Tetra-μ-acetato-κ8O:O′-bis­{[2-methyl­sulfanyl-4-(pyridin-4-yl-κN)pyrimidine]­copper(II)}(Cu—Cu)

Zhu, H.-B.; Yang, W.-N.

doi:10.1107/S1600536811029837

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 67| Part 8| August 2011| Page m1168

doi:10.1107/S1600536811029837

Open

access

Tetra-μ-acetato-κ⁸O:O′-bis{[2-methylsulfanyl-4-(pyridin-4-yl-κN)pyrimidine]copper(II)}(Cu—Cu)

Hai-Bin Zhu ^a ^* and Wen-Na Yang ^a

^aSchool of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
^*Correspondence e-mail: zhuhaibin@seu.edu.cn

(Received 12 July 2011; accepted 23 July 2011; online 30 July 2011)

The binuclear title compound, [Cu₂(CH₃CO₂)₄(C₁₀H₉N₃S)₂], comprises a Cu₂(CH₃CO₂)₄ paddle-wheel core axially bound by two 2-methylsulfanyl-4-(pyridin-4-yl)pyrimidine ligands. The complex molecule has an inversion center lying at the mid-point of the Cu—Cu bond.

Related literature

For a related structure, see: Li et al. (2009 ).

Experimental

Crystal data

[Cu₂(C₂H₃O₂)₄(C₁₀H₉N₃S)₂]
M_r = 769.82
Monoclinic, P 2₁ /c
a = 15.192 (2) Å
b = 13.003 (2) Å
c = 8.6108 (13) Å
β = 103.781 (2)°
V = 1652.0 (4) Å³
Z = 2
Mo Kα radiation
μ = 1.47 mm⁻¹
T = 298 K
0.41 × 0.25 × 0.18 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ) T_min = 0.650, T_max = 0.768
9568 measured reflections
2827 independent reflections
2354 reflections with I > 2σ(I)
R_int = 0.024

Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.097
S = 1.04
2827 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Table 1
Selected bond lengths (Å)

Cu1—O1ⁱ	1.970 (2)
Cu1—O2	1.967 (2)
Cu1—O3ⁱ	1.974 (2)
Cu1—O4	1.967 (2)
Cu1—N1	2.183 (2)
Cu1—Cu1ⁱ	2.6299 (7)
Symmetry code: (i) -x+1, -y, -z+1.

Data collection: APEX2 (Bruker, 2007 ); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811029837/hy2450sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811029837/hy2450Isup2.hkl

checkCIF report

Comment top

In our previous work, we have reported a mononuclear Cu(II) complex with 4-(pyridin-4-yl)pyrimidine-2-sulfonate ligand (Li et al., 2009). Herein, we report a binuclear Cu(II) coordination compound with 2-(methylthio)-4-(pyridin-4-yl)pyrimidine (L) ligand. The title compound lies on an inversion center with a Cu—Cu separation of 2.6299 (7) Å (Fig. 1). The L ligand acts as a terminal ligand via its pyridine N atom, with a Cu—N distance of 2.183 (2) Å (Table 1).

Related literature top

For a related structure, see: Li et al. (2009).

Experimental top

A mixture of Cu(CH₃CO₂)₂ (0.1 mmol), L (0.1 mmol) in ethanol (15 ml) was stirred for 20 min at room temperature. After filtration, the mother liquid was allowed to stand for one week to give blue crystals suitable for X-ray diffraction analysis.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT-Plus (Bruker, 2007); data reduction: SAINT-Plus (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 30% probability level. H atoms have been omitted for clarity. [Symmetry code: (A) 1-x, -y, 1-z.]

Tetra-µ-acetato-κ⁸O:O'-bis{[2-methylsulfanyl- 4-(pyridin-4-yl-κN)pyrimidine]copper(II)}(Cu—Cu) top

Crystal data top

[Cu₂(C₂H₃O₂)₄(C₁₀H₉N₃S)₂]	F(000) = 788
M_r = 769.82	D_x = 1.548 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2827 reflections
a = 15.192 (2) Å	θ = 2.3–25.5°
b = 13.003 (2) Å	µ = 1.47 mm⁻¹
c = 8.6108 (13) Å	T = 298 K
β = 103.781 (2)°	Block, blue
V = 1652.0 (4) Å³	0.41 × 0.25 × 0.18 mm
Z = 2

