supplementary materials


wm2573 scheme

Acta Cryst. (2012). E68, m45    [ doi:10.1107/S1600536811052834 ]

cis-Dichloridobis(di-2-pyridylamine-[kappa]2N,N')manganese(II)

K. Ha

Abstract top

In the title complex, [MnCl2(C10H9N3)2], the MnII ion is six-coordinated in a considerably distorted cis-N4Cl2 octahedral environment defined by four N atoms of two chelating di-2-pyridylamine (dpa) ligands and two Cl- anions. In the crystal, the dpa ligands are not planar, the dihedral angles between the two pyridine rings being 29.3 (2) and 30.9 (2)°. The complex molecules are stacked in columns along the c axis and are connected by intermolecular N-H...Cl hydrogen bonds, forming a three-dimensional network. Weak inter- and intramolecular [pi]-[pi] interactions are present between the pyridine rings, the shortest centroid-centroid distance being 4.406 (3) Å.

Comment top

Neutral and cationic MnII complexes of the di-2-pyridylamine (dpa; C10H9N3) ligand, such as [MnX2(dpa)2].H2O, [MnX(dpa)2(H2O)]ClO4 (X = N3-, NCO-) (Bose et al., 2005) and [MnX(dpa)2(H2O)]X (X = I, Br) (Ha, 2011a,b), have been investigated previously.

In the title complex, [MnCl2(dpa)2], the MnII ion is six-coordinated in a considerably distorted cis-N4Cl2 octahedral environment defined by four N atoms of two chelating dpa ligands and two Cl- anions (Fig. 1). The main contributions to the distortion are the tight N—Mn—N chelating angles (Table 1), which results in non-linear trans axes [N3—Mn1—N4 = 161.55 (11)°, N6—Mn1—Cl1 = 173.54 (11)° and N1—Mn1—Cl2 = 170.18 (10)°]. Because the Mn—N bond lengths are nearly equivalent (Table 1), the different trans effects of the Cl and N atoms cannot be observed reliably. In the crystal structure, the dpa ligands are not planar, the dihedral angles between the two pyridine rings being 29.3 (2)° and 30.9 (2)°. The complex molecules are stacked in columns along the c axis and connected by intermolecular N—H···Cl hydrogen bonds, forming a three-dimensional network (Fig. 2, Table 2). In the columns, numerous weak inter- and intramolecular ππ interactions are present between the pyridine rings, the shortest centroid-centroid distance being 4.406 (3) Å.

Related literature top

For the crystal structures of related MnII complexes with dpa, see: Bose et al. (2005); Ha (2011a,b).

Experimental top

To a solution of MnCl2.4H2O (0.1988 g, 1.005 mmol) in EtOH (20 ml) was added di-2-pyridylamine (0.3465 g, 2.024 mmol) and stirred for 3 h at room temperature. The formed precipitate was separated by filtration and washed with EtOH and acetone, and dried at 323 K, to give a white powder (0.2982 g). Crystals suitable for X-ray analysis were obtained by slow evaporation from a CH3CN solution.

