metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 4| April 2012| Pages m385-m386

Poly[(μ2-2-amino­pyrimidine-κ2N1:N3)di-μ2-chlorido-mercury(II)]

aDepartment of Chemistry, Ferdowsi University of Mashhad, 917791436 Mashhad, Iran, and bFaculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland
*Correspondence e-mail: heshtiagh@um.ac.ir

(Received 8 February 2012; accepted 27 February 2012; online 7 March 2012)

The title compound, [HgCl2(C4H5N3)]n, features a two-dimensional network parallel to (001) that is based on an HgII atom octahedrally coordinated by four μ2-Cl atoms and two μ2-2-amino­pyrimidine (apym) ligands in trans positions, yielding a distorted HgCl4N2 octa­hedron. The coordination network can be described as an uninodal 4-connected net with the sql topology. The HgII ion lies on a site of -1 symmetry and the apym ligand lies on sites of m symmetry with the mirror plane perpendicular to the pyrimidine plane and passing through the NH2 group N atom. This polymeric structure is stabilized by N—H⋯Cl hydrogen bonds and columnar ππ stacking of pyrimidine rings, with a centroid–centroid distance of 3.832 (2) Å.

Related literature

For pyridine complexes of mercury(II) halides see: Hu et al. (2007[Hu, Ch., Kalf, I. & Englert, U. (2007). CrystEngComm, 9, 603-610.]). For mercury(II) coordination polymers, see: Mahmoudi & Morsali (2009[Mahmoudi, Gh. & Morsali, A. (2009). CrystEngComm, 11, 1868-1879.]). For the same topological type of two-dimensional coordination networks, see: Nockemann & Meyer (2004[Nockemann, P. & Meyer, G. (2004). Acta Cryst. E60, m744-m746.]); Xie & Wu (2007[Xie, Y.-M. & Wu, J.-H. (2007). Acta Cryst. C63, m220-m221.]). For topological analysis, see: Blatov (2006[Blatov, V. A. (2006). IUCrCompComm Newsl. 7, 4-38.]). For an isotypic CdII complex, see: Salinas-Castillo et al. (2011[Salinas-Castillo, A., Calahorro, A. J., Choquesillo-Lazarte, D., Seco, J. M. & Rodriguez-Dieguez, A. (2011). Polyhedron, 30, 1295-1298.]). For our previous work on structures with an apym ligand, see: Eshtiagh-Hosseini et al. (2009[Eshtiagh-Hosseini, H., Yousefi, Z. & Mirzaei, M. (2009). Acta Cryst. E65, o2816.], 2010[Eshtiagh-Hosseini, H., Yousefi, Z., Mirzaei, M., Chen, Y. G., Beyramabadi, S. A., Shokrollahi, A. & Aghaei, R. (2010). J. Mol. Struct. 973, 1-8.], 2011[Eshtiagh-Hosseini, H., Mirzaei, M., Yousefi, Z., Puschmann, H., Shokrollahi, A. & Aghaei, R. (2011). J. Coord. Chem., 64, 3969-3979.]).

[Scheme 1]

Experimental

Crystal data
  • [HgCl2(C4H5N3)]

  • Mr = 366.60

  • Monoclinic, P 21 /m

  • a = 3.8317 (1) Å

  • b = 14.1366 (3) Å

  • c = 7.0773 (2) Å

  • β = 96.814 (2)°

  • V = 380.65 (2) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 20.84 mm−1

  • T = 294 K

  • 0.45 × 0.04 × 0.02 mm

Data collection
  • Oxford Diffraction Xcalibur E diffractometer

  • Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.]) Tmin = 0.160, Tmax = 1.000

  • 9437 measured reflections

  • 992 independent reflections

  • 867 reflections with I > 2σ(I)

  • Rint = 0.033

Refinement
  • R[F2 > 2σ(F2)] = 0.020

  • wR(F2) = 0.049

  • S = 1.12

  • 992 reflections

  • 52 parameters

  • H-atom parameters constrained

  • Δρmax = 0.84 e Å−3

  • Δρmin = −1.01 e Å−3

Table 1
Selected geometric parameters (Å, °)

Hg1—Cl1 2.3987 (8)
Hg1—N2 2.618 (3)
Hg1—Cl1i 2.9881 (9)
Cl1—Hg1—N2ii 91.45 (7)
Cl1—Hg1—N2 88.55 (7)
N2ii—Hg1—N2 180.0
N2—Hg1—Cl1iii 92.95 (7)
Cl1—Hg1—Cl1i 90.00 (3)
N2—Hg1—Cl1i 87.05 (7)
Symmetry codes: (i) x-1, y, z; (ii) -x, -y+1, -z; (iii) -x+1, -y+1, -z.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯Cl1iii 0.96 2.41 3.363 (3) 173
Symmetry code: (iii) -x+1, -y+1, -z.

