2-(1H-Imidazol-1-yl)-4,6-dimethyl­pyrimidine

Yu, D.-H.; Wu, J.-Y.

doi:10.1107/S1600536811044357

organic compounds

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ISSN: 2056-9890

Volume 67| Part 11| November 2011| Page o3111

doi:10.1107/S1600536811044357

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2-(1H-Imidazol-1-yl)-4,6-dimethylpyrimidine

Dao-Hui Yu ^a and Jie-Ying Wu ^a ^*

^aDepartment of Chemistry, Anhui University, Hefei 230039, People's Republic of China, and Key Laboratory of Functional Inorganic Materials Chemistry, Hefei 230039, People's Republic of China
^*Correspondence e-mail: jywu1957@163.com

(Received 12 October 2011; accepted 25 October 2011; online 29 October 2011)

The asymmetric unit of the title compound, C₉H₁₀N₄, consists of two molecules in which the dihedral angles between the planes of the imidazole and pyrimidine rings are 4.8 (1) and 2.1 (1)°.

Related literature

For related pyrimidine derivatives, see: Wu et al. (2008 ); Cetina et al. (2005 ); Liu et al. (2007 ).

Experimental

Crystal data

C₉H₁₀N₄
M_r = 174.21
Monoclinic, P 2₁ /c
a = 9.304 (5) Å
b = 26.756 (5) Å
c = 7.129 (5) Å
β = 91.259 (5)°
V = 1774.2 (16) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.20 × 0.10 × 0.10 mm

Data collection

Bruker SMART diffractometer
11971 measured reflections
3091 independent reflections
2365 reflections with I > 2σ(I)
R_int = 0.040

Refinement

R[F² > 2σ(F²)] = 0.064
wR(F²) = 0.197
S = 1.14
3091 reflections
240 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: SMART (Bruker, 2002 ); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; 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/S1600536811044357/ng5247sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811044357/ng5247Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811044357/ng5247Isup3.cml

checkCIF report

Comment top

In recent years,pyrimidine-based materials had been widely investigated for their high electron affinity in the area of nonlinear optical materials (Liu et al., 2007); the crystal structures of a small number of pyrimidine derivatives have been widely reported (Wu et al., 2008; Cetina et al., 2005). The title molecule is a contribution to this topic. In (I), (Fig.1), the dihedral angles between imidazole and pyrimidine rings of the two molecules are only 4.8 (1) and 2.1 (1) °, which indicate that the molecules are almost co-planar. In the crystal structure, neighboring molecules are connected through weak intermolecular C—H···N interactions (Fig. 2).

Related literature top

For related pyrimidine derivatives, see: Wu et al. (2008); Cetina et al. (2005); Liu et al. (2007).

Experimental top

CuI (0.19 g,1 mmol), 1,10-phenanthroline (0.6 g,3 mmol) and DMF (5 ml) were added to a three-necked flask equipped with a magnetic stirrer and a reflux condenser. The reaction mixture turned brown and was kept stirred for 5 min. Then, t-BuOK (1.12 g,10 mmol), imidazole (1.36 g, 20 mmol), 2-iodo-4,6-dimethylpyrimidine (0.46 g, 2 mmol) and a catalytic amount of 18-crown-6 were added in sequentially. After complete addition, the mixture was heated under nitrogen for about 2 h, then cooled to room temperature. The residue was extracted with 200 ml of dichloromethane, washed four times with distilled water, and dried with anhydrous MgSO₄. Then it was filtered and concentrated and purified by flash column- chromatography on silica. Elution with petroleum/ethyl acetate (2:1) gave colorless crystals. Yield: 0.2 g (60%).

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); 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 molecule(I) showing 30% probability displacement ellipsoids.
	Fig. 2. The packing diagram of the title compound(I). H atoms not involved in hydrogen bonds are omitted.

