Cis-Dichloro[tris(2-benzimidazolylmethyl)amine]iron(III) chloride ethanol dihydrate: Hydrogen bonding changing the arrangement of tapes built from π-π and C - H...πctions

Article abstract of DOI:10.1107/S0108270106002630

The title compound, [FeCl₂(C₂₄H₂₁N ₇)]Cl·C₂H₅OH·2H₂O, comprises an [FeCl₂(C₂₄H₂₁N₇)] ⁺ cation, a Cl^- anion, an ethanol molecule and two water molecules. The cations are linked by π-π and C - H...π interactions into one-dimensional tapes, and hydrogen bonding between the cations, Cl^- anions, and ethanol and water molecules links these tapes into a three-dimensional network.

Full text of DOI:10.1107/S0108270106002630

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
In the cation, the four TBA N atoms and two mutually cis Cl
anions coordinate to Fe3+. Three TBA N atoms (N1, N2 and
N4) and atom Cl1 form an equatorial plane, from which the
Fe3+ ion is displaced by only 0.067 (1) A in the direction of
Ê
ISSN 0108-2701
Cl2. The two axial sites are occupied by atoms Cl2 and N6
(from TBA). The FeÐN(Bzim) bond lengths [2.095 (2)±
Ê
2.113 (2) A] are much shorter than the FeÐN(amine) bond
Ê
length [2.330 (2) A]. This is due to the fact that the benzimi-
dazole groups are good ꢁ donors and good ꢀ acceptors
compared with the amine (Li et al., 2003).
cis-Dichloro[tris(2-benzimidazolyl-
methyl)amine]iron(III) chloride
ethanol dihydrate: hydrogen bonding
changing the arrangement of tapes
built from p±p and CÐHÁ Á Áp inter-
actions
Ê
The FeÐCl2 bond [2.3299 (9) A] is signi®cantly longer than
Ê
the FeÐCl1 bond [2.2426 (9) A], due to the different trans
in¯uences of the tertiary amine and benzimidazole groups
(Horng & Lee, 1999). Three TBA N atoms coordinate to Fe3+,
with angles of 86.00 (9)ꢀ for N2ÐFe1ÐN6 and 86.53 (9)ꢀ for
N4ÐFe1ÐN6, very similar to the values of 84.9 (1) and
86.1 (1)ꢀ in [FeCl2(TBA)]ClÁ3CH3OH (Pascaly et al., 2000)
and 86.9 (2) and 86.8 (2)ꢀ in [FeCl2(TBA)]ClO4 (Kwak et al.,
1999). Two benzimidazole rings (N2/N3/C2±C8 and N4/N5/
C10±C16) are almost coplanar [dihedral angle = 9.6 (1)ꢀ],
while the third (N6/N7/C18±C24) lies approximately ortho-
gonal to them, with dihedral angles of 88.4 (1) and 78.9 (1)ꢀ,
respectively. Overall, therefore, the cation in (I) is structurally
very similar to those in the related complexes [FeCl2-
(TBA)]ClÁ3CH3OH and [FeCl2(TBA)]ClO4.
Si-Si Feng, Li-Ping Lu,* Shu-Xia Wang, Li Li and Miao-Li
Zhu*
Institute of Molecular Science, Key Laboratory of Chemical Biology and Molecular
Engineering of the Education Ministry, Shanxi University, Taiyuan, Shanxi 030006,
People's Republic of China
Correspondence e-mail: luliping@sxu.edu.cn, miaoli@sxu.edu.cn
Received 7 December 2005
Accepted 22 January 2006
Online 11 February 2006
Although many crystal structures of TBA coordinated to
transition metal ions have been reported, there has been little
The title compound, [FeCl2(C24H21N7)]ClÁC2H5OHÁ2H2O,
comprises an [FeCl2(C24H21N7)]+ cation, a Cl anion, an
ethanol molecule and two water molecules. The cations are
linked by ꢀ±ꢀ and CÐHÁ Á Áꢀ interactions into one-dimen-
sional tapes, and hydrogen bonding between the cations, Cl
anions, and ethanol and water molecules links these tapes into
a three-dimensional network.