Data collection: CrysAlis PRO (Agilent, 2011[Agilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

Mercury with its d10 electronic configuration exhibits a wide range of geometry in coordination sphere giving rise to a variety of topological types of one-dimensional, two-dimensional and three-dimensional polymers (Mahmoudi & Morsali, 2009).

In this contribution, we have synthesized and characterized a two-dimensional framework containing [Hg(apym)Cl2] unit in which HgII ion is six coordinated via four chloride anions and a two apym molecules (Fig. 1). HgII ion exhibits slightly distorted octahedral coordination geometry for which the maximum deviation of twelve octahedral angles from an ideal 90° for cis angles is 0.82 (7)°.

In the crystal structure, HgII ion lies on an inversion centre and the apym molecule lies on a special position of m site symmetry with mirror plane passing through an amino nitrogen. HgII ions are connected to each other by the bridging chloride ions in [100] direction; the seperation between the two bridged HgII ions is 3.8317 (1) Å, and is shorter than that in [Hg(µ2-Cl)2(C7H9N)22HgCl)3] [3.9960 (9) Å, Hu et al., 2007]. The four-membered Hg2Cl2 ring is planar and contains pairs of long and short Hg— Cl bonds [Hg1— Cl1 2.9881 (9) Å & Hg1— Cl1 2.3987 (8) Å]. The apym molecule acts as a bidentate ligand that links two neighbouring HgII ions in the crystallographic b direction with seperation Hg1···Hg1 distance of 7.0683 (3) Å, in consequence leading to formation of two-dimensional infinite framework with grid size of 7.068×3.832 Å2 (Fig. 2). The topological type of this layer arrangement is sql {44.62}(Blatov, 2006). Similar two-dimensional neutral polymer consisting of mercury(II) ions bridged by both pyrazine and bromide ligands has been reported by Mahmoudi & Morsali (2009). The title compound is isostructural with its Cd analogoue, reported by Salinas-Castillo et al. (2011).

It is noteworthy that in our previous works, apym either played a role of a counter ion for an anionic network or acted as an uncharged monodentate ligand ( Eshtiagh-Hosseini et al., 2009, 2010, 2011).

Another point of interest is the existance of N— H···Cl hydrogen bonds as well as columnar ππ interactions between pyrimidine rings of apym ligands which are arranged into stacks propagating in the a direction (see Fig. 2) with the perpendicular separation of 3.509 (2) Å and the centroid-to-centroid distance of 3.832 (2) Å.

Related literature top

For pyridine complexes of mercury(II) halides see: Hu et al. (2007). For mercury(II) coordination polymers, see: Mahmoudi & Morsali (2009). For the same topological type of two-dimensional coordination network, see: Nockemann & Meyer (2004); Xie & Wu (2007). For topological analysis, see: Blatov (2006). For an isotypic CdII complex, see: Salinas-Castillo et al. (2011). For our previous work on an apym ligand, see: Eshtiagh-Hosseini et al. (2009, 2010, 2011).

Experimental top

To a solution of HgCl2 (0.050 g, 0.2 mmol) in 10 ml of MeOH was added dropwise a solution of pyridine-2,5-dicarboxylic acid (0.018 g, 0.1 mmol) in 10 ml of MeOH in the reflux condition. After 15 min, 2-aminopyrimidine (0.020 g, 0.2 mmol) was added as solid form, and the resultant solution stirred and refluxed for 12 h. After cooling the solution, a colourless needle-like crystals were obtained (yield: 70%).

Refinement top

H atoms bound to C atoms were placed in their idealized positions and were refined as riding on their parent atoms with C—H distance of 0.93 Å. The symmetry independent amine H-atom was first found in a difference Fourier map and then refined using a riding model with Uiso 1.2Uiso(N). The highest peak in the final electron density difference map is located 1.07 Å from Hg1 atom.