Data collection top

Bruker APEXII CCD diffractometer	2827 independent reflections
Radiation source: fine-focus sealed tube	2354 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.024
ϕ and ω scans	θ_max = 25.0°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −15→18
T_min = 0.650, T_max = 0.768	k = −15→15
9568 measured reflections	l = −10→10

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.097	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0614P)² + 0.3763P] where P = (F_o² + 2F_c²)/3
2827 reflections	(Δ/σ)_max < 0.001
208 parameters	Δρ_max = 0.38 e Å⁻³
0 restraints	Δρ_min = −0.32 e Å⁻³

Crystal data top

[Cu₂(C₂H₃O₂)₄(C₁₀H₉N₃S)₂]	V = 1652.0 (4) Å³
M_r = 769.82	Z = 2
Monoclinic, P2₁/c	Mo Kα radiation
a = 15.192 (2) Å	µ = 1.47 mm⁻¹
b = 13.003 (2) Å	T = 298 K
c = 8.6108 (13) Å	0.41 × 0.25 × 0.18 mm
β = 103.781 (2)°

Data collection top

Bruker APEXII CCD diffractometer	2827 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	2354 reflections with I > 2σ(I)
T_min = 0.650, T_max = 0.768	R_int = 0.024
9568 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	0 restraints
wR(F²) = 0.097	H-atom parameters constrained
S = 1.04	Δρ_max = 0.38 e Å⁻³
2827 reflections	Δρ_min = −0.32 e Å⁻³
208 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cu1	0.42790 (2)	0.03013 (2)	0.39231 (4)	0.03313 (14)
O2	0.39177 (14)	−0.11545 (15)	0.3826 (3)	0.0474 (5)
O4	0.50560 (15)	−0.00064 (17)	0.2452 (2)	0.0462 (5)
N1	0.31254 (16)	0.08776 (18)	0.2112 (3)	0.0380 (5)
O1	0.62838 (15)	−0.05037 (17)	0.4261 (3)	0.0522 (6)
O3	0.51441 (14)	−0.16651 (15)	0.5641 (3)	0.0518 (6)
C14	0.5845 (2)	−0.03341 (19)	0.2841 (4)	0.0396 (7)
C8	0.2390 (2)	0.0311 (2)	0.1478 (4)	0.0440 (7)
H8	0.2376	−0.0368	0.1810	0.053*
C6	0.16582 (19)	0.1693 (2)	−0.0149 (3)	0.0377 (6)
C10	0.2425 (2)	0.2277 (2)	0.0483 (3)	0.0427 (7)
H10	0.2459	0.2956	0.0164	0.051*
C9	0.3132 (2)	0.1843 (2)	0.1582 (3)	0.0410 (7)
H9	0.3644	0.2243	0.1980	0.049*
C12	0.4403 (2)	−0.1827 (2)	0.4653 (4)	0.0412 (7)
C7	0.1662 (2)	0.0681 (2)	0.0368 (4)	0.0477 (7)
H7	0.1169	0.0256	−0.0042	0.057*
N2	0.02885 (17)	0.1470 (2)	−0.2225 (3)	0.0491 (6)
C5	0.08668 (19)	0.2131 (2)	−0.1331 (3)	0.0417 (7)
C4	0.0726 (2)	0.3178 (3)	−0.1478 (4)	0.0573 (9)
H4	0.1123	0.3640	−0.0846	0.069*
S1	−0.11441 (7)	0.09520 (9)	−0.43675 (14)	0.0806 (3)
N3	−0.0610 (2)	0.2871 (3)	−0.3527 (4)	0.0620 (8)
C13	0.6315 (3)	−0.0562 (3)	0.1536 (4)	0.0579 (9)
H13A	0.5910	−0.0426	0.0517	0.087*
H13B	0.6494	−0.1271	0.1590	0.087*
H13C	0.6842	−0.0133	0.1664	0.087*
C2	−0.0421 (2)	0.1878 (3)	−0.3268 (4)	0.0514 (8)
C11	0.4090 (2)	−0.2928 (2)	0.4448 (5)	0.0609 (9)
H11A	0.4514	−0.3358	0.5166	0.091*
H11B	0.4050	−0.3141	0.3366	0.091*
H11C	0.3504	−0.2986	0.4681	0.091*
