Bis(methacrylato-κO)bis-(2,4,6-trimethyl-pyridine-κN)copper(II).

Abstract

In the monomeric title complex, [Cu(C(4)H(5)O(2))(2)(C(8)H(11)N)(2)], the Cu(II) atom lies on a centre of inversion. Its coordination by two substituted pyridine ligands and two carboxyl-ate anions leads to a slightly distorted trans-CuN(2)O(2) square-planar geometry. The dihedral angle between the mean planes of the pyridine (py) ring and the carboxyl-ate group is 74.71 (7)°. The dihedral angles between the planar CuN(2)O(2) core and the py ring and carboxyl-ate plane are 67.72 (5) and 89.95 (5)°, respectively. Based on the refined C=C and C-C bond lengths, the terminal =CH(2) and -CH(3) groups of the carboxyl-ate anion may be disordered, but the disorder could not be resolved in the present experiment. Several intra-molecular C-H⋯O inter-actions occur. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, generating chains propagating in [100].

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Bis(methacrylato-jO)bis(2,4,6-trimethyl-
pyridine-jN)copper(II)
Ejaz,aIslam Ullah Khan,a* Alina Murtazaaand
William T. A. Harrisonb
aMaterials Chemistry Laboratry, Department of Chemistry, GC University, Lahore
54000, Pakistan, andbDepartment of Chemistry, University of Aberdeen, Meston
Walk, Aberdeen AB24 3UE, Scotland
Correspondence e-mail: iuklodhi@yahoo.com
Received 30 September 2011; accepted 6 March 2012
Key indicators: single-crystal X-ray study; T = 296 K; mean ?(C–C) = 0.003 A ˚;
R factor = 0.032; wR factor = 0.098; data-to-parameter ratio = 20.7.
In the monomeric title complex, [Cu(C4H5O2)2(C8H11N)2], the
CuIIatom lies on a centre of inversion. Its coordination by two
substituted pyridine ligands and two carboxylate anions leads
to a slightly distorted trans-CuN2O2square-planar geometry.
The dihedral angle between the mean planes of the pyridine
(py) ring and the carboxylate group is 74.71 (7)?. The dihedral
angles between the planar CuN2O2core and the py ring and
carboxylate plane are 67.72 (5) and 89.95 (5)?, respectively.
Based on the refined C
C and C—C bond lengths, the
terminalCH2and –CH3groups of the carboxylate anion
may be disordered, but the disorder could not be resolved in
the present experiment. Several intramolecular C—H???O
interactions occur.In the crystal,molecules are linked by weak
C—H???O hydrogen bonds, generating chains propagating in
[100].
Related literature
For the crystal structures of related monomeric complexes
containing a trans-CuN2O2 core, see: Borel et al. (1981);
Heimer & Ahmed (1982); Jedrzejas et al. (1994).
Experimental
Crystal data
[Cu(C4H5O2)2(C8H11N)2]
Mr= 476.06
Monoclinic, P21=n
a = 8.2295 (2) A˚
b = 17.0921 (6) A˚
c = 9.1683 (3) A˚
? = 109.220 (1)?
V = 1217.73 (7) A˚3
Z = 2
Mo K? radiation
? = 0.93 mm?1
T = 296 K
0.08 ? 0.06 ? 0.06 mm
Data collection
Bruker APEXII CCD
diffractometer
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
Tmin= 0.930, Tmax= 0.947
11795 measured reflections
3017 independent reflections
2439 reflections with I > 2?(I)
Rint= 0.030
Refinement
R[F2> 2?(F2)] = 0.032
wR(F2) = 0.098
S = 1.05
3017 reflections
146 parameters
H-atom parameters constrained
??max= 0.24 e A˚?3
??min= ?0.21 e A˚?3
Table 1
Selected geometric parameters (A˚,?).
Cu1—O2 1.9406 (12)Cu1—N1 2.0404 (14)
O2—Cu1—N1 91.73 (6)
Table 2
Hydrogen-bond geometry (A˚,?).
D—H???A
C4—H4???O1i
C6—H6A???O1
C6—H6C???O2ii
C8—H8A???O1ii
C8—H8C???O2
Symmetry codes: (i) x þ 1;y;z; (ii) ?x þ 1;?y þ 1;?z þ 1.
D—HH???AD???AD—H???A
0.93
0.96
0.96
0.96
0.96
2.45
2.49
2.48
2.49
2.51
3.338 (2)
3.369 (3)
3.139 (3)
3.357 (3)
3.124 (2)
161
153
126
150
122
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT
(Bruker, 2007); data reduction: SAINT; program(s) used to solve
structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine
structure:SHELXL97 (Sheldrick,
ORTEP-3 (Farrugia, 1997); software used to prepare material for
publication: SHELXL97.
2008);moleculargraphics:
IUK thanks the Higher Education Commission of Pakistan
for its financial support under the project to strengthen the
Materials Chemistry Laboratory at GCUL.
Supplementary data and figures for this paper are available from the
IUCr electronic archives (Reference: RN2095).
metal-organic compounds
Acta Cryst. (2012). E68, m469–m470doi:10.1107/S1600536812009919Ejaz et al.
m469
Acta Crystallographica Section E
Structure Reports
Online
ISSN 1600-5368