Refinement top

Carbon-bound H atoms were positioned geometrically and allowed to ride on their respective parent atoms [C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C)]. Nitrogen-bound H atoms were located from Fourier difference maps then allowed to ride on their parent atoms in the final cycles of refinement with N—H = 0.92 Å and Uiso(H) = 1.5 Ueq(N). The highest peak (0.51 e Å-3) and the deepest hole (-0.56 e Å-3) in the difference Fourier map are located 1.40 Å and 1.08 Å from the atoms H9 and N4, respectively.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title complex, with displacement ellipsoids drawn at the 40% probability level for non-H atoms.
[Figure 2] Fig. 2. View of the unit-cell contents of the title complex. Hydrogen-bonding interactions are drawn with dashed lines.
cis-Dichloridobis(di-2-pyridylamine-κ2N,N')manganese(II) top
Crystal data top
[MnCl2(C10H9N3)2]F(000) = 956
Mr = 468.24Dx = 1.539 Mg m3
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2nCell parameters from 4041 reflections
a = 16.236 (3) Åθ = 2.5–27.8°
b = 12.542 (2) ŵ = 0.94 mm1
c = 9.9233 (17) ÅT = 200 K
V = 2020.7 (6) Å3Block, colorless
Z = 40.31 × 0.28 × 0.19 mm
Data collection top
Bruker SMART 1000 CCD
diffractometer
4293 independent reflections
Radiation source: fine-focus sealed tube2982 reflections with I > 2σ(I)
graphiteRint = 0.072
φ and ω scansθmax = 28.4°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2000)
h = 2121
Tmin = 0.849, Tmax = 1.000k = 1615
14151 measured reflectionsl = 139
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.092 w = 1/[σ2(Fo2) + (0.0271P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max < 0.001
4293 reflectionsΔρmax = 0.51 e Å3
262 parametersΔρmin = 0.57 e Å3
1 restraintAbsolute structure: Flack (1983), 1616 Friedel pairs
Primary atom site location: structure-invariant direct methodsFlack parameter: 0.04 (2)
Crystal data top
[MnCl2(C10H9N3)2]V = 2020.7 (6) Å3
Mr = 468.24Z = 4
Orthorhombic, Pna21Mo Kα radiation
a = 16.236 (3) ŵ = 0.94 mm1
b = 12.542 (2) ÅT = 200 K
c = 9.9233 (17) Å0.31 × 0.28 × 0.19 mm
Data collection top
Bruker SMART 1000 CCD
diffractometer
4293 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2000)
2982 reflections with I > 2σ(I)
Tmin = 0.849, Tmax = 1.000Rint = 0.072
14151 measured reflectionsθmax = 28.4°
Refinement top
R[F2 > 2σ(F2)] = 0.042H-atom parameters constrained
wR(F2) = 0.092Δρmax = 0.51 e Å3
S = 1.01Δρmin = 0.57 e Å3
4293 reflectionsAbsolute structure: Flack (1983), 1616 Friedel pairs
262 parametersFlack parameter: 0.04 (2)
1 restraint
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
Mn10.20798 (3)0.33815 (4)0.89348 (7)0.02448 (14)
Cl10.14448 (5)0.52067 (7)0.88475 (14)0.0317 (2)
Cl20.09525 (6)0.25950 (9)1.02667 (13)0.0376 (3)
N10.3262 (2)0.4028 (3)0.8006 (4)0.0270 (8)
N20.4152 (2)0.3360 (3)0.9693 (4)0.0293 (8)
H2N0.46430.30160.98420.044*
N30.28805 (19)0.3701 (2)1.0774 (3)0.0251 (8)