Structure description top

Mercury with its d10 electronic configuration exhibits a wide range of geometry in coordination sphere giving rise to a variety of topological types of one-dimensional, two-dimensional and three-dimensional polymers (Mahmoudi & Morsali, 2009).

In this contribution, we have synthesized and characterized a two-dimensional framework containing [Hg(apym)Cl2] unit in which HgII ion is six coordinated via four chloride anions and a two apym molecules (Fig. 1). HgII ion exhibits slightly distorted octahedral coordination geometry for which the maximum deviation of twelve octahedral angles from an ideal 90° for cis angles is 0.82 (7)°.

In the crystal structure, HgII ion lies on an inversion centre and the apym molecule lies on a special position of m site symmetry with mirror plane passing through an amino nitrogen. HgII ions are connected to each other by the bridging chloride ions in [100] direction; the seperation between the two bridged HgII ions is 3.8317 (1) Å, and is shorter than that in [Hg(µ2-Cl)2(C7H9N)22HgCl)3] [3.9960 (9) Å, Hu et al., 2007]. The four-membered Hg2Cl2 ring is planar and contains pairs of long and short Hg— Cl bonds [Hg1— Cl1 2.9881 (9) Å & Hg1— Cl1 2.3987 (8) Å]. The apym molecule acts as a bidentate ligand that links two neighbouring HgII ions in the crystallographic b direction with seperation Hg1···Hg1 distance of 7.0683 (3) Å, in consequence leading to formation of two-dimensional infinite framework with grid size of 7.068×3.832 Å2 (Fig. 2). The topological type of this layer arrangement is sql {44.62}(Blatov, 2006). Similar two-dimensional neutral polymer consisting of mercury(II) ions bridged by both pyrazine and bromide ligands has been reported by Mahmoudi & Morsali (2009). The title compound is isostructural with its Cd analogoue, reported by Salinas-Castillo et al. (2011).

It is noteworthy that in our previous works, apym either played a role of a counter ion for an anionic network or acted as an uncharged monodentate ligand ( Eshtiagh-Hosseini et al., 2009, 2010, 2011).

Another point of interest is the existance of N— H···Cl hydrogen bonds as well as columnar ππ interactions between pyrimidine rings of apym ligands which are arranged into stacks propagating in the a direction (see Fig. 2) with the perpendicular separation of 3.509 (2) Å and the centroid-to-centroid distance of 3.832 (2) Å.