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References
Borel, M. M., Busnot, A., Busnot, F., Leclaire, A. & Bernard, M. A. (1981).
Rev. Chem. Mineral. 18, 74–82.
Bruker (2007). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison,
Wisconsin, USA.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
Heimer, N. E. & Ahmed, I. V. (1982). Inorg. Chim. Acta, 65, L65–L66.
Jedrzejas, M.J.,Towns, R. L.R., Baker, R. J.,Duraj,S. A.&Hepp,A.F. (1994).
Acta Cryst. C50, 1442–1443.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
metal-organic compounds
m470
Ejaz et al.
? [Cu(C4H5O2)2(C8H11N)2]
Acta Cryst. (2012). E68, m469–m470

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supplementary materials
sup-1
Acta Cryst. (2012). E68, m469–m470
supplementary materials
Acta Cryst. (2012). E68, m469–m470 [doi:10.1107/S1600536812009919]
Bis(methacrylato-κO)bis(2,4,6-trimethylpyridine-κN)copper(II)
Ejaz, Islam Ullah Khan, Alina Murtaza and William T. A. Harrison
Comment
The title compound, (I), is a centrosymmetric neutral monomeric copper(II) complex (Fig. 1). Related structures
containing a copper(II) ion bonded to a pair of susbtituted pyridine ligands and a pair of monodentate carboxylate anions
have been described previously (Borel et al., 1981; Heimer & Ahmed, 1982; Jedrzejas et al., 1994).
The Cu ion in (I) lies on an inversion centre, resulting in a slightly distorted trans-CuN2O2 square planar geometry for
the metal ion (Table 1). If a very long contact between Cu1 and O1 [2.8229 (17)Å] is considered to have any significance
as a bond, a grossly disorted trans-CuN2O4 octahedron results. The mean planes of the pyridine ring (r.m.s. deviation =
0.0099Å) and the carboxylate group (r.m.s. deviation = 0.0003Å) are roughly perpendicular [dihedral angle = 74.71 (7)°],
which presumably minimises steric interactions between the ligands. The dihedral angles between the planar CuN2O2 core
and the py ring and carboxylate plane are are 67.72 (5) and 89.95 (5)°, respectively. The Cu ion is displaced by
0.256 (3)Å from the py ring plane and by 0.252 (3)Å from the carboxylate plane. The carboxylate C—O bond lengths of
1.222 (2)Å for O1 and 1.276 (2)Å for O2 suggest the presence of relatively localised single and double bonds in the
anion.
The terminal CH2 and CH3 groups of the carboxylate anion are probably disordered: the nominal C10—C11 single bond
is short [1.422 (4)Å] and the nominal C10=C12 double bond is long [1.378 (4)Å]. This may also correlate with the
Hirshfeld rigid bond alert for the C10—C12 bond. The presumed disorder could not be resolved in the present
experiment. Several intramolecular C—H···O interactions occur (Table 1). In the crystal, the molecules are linked by C—
H···O hydrogen bonds to generate chains in the [100] direction.
In trans-bis(acetato-O)bis(4-methyl pyridine-N)copper(II) (Jedrzejas et al., 1994), (II), the dihedral angle between the
ligands is 78.2° (s.u. not stated), and the dihedral angle between the py ring and the CuN2O2 plane is 31.6°. The
uncoordinated Cu···O separation of 2.623 (4)Å in (II) is significantly shorter than that seen in (I). However, it is notable
that the carboxylate C—O bonds lengths in (II) [1.227 (7) and 1.279 (6)Å] are almost identical to those seen here.
Experimental
Copper sulfate (0.16 g, 1.0 mmol) was dissolved in methanol (20 ml). Then, 2,4,6-trimethyl pyridine (0.264 ml, 2.0
mmol) was added to this solution, which turned green. This reaction mixture was refluxed for 30 minutes followed by
addition of methacrylic acid (0.169 ml, 2.0 mmol), at which point the solution remained green. After refluxing for one
hour, the solution was filtered and kept for a few days. Blue-green blocks of (I) were obtained from filtrate by slow
evaporation.
Refinement
Attempts were made to represent the disordered C11 (nominal CH2 group) and C12 (nominal CH3 group) atoms with a
double-site model, but the refinement was unstable. The hydrogen atoms were placed in calculated positions (C—H =