C3	−0.0023 (3)	0.3513 (3)	−0.2593 (5)	0.0657 (10)
H3	−0.0127	0.4216	−0.2707	0.079*
C1	−0.2020 (2)	0.1704 (4)	−0.5637 (5)	0.0900 (14)
H1A	−0.2452	0.1254	−0.6301	0.135*
H1B	−0.1757	0.2145	−0.6298	0.135*
H1C	−0.2319	0.2114	−0.4990	0.135*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0360 (2)	0.0322 (2)	0.0284 (2)	0.00451 (13)	0.00199 (15)	−0.00098 (13)
O2	0.0452 (12)	0.0375 (11)	0.0524 (13)	−0.0012 (9)	−0.0028 (10)	0.0009 (9)
O4	0.0511 (13)	0.0567 (12)	0.0316 (11)	0.0104 (10)	0.0111 (10)	0.0027 (9)
N1	0.0412 (14)	0.0382 (13)	0.0322 (13)	0.0043 (10)	0.0039 (11)	0.0004 (10)
O1	0.0528 (13)	0.0680 (15)	0.0362 (12)	0.0198 (11)	0.0116 (11)	0.0003 (10)
O3	0.0536 (14)	0.0350 (10)	0.0552 (13)	−0.0022 (10)	−0.0099 (11)	−0.0011 (9)
C14	0.0538 (19)	0.0307 (14)	0.0372 (17)	0.0042 (13)	0.0166 (15)	0.0001 (12)
C8	0.0453 (18)	0.0382 (15)	0.0444 (18)	0.0003 (13)	0.0024 (15)	0.0087 (13)
C6	0.0379 (16)	0.0397 (15)	0.0339 (15)	0.0062 (12)	0.0057 (13)	0.0037 (12)
C10	0.0484 (18)	0.0342 (14)	0.0410 (17)	0.0016 (13)	0.0019 (14)	0.0030 (12)
C9	0.0419 (16)	0.0369 (15)	0.0393 (16)	0.0005 (12)	0.0001 (13)	−0.0026 (12)
C12	0.0482 (18)	0.0357 (15)	0.0396 (17)	−0.0016 (13)	0.0103 (14)	−0.0075 (13)
C7	0.0403 (17)	0.0469 (17)	0.0503 (19)	−0.0071 (14)	−0.0002 (15)	0.0053 (14)
N2	0.0401 (15)	0.0544 (15)	0.0480 (16)	0.0030 (12)	0.0009 (13)	0.0101 (12)
C5	0.0365 (16)	0.0485 (16)	0.0384 (17)	0.0052 (13)	0.0056 (14)	0.0069 (13)
C4	0.053 (2)	0.0488 (18)	0.062 (2)	0.0087 (16)	−0.0018 (17)	0.0036 (16)
S1	0.0607 (6)	0.0805 (7)	0.0812 (8)	−0.0150 (5)	−0.0214 (5)	0.0158 (6)
N3	0.0477 (17)	0.0690 (19)	0.0622 (19)	0.0113 (14)	−0.0007 (15)	0.0157 (15)
C13	0.077 (3)	0.057 (2)	0.047 (2)	0.0175 (18)	0.0314 (19)	0.0038 (16)
C2	0.0376 (17)	0.067 (2)	0.0468 (19)	0.0017 (15)	0.0045 (15)	0.0123 (16)
C11	0.063 (2)	0.0362 (16)	0.076 (2)	−0.0064 (15)	0.0006 (19)	−0.0080 (16)
C3	0.062 (2)	0.052 (2)	0.076 (3)	0.0151 (18)	0.001 (2)	0.0134 (19)
C1	0.045 (2)	0.126 (4)	0.082 (3)	−0.004 (2)	−0.020 (2)	0.018 (3)

Geometric parameters (Å, º) top

Cu1—O1ⁱ	1.970 (2)	C12—C11	1.505 (4)
Cu1—O2	1.967 (2)	C7—H7	0.9300
Cu1—O3ⁱ	1.974 (2)	N2—C2	1.338 (4)
Cu1—O4	1.967 (2)	N2—C5	1.335 (4)
Cu1—N1	2.183 (2)	C5—C4	1.379 (4)
Cu1—Cu1ⁱ	2.6299 (7)	C4—C3	1.373 (5)
O2—C12	1.251 (4)	C4—H4	0.9300
O4—C14	1.241 (4)	S1—C2	1.748 (4)
N1—C9	1.337 (4)	S1—C1	1.796 (4)
N1—C8	1.341 (4)	N3—C2	1.330 (5)
O1—C14	1.265 (4)	N3—C3	1.341 (5)
O3—C12	1.257 (4)	C13—H13A	0.9600
C14—C13	1.498 (4)	C13—H13B	0.9600
C8—C7	1.366 (4)	C13—H13C	0.9600
C8—H8	0.9300	C11—H11A	0.9600
C6—C10	1.388 (4)	C11—H11B	0.9600
C6—C7	1.389 (4)	C11—H11C	0.9600
C6—C5	1.491 (4)	C3—H3	0.9300
C10—C9	1.372 (4)	C1—H1A	0.9600
C10—H10	0.9300	C1—H1B	0.9600
C9—H9	0.9300	C1—H1C	0.9600

