Complexes between copper(I) halides and 1,2-phenylenediamine

Article abstract of DOI:10.1016/j.ica.2004.11.003

Two copper(I) compounds containing 1,2-phenylenediamine have been prepared and characterised by means of crystal structure determination. The compounds catena-μ-1,2-phenylenediamine(acetonitrile)chlorocopper(I) (1) and catena-μ-1,2-phenylenediamine(acetonitrile)bromocopper(I) (2) are isostructural, bridging to form polymeric chains being effected solely by the aromatic amine and not by halide. Copper(I) exhibits distorted tetrahedral coordination geometry in both complexes. The chains are interconnected to form layers through short intermolecular X?H interactions of 2.3-2.6 A?, involving amine hydrogen atoms and the terminal chloride or bromide bonded to copper(I). Neither compound is prone to decomposition by loss of the acetonitrile ligand, the reason for this being apparent from inspection of their crystal structures.

Full text of DOI:10.1016/j.ica.2004.11.003

Inorganica Chimica Acta 358 (2005) 1327–1330
www.elsevier.com/locate/ica
Note
Complexes between copper(I) halides and 1,2-phenylenediamine
a
Bjo¨rn Gustafsson , Mikael Hakansson , Alan T. Hutton , John R. Moss ,
b
c
c
˚
a,
*
Susan Jagner
a
Department of Inorganic Chemistry, Chalmers University of Technology, SE-412 96 Go¨teborg, Sweden
b
Department of Chemistry, Go¨teborg University, SE-412 96 Go¨teborg, Sweden
Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
c
Received 8 October 2004; accepted 10 November 2004
Available online 5 January 2005
Abstract
Two copper(I) compounds containing 1,2-phenylenediamine have been prepared and characterised by means of crystal structure
determination. The compounds catena-l-1,2-phenylenediamine(acetonitrile)chlorocopper(I) (1) and catena-l-1,2-phenylenedi-
amine(acetonitrile)bromocopper(I) (2) are isostructural, bridging to form polymeric chains being effected solely by the aromatic
amine and not by halide. Copper(I) exhibits distorted tetrahedral coordination geometry in both complexes. The chains are inter-
˚
connected to form layers through short intermolecular Xꢀ ꢀ ꢀH interactions of 2.3–2.6 A, involving amine hydrogen atoms and the
terminal chloride or bromide bonded to copper(I). Neither compound is prone to decomposition by loss of the acetonitrile ligand,
the reason for this being apparent from inspection of their crystal structures.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Copper(I); Bromide; Chloride; Acetonitrile; 1,2-Phenylenediamine; Crystal packing
1. Introduction
plexes between copper(I) and simple aromatic diamines
such as the phenylenediamines. We reported recently
on a complex between copper(I) chloride and 1,4-
phenylenediamine: catena-l-chloro-l-1,4-phenylenedi-
amine(acetonitrile)copper(I) [4a]. We have now
succeeded in isolating the 1,2-phenylenediamine ana-
logues with copper(I) chloride and with copper(I)
bromide (see Fig. 1): catena-l-1,2-phenylenediamine
The rich structural chemistry and ensuing properties
of haloaminecopper(I) complexes have been described
in a comprehensive review [1]. Further investigations,
since then, include the incorporation of ligands con-
taining N- and both N- and P-donors into halocup-
rate(I) species [2]. Our interest in this field stemmed
from investigation of complexes between copper(I)
and hard donors such as oxygen and the reactivity
of such complexes with respect to carbonylation [3].
Recently, our work has also dealt with complexes be-
tween copper(I) chloride and N-donor ligands [4].
Somewhat surprisingly, however, there still appears
to be a lack of structural information concerning com-
(acetonitrile)chlorocopper(I)
(1)
and
2-phenylenediamine(acetonitrile)bromocopper(I)
catenal-1,
(2),
respectively. The results of this study are reported
below.
2. Experimental
2.1. General
*
Corresponding author. Tel.: +46 31 772 2852; fax: +46 31 772
All operations were performed under nitrogen or ar-
gon atmosphere using standard Schlenk techniques at
2846.
E-mail address: susan@chem.chalmers.se (S. Jagner).
0020-1693/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.11.003