2-(1H-Imidazol-1-yl)-4,6-dimethylpyrimidine top

Crystal data top

C₉H₁₀N₄	F(000) = 736
M_r = 174.21	D_x = 1.304 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybc	Cell parameters from 3786 reflections
a = 9.304 (5) Å	θ = 2.7–25.4°
b = 26.756 (5) Å	µ = 0.09 mm⁻¹
c = 7.129 (5) Å	T = 296 K
β = 91.259 (5)°	Needle, white
V = 1774.2 (16) Å³	0.20 × 0.10 × 0.10 mm
Z = 8

Data collection top

Bruker SMART diffractometer	2365 reflections with I > 2σ(I)
Radiation source: sealed tube	R_int = 0.040
Graphite monochromator	θ_max = 25.0°, θ_min = 1.5°
ω scans	h = −11→10
11971 measured reflections	k = −26→31
3091 independent reflections	l = −8→8

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.064	H-atom parameters constrained
wR(F²) = 0.197	w = 1/[σ²(F_o²) + (0.0895P)² + 0.9302P] where P = (F_o² + 2F_c²)/3
S = 1.14	(Δ/σ)_max < 0.001
3091 reflections	Δρ_max = 0.25 e Å⁻³
240 parameters	Δρ_min = −0.19 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.008 (2)

Crystal data top

C₉H₁₀N₄	V = 1774.2 (16) Å³
M_r = 174.21	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.304 (5) Å	µ = 0.09 mm⁻¹
b = 26.756 (5) Å	T = 296 K
c = 7.129 (5) Å	0.20 × 0.10 × 0.10 mm
β = 91.259 (5)°

Data collection top

Bruker SMART diffractometer	2365 reflections with I > 2σ(I)
11971 measured reflections	R_int = 0.040
3091 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.064	0 restraints
wR(F²) = 0.197	H-atom parameters constrained
S = 1.14	Δρ_max = 0.25 e Å⁻³
3091 reflections	Δρ_min = −0.19 e Å⁻³
240 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

