~ i r(Ed.:
p / t ~ K.
r i i M.
i . ~Smith). Elsevier. Amsterdam. 1975.
p. 720. R Cirigg in T i i r P ~ ) ~ ) / i ? . KJ/.
r t ~ .I~I (, E d . : D Dolphin). Academic Press.
Neu York. 1978. p. 327: N. S. Genokhova. T. A. Melent'eva. V. M. Bere/o\.;hii. 1 \p Kiiini. 1980, 49. 2132 [Kro\. C h i ? . Rei,. (Eiifil. fiun\/.) 1980. 49.
10561. 1 A Melent'eka, h i d 1983.52. 1136 [and 1983. 52,6411: K. M. Kadish.
W. tioh. 1'. Tagliatesta. D. Sarou. R . Poolesse. S. Licoccia. T. Boschi. /iiiirg.
C'liivt!. IY92. 31. 7305: R. Paolesx. S.Licoccia. M . Fanciullo. E. Morgante. T.
Bnsclii. litorg. C ~ h n t t .Acru 1993. 203. 107.
a) S. Will. A. Rahbar. H. Schmickler. J. Lex. E. Vogel. Aitgeii'. Chent. 1990, 102.
1434. 4iig(,ii~.C7tcvit. Jiil. Ed. Engl. 1990. 29. 1390, h) E. Vogcl. Purc .4pp/,
C ' h c i i / . 1993. 6 5 . 143.
a ) V hl. Lemuc. R. Herak, B. Prelesnik. S. R. Niketic. 1 Clieiti. Soc. Dr~/rori
T r Z i i t s . 1991. 22Y5: b) N . V Gerheleu. Y. A. Simonov. V. B. Arion, V. M. Leov:ic. ti I Tui-t& K . M . Indrichan. D. I. Gradinaru, v. E. Zavodnik. T. I.
Malinovskii. Iitorfi. Chein. 1992. 31, 3264: c ) U. tinof. T. Weyhermuller. T.
Wulter. K h i c g h a r d t . E. Bill. C. Butzlaff. A. X. Trautuein. Angwv. Cltrin.
1993. I ( / > . 1701. . 4 i y m . Chertt. I n / . Ed. Enyl. 1993. 3?,1635.
Further cxiiinples of non-porphyrinoid iron(w) complexes with N, ligands: W.
Hillcr. J. Striihle. A. Datz. M . Hanack. W. E. Hatfield, L. W. ter Haar. P.
Giitlich. .L 4/11,Clinti. S i i c . 1984. 106, 329; T. J. Collins. K. L. Kostka. E.
Munch. E S. Ut'fclman, ;bid 1990, 112. 5637: T. J. Collins. B. G. For. Z. G.
Hu. ti. L tio\tka. E. Munck. C. E. F. Rickard. L. J. Wright. ;hid. 1992. 114.
X723. K L. tiostka. B. G. Fox. M. P. Hendrich. T J Collins. C. E. F. Rickard.
L. J Wi-ighl. E. Mdnck. !hid 1993. 11s. 6746. For other Fe'* compounds seeF. M . Nelson in ('oittprehi,ii.,i~i, C'oor-dinutiott C/trmistrj, Ed. 4 (Eds.: G.
Wilkin~on.R . D Gillard. J. A McCleverty). Percamon. Oxford. 1987. p. 217;
D. Sellmtinn. M .Geck. F. Knoch. G. Ritter. 1. Dengler. J Aipi. Chein. SIC.
1991.
113. 3x19.
It ihould he notcd here. that in the case ofcomplexes containing ligands having
rvtended r[ systems (so-called noninnocent ligands) the metal cannot be assigned ;I definite oxidation state-the reason for this is the mixing of metal and
Ii@md oi-bit;ils. For discussion of this subtle problem see: F. C. Anson, T. J.
Collins. I' G. Richmond. B. D. Santarsiero, J. E. Toth. B. G. R. T. Trcco.J Ant.
Chrtti. .S<tc. 1987. 109. 2974: reference [Sc]
M . C'unlon. A. W. Johnson. W. R. Overend. D. Rajapaksa. C. M . Elson. J,
Ckiti. S v i . l'wkiir T,-uns. I 1973, 2281: b) Y. Murakami. Y Aoyama, M.
Haqa\hid,i. .1. C'/ti,tti. S O < C'/win.
.
