Diamminebis(2,4,6-tribromophenolato-O)copper(II)

Article abstract of DOI:10.1107/S0108270100003966

The title compound, [Cu(C₆H₂Br₃O)₂(NH₃)₂], a monomeric centrosymmetric Cu^II complex, crystallizes in the monoclinic system. The CuO₂N₂ coordination sphere in trans planar, [Cu-O 1.943 (5) angstroms and Cu-N 1.977 (6) angstroms], with the fifth and sixth coordination sites occupied by Br atoms from the phenoxide ions [Cu-Br 3.129 (1) angstroms], resulting in an elongated distorted octahedral structure for the CuO₂N₂Br₂ coordination. Each of the NH₃ groups forms two hydrogen bonds with the Br and O atoms of the CuO₂N₂Br₂ moiety of a neighbouring molecule. This arrangement constitutes a one-dimensional chain along the x axis of the unit cell.

Full text of DOI:10.1107/S0108270100003966

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
ISSN 0108-2701
Diamminebis(2,4,6-tribromophenol-
ato-O)copper(II)
Figure 1
a
b
a
ORTEP-3 for Windows (Farrugia, 1997) drawing of (I) with the atom-
numbering scheme. Displacement ellipsoids are drawn at the 50%
probability level and H atoms are shown as small circles of arbitrary radii.
Symmetry code as in Table 1.
È
Leyla Tatar, * Gulsun GokagÆac and DincËer Ulku
È
È È
È
aHacettepe University, Department of Engineering Physics, Beytepe 06532, Ankara,
Turkey, and bMiddle East Technical University, Department of Chemistry, 06531
Ankara, Turkey
Correspondence e-mail: tatar@lidya.cc.hun.edu.tr
affects the coordination sphere around the transition metal. In
the isostructural complexes, the Cu atom is located in the
inversion centre at the origin. The coordination around the Cu
atom is a tetragonally elongated octahedron, involving
centrosymmetrically related O and N atoms from two THP
molecules in the equatorial plane and with Br atoms as a
secondary interaction in the axial positions. In (I), the bond
lengths CuÐN, CuÐO and CuÐBr are 1.977 (6), 1.943 (5)
Received 27 January 2000
Accepted 10 March 2000
The title compound, [Cu(C6H2Br3O)2(NH3)2], a monomeric
centrosymmetric CuII complex, crystallizes in the monoclinic
system. The CuO2N2 coordination sphere is trans planar,
Ê
Ê
[CuÐO 1.943 (5) A and CuÐN 1.977 (6) A], with the ®fth and
sixth coordination sites occupied by Br atoms from the
Ê
and 3.129 (1) A, respectively. The bond angles NÐCuÐO
Ê
phenoxide ions [CuÐBr 3.129 (1) A], resulting in an elon-
[89.1 (2)ꢁ], NÐCuÐOi [90.9 (2)ꢁ; symmetry code: (i) x, y,
z], BrÐCuÐN [87.1 (2)ꢁ] and BrÐCuÐO [70.9 (2)ꢁ] indi-
cate that the tetragonally elongated octahedron is distorted.
The BrÐBri axis has a more noticeable tilt towards the CuÐO
bond than towards the CuÐN bond. These bond lengths and
angles are very similar to the corresponding values observed
in the isostructural complex where Br atoms are replaced by
Cl atoms. On the other hand, in the Co complex mentioned
gated distorted octahedral structure for the CuO2N2Br2
coordination. Each of the NH3 groups forms two hydrogen
bonds with the Br and O atoms of the CuO2N2Br2 moiety of a
neighbouring molecule. This arrangement constitutes a one-
dimensional chain along the x axis of the unit cell.
Comment
Several complexes of CuL2(THP)2 have been utilized to
synthesize poly(dihalophenylene oxide) using either thermal
polymerization or electro-initiation in solution as well as in the
solid state (L = pyridine or ethylenediamine, THP = 2,4,6-
trichlorophenolato, 2,4,6-tribromophenolato, 4-chloro-2,6-di-
È
bromophenolato or 4-¯uoro-2,6-dibromophenolato; BasËturk-
men et al., 1993; Kõsakurek et al., 1998; SËanlõ et al., 1995;
È
Toppare et al., 1990). Halogenated poly(phenylene oxides)
exhibit interesting mechanical, electrical and thermal proper-
ties, such as ®re resistivity. Investigations have showed that L,
the halogens and their positions in the complex affect the
mechanism of polymerization (Pulat et al., 1994). The title
complex, (I), has been prepared and its crystal structure
studied in order to obtain a better understanding of the
polymerization process.
We have previously reported the structures of other
complexes of this type, namely [Co(C6H2Br3O)2(C5H5N)2]
È
È
È
Æ
(Ulku et al., 1997) and [Cu(C6H2Cl3O)2(NH3)2] (Gokagac et
al., 1999). The latter complex is isostructural with (I) but not
with the former. Using a different nitrogen-donor ligand
Figure 2
PLATON99 (Spek, 1990) drawing illustrating the hydrogen bonding in
(I).
ꢀ
668 # 2000 International Union of Crystallography
Printed in Great Britain ± all rights reserved
Acta Cryst. (2000). C56, 668±669