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B. Gustafsson et al. / Inorganica Chimica Acta 358 (2005) 1327–1330
Table 1
Crystallographic data for [CuCl(CH3CN){l-C6H4(NH2)2}] (1) and
1
[CuBr(CH3CN){l-C6H4(NH2)2}] (2)
1
Compound
1
2
NCCH3
Empirical formula
Mr
C8H11ClCuN3
248.2
C8H11BrCuN3
292.7
NH2
Br
Cu
NH2
Br
H2N
H2N
NH2
Crystal system
Space group
Unit cell dimensions
monoclinic
P21/c
monoclinic
P21/c
Cu
NH2
˚
a (A)
10.604(3)
9.180(3)
10.375(3)
99.27(1)
996.7(5)
4
10.758(4)
9.284(6)
10.598(5)
99.67(3)
1043.4(9)
4
NCCH3
˚
b (A)
˚
c (A)
b (°)
3
˚
V (A )
Z
Dcalc (g cmꢁ3
l(Mo Ka) (cmꢁ1
)
1.65
24.1
1.86
58.8
Fig. 1. Schematic drawing of catena-l-1,2-phenylenediamine-bromo-
copper(I) (2); the chloro complex (1) is isostructural.
)
Temperature (°C)
2h Range (°)
Absorption correction
Data/restraints/parameters
R1 (I > 2r(I))
20(2)
20(2)
5.9 < 2h < 63.8
empirical
2752/0/132
0.051
5.8 < 2h < 63.5
empirical
2605/0/132
0.045
ambient temperature. Acetonitrile was degassed, but
otherwise used as purchased (Riedel de-Hae¨n, max
0.001% H2O). Copper(I) chloride was purified according
to the methods described in the literature [5]. Copper(I)
bromide (Aldrich 99.999%) and 1,2-phenylenediamine
(Aldrich, 99+ %) were used as purchased.
wR2 (all reflections)
Maximum/minimum reꢁsi3dual
0.133
0.60; ꢁ0.54
0.115
0.61; ꢁ0.94
˚
electron density (e A
)
2
2
1=2
R1 = RiFo| ꢁ |Fci/R|Fo|; wR2 ¼ fR½wðF 2o ꢁ F c2Þ ꢂ=R½wðF o2Þ ꢂg
.
2.2. Preparation of [CuCl(CH3CN){l-C6H4(NH2)2}]
(1)
1
processed using the CRYSTALCLEAR software package.
Empirical corrections were applied for the effects of
absorption using the REQAB program under CRYSTAL-
CLEAR. The structures were solved by direct methods
Copper(I) chloride (0.085 g, 0.86 mmol) was dis-
solved in acetonitrile (2 ml) in a Schlenk tube. 1,2-
Phenylenediamine (0.094 g, 0.87 mmol), dissolved in
acetonitrile (4 ml), was added to this solution. A dark
precipitate was formed almost immediately and the solu-
tion turned brown. The solution was filtered and colour-
less flake-shaped crystals were formed, at ꢁ20 °C, within
a few days.
(
SIR92) [6] and refined using full-matrix least-squares
SHELXL97) [7] on all reflections,
calculations on F2
(
both programs operating under the WINGX program
package [8]. Anisotropic thermal displacement parame-
ters were refined for all non-hydrogen atoms; the
hydrogen atoms were included as a riding contribution
except for those of the amine groups which were located
from difference maps and refined with fixed isotropic
thermal parameters. Structural illustrations have been
drawn with ORTEP-3 for Windows [9] under WINGX [8]
(Figs. 2 and 3).
2.3. Preparation of [CuBr(CH3CN)
{l-C6H4(NH2)2}] (2)
1
Copper(I) bromide (0.150 g, 1.05 mmol) was dis-
solved in acetonitrile (8 ml) in a Schlenk tube. 1,2-
Phenylenediamine (0.094 g, 0.87 mmol) was dissolved
in acetonitrile (4 ml) and added to the solution of cop-
per(I) bromide. Small colourless flake-shaped crystals
of 2 were deposited, almost immediately, from a brown
solution.
For 1, refinement of 132 parameters based on all 2752
reflections yielded R1 = 0.051 and wR2 = 0.118 for
I > 2r(I) (1344 reflections) and R1 = 0.086 and
wR2 = 0.133 for all reflections; maximum ꢁa3nd minimum
˚
residual electron density: 0.60; ꢁ0.54 e A
.
For 2, refinement of 132 parameters based on all 2605
reflections yielded R1 = 0.045 and wR2 = 0.109 for
I > 2r(I) (1887 reflections) and R1 = 0.065 and
2.4. X-ray crystallography
wR2 = 0.115 for all reflections; maximum ꢁa3nd minimum
Crystal and experimental data are summarised in
Table 1. Crystals of 1 and 2 were mounted in glass cap-
illaries and transferred to a Rigaku R-AXIS IIc diffrac-
tometer. Diffracted intensities were measured at ambient
temperature, using graphite-monochromated Mo Ka
radiation (k = 0.71073 A) from a RU200 rotating anode
operated at 50 kV and 90 mA. Ninety oscillation photo-
graphs with a rotation angle of 2° were collected and
˚
residual electron density: 0.61; ꢁ0.94 e A
.
3. Results and discussion
˚
The polymeric chains of 1 and 2, depicted in Figs. 2
and 3, respectively, differ from the 1,4-phenylenedi-