O4—Cu1—O2	88.92 (9)	O2—C12—C11	118.1 (3)
O4—Cu1—O1ⁱ	168.10 (9)	O3—C12—C11	116.5 (3)
O2—Cu1—O1ⁱ	89.58 (9)	C8—C7—C6	119.9 (3)
O4—Cu1—O3ⁱ	89.87 (9)	C8—C7—H7	120.0
O2—Cu1—O3ⁱ	168.30 (8)	C6—C7—H7	120.0
O1ⁱ—Cu1—O3ⁱ	89.20 (10)	C2—N2—C5	116.5 (3)
O4—Cu1—N1	96.46 (9)	N2—C5—C4	121.1 (3)
O2—Cu1—N1	97.57 (9)	N2—C5—C6	117.4 (3)
O1ⁱ—Cu1—N1	95.44 (9)	C4—C5—C6	121.5 (3)
O3ⁱ—Cu1—N1	94.13 (9)	C3—C4—C5	117.5 (3)
O4—Cu1—Cu1ⁱ	82.34 (7)	C3—C4—H4	121.3
O2—Cu1—Cu1ⁱ	85.43 (6)	C5—C4—H4	121.3
O1ⁱ—Cu1—Cu1ⁱ	85.77 (7)	C2—S1—C1	103.5 (2)
O3ⁱ—Cu1—Cu1ⁱ	82.88 (6)	C2—N3—C3	114.7 (3)
N1—Cu1—Cu1ⁱ	176.77 (7)	C14—C13—H13A	109.5
C12—O2—Cu1	121.89 (19)	C14—C13—H13B	109.5
C14—O4—Cu1	125.8 (2)	H13A—C13—H13B	109.5
C9—N1—C8	116.8 (2)	C14—C13—H13C	109.5
C9—N1—Cu1	119.7 (2)	H13A—C13—H13C	109.5
C8—N1—Cu1	123.46 (19)	H13B—C13—H13C	109.5
C14—O1—Cu1	65.15 (17)	N3—C2—N2	127.2 (3)
C12—O3—Cu1	66.66 (15)	N3—C2—S1	119.7 (3)
O4—C14—O1	125.0 (3)	N2—C2—S1	113.1 (3)
O4—C14—C13	117.9 (3)	C12—C11—H11A	109.5
O1—C14—C13	117.1 (3)	C12—C11—H11B	109.5
N1—C8—C7	123.3 (3)	H11A—C11—H11B	109.5
N1—C8—H8	118.4	C12—C11—H11C	109.5
C7—C8—H8	118.4	H11A—C11—H11C	109.5
C10—C6—C7	117.0 (3)	H11B—C11—H11C	109.5
C10—C6—C5	121.6 (3)	N3—C3—C4	123.0 (3)
C7—C6—C5	121.4 (3)	N3—C3—H3	118.5
C9—C10—C6	119.5 (3)	C4—C3—H3	118.5
C9—C10—H10	120.3	S1—C1—H1A	109.5
C6—C10—H10	120.3	S1—C1—H1B	109.5
N1—C9—C10	123.5 (3)	H1A—C1—H1B	109.5
N1—C9—H9	118.2	S1—C1—H1C	109.5
C10—C9—H9	118.2	H1A—C1—H1C	109.5
O2—C12—O3	125.4 (3)	H1B—C1—H1C	109.5