Comment
Benzimidazole (Bzim) is an important chemical group in the
design of antitumour agents (Arrowsmith et al., 2002; Hay et
al., 2003), and its metal complexes have been reported as
having the functions of the enzymes superoxide dismutase
(SOD) (Nishida et al., 1991; Kwak et al., 1999; Liao et al., 2001;
Qin et al., 2005) and nuclease (Liu et al., 2004). Because of our
interest in these areas, we have prepared the title compound,
(I), and determined its crystal structure.
Figure 1
A view of the structure of (I), with displacement ellipsoids drawn at the
25% probability level. The minor disorder components and the H atoms
have been omitted for clarity. Hydrogen bonds are indicated by dotted
lines.
Compound (I) consists of a cis-[FeCl2(TBA)]+ cation [TBA
is tris(2-benzimidazolylmethyl)amine], a Cl anion, an ethanol
solvent molecule and two water molecules (Fig. 1 and Table 1).
Acta Cryst. (2006). C62, m105±m108
DOI: 10.1107/S0108270106002630
# 2006 International Union of Crystallography m105

metal-organic compounds
investigation of non-covalent interactions. Several types of
non-covalent interaction organize the molecules of (I) into
the supramolecular architecture shown in Figs. 2 and 3. Firstly,
two cations interact in an antiparallel tail-to-tail manner
via ꢀ±ꢀ and CÐHÁ Á Áꢀ interactions, which form a loop
through four neighbouring benzimidazole groups, linking the
[FeCl2(TBA)]+ cations into ladders which are then cross-
linked to form tapes (Fig. 2). This is also observed in
Figure 2
The face-to-face ꢀ±ꢀ and edge-to-face CÐHÁ Á Áꢀ interactions (dotted lines) and the perpendicular arrangement of the tapes in (I). Fe atoms are shaded,
N atoms have a central dot, Cl atoms are large and cross-hatched, C atoms are plain spheres and H atoms are small circles. The minor disorder
components have been omitted for clarity. [Symmetry codes: (i) 3 + x, y, z; (ii) 3 x, 2 y, 1 z; (iii) 2 + x, y, z; (iv) 2 x, 2 y, 1 z; (v) 3 x,
12 + y, 32 z.]
Figure 3
A view of the hydrogen-bonding motif in (I). Fe atoms are shaded, N atoms have a central dot, Cl atoms are large and cross-hatched, C atoms are plain
spheres and H atoms are small circles. Dotted lines indicate hydrogen bonds. [Symmetry codes: (i) x, 12 + y, 23 z; (ii) x, 1 y, 1 z; (iii) x, 23 y,
12 + z; (iv)
1
x, 1 y, 1 z; (v) 1 + x, y, z.]
ꢁ
m106 Feng et al. [FeCl2(C24H21N7)]ClÁC2H6OÁ2H2O
Acta Cryst. (2006). C62, m105±m108

metal-organic compounds
Crystal data
[FeCl2(TBA)]ClÁ3CH3OH (Pascaly et al., 2000) and both
[FeCl2(TBA)]ClO4 (Kwak et al., 1999), indicating the role of
the cation in directing the packing within the crystals. The
centroid±centroid distance [Cg1Á Á ÁCg2i; symmetry code: (i)
x, 2 y, 1 z] associated with the ꢀ±ꢀ interaction between
the six-membered (C19±C24; centroid Cg1) and ®ve-
membered rings (N6/C18/N7/C20/C19; centroid Cg2) of the
3
[FeCl2(C24H21N7)]ClÁC2H6OÁ2H2O
Dx = 1.457 Mg m
Mo Kꢄ radiation
Cell parameters from 2889
re¯ections
Mr = 651.78
Monoclinic, P21=c
Ê
a = 10.3541 (12) A
Ê
b = 13.5873 (15) A
ꢅ = 2.4±23.2ꢀ
ꢆ = 0.82 mm
T = 298 (2) K
1
Ê
c = 21.746 (3) A
ꢃ = 103.791 (5)ꢀ
3
Ê
V = 2971.1 (6) A
Z = 4
Needle, red
0.44 Â 0.06 Â 0.06 mm
Ê
antiparallel benzimidazoles is 3.704 (2) A and the two rings
Ê
have a perpendicular separation of 3.462 (2) A. The CÁ Á ÁCg
Data collection
distances involved in the CÐHÁ Á Áꢀ interactions are 3.647 (4)
Bruker SMART 1K CCD area-
detector diffractometer
! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
Tmin = 0.715, Tmax = 0.953
13948 measured re¯ections
5216 independent re¯ections
3851 re¯ections with I > 2ꢁ(I)
Rint = 0.040
ꢅmax = 25.0ꢀ
[C5Á Á ÁCg1ii; symmetry code: (ii) 1 + x, y, z] and 3.665 (4) A
Ê
[C21Á Á ÁCg3i; Cg3 is the centroid of the ring C3±C8].
