Copper(I) halide complexes with N,N′-diallyl-N,N,N′,N′- tetramethylethylenediaminium (L2+). Synthesis and crystal structures of the complexes [L0.5CuCl2], [L0.5CuCl 0.72Br1.28], and [L0.5CuBr2]

Article abstract of DOI:10.1134/S1070328411010106

The Eschweiler-Clarke reaction of ethylenediamine with formaldehyde and formic acid yielded N,N,N′,N′-tetramethylethylenediamine, which was alkylated with allyl chloride or allyl bromide to give the corresponding N,N′-diallyl-N,N,N′,N′-tetramethylethylenediaminium (L ²⁺) dihalides. In methanolic solutions of copper(II) halide and an appropriate ligand, ac electrochemical synthesis with copper wire electrodes afforded single crystals of Cu(I) complexes with L²⁺: [L _0.5CuCl₂] (I), [L_0.5CuCl_0.72Br _1.28] (II), and [L_0.5CuBr₂] (III). The crystal structures of complexes I-III were determined by X-ray diffraction study. The isostructural crystals of I and II are monoclinic, space group P2₁/n, Z = 4. For I: a = 7.632(4) A, b = 11.318(5) A, c = 10.635(5) A, β = 98.551(7)°, V = 908.4(7) A³. For II: a = 7.7415(7) A, b = 11.4652(9) A, c = 10.7267(10) A, β = 98.351(4)°, V = 942.0(2) A³. The organic cation L ²⁺ acts as a bridge linking a pair of separate cuprous halide fragments Cu₂X₄. Although being isostoichiometric with I and II, complex III has a different structure. The crystals of III are monoclinic, space group P2₁/c, a = 6.519(2) A, b = 9.060(3) A, c = 16.284(6) A, β = 97.219(4)°, V = 954.2(6) A³, Z = 4. In structure III, the inorganic fragment forms infinite polymer chains (CuBr ₂ ^- ) _n . The organic and inorganic parts are held together only by electrostatic interactions. Structures I-III are stabilized by hydrogen bonds (C)H...X (2.6-2.9 A).

Full text of DOI:10.1134/S1070328411010106

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2011, Vol. 37, No. 2, pp. 143–148. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © M.M. Monchak, E.A. Goreshnik, M.G. Mys’kiv, 2011, published in Koordinatsionnaya Khimiya, 2011, Vol. 37, No. 2, pp. 145–150.
Copper(I) Halide Complexes with N,N'ꢀDiallylꢀN,N,N',N'ꢀ
Tetramethylethylenediaminium (L2+). Synthesis and Crystal
Structures of the Complexes [L0.5CuCl2], [L0.5CuCl0.72Br1.28],
and [L0.5CuBr2]
,
M. M. Monchaka, E. A. Goreshnikb, and M. G. Mys’kiva *
a Ivan Franko National University, ul. Kirila i Mefodiya 6, Lviv, 790005 Ukraine
b Jozef Stefan Institute, Ljubljana, Slovenia
*Eꢀmail: myskiv@franko.lviv.ua
Received July 1, 2010
Abstract—The Eschweiler–Clarke reaction of ethylenediamine with formaldehyde and formic acid yielded
N,N,N',N'ꢀtetramethylethylenediamine, which was alkylated with allyl chloride or allyl bromide to give the
corresponding N,N'ꢀdiallylꢀN,N,N',N'ꢀtetramethylethylenediaminium (L2+) dihalides. In methanolic soluꢀ
tions of copper(II) halide and an appropriate ligand, ac electrochemical synthesis with copper wire electrodes
afforded single crystals of Cu(I) complexes with L2+: [L0.5CuCl2] (
I
), [L0.5CuCl0.72Br1.28] (II), and
[L0.5CuBr2] (III). The crystal structures of complexes
isostructural crystals of and II are monoclinic, space group
11.318(5) Å, = 10.635(5) Å, = 98.551(7)°,
= 908.4(7) Å3. For II
= 10.7267(10) Å, = 98.351(4)°,
separate cuprous halide fragments Cu2X4. Although being isostoichiometric with
different structure. The crystals of III are monoclinic, space group 21/ = 6.519(2) Å,
I–III were determined by Xꢀray diffraction study. The
I
P21/n
,
Z
a
= 4. For
= 7.7415(7) Å, b
I:
a
= 7.632(4) Å,
b =
c
β
V
:
= 11.4652(9) Å,
c
β
V
= 942.0(2) Å3. The organic cation L2+ acts as a bridge linking a pair of
I
and II, complex III has a
= 9.060(3) Å,
P
c
,
a
b
c =
16.284(6) Å, = 97.219(4)°, V Z = 4. In structure III, the inorganic fragment forms infinite
= 954.2(6) Å3,
β
polymer chains (CuBr2–)n. The organic and inorganic parts are held together only by electrostatic interacꢀ
...