metal-organic compounds
Table 2
Hydrogen-bonding geometry (A, ).
above, the coordination around the Co atom is a distorted
tetrahedron.
ꢁ
Ê
The dihedral angle between the equatorial plane (N/O/Ni/
Oi) around the Cu atom and the six-membered bromophenol
ring (C1±C6) is 82.6 (2)ꢁ. This is similar to the corresponding
value of 81.7 (1)ꢁ observed in the Cu±trichlorophenol
complex. The CÐC bond lengths in the tribromophenol ligand
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
NÐH11Á Á ÁOi
0.96
0.86
2.06
2.85
2.976 (7)
3.648 (6)
159
157
NÐH13Á Á ÁBr3ii
Symmetry codes: (i)
1
x; y; z; (ii) x 1; y; z.
Ê
have values between 1.37 (1) and 1.40 (1) A, which indicates
delocalization of the double bonds (Csp2ÐCsp2) within the
tribromophenol ring.
Crystal data
3
[Cu(C6H2Br3O)2(NH3)2]
Mr = 757.2
Dx = 2.573 Mg m
Cu Kꢁ radiation
Intermolecular hydrogen bonds exist between the H atoms
of the NH3 group and one of the Br atoms of one 2,4,6-tri-
bromophenol ligand, as well as the O atom of the second 2,4,6-
tribromophenol ligand. The two ligands are trans to each
other. This constitutes a one-dimensional chain along the [100]
direction, where neighbouring centrosymmetric molecules are
linked through four intermolecular hydrogen bonds, keeping
the structure together. Hydrogen bonds were calculated with
PLATON99 (Spek, 1990). Details of the hydrogen-bonding
geometry are given in Table 2. The closest contacts between
Monoclinic, P21=n
Cell parameters from 25
re¯ections
Ê
a = 4.8249 (5) A
b = 13.0267 (16) A
ꢂ = 12.89±42.94ꢁ
Ê
1
Ê
c = 15.5518 (11) A
ꢃ = 16.02 mm
T = 295 K
ꢀ = 90.766 (7)ꢁ
3
Ê
V = 977.4 (1) A
Z = 2
Prismatic, dark brown
0.10 Â 0.10 Â 0.08 mm
Data collection
Enraf±Nonius CAD-4 diffract-
ometer
!/2ꢂ scans
Absorption correction: empirical
via scans (Fair, 1990)
Tmin = 0.239, Tmax = 0.301
2330 measured re¯ections
1979 independent re¯ections
1662 re¯ections with I > 2ꢄ(I)
Rint = 0.030
ꢂmax = 74.3ꢁ
h = 0 ! 6
Ê
k = 16 ! 0
the chains are between CuÐH11(1 + x, y, z) [3.1217 (2) A]
1
l = 19 ! 19
1
2
and Br1ÐH5(12 x,
+ y,
Ê
z) [3.1357 A]. High residual
2
3 standard re¯ections
frequency: 120 min
intensity decay: 0.05%
Ê
electron-density regions were observed within 0.9 A of the Br
atoms.
Re®nement
Re®nement on F
R = 0.045
wR = 0.057
S = 1.00
1662 re¯ections
106 parameters
H-atom parameters constrained
w = 1/[ꢄ2(F) + (0.02F)2 + 0.64]
(Á/ꢄ)max < 0.001
Experimental
3
Ê
An aqueous solution (25 ml) of sodium 2,4,6-tribromophenolate was
prepared by mixing excess NaOH (0.21500 g, 0.00537 mol) dissolved