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supplementary materials
sup-2
Acta Cryst. (2012). E68, m469–m470
0.93–0.96Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C). The methyl groups were allowed
to rotate, but not to tip, to best fit the electron density.
Computing details
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007);
program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97
(Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication:
SHELXL97 (Sheldrick, 2008).
Figure 1
The molecular structure of (I) showing 50% displacement ellipsoids. Symmetry code: (i) 1–x, 1–y, 1–z.
Figure 2
Fragment of a [100] chain of complex molecules linked by C—H···O hydrogen bonds (double dashed lines). Symmetry
code: (i) 1+x, y, z.

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supplementary materials
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Acta Cryst. (2012). E68, m469–m470
Bis(methacrylato-κO)bis(2,4,6-trimethylpyridine-κN)copper(II)
Crystal data
[Cu(C4H5O2)2(C8H11N)2]
Mr = 476.06
Monoclinic, P21/n
Hall symbol: -P 2yn
a = 8.2295 (2) Å
b = 17.0921 (6) Å
c = 9.1683 (3) Å
β = 109.220 (1)°
V = 1217.73 (7) Å3
Z = 2
F(000) = 502
Dx = 1.298 Mg m−3
Mo Kα radiation, λ = 0.71073 Å
Cell parameters from 3020 reflections
θ = 2.4–28.3°
µ = 0.93 mm−1
T = 296 K
Block, blue-green
0.08 × 0.06 × 0.06 mm
Data collection
Bruker APEXII CCD
diffractometer
Radiation source: fine-focus sealed tube
Graphite monochromator
ω scans
Absorption correction: multi-scan
(SADABS; Bruker, 2007)
Tmin = 0.930, Tmax = 0.947
11795 measured reflections
3017 independent reflections
2439 reflections with I > 2σ(I)
Rint = 0.030
θmax = 28.3°, θmin = 2.9°
h = −10→10
k = −22→21
l = −12→12
Refinement
Refinement on F2
Least-squares matrix: full
R[F2 > 2σ(F2)] = 0.032
wR(F2) = 0.098
S = 1.05
3017 reflections
146 parameters
0 restraints
Primary atom site location: structure-invariant
direct methods
Secondary atom site location: difference Fourier
map
Hydrogen site location: inferred from
neighbouring sites
H-atom parameters constrained
w = 1/[σ2(Fo2) + (0.0554P)2 + 0.2257P]
where P = (Fo2 + 2Fc2)/3
(Δ/σ)max = 0.001
Δρmax = 0.24 e Å−3
Δρmin = −0.21 e Å−3
Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance
matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles;
correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate
(isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2,
conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is
used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based
on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
xyzUiso*/Ueq
Cu1
N1
C1
C2
H2
0.5000
0.66520 (18)
0.6584 (2)
0.7823 (2)
0.7740
0.5000
0.59275 (8)
0.64975 (10)
0.70758 (11)
0.7465
0.5000
0.54344 (15)
0.64342 (19)
0.6865 (2)
0.7546
0.03574 (11)
0.0370 (3)
0.0418 (4)
0.0468 (4)
0.056*