tions. Structures I–III are stabilized by hydrogen bonds (C)H X (2.6–2.9 Å).
DOI: 10.1134/S1070328411010106
T, °C
Our previous investigations have dealt with the synꢀ
thesis and Xꢀray diffraction study of copper complexes
with N,N,N,N',N',N'ꢀhexaallylethylenediaminium
(CH3)2NC2H4N(CH3)2 + 4CO2 + 4H2O.
Formaldehyde (35% solution, 38 ml) and 90% forꢀ
mic acid (52 ml) were added to ethylenediamine
(6.65 ml, 6.0 g). The reaction mixture was refluxed on
a water bath. After vigorous evolution of СО2 ceased,
the heating was continued for several hours (the total
time of the synthesis was ~11 h). Then an excess of
36% HCl (18 ml) was added; the unreacted formaldeꢀ
hyde and formic acid were removed. The free ligand
was liberated from its hydrochloride by adding an
excess of concentrated aqueous KOH to the residue
and extracted with benzene. The solvent and other
volatile impurities were removed to give virtually pure
ligand L in ~80% yield, which then was distilled under
reduced pressure (40 mmHg/80°C).
(L
6) – [{L6}0.5Cu2Br3] [1], N,N,N,N',N'ꢀpentaallylꢀ
ethylenediaminium
(
L
5) – [L5(H+)Cu4Br6]
L4
, and
N,N,N',N'ꢀtetraallylethylenediaminium
(
)
–
[{L4(H+)2}0.5Cu2Cl3] [2]. To understand better the
complexation between Nꢀallyl derivatives of ethyleneꢀ
diamine and copper(I) halides, here we obtained
Cu(I) complexes with N,N'ꢀdiallylꢀN,N,N',N'ꢀtetꢀ
ramethylethylenediaminium (
[L0.5CuCl0.72Br1.28] (II), and [L0.5CuBr2] (III
L
2+) – [L0.5CuCl2] (
) and
I),
)
examined their structures using Xꢀray diffraction.
EXPERIMENTAL
N,N'ꢀDiallylꢀN,N,N',N'ꢀtetramethylethylenediꢀ
aminium dichloride LCl2 was obtained from L and
allyl chloride in a molar ratio of 1 : 2.2. The reaction
mixture was refluxed in benzene with vigorous stirring
for 17 h. The resulting white precipitate of the ligand
was filtered off.
Synthesis.
N,N,N',N'ꢀTetramethylethylenediꢀ
amine ( ) was prepared by the Eschweiler–Clarke
L
reaction of ethylenediamine with formaldehyde and
formic acid according to a general procedure for the
synthesis of tertiary amines from primary or secondary
ones [3]:
N,N'ꢀDiallylꢀN,N,N',N'ꢀtetramethylethylenediꢀ
aminium dibromide LBr2 was obtained from L and
H2NC2H4NH2 + 4CH2O + 4HCOOH
143

144
MONCHAK et al.
y
z
C(6)
x
Cl(2)
C(5)
C(3)
C(2)
N
C(1)
Cu
H
C(4)
Cl(1)
Fig. 1. Bridging function of N,N'ꢀdiallylꢀN,N,N',N'ꢀtetramethylethylenediaminium in structure
CuꢀCl(2), 2.242(2) Å; Cuꢀ
bond).