Secondly, R66(12) hydrogen-bonded rings [O1/Cl3/O2iii/O1iv/
h = 12 ! 12
Cl3iv/O2v; symmetry codes: (iii) x, 21 + y, 32 z; (iv) x, 2 y,
k = 16 ! 15
3
2
y, 12 + z] consisting of four water molecules
l = 25 ! 14
2
z; (v) x,
and two Cl anions directly connect four and indirectly
another two neighbouring cations through ethanol molecules
via hydrogen bonds (Fig. 3), arranging neighbouring tapes
perpendicular to each other and leading to the CÐHÁ Á Áꢀ
interaction, with a C7Á Á ÁCg4iii (Cg4 is the centroid of the ring
Re®nement
Re®nement on F2
R[F2 > 2ꢁ(F2)] = 0.044
wR(F2) = 0.113
S = 0.97
5216 re¯ections
395 parameters
H-atom parameters constrained
w = 1/[ꢁ2(Fo2) + (0.0616P)2]
where P = (Fo + 2Fc2)/3
2
(Á/ꢁ)max = 0.001
3
Ê
Áꢇmax = 0.45 e A
Ê
3
N4/C10/N5/C12/C11) distance of 3.332 (4) A between the
Ê
0.27 e A
Áꢇmin
=
tapes (Fig. 2).
As a result of the hydrogen-bonding and CÐHÁ Á Áꢀ inter-
actions, compound (I) forms a three-dimensional supramole-
cular network. This structural motif is clearly different from
those in [FeCl2(TBA)]ClÁ3CH3OH and [FeCl2(TBA)]ClO4,
where the different hydrogen-bonding patterns give tapes
arranged in a head-to-head parallel manner via ꢀ±ꢀ inter-
actions, rather than the CÐHÁ Á Áꢀ interaction (C7Á Á ÁCg4) seen
in (I) between the horizontal benzimidazoles of the tapes.
Therefore, the R66(12) hydrogen-bonded rings, together with
the hydrogen bonds involving ethanol molecules, change the
arrangement of the tapes, resulting in CÐHÁ Á Áꢀ interactions
between the cations of the tapes in (I).
Table 1
Selected geometric parameters (A, ).
ꢀ
Ê
Fe1ÐCl1
Fe1ÐCl2
Fe1ÐN1
2.2426 (9)
2.3299 (9)
2.330 (2)
Fe1ÐN2
Fe1ÐN4
Fe1ÐN6
2.095 (2)
2.110 (2)
2.113 (2)
Cl1ÐFe1ÐCl2
Cl1ÐFe1ÐN1
Cl1ÐFe1ÐN2
Cl1ÐFe1ÐN4
Cl1ÐFe1ÐN6
Cl2ÐFe1ÐN1
Cl2ÐFe1ÐN2
Cl2ÐFe1ÐN4
95.70 (4)
175.43 (6)
107.46 (7)
103.77 (7)
96.81 (7)
88.51 (6)
89.21 (7)
91.56 (7)
Cl2ÐFe1ÐN6
N1ÐFe1ÐN2
N1ÐFe1ÐN4
N1ÐFe1ÐN6
N2ÐFe1ÐN4
N2ÐFe1ÐN6
N4ÐFe1ÐN6
167.44 (7)
74.30 (9)
74.26 (9)
79.03 (9)
148.52 (9)
86.00 (9)
86.53 (9)
Table 2
Geometry of short contacts (A).