	x	y	z	U_iso*/U_eq
N7	0.3875 (2)	0.45208 (8)	0.7788 (3)	0.0472 (6)
N2	0.1912 (2)	0.21267 (8)	0.6762 (3)	0.0493 (6)
N4	−0.0469 (2)	0.22566 (9)	0.5881 (3)	0.0483 (6)
N8	0.5461 (2)	0.52131 (8)	0.7336 (3)	0.0461 (6)
N6	0.3095 (2)	0.53376 (8)	0.8162 (3)	0.0465 (6)
C13	0.4215 (3)	0.50025 (10)	0.7736 (4)	0.0420 (6)
C14	0.4946 (3)	0.42061 (10)	0.7404 (4)	0.0471 (7)
N3	0.1114 (2)	0.29410 (9)	0.6535 (3)	0.0513 (6)
C15	0.6291 (3)	0.43849 (11)	0.6982 (4)	0.0517 (7)
H15	0.7034	0.4164	0.6727	0.062*
C4	0.0780 (3)	0.24630 (10)	0.6363 (4)	0.0453 (7)
N5	0.0973 (3)	0.56080 (10)	0.9067 (4)	0.0649 (8)
C5	0.0032 (3)	0.32600 (11)	0.6131 (4)	0.0539 (8)
C16	0.6525 (3)	0.48921 (11)	0.6942 (4)	0.0474 (7)
C7	−0.1541 (3)	0.25785 (11)	0.5495 (4)	0.0494 (7)
C6	−0.1306 (3)	0.30860 (11)	0.5581 (4)	0.0550 (8)
H6	−0.2041	0.3309	0.5271	0.066*
C10	0.1743 (3)	0.52165 (12)	0.8750 (4)	0.0552 (8)
H10	0.1420	0.4890	0.8903	0.066*
N1	0.4063 (3)	0.18529 (10)	0.7662 (5)	0.0728 (9)
C11	0.3144 (3)	0.58522 (11)	0.8102 (4)	0.0548 (8)
H11	0.3914	0.6051	0.7755	0.066*
C9	−0.2980 (3)	0.23589 (13)	0.4997 (5)	0.0647 (9)
H9A	−0.2873	0.2114	0.4027	0.097*
H9B	−0.3615	0.2619	0.4560	0.097*
H9C	−0.3373	0.2203	0.6086	0.097*
C3	0.3271 (3)	0.22439 (12)	0.7368 (5)	0.0622 (9)
H3	0.3593	0.2570	0.7551	0.075*
C18	0.7944 (3)	0.51142 (13)	0.6463 (5)	0.0625 (9)
H18A	0.7812	0.5352	0.5464	0.094*
H18B	0.8582	0.4854	0.6070	0.094*
H18C	0.8351	0.5279	0.7546	0.094*
C17	0.4608 (4)	0.36581 (11)	0.7441 (5)	0.0664 (9)
H17A	0.3708	0.3607	0.8044	0.100*
H17B	0.5356	0.3484	0.8123	0.100*
H17C	0.4545	0.3533	0.6180	0.100*
C1	0.1867 (3)	0.16122 (11)	0.6687 (5)	0.0629 (9)
H1	0.1088	0.1413	0.6328	0.076*
C12	0.1844 (3)	0.60062 (12)	0.8651 (5)	0.0647 (9)
H12	0.1569	0.6339	0.8738	0.078*
C8	0.0358 (4)	0.38062 (12)	0.6319 (6)	0.0768 (11)
H8A	0.0052	0.3923	0.7520	0.115*
H8B	−0.0143	0.3987	0.5344	0.115*
H8C	0.1374	0.3859	0.6214	0.115*
C2	0.3180 (3)	0.14584 (13)	0.7239 (6)	0.0734 (10)
H2	0.3456	0.1125	0.7323	0.088*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N7	0.0400 (13)	0.0420 (13)	0.0596 (14)	−0.0005 (10)	−0.0030 (10)	−0.0009 (10)
N2	0.0380 (13)	0.0443 (14)	0.0659 (15)	−0.0011 (10)	0.0068 (11)	0.0059 (11)
N4	0.0401 (13)	0.0492 (14)	0.0559 (14)	−0.0035 (10)	0.0065 (10)	0.0015 (10)
N8	0.0342 (12)	0.0457 (14)	0.0583 (14)	−0.0013 (10)	−0.0026 (10)	−0.0007 (10)
N6	0.0354 (12)	0.0439 (13)	0.0601 (14)	0.0023 (10)	−0.0018 (10)	−0.0037 (10)
C13	0.0358 (14)	0.0414 (15)	0.0485 (15)	0.0028 (11)	−0.0041 (11)	−0.0017 (11)
C14	0.0433 (15)	0.0424 (15)	0.0553 (16)	0.0035 (12)	−0.0057 (12)	−0.0024 (12)
N3	0.0425 (13)	0.0436 (14)	0.0681 (15)	−0.0002 (11)	0.0125 (11)	0.0031 (11)
C15	0.0395 (15)	0.0509 (18)	0.0645 (18)	0.0094 (13)	−0.0011 (13)	−0.0025 (13)
C4	0.0387 (15)	0.0454 (16)	0.0522 (16)	0.0021 (12)	0.0109 (12)	0.0040 (12)
N5	0.0360 (13)	0.0625 (17)	0.096 (2)	0.0053 (12)	0.0027 (13)	−0.0125 (14)
C5	0.0479 (17)	0.0472 (17)	0.0672 (18)	0.0042 (13)	0.0165 (14)	0.0047 (13)
C16	0.0366 (14)	0.0505 (17)	0.0548 (17)	0.0018 (12)	−0.0038 (12)	0.0009 (12)
C7	0.0404 (15)	0.0578 (18)	0.0504 (16)	0.0026 (13)	0.0092 (12)	0.0050 (13)
C6	0.0411 (16)	0.0547 (19)	0.0694 (19)	0.0047 (13)	0.0094 (14)	0.0074 (14)
C10	0.0357 (15)	0.0547 (18)	0.075 (2)	−0.0004 (13)	0.0035 (13)	−0.0041 (14)
N1	0.0422 (15)	0.0608 (18)	0.115 (2)	0.0029 (13)	0.0018 (15)	0.0157 (16)
C11	0.0427 (16)	0.0431 (16)	0.078 (2)	0.0040 (13)	0.0000 (14)	−0.0005 (14)
C9	0.0428 (17)	0.081 (2)	0.071 (2)	−0.0022 (16)	0.0011 (14)	−0.0004 (17)
C3	0.0402 (17)	0.0538 (19)	0.093 (2)	−0.0027 (14)	−0.0002 (15)	0.0081 (16)
C18	0.0376 (16)	0.064 (2)	0.086 (2)	0.0005 (14)	0.0039 (15)	0.0028 (16)
C17	0.0557 (19)	0.0439 (18)	0.100 (2)	−0.0009 (15)	0.0019 (17)	−0.0026 (16)
C1	0.0459 (17)	0.0442 (17)	0.099 (2)	−0.0030 (14)	0.0063 (16)	0.0055 (16)
C12	0.0490 (18)	0.0501 (19)	0.095 (2)	0.0104 (15)	−0.0030 (16)	−0.0094 (16)
C8	0.060 (2)	0.0479 (19)	0.124 (3)	0.0022 (16)	0.015 (2)	0.0013 (19)
C2	0.0458 (18)	0.0491 (19)	0.126 (3)	0.0060 (15)	0.0120 (18)	0.0158 (19)