I
: CuꢀCl(1), 2.261(2) Å;
m
*, 1.953(1) Å; C(4)CuC(3), 38.6(2)°; C(3)
⎯
C(4), 1.368(9) Å (
m
* is the midpoint of the C(3) C(4)
⎯
allyl bromide in a molar ratio of 1 : 2.2. Because the deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.
reaction is exothermic, allyl bromide was slowly added uk).
dropwise. The reaction mixture was refluxed in benꢀ
zene with vigorous stirring for 10 h. The resulting
white precipitate of LBr2 was filtered off.
RESULTS AND DISCUSSION
Colorless prismatic crystals of complexes I and II
In the isostructural crystals of complexes I and II,
were obtained by an ac electrochemical synthesis [4]
with copper wire electrodes in methanolic solutions of
CuCl2 · 2H2O containing LCl2 or LBr2, respectively.
both allyl groups of N,N'ꢀdiallylꢀN,N,N',N'ꢀtetrameꢀ
thylethylenediaminium are ꢀcoordinated by the copꢀ
π
per atoms (Fig. 1). The structure contains a cenꢀ
trosymmetric inorganic island fragment Cu2X4. The
coordination polyhedron of copper(I) is a trigonal
pyramid with two halogen atoms and the allyl С=С
bond the alkyl group of ligand L2+ in the base and an
apical halogen atom. The length of the coordinated
Crystals of complex I grew after 24 h. Small crystals of
complex II formed after three days grew up to a
required size for three weeks.
Colorless prismatic crystals of complex III were
obtained by an ac electrochemical synthesis with copꢀ
per wire electrodes in a methanolic solution of CuBr2
and LBr2 for three days. The crystals grew up to a
required size for three and half weeks.
C=C bond is 1.368(9) Å in I and 1.364(9) Å in II. Earꢀ
lier, the fragment Cu2X4 has been found in copper
complexes with asymmetric alkyl derivatives of ethylꢀ
enediamine: [(CH3)2NC2H4NH(CH3)Cu2IICl4] [9] and
Xꢀray diffraction analysis. After a preliminary phoꢀ
tometric study, structures I–III were identified using
arrays of reflection intensities collected on a Rigaku
AFC7R singleꢀcrystal diffractometer (CCD detector,
[
(C2H5)2NC2H4NH(C2H5)Cu2IICl4] [10], as well as
with allyl onium derivatives of aliphatic amines [11,
2−
12]. The anion
is also contained in a copper
Cu2Br4
Mo
K
radiation, graphite monochromator,
ω
scan
α
π
ꢀcomplex with N,N,N,N',N',N'ꢀhexaallylethyleneꢀ
mode, a lowꢀtemperature attachment) and corrected
for the Lorentz and polarization factors. The data
obtained were processed with the Rigaku CrystalClear
program package [5]. Structures I–III were solved by
the direct methods. Light atoms were located from difꢀ
ference electronꢀdensity maps. An absorption correcꢀ
diaminium bromide, [{L6}0.5CuBr2] [13]. In other copꢀ
per complexes with tetraꢀ (L4), pentaꢀ (L5), and
hexaallylethylenediamines (L6), the inorganic fragꢀ
ment has a more complicated structure: either an
islandꢀtype structure (but with a different composiꢀ
tion) as in [{L4(H+)2}0.5Cu2Cl3] [2] or a polymeric one
tion was applied analytically [6]. Structures
solved with the SIRꢀ92 program [7] and refined with
I–III were
as in [L5(H+)Cu4Br6] [1] and [{L6}0.5Cu2Br3] [2]. The
the SHELX program package [8]. All hydrogen atoms C=C bonds of the allyl groups of the organic cation
L2+ in complexes
I and II are coordinated by the metal
were located geometrically. Crystallographic parameꢀ
2−
ters and the data collection statistics for structures I–
atoms of two anions
Thus, the ligand acts as a
Cu2X4 .