Ê
Experimental
Cg1 is the centroid of ring C19±C24, Cg2 is the centroid of ring N6/C18/N7/
C20/C19, Cg3 is the centroid of ring C3±C8 and Cg4 is the centroid of ring N4/
C10/N5/C12/C11.
All chemicals were of reagent grade, were commercially avail-
able and were used without further puri®cation. For the
synthesis of the ligand tris(2-benzimidazolylmethyl)amine (TBA),
nitrilotriacetic acid (0.479 g, 2.50 mmol) and 1,2-diaminobenzene
(0.812 g, 7.50 mmol) were dissolved in glycol (10 ml) and the mixture
irradiated intermittently (15 Â 1 min) using a WP700 LG microwave
oven with an output power of 350 W. The solution was cooled to room
temperature, and when distilled water (ca 80 ml) was added a yellow
precipitate formed immediately. This was ®ltered off, washed with
distilled water and dried in air. IR data (KBr pellet, ꢂ, cm 1): 3000±
3500 (w), 1624 (ms), 1591.2 (ms), 1436.9 (s), 1325 (ms), 1274.9 (s),
1220.9 (ms), 1116.7 (s), 1024.1 (ms), 968.2 (ms), 740.6 (s). FeCl3Á6H2O
(0.0344 g, 0.125 mmol) was added to a solution of TBA (0.0514 g,
0.125 mmol) in absolute ethanol (10 ml) and the mixture was stirred
for 1 h. The clear solution was left at room temperature and red
needles of (I) were obtained by slow evaporation of the solvent over
several days. IR data (KBr pellet, ꢂ, cm 1): 3446 (w), 1629.7 (w),
1593.1 (w), 1548.7 (w), 1471.6 (s), 1450.4 (s), 1390.6 (ms), 1325 (ms),
1274.9 (s), 1218.9 (ms), 1049.2 (s), 995.2 (w), 894.9 (ms), 756 (s).
Elemental analysis found: C 47.79, H 4.80, N 14.70%; calculated for
C26H31Cl3FeN7O3: C 47.91, H 4.79, N 15.05%.
Cg1Á Á ÁCg2i
3.704 (2)
3.647 (4)
C7ÐH7Á Á ÁCg4iii
3.332 (4)
3.665 (4)
C5ÐH5Á Á ÁCg1ii
C21ÐH21Á Á ÁCg3i
Symmetry codes: (i) x; y ‡ 2; z ‡ 1; (ii) x 1; y; z; (iii) x; y ‡ 12; z ‡ 23.
Table 3
Hydrogen-bond geometry (A, ).
ꢀ
Ê
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
N3ÐH3Á Á ÁO3Biv
N3ÐH3Á Á ÁO3Aiv
O3AÐH3AÁ Á ÁCl3
O3BÐH3BÁ Á ÁCl3
N5ÐH5AÁ Á ÁO2
N7ÐH7AÁ Á ÁO1v
O1ÐH32Á Á ÁCl3
O1ÐH31Á Á ÁCl2
O2ÐH33Á Á ÁO1vi
O2ÐH34Á Á ÁCl3v
0.86
0.86
0.82
0.82
0.86
0.86
0.85
0.85
0.85
0.85
1.86
1.94
2.31
2.40
2.02
2.00
2.32
2.42
2.03
2.34
2.701 (9)
2.779 (16)
3.104 (16)
3.145 (8)
2.828 (4)
2.831 (4)
3.113 (3)
3.193 (3)
2.877 (4)
3.153 (3)
165
164
164
151
156
162
155
151
170
162
Symmetry codes: (iv) x 1; y ‡ 32; z 21; (v) x; y ‡ 23; z 12; (vi) x; y
;
z ‡ 32.