Cointttiiii. 1980, 501; c) T. Boschi. S Licoccia,
R. Ptiolc\sc. P. Xigliatesta. M . A. Tehran. G. Peli7zi. F. Vitali. J. C%on Sor.
Dulioii Tiairs. 1990. 463: d) S. Licoccia, M. Paci. R. Paolesse. T. Boschi. ;hid
1991 361
[12] Y. Murahaini. Y. Mntsuda. ti. Sakata. S. Yamada. Y. Tanaka. Y. Aoyama. Bull.
('/ijl(w .Sol. J p n 1981..54. 163 The synthesis ofochethylcorrole 5 by oxidative
intriiii~~rlccuI:ircoupling of 1.19-dideoxyoctaethylbIladiene-~t~-dihydrobromide proceeds a , follows: the tetrlipyrrole starting material in methanol 15treated
w t h chlor;iiiil at room temperature in the presence of potassium hydrogen
carbonate ( 5 n i m ) . After addition of hydrarme (to dcprotonatc the corrole
hydruhi-oinide and to reduce the excess chloranil) the corrole 5 separates. and
illi/cd from mcthanol:chloroforin (9: 1) to give pure material; 1n.p126
227 C'(1irld isincreased from 19 t o 6 0 % compared with the previousmethod).
dtwti.\rrl.
[13] 7: C7,H8,,Fe,N,0. crystals from hexdne; monoclinic. space group F 1 ; n ,( I =
15.S89(4), h =15.950(4). 1' = 25.933(7) A, /I = 90.84(2) Z = 4: pLrlr,,
=
1.202 g ~ m - plhl0
~ , = 4.98 c m - l ; 10412 observed rellections: O,,,,, = 27 : R1 =
0.0421. wR2 = 0.1178.8: C,,H,,ClFeN;C,H,.crystals
from hentene: tricliiiic,spacegroupP7,u =10.191(2).h =13.973(3),~=14.684(3) . & , r = 82.62(2).
/(=71.19(2), ~ = 6 9 . 6 5 ( 2 ) .2 = 2 ; p ' r , i d = 1 . 2 3 4 g c m ~ " .l i u , , = 5 . 1 2 c m - ' ;
5844 observed reflections. ,,O = 2 7 " , R1 = 0.0646. II R2 = (lLl614. 9 .
C,,H,,FeN,,
crystals from hexane;ether; triclinic, space group Pi. u =
11.989(2), h =12.443(2). i~ =14.970(2) A. n = 60.39(2). /i= 68.50(2). ;'=
67.88(2)', Z = 2 ; psalcd
=1.237 gcm-': p,,, = 4 . 6 4 c m - ' ; 4908 observed rellections: Om,, = 25': R l = 0.0644. w R 2 = 0.1882. LO: C,,,H,,FeN,. crystals
from pentane:pyridine: monoclinic, space group PZL;n, u = 12.761(3). h =
14.644(4). < = 1X.662(5) A.1 = 95.58(2) . Z = 4: prLlLd
= 1 . 3 3 gcni-' / ~ M , . =
4 . 7 0 c n i - ' : 6186 obserbed reflections. Omax = 27 : X I = 0.0361. 11x2=
0.1121. The measurement of the reflection intensities was carried out on a n
Enraf-Nonius CAD4 diffractometer (room temperature, Mo,, radiation I =
0.71069
The structures were solved uith direct methods a n d refined mith F 2
for all indepciidently observed reflections with (F: > ZG yf)(licavy iitoins wiih
anisotropic. H atoms with isotropic temperature kictors): I I R2 =
[Z w(c: - F;L)2;Z(F~)2]'".Programs used: for solving the structures MolEN
(Enraf-Nonius)and for the refinement SHELXL-93 (G.M. Sheldrick. Univers i t 3 Gotlingen). Further details of the crystal structure investigations may he
obtained from the FachinformationsLentrum tiarlsruhe. 0-76344 EggensteiiiLeopoldshafen ( F R G ) on quoting the depository number CSII-57965.
[14] For the only X-ray structure analysis of an uncomplexed corrole so far, that of
8,12-diethy1-2.3,7.13.17,1X-hexamethylcorrole.
\ee: H. R. H;irrixin. 0 . J. R.
Hodder. D. C. Hodgkin. J. Chin. Soi.. B 1971. 640.
(151 a ) W. R. Scheidt. C. A. Reed. Chrtn. Rc~r.1981, 81, 543: h j W. K. Scheidt. M .
Goutcrman in Iron Porp/tuviJ, Purl I (Eds: A. B. P. Lever. H. B. Gray).