For pyridine complexes of mercury(II) halides see: Hu et al. (2007). For mercury(II) coordination polymers, see: Mahmoudi & Morsali (2009). For the same topological type of two-dimensional coordination network, see: Nockemann & Meyer (2004); Xie & Wu (2007). For topological analysis, see: Blatov (2006). For an isotypic CdII complex, see: Salinas-Castillo et al. (2011). For our previous work on an apym ligand, see: Eshtiagh-Hosseini et al. (2009, 2010, 2011).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. ORTEP view of coordination sphere of mercury (II). Symmetry code: (i) x, 1.5 - y, z; (ii) -x, 1 - y, -z; (iii) -x, -0.5 + y, -z; (iv) 1 + x, y, z; (v) 1 - x, 1 - y, -z; (vi) -1 + x, y, z; (vii) -x, 1 - y, -z. Displacement ellipsoids are given at the 50% probability level.
[Figure 2] Fig. 2. Representation of two-dimensional coordination polymer. Dashed lines denote intermolecular N— H···Cl hydrogen bonds. The columnar ππ stacking interactions are highlighted in pink.
Poly[(µ2-2-aminopyrimidine-κ2N1:N3)di-µ2- chlorido-mercury(II)] top
Crystal data top
[HgCl2(C4H5N3)]F(000) = 328
Mr = 366.60Dx = 3.198 Mg m3
Monoclinic, P21/mMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybCell parameters from 3794 reflections
a = 3.8317 (1) Åθ = 2.9–29.0°
b = 14.1366 (3) ŵ = 20.84 mm1
c = 7.0773 (2) ÅT = 294 K
β = 96.814 (2)°Needle, colourless
V = 380.65 (2) Å30.45 × 0.04 × 0.02 mm
Z = 2
Data collection top
Oxford Diffraction Xcalibur E
diffractometer
992 independent reflections
Radiation source: Enhance (Mo) X-ray Source867 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.033
Detector resolution: 16.1544 pixels mm-1θmax = 29.0°, θmin = 2.9°
ω scansh = 54
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
k = 1819
Tmin = 0.160, Tmax = 1.000l = 99
9437 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.020Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.049H-atom parameters constrained
S = 1.12 w = 1/[σ2(Fo2) + (0.0245P)2 + 0.3601P]
where P = (Fo2 + 2Fc2)/3
992 reflections(Δ/σ)max < 0.001
52 parametersΔρmax = 0.84 e Å3
0 restraintsΔρmin = 1.01 e Å3
Crystal data top
[HgCl2(C4H5N3)]V = 380.65 (2) Å3
Mr = 366.60Z = 2
Monoclinic, P21/mMo Kα radiation
a = 3.8317 (1) ŵ = 20.84 mm1
b = 14.1366 (3) ÅT = 294 K
c = 7.0773 (2) Å0.45 × 0.04 × 0.02 mm
β = 96.814 (2)°
Data collection top
Oxford Diffraction Xcalibur E
diffractometer
992 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2011)
867 reflections with I > 2σ(I)
Tmin = 0.160, Tmax = 1.000Rint = 0.033
9437 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0200 restraints
wR(F2) = 0.049H-atom parameters constrained
S = 1.12Δρmax = 0.84 e Å3
992 reflectionsΔρmin = 1.01 e Å3
52 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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) top
xyzUiso*/Ueq
Hg10.00000.50000.00000.03124 (9)
Cl10.4453 (2)0.44666 (6)0.24361 (12)0.02963 (19)
C10.0775 (12)0.75000.0879 (7)0.0249 (10)
N10.1926 (13)0.75000.0838 (7)0.0355 (10)
H10.29720.69150.11760.043*
N20.0202 (8)0.6654 (2)0.1677 (4)0.0277 (6)
C40.1355 (15)0.75000.4342 (8)0.0353 (12)
H40.20540.75000.55560.042*
C30.0821 (10)0.6677 (3)0.3413 (5)0.0327 (8)
H30.11850.61070.40160.039*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Hg10.02661 (13)0.03241 (14)0.03432 (14)0.00086 (7)0.00197 (9)0.00342 (8)
Cl10.0305 (4)0.0297 (4)0.0287 (4)0.0022 (3)0.0036 (3)0.0019 (4)
C10.023 (2)0.023 (2)0.028 (3)0.0000.000 (2)0.000
N10.051 (3)0.022 (2)0.037 (3)0.0000.017 (2)0.000
N20.0347 (16)0.0219 (15)0.0261 (15)0.0005 (12)0.0014 (12)0.0007 (12)
C40.043 (3)0.040 (3)0.024 (3)0.0000.007 (2)0.000
C30.040 (2)0.029 (2)0.0280 (19)0.0055 (16)0.0025 (16)0.0036 (16)
Geometric parameters (Å, º) top
Hg1—Cl1i2.3987 (8)C1—N21.352 (4)
Hg1—Cl12.3987 (8)C1—N2v1.352 (4)
Hg1—N2i2.618 (3)N1—H10.9618
Hg1—N22.618 (3)N2—C31.334 (5)
Hg1—Cl1ii2.9881 (9)C4—C31.364 (5)
Hg1—Cl1iii2.9881 (9)C4—C3v1.364 (5)
Cl1—Hg1iv2.9881 (9)C4—H40.9300
C1—N11.340 (6)C3—H30.9300
Cl1i—Hg1—Cl1180.00 (3)Hg1—Cl1—Hg1iv90.00 (3)
Cl1i—Hg1—N2i88.55 (7)N1—C1—N2117.7 (2)
Cl1—Hg1—N2i91.45 (7)N1—C1—N2v117.7 (2)
Cl1i—Hg1—N291.45 (7)N2—C1—N2v124.5 (5)
Cl1—Hg1—N288.55 (7)C1—N1—H1114.7
N2i—Hg1—N2180.0C3—N2—C1116.3 (4)
Cl1i—Hg1—Cl1ii90.00 (3)C3—N2—Hg1116.3 (2)
Cl1—Hg1—Cl1ii90.00 (3)C1—N2—Hg1126.8 (3)
N2i—Hg1—Cl1ii87.05 (7)C3—C4—C3v117.1 (5)
N2—Hg1—Cl1ii92.95 (7)C3—C4—H4121.4
Cl1i—Hg1—Cl1iii90.00 (3)C3v—C4—H4121.4
Cl1—Hg1—Cl1iii90.00 (3)N2—C3—C4122.9 (4)
N2i—Hg1—Cl1iii92.95 (7)N2—C3—H3118.6
N2—Hg1—Cl1iii87.05 (7)C4—C3—H3118.6
Cl1ii—Hg1—Cl1iii180.00 (3)
Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z; (iii) x1, y, z; (iv) x+1, y, z; (v) x, y+3/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cl1ii0.962.413.363 (3)173
Symmetry code: (ii) x+1, y+1, z.