Geometric parameters (Å, º) top

N7—C13	1.328 (3)	C7—C9	1.497 (4)
N7—C14	1.337 (4)	C6—H6	0.9300
N2—C3	1.363 (4)	C10—H10	0.9300
N2—C1	1.378 (4)	N1—C3	1.294 (4)
N2—C4	1.410 (4)	N1—C2	1.367 (4)
N4—C4	1.325 (4)	C11—C12	1.344 (4)
N4—C7	1.342 (4)	C11—H11	0.9300
N8—C13	1.326 (3)	C9—H9A	0.9600
N8—C16	1.345 (3)	C9—H9B	0.9600
N6—C10	1.373 (4)	C9—H9C	0.9600
N6—C11	1.379 (4)	C3—H3	0.9300
N6—C13	1.413 (3)	C18—H18A	0.9600
C14—C15	1.379 (4)	C18—H18B	0.9600
C14—C17	1.500 (4)	C18—H18C	0.9600
N3—C4	1.321 (4)	C17—H17A	0.9600
N3—C5	1.347 (4)	C17—H17B	0.9600
C15—C16	1.375 (4)	C17—H17C	0.9600
C15—H15	0.9300	C1—C2	1.340 (5)
N5—C10	1.292 (4)	C1—H1	0.9300
N5—C12	1.375 (4)	C12—H12	0.9300
C5—C6	1.378 (4)	C8—H8A	0.9600
C5—C8	1.498 (4)	C8—H8B	0.9600
C16—C18	1.495 (4)	C8—H8C	0.9600
C7—C6	1.377 (4)	C2—H2	0.9300

C13—N7—C14	115.3 (2)	C12—C11—N6	105.5 (3)
C3—N2—C1	105.6 (2)	C12—C11—H11	127.3
C3—N2—C4	126.9 (3)	N6—C11—H11	127.3
C1—N2—C4	127.4 (2)	C7—C9—H9A	109.5
C4—N4—C7	115.4 (2)	C7—C9—H9B	109.5
C13—N8—C16	115.1 (2)	H9A—C9—H9B	109.5
C10—N6—C11	106.0 (2)	C7—C9—H9C	109.5
C10—N6—C13	126.9 (2)	H9A—C9—H9C	109.5
C11—N6—C13	127.0 (2)	H9B—C9—H9C	109.5
N8—C13—N7	128.9 (2)	N1—C3—N2	112.7 (3)
N8—C13—N6	115.4 (2)	N1—C3—H3	123.6
N7—C13—N6	115.6 (2)	N2—C3—H3	123.6
N7—C14—C15	120.7 (3)	C16—C18—H18A	109.5
N7—C14—C17	117.0 (3)	C16—C18—H18B	109.5
C15—C14—C17	122.3 (3)	H18A—C18—H18B	109.5
C4—N3—C5	114.8 (3)	C16—C18—H18C	109.5
C16—C15—C14	119.5 (3)	H18A—C18—H18C	109.5
C16—C15—H15	120.3	H18B—C18—H18C	109.5
C14—C15—H15	120.3	C14—C17—H17A	109.5
N3—C4—N4	129.1 (3)	C14—C17—H17B	109.5
N3—C4—N2	115.2 (2)	H17A—C17—H17B	109.5
N4—C4—N2	115.7 (2)	C14—C17—H17C	109.5
C10—N5—C12	105.0 (3)	H17A—C17—H17C	109.5
N3—C5—C6	120.9 (3)	H17B—C17—H17C	109.5
N3—C5—C8	116.8 (3)	C2—C1—N2	105.5 (3)
C6—C5—C8	122.4 (3)	C2—C1—H1	127.2
N8—C16—C15	120.6 (2)	N2—C1—H1	127.2
N8—C16—C18	116.9 (2)	C11—C12—N5	111.3 (3)
C15—C16—C18	122.6 (3)	C11—C12—H12	124.3
N4—C7—C6	120.5 (3)	N5—C12—H12	124.3
N4—C7—C9	116.9 (3)	C5—C8—H8A	109.5
C6—C7—C9	122.6 (3)	C5—C8—H8B	109.5
C7—C6—C5	119.2 (3)	H8A—C8—H8B	109.5
C7—C6—H6	120.4	C5—C8—H8C	109.5
C5—C6—H6	120.4	H8A—C8—H8C	109.5
N5—C10—N6	112.2 (3)	H8B—C8—H8C	109.5
N5—C10—H10	123.9	C1—C2—N1	111.6 (3)
N6—C10—H10	123.9	C1—C2—H2	124.2
C3—N1—C2	104.5 (3)	N1—C2—H2	124.2