Addison-Wesley. ReadingMaas;ichiisetts. 1983, p. 89; c) W. R. Scheidt, Y. J.
Lee. Stnrrl. Bonding (Bcrlin) 1987. 64. 1 .
[16] W. R. Scheidt. B. Cheng, M . K. Safo. F. Cukiernik. J.-C. Marchoii. P G Debrunner. J. Ant. CIicm. So<. 1992. 114. 4420 (ref [Xg]).
[17] K . Tatsumi, R. Hoffman, J A m . CIwt?..So<. 1981, 103, 3328. In a n ji-oxodiiron
complex containing a pentanc-2.4-dione-bis(S-alkylisoth1oseinicarbazonate)
lieand, described in reference [Xb]. the Fe-0-Fe angle is only 153.7
[IX] The susceptibility measurements were carried out on powdered sainples in the
temperature range of 81 to 293K on a Faraday balance: the diamagnetic
correction was calculated by using Pascal constants. The Miissbauer experiments were carried out on powdered samples at 4.2K and 77K in xero lield.
[19] The perimeter protons in metalloporphyrin dimers are shifted to highfield duc
to the magnetic anisotropic). of the ligands. This shift amounts to about
0.5 ppm in the case of the tncso protons in the poxodiscandium complex of
ocraethylporphyrin (see ref. [ 2 2 ] ) .By the clamping together 01' two porphyrin
units, the distance between the ring frameworks is reduced to 3.4 A. In l h i s way
shifts of up to 1.5 ppm are observed (see M . 0. Senge, ti. R . Ger7evske. M. G .
H. Vicentc. T. P. Forsyth. K . M. Smith, A n g e i ~ Chcnt.
,
1993, 1U5. 745: Angcii
C h i . In/. Ed GiyI. 1993, 32, 750). Since the average separation of the ring
frameworks i n 7 is 4.3
it seems nnlikely that the shifts cncoimtered in this
work are solely due to a conventional anisotropy effect.
[20] D. M. Kurtr, Jr., Ch~rn.Rev. 1990, YO. 5x5
[21] M. Lausmann. I. Zimmer. J. Lex. H. Lueken, ti. Wieghardt. E. Vopel. Aiigtw.
C ' h i w i . 1994. 106. 776: Angivi'. Chm?.I n / . E d EngI. 1994. 33, 736.
[22] J. W. Buchler. H. H . Schneehage, Z . Niiriirfur,sr/i. B 1973. 38. 433.
[23] R. D. Ardsasingham, A . L. Balch. R. L. Hart, L. Latos-Graxynski. .I 4 m .
Cficm. Soc 1990. 112, 7566.
[24] J. Ernst. J. Subramanian. J.-H. Fuhrhop, Z.Nuturjorsch. A 1977. 32, I 1 29.
[25] G. N. La Mar. F. A. Walker (Jensen) in The Porp/7~.riitr,Voi. I I (Ed: 0 . Dolphin). Academic Press. Neu York, 1979. p. 61, H . M. Goff in Iron I'orp/twins.
Purr I (Eds.: A. B. P. Lever, H. B. Gray), Addison-Wesley, Readmg:Massnchusetts, 1983, p. 237.
[26] The ' H N M R spectrum of 9 was assigned by comparison Mith those of thc
[DJphenyl derivative. the it?-tolplcompound. and the complex 9 deuterated i n
the inrso positions; i n the case of 10, the ' H N M R spectra of t h e [DJpyridine
complex and the 3-methylpyridine derivative served as references.
(271 E. Bill. X:Q. Ding. E. L. Bominaar, A. X. Trautwein. H. Winkler. D. Mandon.
R. Weiss, A. Gold, K. JayaraJ. W. E. Hatfield. M. L. Kirk, Eiir. J. Bio(~/ioit.
1990. 188, 665.
[28] W. R. Scheidt. D. K. Geiger, Y J. Lee. C . A. Reed. G. Lang, /tmrg. Chcm. 1987.
26, 1039.
[29] P. G Debrunner in Iron Piirphvrins, Purt III (Eds.: A. B. P Lever. H. B.
Gray). VCH, New York. 1989. p. 137.
[30] Theonly previousexampleofthis~stheoxochromiurn(v)complexol'7.8.12,l3tetrnethyl-2.3.17.18-tetramethylcorrole: Y Matsuda, S. Yam;ida, Y. M u rakami. Inorg. Chim. Acra 1980. 44, L309.
.
.
A).
A,
135
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