1
2
ꢁ
Acta Cryst. (2006). C62, m105±m108
Feng et al.
[FeCl2(C24H21N7)]ClÁC2H6OÁ2H2O m107

metal-organic compounds
Atoms C25, C26 and O3 of the ethanol solvent molecule were
found to be disordered and were modelled over two sets of positions
using restraints on their anisotropic displacement parameters. The
major and minor disorder components had re®ned occupancies of
0.638 (11) and 0.362 (11), respectively. The H atoms attached to C, N
and alcohol O atoms of (I) were placed in geometrically idealized
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: BM3001). Services for accessing these data are
described at the back of the journal.
References
Arrowsmith, J., Jennings, S. A., Clark, A. S. & Stevens, M. F. G. (2002). J. Med.
Chem. 45, 5458±5470.
Bruker (2000). SMART (Version 5.0) and SAINT (Version 6.02). Bruker AXS
Inc., Madison, Wisconsin, USA.
Hay, M. P., Anderson, R. F., Ferry, D. M., Wilson, W. R. & Denny, W. A. (2003).
J. Med. Chem. 46, 5533±5545.
Horng, D.-N. & Lee, K.-M. (1999). J. Chem. Soc. Dalton Trans. pp. 2205±2210.
Kwak, B., Cho, K. W., Pyo, M. & Lah, M. S.(1999). Inorg. Chim. Acta, 290, 21±
27.
Li, D.-F., Liao, Z.-R., Wei, Y.-G., Du, F., Wang, M., Chen, W.-X., Li, W.-K. &
Mao, X.-A. (2003). Dalton Trans. pp. 2164±2169.
Liao, Z.-R., Zheng, X.-F., Luo, B.-S., Shen, L.-R., Li, D.-F., Liu, H.-L. & Zhao,
W. (2001). Polyhedron, 20, 2813±2821.
Liu, C.-L., Wang, M., Zhang, T.-L. & Sun, H.-Z. (2004). Coord. Chem. Rev.
248, 147±168.
Nishida, Y., Watanabe, I. & Unoura, K. (1991). Chem. Lett. pp. 1517±1520.
Ê
positions, with CÐH = 0.93±0.97 A, NÐH = 0.86 A and OÐH =
Ê
Ê
0.82±0.85 A, and re®ned with Uiso(H) = 1.2Ueq(parent), except for the
H atoms on the O and methyl C atoms of the ethanol molecule, which
were re®ned with Uiso(H) = 1.5Ueq(parent). The water H atoms
were located in a difference Fourier map and re®ned with a global
Uiso(H) = 1.5Ueq(O).
Data collection: SMART (Bruker, 2000); cell re®nement: SAINT
(Bruker, 2000); data reduction: SAINT; program(s) used to solve
structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne
structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
SHELXTL/PC (Sheldrick, 1999); software used to prepare material
for publication: SHELXTL/PC.
È
Pascaly, M., Nazikkol, C. E., Schweppe, F., Wiedemann, A., Zurlinden, K. &
Krebs, B. (2000). Z. Anorg. Allg. Chem. 626, 50±55.
Qin, S.-D., Feng, S.-S., Zhang, H.-M., Zhu, M.-L. & Yang, P. (2005). Acta Chim.
Sin. 63, 1155±1160.
The authors acknowledge ®nancial support from the
National Natural Science Foundation of China (grant No.
20471033), the Provincial Natural Science Foundation of
Shanxi Province of China (grant No. 20051013), and the
Overseas Returned Scholar Foundation of Shanxi Province of
China in 2002.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
È
Gottingen, Germany.
Sheldrick, G. M. (1999). SHELXTL/PC. Version 6.10. Bruker AXS Inc.,
Madison, Wisconsin, USA.
Sheldrick, G. M. (2000). SADABS. University of GoÈttingen, Germany.
ꢁ
m108 Feng et al. [FeCl2(C24H21N7)]ClÁC2H6OÁ2H2O
Acta Cryst. (2006). C62, m105±m108