III are summarized in Table 1. Selected bond lengths
bridge, which is also characteristic of other allyl derivꢀ
atives of ethylenediamine [1, 2]; in contrast,
and bond angles are given in the figure captions.
The atomic coordinates and other parameters of N,N,N',N'ꢀtetramethylethylenediamine forms cheꢀ
complexes
bridge
I
–
III have been deposited with the Camꢀ late complexes with copper(I) halides [14]. Structures
Crystallographic Data Collection and II are built from infinite chains of interconꢀ
I
(nos. 780362, 780363, and 780364, respectively; nected cations and anions (Fig. 2). The chains are
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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2011

COPPER(I) HALIDE COMPLEXES
145
Table 1. Crystallographic parameters and the data collection statistics for structures I–III
Value
Parameter
I
II
III
Empirical formula
М
C6H13NCl2Cu
233.62
C6H13NCl0.72Br1.28Cu
290.52
C6H13NBr2Cu
322.52
Crystal size, mm
Temperature, K
Space group
0.13
×
0.07
296
×
0.06
0.12
×
0.10
200
×
0.09
0.1
×
0.07
200
×
0.06
P
21/n
P
21/n
P21/c
Unit cell parameters
:
a
, Å
, Å
, Å
, deg
Å3
7.632(4)
7.7415(7)
11.4652(9)
10.7267(10)
98.351(4)
942.0(2)
4
6.519(2)
9.060(3)
16.284(6)
97.219(4)
954.2(6)
4
b
11.318(5)
10.635(5)
98.551(7)
908.4(7)
4
c
β
V
,
Z
ρcalcd, g/cm3
ρexp, g/cm3
1.708
2.048
2.245
1.70
2.04
2.23
μ
, mm–1
2.92
7.90
10.60
F(000)
476
567.8
620
Ranges of h, k, and l indices
–9 <
h
< 10
–7 <
h
< 10
–8 < h < 6
–14 <
–13 <
k
< 9
–15 <
k
< 15
< 8
–11 <
–21 <
k
< 6
l
< 11
–13 <
l
l
< 20
Rint
0.049
4007
1485
91
0.037
3966
1590
93
0.039
4190
1699
92
Number of measured reflections
Number of reflections with
Number of parameters refined
θmах, deg
F
> 4 (F)*
σ
2
58.0
58.0
58.4
2
2
2
2
2
2
2
2
2
[σ
(Fo) + (0.0743
P
)
[σ
(Fo) + (0.052
P
)
[σ
(Fo) + (0.0392
P)
Weighting scheme**
F2)(F > 4
))
–1
+ 1.886P –1
]
+ 1.5641
P]
+ 0.7846P –1
]
R(
σ
(
F
0.070
0.1645
0.054
0.135
1.11
0.043
0.098
wR
GООF
1.12
1.18
Δρmax/Δρmin
,
e
Å–3
0.67/–0.63
0.83/–0.97
0.76/–1.01
* A correction for the Lorentz and polarization factors was applied.
** P = (F2o + 2F2c)/3.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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2011

146
MONCHAK et al.
H
Cl
N
Cu
C
y
z
x
Fig. 2. Fragment of structure I.