N40.16475 (18)0.2772 (2)0.6889 (4)0.0285 (8)
N50.2814 (2)0.1689 (3)0.6387 (4)0.0301 (8)
H5N0.30740.13430.56900.045*
N60.27298 (17)0.1710 (2)0.8770 (4)0.0246 (7)
C10.3191 (3)0.4552 (3)0.6826 (5)0.0330 (10)
H10.26520.47220.65180.040*
C20.3842 (3)0.4853 (3)0.6045 (5)0.0363 (11)
H20.37580.52250.52220.044*
C30.4629 (3)0.4602 (3)0.6481 (5)0.0421 (12)
H30.50950.47870.59500.051*
C40.4730 (2)0.4089 (3)0.7678 (5)0.0346 (11)
H40.52650.39090.79910.042*
C50.4036 (2)0.3830 (3)0.8440 (4)0.0266 (10)
C60.3676 (2)0.3427 (3)1.0850 (4)0.0257 (9)
C70.4062 (3)0.3193 (3)1.2082 (4)0.0356 (11)
H70.46180.29561.21000.043*
C80.3632 (3)0.3312 (3)1.3248 (5)0.0410 (11)
H80.38790.31451.40900.049*
C90.2820 (3)0.3684 (4)1.3191 (5)0.0393 (12)
H90.25190.38271.39920.047*
C100.2472 (2)0.3836 (3)1.1952 (5)0.0318 (10)
H100.19110.40481.19150.038*
C110.0903 (2)0.3143 (3)0.6470 (4)0.0294 (10)
H110.06120.36080.70560.035*
C120.0546 (3)0.2892 (3)0.5268 (5)0.0386 (11)
H120.00290.31860.50200.046*
C130.0957 (3)0.2196 (4)0.4416 (5)0.0446 (13)
H130.07260.20110.35670.054*
C140.1699 (3)0.1775 (3)0.4811 (5)0.0361 (11)
H140.19840.12870.42460.043*
C150.2032 (2)0.2078 (3)0.6067 (4)0.0261 (9)
C160.3129 (3)0.1420 (3)0.7646 (5)0.0256 (10)
C170.3864 (2)0.0827 (3)0.7674 (5)0.0302 (11)
H170.41410.06500.68610.036*
C180.4171 (2)0.0510 (3)0.8890 (6)0.0369 (10)
H180.46800.01390.89360.044*
C190.3733 (3)0.0735 (4)1.0062 (5)0.0366 (12)
H190.39180.04871.09140.044*
C200.3017 (3)0.1336 (3)0.9945 (5)0.0298 (11)
H200.27150.14891.07420.036*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mn10.0197 (3)0.0278 (3)0.0260 (3)0.0000 (2)0.0022 (3)0.0011 (4)
Cl10.0290 (5)0.0306 (5)0.0355 (6)0.0023 (4)0.0053 (6)0.0022 (6)
Cl20.0253 (5)0.0455 (6)0.0421 (6)0.0082 (5)0.0032 (5)0.0019 (6)
N10.0235 (18)0.0270 (18)0.031 (2)0.0015 (14)0.0000 (15)0.0022 (16)
N20.0211 (18)0.038 (2)0.029 (2)0.0048 (15)0.0009 (16)0.0002 (17)
N30.0195 (18)0.0309 (18)0.025 (2)0.0009 (14)0.0034 (15)0.0008 (16)
N40.0236 (18)0.0278 (18)0.034 (2)0.0006 (14)0.0041 (16)0.0060 (16)
N50.0285 (19)0.037 (2)0.024 (2)0.0072 (15)0.0035 (16)0.0052 (16)
N60.0213 (15)0.0248 (15)0.028 (2)0.0013 (12)0.0028 (17)0.0002 (18)
C10.035 (2)0.033 (2)0.032 (3)0.0018 (18)0.003 (2)0.003 (2)
C20.048 (3)0.033 (2)0.028 (3)0.005 (2)0.006 (2)0.005 (2)
C30.042 (3)0.041 (3)0.043 (3)0.012 (2)0.014 (2)0.001 (2)
C40.023 (2)0.037 (2)0.044 (3)0.0021 (18)0.005 (2)0.004 (2)
C50.022 (2)0.025 (2)0.033 (3)0.0015 (17)0.0012 (18)0.0053 (18)
C60.020 (2)0.028 (2)0.028 (2)0.0009 (16)0.0025 (18)0.0011 (19)
C70.026 (2)0.048 (3)0.033 (3)0.0042 (19)0.005 (2)0.005 (2)
C80.044 (3)0.048 (3)0.031 (3)0.002 (2)0.008 (2)0.003 (2)
C90.043 (3)0.046 (3)0.029 (3)0.001 (2)0.001 (2)0.005 (2)
C100.028 (2)0.034 (2)0.033 (3)0.0005 (18)0.001 (2)0.007 (2)
C110.028 (2)0.029 (2)0.031 (3)0.0005 (17)0.0078 (19)0.004 (2)
C120.029 (2)0.038 (2)0.048 (3)0.0030 (19)0.014 (2)0.000 (2)
C130.036 (3)0.057 (3)0.041 (3)0.002 (2)0.020 (2)0.009 (2)