B. Gustafsson et al. / Inorganica Chimica Acta 358 (2005) 1327–1330
1329
C8
C7
N3
N1
N2
Cu1
Cl1
C1
C2
C6
C3
C4
C5
Fig. 2. View of the [CuCl(CH3CN){l-C6H4(NH2)2}] chain in 1, showing the crystallographic numbering. Thermal ellipsoids enclose 50%
1
probability. Hydrogen atoms have been omitted.
Copper(I) exhibits distorted tetrahedral coordination
geometry (see Table 2) and the terminal Cu–Cl bond of
˚
2.241(1) A lies within the range observed for non-
bridged chloride ligands in a tetrahedral copper(I) coor-
C4
C5
dination environment [1,10]. It is, however, appreciably
shorter than that determined for the monomeric com-
plex bis[tris(4-aminophenyl)amine](acetonitrile)chloro-
C3
C6
˚
copper(I), viz. 2.341(2) A [4a]. The Cu–N(amine)
distances are similar to those in catena-l-chloro-l-1,4-
phenylenediamine(acetonitrile)copper(I) and in bis-
[tris(4-aminophenyl)amine](acetonitrile)chlorocopper(I)
[4a]. As in the two aforementioned compounds, the Cu–
N(amine) distances are longer than Cu–N(acetonitrile),
owing to delocalisation of the lone-pair on the amine
donors over the phenyl ring, causing the amine nitrogen
ligands to act as poorer donors in comparison with the
C2
C1
Br1
N2
N1
Cu1
N3
Table 2
˚
Selected bond distances (A) and angles (°) for [CuCl(CH3CN){l-
C7
C6H4(NH2)2}] (1) and [CuBr(CH3CN){l-C6H4(NH2)2}] (2)
1
1
1
2
Cu(1)–N(1)
Cu(1)–N(2)i
Cu(1)–N(3)
Cu(1)–Cl(1)
N(1)–C(1)
N(2)–C(2)
N(3)–C(7)
C(7)–C(8)
2.146(3)
2.213(4)
1.980(4)
2.241(1)
1.413(4)
1.412(5)
1.124(5)
1.434(6)
Cu(1)–N(1)
Cu(1)–N(2)i
Cu(1)–N(3)
Cu(1)–Br(1)
N(1)–C(1)
N(2)–C(2)
N(3)–C(7)
C(7)–C(8)
2.132(3)
2.224(3)
1.972(4)
2.385(1)
1.427(4)
1.420(5)
1.130(5)
1.443(6)
C8
Fig. 3. View of the asymmetric unit in [CuBr(CH3CN){l-
C6H4(NH2)2}] (2), showing the crystallographic numbering. Thermal
1
ellipsoids enclose 50% probability.
N(1)–Cu(1)–N(2)i
N(1)–Cu(1)–N(3)
N(2)i–Cu(1)–N(3)
N(1)–Cu(1)–Cl(1)
N(2)–Cu(1)–Cl(1)
N(3)–Cu(1)–Cl(1)
Cu(1)–N(3)–C(7)
N(3)–C(7)–C(8)
95.2(1)
104.8(1)
96.4(2)
N(1)–Cu(1)–N(2)i
N(1)–Cu(1)–N(3)
N(2)i–Cu(1)–N(3)
N(1)–Cu(1)–Br(1)
N(2)i–Cu(1)–Br(1)
N(3)–Cu(1)–Br(1)
Cu(1)–N(3)–C(7)
N(3)–C(7)–C(8)
97.2(1)
107.2(1)
97.2(1)
amine counterpart with copper(I) chloride, catena-
l-chloro-l-1,4-phenylenediamine(acetonitrile)copper(I),
[Cu2(l-Cl)2(CH3CN)2{l-C6H4(NH2)2}] [4a], in that
1
119.6(1)
109.3(1)
124.9(1)
160.9(3)
178.5(5)
116.4(1)
109.5(1)
124.2(1)
159.2(3)
178.5(5)
bridging in 1 and 2 is effected solely by 1,2-phenylen-
ediamine and not by halide. Consequently, the
CuX(CH3CN): {C6H4(NH2)2} stoichiometry is 1:1 in
compounds 1 and 2, but 2:1 in [Cu2(l-Cl)2(CH3CN)2-
{l-C6H4(NH2)2}] [4a].
Symmetry code (i): 1 ꢁ x, 1/2 + y, 1/2 ꢁ z.
1