united, both within a layer and between adjacent layꢀ
ers, through a branched system of hydrogen bonds allyl groups are not
(С)Н⋅⋅⋅ (Table 2). atoms. A similar pattern has been noted for Nꢀallyl
Complex III has a different structure (Fig. 3). The
π
ꢀcoordinated by the copper(I)
Х
Table 2. Geometrical parameters of the hydrogen bonds in structures I–III
Bond lengths
⋅⋅⋅
,
Å
D–H⋅⋅⋅A angle,
Contact D–H⋅⋅⋅
A
Coordinates of atom A
deg
D–H
H
A
D⋅⋅⋅A
I
C(1)–H(12)⋅⋅⋅Cl(2)
C(2)–H(22)⋅⋅⋅Cl(1)
C(5)–H(52)⋅⋅⋅Cl(1)
C(6)–H(61)⋅⋅⋅Cl(1)
C(6)–H(63)⋅⋅⋅Cl(2)
0.97
0.97
0.96
0.96
0.96
2.81
2.86
2.61
2.77
2.73
3.71(2)
3.73(1)
3.53(2)
154
149
161
174
144
2.5 –
–1 +
2.5 –
x
, –0.5 +
y
, 0.5 –
z
x, y, z
x
, –0.5 +
, 0.5 –
, 1 –
y
, 0.5 –
, 0.5 +
z
z
3.72(2)
3.55(1)
–0.5 + x
y
2 –
x
x
y, 1 –
z
II
C(5)–H(53)⋅⋅⋅Cl(2)
C(6)–H(62)⋅⋅⋅Br(1)
C(2)–H(22)⋅⋅⋅Cl(2)
C(1)–H(12)⋅⋅⋅Br(1)
0.96
0.96
0.97
0.97
2.87
2.88
2.94
2.91
3.68(2)
3.82(2)
3.80(1)
3.81(2)
142
167
149
155
1 +
, y, z
0.5 +
1 +
1.5 –
x, 1.5 –
y, –0.5 +
z
z
x,
y
,
z
x, –0.5 +
y, 0.5 –
III
C(1)–H(12)⋅⋅⋅Br(2)
C(1)–H(11)⋅⋅⋅Br(2)
C(2)–H(22)⋅⋅⋅Br(1)
C(5)–H(53)⋅⋅⋅Br(1)
0.97
0.97
0.97
0.96
2.89
2.94
3.01
2.83
3.82(2)
3.85(2)
3.86(1)
3.74(2)
161
156
147
159
x, y, z
1 +
x,
y
,
,
,
z
z
z
x
, 1 +
, 1 +
y
y
x
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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COPPER(I) HALIDE COMPLEXES
147
C(3)
C(2)
C(5)
C(4)
C(1)
H(11)
N
C(6)
H(12)
H(53)
Br(2)i
Br(2)
Br(1)i
Cu
Br(1)
Br(2)ii
Fig. 3. Geometry of the coordination entity in structure III: Cu Br(1), 2.487(2) Å; Cu
⎯
⎯
Br(2), 2.512(2) Å; Cu⎯
Br(1)i,
2.520(2) Å; Cu + 1, y, ⎯z + 1).
⎯
Br(2)ii, 2.523(2) Å (i + 1; ii
⎯
x
⎯
y,
⎯
z
⎯
x,
⎯
C
N
H
Br
Cu
y
z
x
Fig. 4. Fragment of structure III
.
derivatives of piperazinium, in which even the partial (Fig. 4). Structure III contains the polymeric inorꢀ
presence of a Br atom in the environment of Cu(I)
precludes the formation of the bond Cu(I)–(C=C)
[15, 16]. The organic and inorganic parts in structure
CuBr−
ganic anion
which is similar to that in copꢀ
,
(
)
2
n
per(I) complexes with the ethylenediaminium cation
III are held together by electrostatic interactions [2]. The tetrahedral environment of the copper
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
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148
MONCHAK et al.
7. Altomare, A., Cascarano, G., Giacovazzo, C., et al., J.
Appl. Crystallogr., 1994, vol. 27, p. 435.
atom consists of bromine atoms (Cu–Br, 2.487(2)–
2.523(2) Å). The determining role in structure III is
played by hydrogen bonds С(Н)⋅⋅⋅Х (Table 2) which
8. Sheldrick, G.M., SHELXSꢀ97 and SHELXLꢀ97. Proꢀ
gram for the Solution and Refinement of Crystal Strucꢀ
tures, Göttingen (Germany): Univ. of Göttingen, 1997.
crosslink the organic and inorganic parts of the strucꢀ
ture, thus ordering the arrangement of the methyl and
allyl groups of the cation L2+
.
9. Marsh, W.E., Patel, K.C., Hatfield, W.E., and Hodgꢀ
son, D.J., Inorg. Chem., 1983, vol. 22, no. 3, p. 511.
10. Johansson, A., Wingstrand, E., and Hakansson, M.,
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