Experimental details

Crystal data
Chemical formula[HgCl2(C4H5N3)]
Mr366.60
Crystal system, space groupMonoclinic, P21/m
Temperature (K)294
a, b, c (Å)3.8317 (1), 14.1366 (3), 7.0773 (2)
β (°) 96.814 (2)
V3)380.65 (2)
Z2
Radiation typeMo Kα
µ (mm1)20.84
Crystal size (mm)0.45 × 0.04 × 0.02
Data collection
DiffractometerOxford Diffraction Xcalibur E
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2011)
Tmin, Tmax0.160, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
9437, 992, 867
Rint0.033
(sin θ/λ)max1)0.682
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.020, 0.049, 1.12
No. of reflections992
No. of parameters52
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.84, 1.01

Computer programs: CrysAlis PRO (Agilent, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Mercury (Macrae et al., 2008), publCIF (Westrip, 2010).

Selected geometric parameters (Å, º) top
Hg1—Cl12.3987 (8)Hg1—Cl1i2.9881 (9)
Hg1—N22.618 (3)
Cl1—Hg1—N2ii91.45 (7)N2—Hg1—Cl1iii92.95 (7)
Cl1—Hg1—N288.55 (7)Cl1—Hg1—Cl1i90.00 (3)
N2ii—Hg1—N2180.0N2—Hg1—Cl1i87.05 (7)
Symmetry codes: (i) x1, y, z; (ii) x, y+1, z; (iii) x+1, y+1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···Cl1iii0.962.413.363 (3)173
Symmetry code: (iii) x+1, y+1, z.
 

Acknowledgements

The authors wish to thank the Ferdowsi University of Mashhad for financial support of this article.

References

First citationAgilent (2011). CrysAlis PRO. Agilent Technologies, Yarnton, England.  Google Scholar
First citationBlatov, V. A. (2006). IUCrCompComm Newsl. 7, 4–38.  Google Scholar
First citationEshtiagh-Hosseini, H., Mirzaei, M., Yousefi, Z., Puschmann, H., Shokrollahi, A. & Aghaei, R. (2011). J. Coord. Chem., 64, 3969-3979.  CAS Google Scholar
First citationEshtiagh-Hosseini, H., Yousefi, Z. & Mirzaei, M. (2009). Acta Cryst. E65, o2816.  Web of Science CrossRef IUCr Journals Google Scholar
First citationEshtiagh-Hosseini, H., Yousefi, Z., Mirzaei, M., Chen, Y. G., Beyramabadi, S. A., Shokrollahi, A. & Aghaei, R. (2010). J. Mol. Struct. 973, 1–8.  CAS Google Scholar
First citationHu, Ch., Kalf, I. & Englert, U. (2007). CrystEngComm, 9, 603–610.  Web of Science CSD CrossRef CAS Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationMahmoudi, Gh. & Morsali, A. (2009). CrystEngComm, 11, 1868–1879.  Web of Science CSD CrossRef CAS Google Scholar
First citationNockemann, P. & Meyer, G. (2004). Acta Cryst. E60, m744–m746.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSalinas-Castillo, A., Calahorro, A. J., Choquesillo-Lazarte, D., Seco, J. M. & Rodriguez-Dieguez, A. (2011). Polyhedron, 30, 1295–1298.  CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWestrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationXie, Y.-M. & Wu, J.-H. (2007). Acta Cryst. C63, m220–m221.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 4| April 2012| Pages m385-m386
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds