Intermolecular interactions in two (ferrocenylmethyl)benzimidazoles incorporating the 4-MeOC6H4 and 3,4-(MeO)2C6H3 groups: Analysis of MeO - C - C distortions from ideal 120° geometry

Full text of DOI:10.1107/S0108270101015591

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
and 2, respectively, were obtained from the respective reac-
tions of 2-(4-methoxyphenyl)- and 2-(3,4-dimethoxyphenyl)-
benzimidazole with (ferrocenylmethyl)trimethylammonium
iodide (Pauson et al., 1966; Ferguson et al., 1994) and K2CO3 in
re¯uxing CH3CN (details in Experimental). These compounds
and close relatives are important electroactive model
compounds for application in anion sensor studies (Thomas et
al., 2000), as well as in malarial parasite research (Howarth &
Hanlon, 2001).
ISSN 0108-2701
Intermolecular interactions in two
(ferrocenylmethyl)benzimidazoles
incorporating the 4-MeOC6H4 and
3,4-(MeO)2C6H3 groups: analysis of
MeOÐCÐC distortions from ideal
120ꢁ geometry
John F. Gallagher,* Keith Hanlon and Joshua Howarth
School of Chemical Sciences, Dublin City University, Dublin 9, Ireland
Correspondence e-mail: john.gallagher@dcu.ie
The Fe1ÐC bond lengths for the substituted cyclopenta-
Ê
dienyl ring of (I) are in the range 2.036 (2)±2.0456 (18) A and
Ê
these are similar to the values of 2.033 (2)±2.039 (2) A in the
unsubstituted ring; for (II), these values are 2.030 (2)±
Received 10 September 2001
Accepted 21 September 2001
Ê
2.049 (2) and 2.037 (2)±2.044 (2) A, respectively. In (I), the
cyclopentadienyl CÐC bond-length ranges are small:
5
The title compounds, 1-ferrocenylmethyl-2-(4-methoxy-
phenyl)-1H-benzimidazole, [Fe(C5H5)(C20H17N2O)], (I), and
2-(3,4-dimethoxyphenyl)-1-ferrocenylmethyl-1H-benzimidaz-
ole, [Fe(C5H5)(C21H19N2O2)], (II), are model electroactive
compounds for anion sensor and antimalarial applications.
Distortions from the ideal 120ꢁ angle about the MeOÐCÐC
groups are evident, with angles of 115.1 (2) and 125.0 (2)ꢁ in
(I), and 115.9 (2) and 124.6 (2)ꢁ, and 115.7 (2) and 125.1 (2)ꢁ in
(II). The main intermolecular hydrogen bonds in (I) comprise
CÐHÁ Á ÁN and CÐHÁ Á Áꢀ(C5H5) interactions, while in (II),
only weak CÐHÁ Á Áꢀ(imidazole) and CÐHÁ Á Áꢀ(arene) inter-
actions are present.
Ê
1.413 (3)±1.423 (3) and 1.399 (4)±1.413 (4) A for the ꢁ (C5H4)
and ꢁ5(C5H5) rings, respectively; for (II), these values are
Ê
1.402 (4)±1.422 (3) and 1.393 (4)±1.410 (4) A, respectively. In
(I), the Fe1Á Á ÁCg1 and Fe1Á Á ÁCg2 distances are 1.6450 (9) and
Ê
1.6487 (12) A, respectively, and Cg1Á Á ÁFe1Á Á ÁCg2 is
179.80 (7)ꢁ, where Cg1 and Cg2 are the centroids of the
ꢁ5(C5H4) and ꢁ5(C5H5) rings, respectively; in (II), these values
Ê
are, respectively, 1.6462 (11) and 1.6571 (12) A, and
178.32 (6)ꢁ. The analogous data for ferrocenylmethyl(3-
Comment
The synthesis of anion receptors is currently an area of intense
research activity, due primarily to the ubiquitous roles which
anions play in both chemical and biological processes, for
example as substrates or co-factors for enzymes, and as
nucleophiles, redox agents and phase-transfer catalysts. In the
past decade, combinations of organometallic moieties with
amide functionalities have been demonstrated to be essential
components in many anion receptors (Beer, 1998; Kingston et
al., 1999). Recently, 1,3-disubstituted imidazolium cations
have been utilized as such (Sato et al., 1999; Thomas et al.,
2000), and their synthetic intermediates (imidazolin-2-yl-
idenes) are of interest as carbenes and are the subject of
several synthetic and structural investigations (Benito et al.,
1995; Bildstein et al., 1998, 1999; Li et al., 1998).