C16—N8—C13—N7	−0.5 (4)	C13—N8—C16—C18	179.4 (3)
C16—N8—C13—N6	179.7 (2)	C14—C15—C16—N8	0.9 (4)
C14—N7—C13—N8	0.9 (4)	C14—C15—C16—C18	−178.9 (3)
C14—N7—C13—N6	−179.3 (2)	C4—N4—C7—C6	1.0 (4)
C10—N6—C13—N8	−175.0 (3)	C4—N4—C7—C9	−178.3 (2)
C11—N6—C13—N8	3.8 (4)	N4—C7—C6—C5	−2.2 (4)
C10—N6—C13—N7	5.2 (4)	C9—C7—C6—C5	177.1 (3)
C11—N6—C13—N7	−176.0 (3)	N3—C5—C6—C7	1.7 (4)
C13—N7—C14—C15	−0.3 (4)	C8—C5—C6—C7	−178.0 (3)
C13—N7—C14—C17	−179.9 (3)	C12—N5—C10—N6	0.7 (4)
N7—C14—C15—C16	−0.6 (4)	C11—N6—C10—N5	−0.5 (4)
C17—C14—C15—C16	179.0 (3)	C13—N6—C10—N5	178.5 (3)
C5—N3—C4—N4	−1.2 (4)	C10—N6—C11—C12	0.1 (3)
C5—N3—C4—N2	179.3 (2)	C13—N6—C11—C12	−178.9 (3)
C7—N4—C4—N3	0.8 (4)	C2—N1—C3—N2	−0.3 (4)
C7—N4—C4—N2	−179.7 (2)	C1—N2—C3—N1	0.3 (4)
C3—N2—C4—N3	2.8 (4)	C4—N2—C3—N1	178.3 (3)
C1—N2—C4—N3	−179.7 (3)	C3—N2—C1—C2	−0.2 (4)
C3—N2—C4—N4	−176.8 (3)	C4—N2—C1—C2	−178.1 (3)
C1—N2—C4—N4	0.8 (4)	N6—C11—C12—N5	0.3 (4)
C4—N3—C5—C6	−0.1 (4)	C10—N5—C12—C11	−0.6 (4)
C4—N3—C5—C8	179.6 (3)	N2—C1—C2—N1	0.0 (4)
C13—N8—C16—C15	−0.4 (4)	C3—N1—C2—C1	0.2 (4)

Experimental details

Crystal data
Chemical formula	C₉H₁₀N₄
M_r	174.21
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	9.304 (5), 26.756 (5), 7.129 (5)
β (°)	91.259 (5)
V (Å³)	1774.2 (16)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.20 × 0.10 × 0.10

Data collection
Diffractometer	Bruker SMART diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	11971, 3091, 2365
R_int	0.040
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.064, 0.197, 1.14
No. of reflections	3091
No. of parameters	240
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.19

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant No. 21071001), the Education Committee of Anhui Province (grant No. KJ2010A030) and the Graduate Students Academic Innovation Research Project of Anhui University (grant No. yqh090019).

References

Bruker (2002). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cetina, M., Nagl, A., Prekupec, S., Raić-Malić, S. & Mintas, M. (2005). Acta Cryst. C61, o158–o160. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Liu, Z. J., Chen, T., Liu, B., Huang, Z. L., Huang, T., Li, S. Y., Xu, Y. X. & Qin, J. G. (2007). J. Mater. Chem. 17, 4685–4689. Web of Science CSD CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wu, F., Zhang, Y.-Q., Zhu, Q.-J., Xue, S.-F. & Tao, Z. (2008). Acta Cryst. E64, o1488. Web of Science CSD CrossRef IUCr Journals Google Scholar