1330
B. Gustafsson et al. / Inorganica Chimica Acta 358 (2005) 1327–1330
acetonitrile nitrogen. Similar features are to be found in
the isostructural bromo counterpart (2), as is apparent
from Table 2.
the Cambridge Crystallographic Data Centre as supple-
mentary publication Nos. CCDC 251238 for 1 and
CCDC 251239 for 2. Copies of the data can be obtained,
free of charge, on application to CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK (fax: +44 1223
336033 or e-mail: deposit@ccdc.cam.ac.uk).
The chains in 1 are interconnected by very short
˚
Clꢀ ꢀ ꢀH interactions of 2.33(4) and 2.59(4) A associated
with the hydrogen atoms on N(1), viz. H(1a) and
H(1b), leading to the formation of layers perpendicular
to the a-axis. In 2, the analogous Brꢀ ꢀ ꢀH distances are
˚
2.59(4) and 2.76(4) A. In the context of hydrogen bonds
Acknowledgements
involving terminal halide bonded to a metal, ‘‘short’’ has
˚
been defined as 62.52 A [11]. It has been demonstrated
Financial support from the Swedish Research Coun-
cil (Natural and Engineering Sciences, VR-NT), from
the National Research Foundation of South Africa
(NRF) and from Sida/NRF (Sweden–South Africa
Bilateral Programme, Project SRP-2001-040) is grate-
fully acknowledged.
that such terminal M–Xꢀ ꢀ ꢀH interactions are appreciably
stronger than their C–Xꢀ ꢀ ꢀH counterparts, owing to the
enhanced acceptor properties of terminally metal-bound
halogen [11,12]. Indeed, C–Xꢀ ꢀ ꢀH interactions are prob-
ably generally best regarded as being of van der Waals
type [13]. The stronger, unconventional hydrogen bond
interaction involving halides, such as chloride and bro-
mide, is considered to play an important role in crystal
engineering and supramolecular chemistry [12].
References
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2319.
Unlike
(acetonitrile)copper(I) [4a], both 1 and 2 are stable with
respect to loss of acetonitrile. In [Cu2(l-Cl)2-
catena-l-chloro-l-1,4-phenylenediamine-
[2] See for example: (a) G.A. Bowmaker, P.C. Healy, D.L. Kepert,
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1
Clꢀ ꢀ ꢀH contacts are between the bridging chloride (there
are no terminal chloride ligands) and the hydrogen
atoms of the amine group. Thus, there are no Cu–
Clꢀ ꢀ ꢀH interactions involving the hydrogen atoms of
the acetonitrile ligand. The Cu–Clꢀ ꢀ ꢀH interactions with
the amine hydrogen atoms lead to the formation of
layers which are, in turn, stacked so as to give rise to
channels extending through the structure, parallel to
the c-axis. It is within these channels that the acetonitrile
molecules reside and from which their release is, conse-
quently, unrestricted.
In the present structures, 1 and 2, short Cu–Xꢀ ꢀ ꢀH
interactions lead, as described above, to the formation
of layers, within which acetonitrile is firmly embedded,
wedged between phenyl groups. In addition to the ab-
sence of channels in the structures, there are terminal
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(X = Br) to acetonitrile hydrogen atoms. Both the ab-
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these compounds to lose acetonitrile.
[7] G.M. Sheldrick, SHELX97 (Release 97-2), Institut fur Anorgani-
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4. Supplementary material
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Crystallographic data (excluding structure factors)
for the structures in this paper have been deposited with