O4—Cu1—O2—C12	81.3 (2)	Cu1—O4—C14—C13	177.6 (2)
O1ⁱ—Cu1—O2—C12	−86.9 (2)	C9—N1—C8—C7	−1.4 (4)
O3ⁱ—Cu1—O2—C12	−2.9 (6)	Cu1—N1—C8—C7	178.6 (2)
N1—Cu1—O2—C12	177.7 (2)	C7—C6—C10—C9	−0.9 (4)
Cu1ⁱ—Cu1—O2—C12	−1.1 (2)	C5—C6—C10—C9	179.2 (3)
O2—Cu1—O4—C14	−85.3 (2)	C8—N1—C9—C10	2.1 (4)
O1ⁱ—Cu1—O4—C14	−2.5 (6)	Cu1—N1—C9—C10	−178.0 (2)
O3ⁱ—Cu1—O4—C14	83.0 (2)	C6—C10—C9—N1	−0.9 (4)
N1—Cu1—O4—C14	177.2 (2)	Cu1—O2—C12—C11	−177.5 (2)
Cu1ⁱ—Cu1—O4—C14	0.2 (2)	N1—C8—C7—C6	−0.4 (5)
O4—Cu1—N1—C9	−80.7 (2)	C10—C6—C7—C8	1.5 (4)
O2—Cu1—N1—C9	−170.5 (2)	C5—C6—C7—C8	−178.6 (3)
O1ⁱ—Cu1—N1—C9	99.2 (2)	C2—N2—C5—C4	0.6 (4)
O3ⁱ—Cu1—N1—C9	9.6 (2)	C2—N2—C5—C6	179.4 (3)
O4—Cu1—N1—C8	99.3 (2)	C10—C6—C5—N2	160.4 (3)
O2—Cu1—N1—C8	9.5 (2)	C7—C6—C5—N2	−19.5 (4)
O1ⁱ—Cu1—N1—C8	−80.8 (2)	C10—C6—C5—C4	−20.7 (4)
O3ⁱ—Cu1—N1—C8	−170.4 (2)	C7—C6—C5—C4	159.4 (3)
O4—Cu1—O1ⁱ—C14ⁱ	4.2 (6)	N2—C5—C4—C3	−0.9 (5)
O2—Cu1—O1ⁱ—C14ⁱ	86.9 (2)	C6—C5—C4—C3	−179.7 (3)
O3ⁱ—Cu1—O1ⁱ—C14ⁱ	−81.4 (2)	C3—N3—C2—N2	−1.7 (5)
N1—Cu1—O1ⁱ—C14ⁱ	−175.5 (2)	C3—N3—C2—S1	178.5 (3)
Cu1ⁱ—Cu1—O1ⁱ—C14ⁱ	1.5 (2)	C5—N2—C2—N3	0.8 (5)
O4—Cu1—O3ⁱ—C12ⁱ	−82.5 (2)	C5—N2—C2—S1	−179.4 (2)
O2—Cu1—O3ⁱ—C12ⁱ	1.5 (6)	C1—S1—C2—N3	−0.4 (3)
O1ⁱ—Cu1—O3ⁱ—C12ⁱ	85.6 (2)	C1—S1—C2—N2	179.7 (2)
N1—Cu1—O3ⁱ—C12ⁱ	−179.0 (2)	C2—N3—C3—C4	1.2 (5)
Cu1ⁱ—Cu1—O3ⁱ—C12ⁱ	−0.2 (2)	C5—C4—C3—N3	0.0 (6)

Symmetry code: (i) −x+1, −y, −z+1.

Experimental details

Crystal data
Chemical formula	[Cu₂(C₂H₃O₂)₄(C₁₀H₉N₃S)₂]
M_r	769.82
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	15.192 (2), 13.003 (2), 8.6108 (13)
β (°)	103.781 (2)
V (Å³)	1652.0 (4)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	1.47
Crystal size (mm)	0.41 × 0.25 × 0.18

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.650, 0.768
No. of measured, independent and observed [I > 2σ(I)] reflections	9568, 2827, 2354
R_int	0.024
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.097, 1.04
No. of reflections	2827
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.38, −0.32

Computer programs: APEX2 (Bruker, 2007), SAINT-Plus (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

Cu1—O1ⁱ	1.970 (2)	Cu1—O4	1.967 (2)
Cu1—O2	1.967 (2)	Cu1—N1	2.183 (2)
Cu1—O3ⁱ	1.974 (2)	Cu1—Cu1ⁱ	2.6299 (7)

Symmetry code: (i) −x+1, −y, −z+1.

Acknowledgements

The authors acknowledge the Research Program for Excellent Young Teachers of Southeast University (grant No. 3207041202).

References

Bruker (2001). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Bruker (2007). APEX2 and SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Li, L., Xu, G. & Zhu, H.-B. (2009). Acta Cryst. E65, m476. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science 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.