C140.035 (3)0.044 (3)0.029 (3)0.000 (2)0.006 (2)0.011 (2)
C150.025 (2)0.028 (2)0.025 (2)0.0007 (16)0.0013 (18)0.0000 (19)
C160.023 (2)0.029 (2)0.025 (3)0.0015 (18)0.0042 (19)0.000 (2)
C170.021 (2)0.035 (3)0.035 (3)0.0047 (18)0.003 (2)0.000 (2)
C180.027 (2)0.034 (2)0.050 (3)0.0023 (16)0.003 (3)0.004 (3)
C190.034 (3)0.037 (3)0.039 (3)0.001 (2)0.005 (2)0.013 (2)
C200.033 (3)0.022 (2)0.035 (3)0.0028 (19)0.003 (2)0.004 (2)
Geometric parameters (Å, °) top
Mn1—N32.276 (3)C4—C51.395 (5)
Mn1—N12.278 (3)C4—H40.9500
Mn1—N42.280 (3)C6—C71.405 (6)
Mn1—N62.353 (3)C7—C81.360 (6)
Mn1—Cl22.4637 (12)C7—H70.9500
Mn1—Cl12.5122 (10)C8—C91.399 (6)
N1—C11.348 (5)C8—H80.9500
N1—C51.351 (5)C9—C101.367 (6)
N2—C61.386 (5)C9—H90.9500
N2—C51.389 (5)C10—H100.9500
N2—H2N0.9200C11—C121.363 (6)
N3—C61.339 (4)C11—H110.9500
N3—C101.355 (5)C12—C131.386 (6)
N4—C151.346 (5)C12—H120.9500
N4—C111.360 (5)C13—C141.373 (6)
N5—C161.392 (6)C13—H130.9500
N5—C151.396 (5)C14—C151.411 (6)
N5—H5N0.9200C14—H140.9500
N6—C161.340 (6)C16—C171.405 (6)
N6—C201.341 (6)C17—C181.365 (7)
C1—C21.365 (6)C17—H170.9500
C1—H10.9500C18—C191.392 (7)
C2—C31.385 (6)C18—H180.9500
C2—H20.9500C19—C201.389 (6)
C3—C41.361 (6)C19—H190.9500
C3—H30.9500C20—H200.9500
N3—Mn1—N177.32 (13)N2—C5—C4118.3 (4)
N3—Mn1—N4161.55 (11)N3—C6—N2120.4 (4)
N1—Mn1—N491.06 (12)N3—C6—C7122.2 (4)
N3—Mn1—N687.50 (12)N2—C6—C7117.4 (3)
N1—Mn1—N684.90 (11)C8—C7—C6119.2 (4)
N4—Mn1—N677.12 (12)C8—C7—H7120.4
N3—Mn1—Cl293.71 (9)C6—C7—H7120.4
N1—Mn1—Cl2170.18 (10)C7—C8—C9119.1 (4)
N4—Mn1—Cl296.59 (9)C7—C8—H8120.4
N6—Mn1—Cl290.79 (9)C9—C8—H8120.4
N3—Mn1—Cl195.84 (8)C10—C9—C8118.2 (4)
N1—Mn1—Cl190.43 (9)C10—C9—H9120.9
N4—Mn1—Cl198.55 (9)C8—C9—H9120.9
N6—Mn1—Cl1173.54 (11)N3—C10—C9123.8 (4)
Cl2—Mn1—Cl194.50 (4)N3—C10—H10118.1
C1—N1—C5116.5 (4)C9—C10—H10118.1
C1—N1—Mn1116.9 (3)N4—C11—C12124.5 (4)
C5—N1—Mn1126.1 (3)N4—C11—H11117.8
C6—N2—C5129.8 (3)C12—C11—H11117.8
C6—N2—H2N112.2C11—C12—C13118.4 (4)
C5—N2—H2N117.4C11—C12—H12120.8
C6—N3—C10117.1 (3)C13—C12—H12120.8
C6—N3—Mn1123.5 (3)C14—C13—C12119.4 (4)
C10—N3—Mn1115.7 (3)C14—C13—H13120.3
C15—N4—C11116.7 (3)C12—C13—H13120.3
C15—N4—Mn1127.8 (3)C13—C14—C15119.0 (4)
C11—N4—Mn1115.5 (3)C13—C14—H14120.5
C16—N5—C15128.6 (4)C15—C14—H14120.5
C16—N5—H5N113.0N4—C15—N5120.6 (4)
C15—N5—H5N114.3N4—C15—C14122.1 (4)
C16—N6—C20117.4 (3)N5—C15—C14117.1 (4)
C16—N6—Mn1121.1 (3)N6—C16—N5120.2 (4)
C20—N6—Mn1114.0 (3)N6—C16—C17122.5 (4)
N1—C1—C2124.2 (4)N5—C16—C17117.3 (4)
N1—C1—H1117.9C18—C17—C16118.8 (4)
C2—C1—H1117.9C18—C17—H17120.6
C1—C2—C3118.3 (4)C16—C17—H17120.6
C1—C2—H2120.8C17—C18—C19119.5 (3)
C3—C2—H2120.8C17—C18—H18120.2
C4—C3—C2119.4 (4)C19—C18—H18120.2
C4—C3—H3120.3C20—C19—C18117.9 (5)
C2—C3—H3120.3C20—C19—H19121.1
C3—C4—C5119.1 (4)C18—C19—H19121.1
C3—C4—H4120.5N6—C20—C19123.6 (5)
C5—C4—H4120.5N6—C20—H20118.2
N1—C5—N2119.3 (4)C19—C20—H20118.2
N1—C5—C4122.4 (4)
N3—Mn1—N1—C1150.8 (3)Mn1—N1—C5—C4167.7 (3)
N4—Mn1—N1—C143.7 (3)C6—N2—C5—N130.3 (6)