Benzimidazole systems have attracted our attention in
synthetic and applied biological research (Howarth et al., 2000;
Thomas et al., 2000; Howarth & Hanlon, 2001; Gallagher,
Hanlon et al., 2001). Compounds (I) and (II), shown in Figs. 1
Figure 1
A view of the molecule of (I) with the atomic numbering scheme.
Displacement ellipsoids are drawn at the 30% probability level and H
atoms are shown as small spheres of arbitrary radii.
ꢀ
1410 # 2001 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2001). C57, 1410±1414

metal-organic compounds
chlorophenyl)benzimidazole, (III) (Gallagher, Hanlon ꢁet al.,
HÁ Á Áꢀ(arene) interactions are of similar strength to those in
Ê
2001), are 1.6467 (10) and 1.6487 (11) A, and 179.12 (7) , and
2-(ferrocenyl)thiophene-3-carboxylic
acid
(Gallagher,
for 2-(ferrocenyl)thiophene-3-carboxylic acid, (IV) (Galla-
Ê
Hudson & Manning, 2001) and are relatively weak. Analysis
of the hydrogen bonding in (II) reveals that there are only two
interactions of signi®cance comprising two CÐHÁ Á Áꢀ inter-
actions involving the phenyl and imidazolyl rings systems
(Fig. 4); details are given in Table 4.
gher, Hudson & Manning, 2001), 1.6435 (10) and 1.656 (3) A,
and 178.42 (11)ꢁ. These results highlight the similarity in the
ferrocenyl bond lengths and angles in (I), (II) and (III). The
cyclopentadienyl rings deviate from an eclipsed geometry in
(I), as evidenced by the C1nÁ Á ÁCg1Á Á ÁCg2Á Á ÁC2n torsion
angles [17.0 (2)±17.5 (2)ꢁ; n = 1±5], and in (II) [17.7 (2)±
18.36 (18)ꢁ], which contrasts with the eclipsed geometry in
(III) but is similar to the 20.6 (5)±21.3 (5)ꢁ range in the major
conformation of (IV) (Gallagher, Hudson & Manning, 2001).
The molecular conformations adopted by (I) and (II) are
different, with angles of 78.07 (8) and 40.22 (9)ꢁ between the
C5H4/imidazolyl rings and the imidazolyl/phenyl rings,
respectively, in (I), and 73.86 (8) and 70.02 (7)ꢁ, respectively,
in (II); these angles are 84.37 (9) and 56.21 (8)ꢁ, respectively,
in (III). An interesting difference between (I) and (II) arises
about N2, with the C1ÐN2ÐC2/C3ÐN2ÐC2 angles differing
by almost 7ꢁ in (I) but being similar in (II). A smaller variation
at C1 of 2.5ꢁ is observed in (I). These differences arise due to
the different molecular and packing geometries in (I) and (II),
while the disparity in (III) is intermediate between (I) and
(II). Differences are also evident in the FeÐCÐCÐN torsion
angles (Tables 1 and 3).
Analysis of the April 2001 version of the Cambridge
Structural Database (CSD) using CONQUEST (Version 1.2;
Allen & Kennard, 1993) for the para-anisole group was
undertaken for structures which ful®l the three-dimensional
coordinates, with R < 0.10 and no disorder criteria (see
Scheme 2). The CÐC6H4OCH3 moiety search gives 767
entries and 1063 observations for CÐCÐOMe distortions in
the range 100±120ꢁ; two entries have CÐCÐOMe angles less
than 110ꢁ [WIBCEP 102.3ꢁ (Niyomura et al., 1999) and
ZOYPAE 109.8ꢁ (Konda et al., 1995)] and these were omitted
from the calculations to give 765 entries and 1060 unique
molecular structures. The mean angles are 115.5 and 124.7ꢁ
about CÐCÐOMe, which is similar to (I). For example, in
tris(4-methoxyphenyl)methanol (HIFVIB; Ferguson et al.,
1996), MeOÐCÐCortho angles of 115.1 (3)/125.5 (3)ꢁ transoid/
cisoid to the ±OCH3 group are distinct and similar to the
values of 116/124ꢁ reported in the electron diffraction study of
anisole, C6H5OCH3 (Siep & Siep, 1973). The mean CÐOÐ
CH3 angle from the CSD search is 117.7ꢁ (range 110±133ꢁ) and
the CÐCÐOÐCH3 torsion angle range is 36.9±33.2ꢁ,
compared with 5.0 (4)ꢁ in (I). Analysis of CÐCÐOMe
angles with both greater than 120ꢁ shows only one structure
(HADVUD; Wey et al., 1993), using identical cut-off criteria,
and three structures with both angles less than 120ꢁ [JIKXAC
(Magnus & Moursounidis, 1991), PEXCOK (Carugo et al.,
1993) and ZAMNIK (Mayer et al., 1995)]; however, these
latter three structures have R factors greater than 6% and the
Analysis of the hydrogen bonding in (I) reveals a
(Cp)C13ÐH13Á Á ÁN1i and a side-on C2ÐH2BÁ Á ÁN1ii inter-
molecular interaction, and two CÐHÁ Á Áꢀ(C5H5) interactions
(Fig. 3); details and symmetry codes are given in Table 2. The
C2ÐH2BÁ Á ÁCg3 descriptor (Cg3 is the imidazolyl ring
ꢁ
Ê
centroid) gives H2BÁ Á ÁCg3 2.86 A, C2ÐH2BÁ Á ÁCg3 135 and
Ê
C2Á Á ÁCg3 3.605 (2) A, stressing the acceptor as N and the
interaction as CÐHÁ Á ÁN not CÐHÁ Á Áꢀ(imidazole). The CÐ
Ê
CÐC s.u.'s range from 0.01 to 0.03 A.
Analysis of the 3,4-veratryl moiety as CÐC6H3(OCH3)2
yields 132 entries and 164 unique structures in the CSD. All
four CÐCÐOMe angles were analysed in the range 100±140ꢁ.
The mean methoxy angles are 115.5 and 125.1ꢁ for the para-
OCH3, and 115.2 and 124.8ꢁ for the meta-OCH3 groups, with
angle ranges typically Æ5ꢁ of the mean values. The methoxy
CÐOÐCH3 angles are similar, 117.2ꢁ for para- and 117.7ꢁ for
meta-OCH3, and are also similar to (II). Unusually, there is a
structure with both para-CÐCÐOMe angles less than 120ꢁ
(FAGHIE; Noyori et al., 1986), at 118.9 and 118.1ꢁ, and CÐ
OÐCH3 angles of 121.5 and 120.3ꢁ, and one structure with
both para-CÐCÐOMe angles greater than 120ꢁ (LOJNED;
McAuley & Subramanian, 2000), at 120.2 and 120.2ꢁ, and
normal CÐOÐCH3 angles of 118.3 and 118.2ꢁ. Analysis of the
meta-CÐOÐCH3 angles less than 120ꢁ shows MXPMNQ
Figure 2
A view of the molecule of (II) with the atomic numbering scheme.
Displacement ellipsoids are drawn at the 30% probability level and H
atoms are shown as small spheres of arbitrary radii.
ꢀ
Acta Cryst. (2001). C57, 1410±1414
John F. Gallagher et al.
[Fe(C5H5)(C20H17N2O)] and [Fe(C5H5)(C21H19N2O2)] 1411

metal-organic compounds
each other. The ®ve remaining CÁ Á ÁC distances are in the
Ê
range 4.21±4.99 A and are intermediate between cisoid and
transoid. The analysis suggests that ortho-related methoxy
groups stagger with respect to one another, with torsion angles
to the aromatic ring close to 0ꢁ. Analysis of ortho-dimethoxy
aromatic compounds by angular group-induced bond alter-
nation (AGIBA; Krygowski et al., 1998) indicates some
distortion of the C6 aromatic ring geometry in (II); (I) does not
display this bond-length alternation.
Extensive structural studies have been reported on the di-
methoxyphenyl group in crystal structures (Kumar et al., 1998;
Dijksma et al., 1998; Bruno et al., 2001). Steric in¯uences
between the CH3 and phenyl-H atoms, or electronic effects
involving the oxygen lone pairs (Kumar et al., 1998; Dijksma et
al., 1998), have been proposed to account for the planarity of
the methoxy groups with the aromatic plane and reported
methoxy OÐCÐC angles, while Bruno et al. (2001) have
recently commented on the possibility of conjugation effects
to determine the planarity of the methoxy groups with the
aromatic plane, using combined ab initio calculations and
database analyses.
Figure 3
A view of the interactions in the crystal structure of (I).
(Amatayakul et al., 1979), with values of 117.2 and 114.7ꢁ, and
118.3 and 119.6ꢁ; however, the R factor is 9.3% and the CÐC
Experimental
Compound (I) was prepared as follows: to a mixture of 2-(4-
methoxyphenyl)benzimidazole (3.0 g, 12.6 mmol) and K2CO3 (2.61 g,
18.9 mmol) in CH3CN (100 ml) was added (ferrocenylmethyl)tri-
methylammonium iodide (4.86 g, 12.6 mmol; Pauson et al., 1966;
Ferguson et al., 1994), and the mixture was re¯uxed for 10 h. The
reaction was cooled to room temperature, water was added and the
suspension extracted into CHCl3. The organic layer was washed with
water, dried (MgSO4) and evaporated under vacuum to leave a
brown solid. The crude product was puri®ed by column chroma-
tography on silica gel using CH2Cl2/CH3OH (97/3) as eluent.
Compound (I) was obtained as a light-orange solid [yield 2.9 g, 54%;
m.p. 142±146 K (uncorrected)]. Spectroscopic analysis: IR (KBr, ꢂ,
cm 1): 3043, 2981, 2310, 1708, 1609, 1534, 1485, 1460, 1416, 1385,
1323, 1261, 1174, 1106, 1032, 1001, 895, 740, 703; 1H NMR (400 MHz,
ꢃH, p.p.m., CDCl3): 7.81 (m, 1H, arom-H), 7.71 (m, 2H, aryl-H), 7.45
(m, 1H, arom-H), 7.30 (m, 2H, aryl-H), 7.09 (m, 2H, arom-H), 5.21 (s,
2H, Fc-CH2) 4.21±4.07 (m, 9H, Cp-H), 3.91 (s, 3H, aryl-OCH3);
13C NMR (ꢃC, p.p.m., CDCl3): 160.78, 153.47, 142.97, 135.62, 131.03,
122.95, 122.46, 119.6, 114.08, 110.27, 83.3, 68.77, 68.13, 55.42, 44.37.
Compound (II) was prepared as follows: to a mixture of 2-(3,4-
dimethoxyphenyl)benzimidazole (5.35 g, 20 mmol) and K2CO3
(4.14 g, 30 mmol) in CH3CN (150 ml) was added (ferrocenyl-
methyl)trimethylammonium iodide (8.1 g, 21 mmol; Pauson et al.,
1966; Ferguson et al., 1994) and the mixture re¯uxed for 16 h. The
work-up was similar to that described for (I) above. Compound (II)
was obtained as a brown oil which later solidi®ed [yield 1.8 g, 38%;
m.p. 192±194 K (uncorrected)]. Spectroscopic analysis: IR (KBr, ꢂ,
cm 1): 3051, 2982, 2849, 2697, 2411, 2320, 1713, 1609, 1495, 1434,
Ê
s.u.'s are in the range 0.01±0.03A. There are no structures with
both meta-CÐOÐCH3 angles greater than 120ꢁ. Thus, the
methoxy angles of 115 and 125ꢁ are not unusual for either the
methoxy compound, (I), or the dimethoxy derivative, (II).
Analysis of the disposition of the two OCH3 groups relative
to one another reveals that for 127 entries (159 unique), the
Ê
range of CÁ Á ÁC distances is narrow, 5.23±5.48 A, with a mean
Ê
of 5.40 A and with the methoxy groups disposed transoid to
1
1420, 1363, 1259, 1145, 1024, 898, 743, 709; H NMR (400 MHz, ꢃH,
p.p.m., CDCl3): 7.81 (m, 1H, arom-H), 7.51 (m, 1H, arom-H), 7.35±
7.03 (m, 5H, aryl-H and arom-H), 5.24 (s, 2H, Fc-CH2), 4.15±4.09 (m,
9H, Cp Fc-H), 4.00 (s, 3H, OCH3), 3.94 (s, 3H, OCH3); 13C NMR (ꢃC,
p.p.m., CDCl3): 153.84, 150.75, 149.51, 136.08, 123.05, 122.84, 122.55,
120.07, 113.21, 111.08, 110.69, 83.86, 69.25, 69.08, 68.57, 56.55, 56.43,
44.89.
Figure 4
A view of the interactions in the crystal structure of (II).
ꢀ
1412 John F. Gallagher et al.
[Fe(C5H5)(C20H17N2O)] and [Fe(C5H5)(C21H19N2O2)]
Acta Cryst. (2001). C57, 1410±1414

metal-organic compounds
Compound (I)
Compound (II)
Crystal data
Crystal data
3
3
[Fe(C5H5)(C20H17N2O)]
Mr = 422.30
Dx = 1.389 Mg m
Mo Kꢅ radiation
[Fe(C5H5)(C21H19N2O2)]
Mr = 452.32
Dx = 1.415 Mg m
Mo Kꢅ radiation
Cell parameters from 50
re¯ections
Monoclinic, P21=n
Cell parameters from 75
re¯ections
Monoclinic, P21=a
Ê
a = 12.4326 (10) A
Ê
a = 11.7089 (10) A
ꢆ = 2.4±15.6ꢁ
Ê
b = 9.5414 (7) A
b = 13.7888 (12) A
ꢆ = 9.0±37.9ꢁ
Ê
1
Ê
c = 17.1682 (8) A
1
Ê
c = 13.2441 (11) A
ꢇ = 0.77 mm
T = 294 (1) K
ꢇ = 0.74 mm
T = 294 (2) K
ꢄ = 97.400 (5)ꢁ
V = 2019.6 (2) A
Z = 4
ꢄ = 96.758 (7)ꢁ
V = 2123.4 (3) A
Z = 4
3
Ê
3
Ê
Block, orange
0.43 Â 0.33 Â 0.30 mm
Block, red
0.35 Â 0.25 Â 0.15 mm
Data collection
Data collection
Siemens P4 diffractometer
! scans
Absorption correction: scan
(North et al., 1968)
Tmin = 0.737, Tmax = 0.803
6105 measured re¯ections
4830 independent re¯ections
3693 re¯ections with I > 2ꢈ(I)
Rint = 0.011
max = 28ꢁ
Siemens P4 diffractometer
! scans
Absorption correction: scan
(North et al., 1968)
Tmin = 0.783, Tmax = 0.900
6262 measured re¯ections
5088 independent re¯ections
3684 re¯ections with I > 2ꢈ(I)
Rint = 0.028
ꢆmax = 28ꢁ
ꢆ
h = 16 ! 1
h = 1 ! 15
k = 1 ! 12
k = 1 ! 18
l = 22 ! 22
l = 17 ! 17
3 standard re¯ections
every 197 re¯ections
intensity variation: Æ1%
3 standard re¯ections
every 197 re¯ections
intensity variation: Æ1%
Re®nement
Re®nement
Re®nement on F2
R[F2 > 2ꢈ(F2)] = 0.040
wR(F2) = 0.110
S = 1.04
4830 re¯ections
w = 1/[ꢈ2(Fo2) + (0.055P)2
+ 0.456P]
Re®nement on F2
R[F2 > 2ꢈ(F2)] = 0.039
wR(F2) = 0.096
S = 1.01
5088 re¯ections
w = 1/[ꢈ2(Fo2) + (0.04P)2
+ 0.537P]
where P = (Fo2 + 2Fc2)/3
(Á/ꢈ)max < 0.001
where P = (Fo2 + 2Fc2)/3
(Á/ꢈ)max < 0.001
3
Ê
3
Ê
Áꢉmax = 0.58 e A
Áꢉmax = 0.21 e A
3
Ê
0.31 e A
3
Ê
0.22 e A
263 parameters
H-atom parameters constrained
Áꢉmin
=
282 parameters
H-atom parameters constrained
Áꢉmin
=
Table 1
Selected geometric parameters (A, ) for (I).
Table 3
Selected geometric parameters (A, ) for (II).
ꢁ
ꢁ
Ê
Ê
O1ÐC34
O1ÐC37
N1ÐC1
N1ÐC4
N2ÐC1
1.373 (2)
1.418 (3)
1.321 (2)
1.381 (2)
1.382 (2)
N2ÐC2
N2ÐC3
C1ÐC31
C2ÐC11
1.457 (2)
1.384 (2)
1.471 (2)
1.502 (3)
O1ÐC33
O1ÐC37
O2ÐC34
O2ÐC38
N1ÐC1
1.368 (3)
1.432 (3)
1.364 (3)
1.423 (3)
1.317 (3)
1.388 (3)
N2ÐC1
N2ÐC2
N2ÐC3
C1ÐC31
C2ÐC11
1.378 (3)
1.466 (3)
1.383 (3)
1.475 (3)
1.498 (3)
N1ÐC4
O1ÐC34ÐC33
O1ÐC34ÐC35
C34ÐO1ÐC37
C1ÐN1ÐC4
C1ÐN2ÐC2
C1ÐN2ÐC3
C2ÐN2ÐC3
N1ÐC1ÐN2
125.0 (2)
115.1 (2)
117.7 (2)
105.47 (15)
130.00 (15)
106.46 (15)
123.24 (15)
112.23 (16)
N1ÐC1ÐC31
N2ÐC1ÐC31
N2ÐC2ÐC11
N2ÐC3ÐC4
N2ÐC3ÐC8
N1ÐC4ÐC3
N1ÐC4ÐC5
C2ÐC11ÐFe1
122.62 (17)
125.14 (16)
112.75 (15)
105.59 (16)
131.71 (18)
110.25 (16)
129.89 (19)
126.56 (13)
O1ÐC33ÐC32
O1ÐC33ÐC34
C33ÐO1ÐC37
O2ÐC34ÐC33
O2ÐC34ÐC35
C34ÐO2ÐC38
C1ÐN1ÐC4
C1ÐN2ÐC2
C1ÐN2ÐC3
C2ÐN2ÐC3
124.6 (2)
115.9 (2)
116.5 (2)
115.7 (2)
125.1 (2)
116.7 (2)
104.98 (17)
126.63 (19)
106.38 (17)
126.32 (18)
N1ÐC1ÐN2
N1ÐC1ÐC31
N2ÐC1ÐC31
N2ÐC2ÐC11
N2ÐC3ÐC4
N2ÐC3ÐC8
N1ÐC4ÐC3
N1ÐC4ÐC5
C2ÐC11ÐFe1
112.98 (19)
123.47 (19)
123.55 (19)
112.21 (18)
105.50 (18)
132.6 (2)
110.14 (19)
129.7 (2)
125.74 (15)
N2ÐC2ÐC11ÐFe1
C1ÐN2ÐC2ÐC11
109.58 (16)
104.5 (2)
N1ÐC1ÐC31ÐC32
C37ÐO1ÐC34ÐC33
38.0 (3)
5.0 (4)
N2ÐC2ÐC11ÐFe1
N1ÐC1ÐC31ÐC32
179.65 (15)
67.3 (3)
C37ÐO1ÐC33ÐC32
C38ÐO2ÐC34ÐC35
11.2 (4)
4.7 (4)
Table 2
Hydrogen-bonding geometry (A, ) for (I).
ꢁ
Ê
Cg1 and Cg2 are the centroids of the ꢁ5(C5H4) and ꢁ5(C5H5) rings,
respectively.
Table 4
Hydrogen-bonding geometry (A, ) for (II).
ꢁ
Ê
Cg1 and Cg2 are the centroids of the ꢁ5(C5H4) and ꢁ5(C5H5) rings,
respectively.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C13ÐH13Á Á ÁN1i
C2ÐH2BÁ Á ÁN1ii
C7ÐH7Á Á ÁCg1iii
C37ÐH37BÁ Á ÁCg2iv
Symmetry codes: (i) x
1 ‡ x; y; z.
0.93
0.97
0.93
0.96
2.48
2.61
2.81
2.85
3.397 (3)
3.404 (3)
3.644 (3)
3.734 (3)
168
139
151
154
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C21ÐH21Á Á ÁCg1i
0.93
0.93
2.88
2.73
3.514 (3)
3.636 (3)
127
163
C7ÐH7Á Á ÁCg2ii
1
2
1
2
1
2
1 1
;
y; z 12; (ii)
x; 12 ‡ y; 12 z; (iii) x
;
2 2
y; 12 ‡ z; (iv)
Symmetry codes: (i) ‡ x; 12 y; z; (ii)
x; 12 ‡ y; z.
1
2
1
2
ꢀ
Acta Cryst. (2001). C57, 1410±1414
John F. Gallagher et al.
[Fe(C5H5)(C20H17N2O)] and [Fe(C5H5)(C21H19N2O2)] 1413

metal-organic compounds
Carugo, O., Clerici, F. & Pocar, D. (1993). Tetrahedron, 49, 9117±9126.
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Â
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JFG thanks the School of Chemical Sciences, Dublin City
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JH thanks Forbairt and Enterprise Ireland for grants in aid of
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ꢀ
1414 John F. Gallagher et al.
[Fe(C5H5)(C20H17N2O)] and [Fe(C5H5)(C21H19N2O2)]
Acta Cryst. (2001). C57, 1410±1414