in water (10 ml) with 2,4,6-tribromophenolate (0.87384 g,
0.00264 mol) in water (15 ml). This solution was added dropwise to a
concentrated aqueous solution (5 ml) of CuSO4 (0.21073 g,
0.00132 mol) with stirring. Initially, the formation of a light-brown
precipitate was observed. The precipitate colour then turned to light
blue after addition of all of the 2,4,6-tribromophenolate solution.
Concentrated ammonia (5.2 ml, 0.06947 mol) and water (60 ml) were
added to this mixture until the light-blue precipitate dissolved to give
a clear dark-blue solution. Upon leaving this solution on the bench
for several days, dark-brown precipitates were formed. These crystals
were collected, washed with a small amount of cold water, dried in a
vacuum overnight and used for X-ray data collection. Elemental
analysis found for C12H10Br6CuN2O2: C 19.27, H 1.36, N 3.55%;
calculated: C 19.03, H 1.33, N 3.70%.
Áꢅmax = 0.57 e A
3
Ê
1.25 e A
Áꢅmin
=
Data collection: CAD-4 EXPRESS (Enraf±Nonius, 1993); cell
re®nement: CAD-4 EXPRESS; data reduction: MolEN (Fair, 1990);
program(s) used to solve structure: MolEN; program(s) used to re®ne
structure: MolEN; molecular graphics: ORTEP-3 for Windows
(Farrugia, 1997); software used to prepare material for publication:
MolEN and PLATON99 (Spek, 1990).
The authors wish to acknowledge the purchase of the
CAD-4 diffractometer under grant DPT/TBAG1 of the
Scienti®c and Technical Research Council of Turkey.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SK1366). Services for accessing these data are
described at the back of the journal.
References
Table 1
Selected geometric parameters (A, ).
ꢁ
Ê
È
È
BasËturkmen, M., IsËcËi, H. & Kõsakurek, D. (1993). Polym. Int. 30, 387±392.
Enraf±Nonius (1993). CAD-4 EXPRESS. Version 1.1. Enraf±Nonius, Delft,
The Netherlands.
CuÐO
CuÐN
CuÐBr3
Br1ÐC2
1.943 (5)
1.977 (6)
3.129 (1)
1.888 (8)
Br2ÐC4
Br3ÐC6
OÐC1
1.903 (8)
1.909 (7)
1.322 (8)
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È
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Æ
1413±1416.
È
È
NÐCuÐO
NÐCuÐOi
Br3ÐCuÐN
Br3ÐCuÐO
CuÐOÐC1
OÐC1ÐC2
OÐC1ÐC6
89.1 (2)
90.9 (2)
87.1 (2)
70.9 (2)
123.7 (4)
122.1 (7)
123.8 (6)
Br1ÐC2ÐC1
Br1ÐC2ÐC3
Br2ÐC4ÐC3
Br2ÐC4ÐC5
Br3ÐC6ÐC1
Br3ÐC6ÐC5
118.5 (5)
117.9 (6)
118.9 (6)
119.5 (7)
118.4 (5)
117.5 (6)
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Æ
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Ç
È
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È
Symmetry code: (i) x; y; z.
ꢀ
Acta Cryst. (2000). C56, 668±669
Leyla Tatar et al. [Cu(C6H2Br3O)2(NH3)2] 669