Bis[N,N′-(2-chloro-benzyl-idene)-ethylene-diamine-κ2 N,N′]copper(I) dichlorido-cuprate(I) acetonitrile solvate

Article abstract of DOI:10.1107/S0108270107054960

The 1:1 adduct of N,N′-bis-(2-chloro-benzyl-idene)ethylene-diamine (cb2en) with copper(I) chloride proves to be an ionic compound with Cu ^I-centred cations and anions, [Cu(C16H14Cl2N2)2][CuCl2]·CH3CN. In the cation, the Cu^I atom has a flattened tetra-hedral coordination geometry, with a small bite angle for the chelating ligands, which form a double-helical arrangement around the metal centre. The anion is almost linear, as expected. The packing of the cations involves inter-molecular π-π inter-actions, which lead to columns of translationally related cations along the shortest unit-cell axis, with anions and solvent mol-ecules in channels between them. International Union of Crystallography 2007.

Full text of DOI:10.1107/S0108270107054960

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
cations (where L is an N-donor ligand) are numerous (Alcon
et al., 2000; Miller & Karpishin, 1999; Panja et al., 2002), there
are a limited number of studies of copper(I) complexes with
isolated linear dihalidocuprate(I) anions (Amirnasr et al.,
2005; Mirkhani et al., 2004). The structures of halidocuprate(I)
compounds are exceptionally varied, and the nature of the
cation plays an important role in determining the coordination
number of CuI in halidocuprates and the tendency of the
anions to form extended structures (Andersson & Jagner,
1989; Hasselgren et al., 1999). Thus, bulky cations with well
screened charges tend to favour the formation of discrete
anions in which CuI has a low coordination number. It has
been recognized that cation properties, such as size, shape and
the distribution of positive charge, are of importance for the
anion con®gurations adopted by halidocuprates(I).
ISSN 0108-2701
Bis[N,N0-(2-chlorobenzylidene)-
ethylenediamine-j2N,N0]copper(I)
dichloridocuprate(I) acetonitrile
solvate
Mohammad Hossein Habibi,a* Morteza
Montazerozohori,b Kazem Barati,a Ross W. Harringtonc
and William Cleggc
aDepartment of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran,
bChemistry Department, Yasouj University, Yasouj 75914-353, Iran, and cSchool of
Natural Science (Chemistry), Newcastle University, Newcastle Upon Tyne NE1 7RU,
England
Correspondence e-mail: habibi@chem.ui.ac.ir
Received 15 October 2007
Accepted 31 October 2007
Online 24 November 2007
The 1:1 adduct of N,N0-bis(2-chlorobenzylidene)ethylene-
diamine (cb2en) with copper(I) chloride proves to be an ionic
compound with CuI-centred cations and anions, [Cu-
(C16H14Cl2N2)2][CuCl2]ÁCH3CN. In the cation, the CuI atom
has a ¯attened tetrahedral coordination geometry, with a small
bite angle for the chelating ligands, which form a double-
helical arrangement around the metal centre. The anion is
almost linear, as expected. The packing of the cations involves
intermolecular ꢀ±ꢀ interactions, which lead to columns of
translationally related cations along the shortest unit-cell axis,
with anions and solvent molecules in channels between them.
In this context, we decided to examine the nature of the
complex formed with an unconjugated diimine ligand. The
title complex, (I), was prepared by reacting the bidentate
ligand N,N0-bis(2-chlorobenzylidene)ethylenediamine (cb2en)
with CuCl. The structure determination of (I) is consistent
Comment
The coordination chemistry of copper(I) complexes has
received increased attention over the last few decades. This is
mainly due to the potential application of these complexes in
catalytic processes (Fife et al., 1985; Bowker et al., 1988;
Bowmarker et al., 2000), photosensitization reactions
Â
(Horvath, 1994; Kutal, 1990), light-harvesting studies (Rosi et
al., 1999; Dietrich-Buchecker & Sauvage, 1987) and the design
of supramolecular arrays (Meghdadi et al., 2002; Foster et al.,
2000). Reaction of copper(I) halides, CuX, with nitrogen-
based ligands (L) yields CuXLn adducts. The steric, electronic
and conformational effects imparted by the coordinated
ligands play an important role in in¯uencing the properties of
the resulting metal complexes. A thorough understanding of
these effects can serve as the basis for the rational design of
complexes with speci®c and predictable properties. The
number of ligands bound to the monovalent CuI ion is greatly
in¯uenced by both the chemical nature and the geometry of
the ligand L, and the particular choice of halogen X (Lange et
al., 2000). Although structural reports on [CuIL4]+ complex
Figure 1
The asymmetric unit of (I), showing the atomic numbering scheme.
Displacement ellipsoids are drawn at the 50% probability level. H atoms
have been omitted for clarity, and only one component is shown for each
disordered group.
m592 # 2007 International Union of Crystallography
DOI: 10.1107/S0108270107054960
Acta Cryst. (2007). C63, m592±m594