N6—Mn1—N1—C1120.6 (3)C6—N2—C5—C4149.2 (4)
Cl1—Mn1—N1—C154.9 (3)C3—C4—C5—N13.1 (6)
N3—Mn1—N1—C537.5 (3)C3—C4—C5—N2176.5 (4)
N4—Mn1—N1—C5128.0 (3)C10—N3—C6—N2174.7 (4)
N6—Mn1—N1—C551.1 (3)Mn1—N3—C6—N228.0 (5)
Cl1—Mn1—N1—C5133.4 (3)C10—N3—C6—C75.6 (6)
N1—Mn1—N3—C644.8 (3)Mn1—N3—C6—C7151.8 (3)
N4—Mn1—N3—C67.3 (6)C5—N2—C6—N321.9 (6)
N6—Mn1—N3—C640.6 (3)C5—N2—C6—C7158.3 (4)
Cl2—Mn1—N3—C6131.2 (3)N3—C6—C7—C84.2 (6)
Cl1—Mn1—N3—C6133.9 (3)N2—C6—C7—C8176.0 (4)
N1—Mn1—N3—C10157.6 (3)C6—C7—C8—C91.3 (7)
N4—Mn1—N3—C10150.4 (3)C7—C8—C9—C104.9 (7)
N6—Mn1—N3—C10117.1 (3)C6—N3—C10—C91.6 (6)
Cl2—Mn1—N3—C1026.5 (3)Mn1—N3—C10—C9157.5 (4)
Cl1—Mn1—N3—C1068.4 (3)C8—C9—C10—N33.6 (7)
N3—Mn1—N4—C157.8 (6)C15—N4—C11—C122.7 (6)
N1—Mn1—N4—C1558.1 (3)Mn1—N4—C11—C12178.5 (3)
N6—Mn1—N4—C1526.4 (3)N4—C11—C12—C131.3 (7)
Cl2—Mn1—N4—C15115.7 (3)C11—C12—C13—C140.7 (7)
Cl1—Mn1—N4—C15148.7 (3)C12—C13—C14—C151.1 (7)
N3—Mn1—N4—C11173.6 (3)C11—N4—C15—N5177.4 (4)
N1—Mn1—N4—C11123.3 (3)Mn1—N4—C15—N54.1 (5)
N6—Mn1—N4—C11152.2 (3)C11—N4—C15—C142.2 (6)
Cl2—Mn1—N4—C1162.9 (3)Mn1—N4—C15—C14179.2 (3)
Cl1—Mn1—N4—C1132.7 (3)C16—N5—C15—N437.4 (6)
N3—Mn1—N6—C16122.6 (3)C16—N5—C15—C14147.1 (4)
N1—Mn1—N6—C1645.1 (3)C13—C14—C15—N40.4 (6)
N4—Mn1—N6—C1647.1 (3)C13—C14—C15—N5175.7 (4)
Cl2—Mn1—N6—C16143.7 (3)C20—N6—C16—N5173.4 (4)
N3—Mn1—N6—C2026.5 (3)Mn1—N6—C16—N538.6 (5)
N1—Mn1—N6—C20103.9 (3)C20—N6—C16—C175.6 (5)
N4—Mn1—N6—C20163.8 (3)Mn1—N6—C16—C17142.5 (3)
Cl2—Mn1—N6—C2067.2 (3)C15—N5—C16—N612.8 (6)
C5—N1—C1—C22.3 (6)C15—N5—C16—C17166.2 (4)
Mn1—N1—C1—C2170.2 (3)N6—C16—C17—C181.8 (6)
N1—C1—C2—C30.4 (6)N5—C16—C17—C18177.2 (4)
C1—C2—C3—C41.4 (6)C16—C17—C18—C193.0 (6)
C2—C3—C4—C50.2 (6)C17—C18—C19—C203.7 (6)
C1—N1—C5—N2175.5 (4)C16—N6—C20—C194.8 (5)
Mn1—N1—C5—N212.7 (5)Mn1—N6—C20—C19145.5 (3)
C1—N1—C5—C44.0 (6)C18—C19—C20—N60.2 (6)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N2—H2N···Cl2i0.922.303.211 (3)171.
N5—H5N···Cl1ii0.922.453.355 (4)170.
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) −x+1/2, y−1/2, z−1/2.
Table 1
Selected geometric parameters (Å, °)
top
Mn1—N32.276 (3)Mn1—N62.353 (3)
Mn1—N12.278 (3)Mn1—Cl22.4637 (12)
Mn1—N42.280 (3)Mn1—Cl12.5122 (10)
N3—Mn1—N177.32 (13)N4—Mn1—N677.12 (12)
Table 2
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
N2—H2N···Cl2i0.922.303.211 (3)171.
N5—H5N···Cl1ii0.922.453.355 (4)170.
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) −x+1/2, y−1/2, z−1/2.
Acknowledgements top

This work was supported by the Priority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010–0029626).

references
References top

Bose, D., Mostafa, G., Fun, H.-K. & Ghosh, B. K. (2005). Polyhedron, 24, 747–758.

Bruker (2000). SADABS, SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.

Flack, H. D. (1983). Acta Cryst. A39, 876–881.

Ha, K. (2011a). Acta Cryst. E67, m1751.

Ha, K. (2011b). Acta Cryst. E67, m1773.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.