metal-organic compounds
with the stoichiometry of a 1:1 copper(I) chloride±ligand
adduct, [CuCl(L)]. The structural connectivity, however, is
that of an ionic complex, the asymmetric unit of the structure
comprising a bis(ligand)copper(I) cation and a dichlorido-
cuprate(I) anion, together with a molecule of acetonitrile
solvent, [L2Cu]+[CuCl2] ÁMeCN (Fig. 1).
are similar to the corresponding angles for ethylenediamine
complexes (Engelhardt et al., 1984), with a small bite angle for
the chelating ligand. The two ligands form a double-helical
arrangement around the CuI atom. Within the cation, the two
benzene rings of each ligand are almost parallel to those of the
other, with a dihedral angle of 2.73 (16)ꢀ for rings C1±C6 and
C27±C32, and 0.38 (17)ꢀ for rings C11±C16 and C17±C22, and
The anion of (I) has no crystallographic symmetry, and one
Cl atom is disordered over two sites. Neither of these gives a
completely linear coordination (Table 1). The geometry is in
good agreement with that of several other previously reported
examples (Kaiser et al., 1974; Engelhardt et al., 1984).
The cation of (I) has a markedly ¯attened tetrahedral
geometry and also lies in a general position with no crystal-
lographic symmetry. The angles at the CuI atom in the cation
Ê
with interplanar spacings of about 3.6 A in each case. This
does not give rise to intramolecular ꢀ±ꢀ stacking, since the
pairs of rings are substantially displaced laterally, the centroid-
Ê
to-centroid distances being 4.877 (4) and 4.846 (4) A, respec-
tively. However, the same pairs of rings are similarly close to
parallel in adjacent molecules along the short a axis (dihedral
angles are the same by symmetry), and here there is inter-
molecular ꢀ±ꢀ stacking (Fig. 2), the centroid-to-centroid
Ê
distances being 3.645 (3) and 3.536 (3) A, respectively, and the
Ê
interplanar spacings being 3.532 and 3.523 A, respectively.
This stacking produces columns of cations along the a axis,
with anions and solvent molecules occupying the channels
between them (Fig. 3).
Experimental
The title compound was prepared by the reaction of CuCl and cb2en
(molar ratio 1:1) in an acetonitrile solution at room temperature. The
solution was then concentrated under vacuum. Red crystals of (I)
were formed by vapour diffusion of diethyl ether into the concen-
trated solution.
Figure 2
Crystal data
The stacking of cations of (I) via ꢀ±ꢀ interactions.
3
Ê
[Cu(C16H14Cl2N2)2][CuCl2]ÁC2H3N
V = 3548 (4) A
Z = 4
Synchrotron radiation
ꢂ = 0.8462 A
ꢃ = 1.68 mm
T = 120 (2) K
Mr = 849.42
Monoclinic, P21=n
Ê
a = 7.845 (5) A
b = 16.965 (10) A
Ê
1
Ê
Ê
c = 26.915 (15) A
ꢁ = 97.896 (9)ꢀ
0.10 Â 0.10 Â 0.10 mm
Data collection
Bruker APEXII CCD
diffractometer
Absorption correction: multi-scan
(TWINABS; Bruker, 2004)
Tmin = 0.730, Tmax = 0.850
30485 measured re¯ections
30485 independent re¯ections
15283 re¯ections with I > 2ꢄ(I)
Rint = 0.000
Re®nement
R[F2 > 2ꢄ(F2)] = 0.056
wR(F2) = 0.127
S = 0.79
30485 re¯ections
456 parameters
24 restraints
H-atom parameters constrained
3
Ê
Áꢅmax = 0.71 e A
3
Ê
0.84 e A
Áꢅmin
=
Table 1
Selected geometric parameters (A, ).
ꢀ
Ê
Cu1ÐN1
Cu1ÐN2
Cu1ÐN3
Cu1ÐN4
Cu2ÐCl5
2.024 (3)
2.024 (3)
2.039 (3)
2.014 (3)
2.0862 (14)
Cu2ÐCl6
N1ÐC7
N1ÐC8
N1ÐC8A
N2ÐC9
2.171 (5)
1.277 (4)
1.535 (8)
1.502 (8)
1.534 (8)
N1ÐCu1ÐN2
N1ÐCu1ÐN4
N2ÐCu1ÐN3
N3ÐCu1ÐN4
85.09 (12)
115.87 (13)
115.33 (12)
85.18 (12)
Cl5ÐCu2ÐCl6
Cu1ÐN2ÐC9
Cu1ÐN2ÐC10
170.5 (4)
108.7 (4)
133.5 (3)
Figure 3
The crystal packing in (I), viewed along the a axis, showing the columns of
cations, with anions and solvent molecules in channels.
ꢁ
Acta Cryst. (2007). C63, m592±m594
Habibi et al.
[Cu(C16H14Cl2N2)2][CuCl2]ÁC2H3N m593

metal-organic compounds
The small size and weak diffraction of the crystals necessitated the
use of synchrotron radiation. The crystal was found to be a non-
merohedral rotation twin about (100), with symmetry-inequivalent
re¯ections overlapping in the diffraction pattern, making it impos-
sible to merge equivalent re¯ections before the re®nement with
SHELXL HKLF5 style data (SHELXTL; Bruker, 2005). The twin
law is (1 0 0/ 0 1 0/ 0.8867 0 1). A number of re¯ections were
rejected in the data processing because of problems with spot shape
or masking by the beam-stop. The deposited structure factors are in
the format generated by the undocumented LIST 7 instruction of
SHELXTL (and SHELXL97), in which the contributions of the twin
components are identi®ed following re®nement of the twin fraction;
this was 0.5415 (5):0.4585 (5).
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SK3174). Services for accessing these data are
described at the back of the journal.
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The authors thank Isfahan University Center of Excellence
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ꢁ
m594 Habibi et al. [Cu(C16H14Cl2N2)2][CuCl2]ÁC2H3N
Acta Cryst. (2007). C63, m592±m594