3-{[4-(4-Pyrid­yl)pyrimidin-2-yl]sulfanylmeth­yl}benzoic acid

Zhu, H.-B.; Wang, H.; Ji, J.-F.

doi:10.1107/S1600536808036799

organic compounds

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ISSN: 2056-9890

Volume 64| Part 12| December 2008| Page o2347

doi:10.1107/S1600536808036799

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3-{[4-(4-Pyridyl)pyrimidin-2-yl]sulfanylmethyl}benzoic acid

Hai-Bin Zhu,^a ^* Hai Wang ^a and Jun-Feng Ji ^a

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

(Received 28 October 2008; accepted 8 November 2008; online 13 November 2008)

The title compound, C₁₇H₁₃N₃O₂S, was prepared by reaction of 4-(4-pyridyl)pyrimidine-2-thiol with 3-(bromomethyl)benzoic acid under basic conditions. Each pair of molecules is mutually linked via O—H⋯N hydrogen bonds, forming a dimer. The packing of the dimers is stablized by C—H⋯π interactions involving the methylene unit of the –CH₂S– linkage and benzene rings.

Related literature

For monodentate and chelating ligands, see: Raper (1996 ). For the structures of binuclear and polynuclear complexes with bridging heterocyclic thionate ligands, see: Raper (1997 ). For O—H⋯N interactions, see: Han et al. (2008 ). For C—H⋯π interactions, see: Choi et al. (2008 ).

Experimental

Crystal data

C₁₇H₁₃N₃O₂S
M_r = 323.36
Triclinic, $[P \overline 1]$
a = 4.4130 (9) Å
b = 10.458 (2) Å
c = 16.432 (3) Å
α = 87.79 (3)°
β = 89.90 (3)°
γ = 80.48 (3)°
V = 747.4 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 298 (2) K
0.30 × 0.10 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.934, T_max = 0.977
3108 measured reflections
2724 independent reflections
1685 reflections with I > 2σ(I)
R_int = 0.048
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.071
wR(F²) = 0.170
S = 1.04
2724 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2A⋯N1ⁱ	0.82	1.84	2.659 (5)	174
C10—H10B⋯Cg3ⁱⁱ	0.97	2.56	3.398 (5)	145
Symmetry codes: (i) -x+2, -y+1, -z+1; (ii) x-1, y, z. Cg3 is the centroid of the phenyl ring.

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 1999 ); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808036799/si2127sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808036799/si2127Isup2.hkl

checkCIF report

Comment top

Heterocyclic thionates (Raper, 1996, 1997) have been extensively studied due to not only their versatile coordination modes but also their close biological relativity. Herein, we report the crystal structure of a new heterocyclic thionate derivative, 3-((4-(4-pyridyl)pyrimidin-2-ylthio)methyl)benzoic acid.

In the molecular structure of the title compound (Fig.1), the pyrimidinyl and pyridinyl rings are not coplanar with the dihedral angle of 11.17 (3)o. Each pair of compound molecules is linked each other via O—H···N hydrogen bonds (Han et.al., 2008) to form a dimer (Fig. 2 and Table 1), and the packing of the dimers is stablized by C—H···π interactions (Choi et al., 2008) between a methylene H atom of the –CH₂S– linkage and the phenyl ring, with a C10—H10B···Cg3ⁱⁱseparation of 2.56 Å (Fig. 3 and Table 1; Cg3 is the centroid of the C11/C12/C13/C14/C15/C16 phenyl ring, symmetry code as in Fig. 3).

Related literature top

For monodentate and chelating ligands, see: Raper (1996). For the structures of binuclear and polynuclear complexes with bridging heterocyclic thionate ligands, see: Raper (1997). For O—H···N interactions, see: Han et al. (2008). For C—H···π interactions, see: Choi et al. (2008). Cg3 is the centroid of the phenyl ring.

Experimental top

The mixture of 4-(4-pyridyl)pyrimidine-2-thiol (0.1890 g,1.0 mmol), 3-(bromomethyl)benzoic acid (0.2150 g,1.0 mmol), NaOH (0.0400 g,1.0 mmol) in 30 ml of H₂O was refluxed for 10 h. After cooled to room temperature, the product was filtered and dried in vaccum. The single crystals suitable for X-ray diffraction were obtained by slow evaporation of the title compound in DMF solution.

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of the title compound with 30% displacement ellipsoids.
	Fig. 2. The hydrogen bonded dimer with O—H···N interactions (dotted lines) [symmetry code: -x + 2, -y + 1, -z + 1].
	Fig. 3. A section of the hydrogen bonded dimers viewed down the c axis. C—H···π interactions are shown as dotted lines. Cg3 denotes the phenyl ring centroid [symmetry code: x - 1, y, z].

3-{[4-(4-Pyridyl)pyrimidin-2-yl]sulfanylmethyl}benzoic acid top

Crystal data top

C₁₇H₁₃N₃O₂S	Z = 2
M_r = 323.36	F(000) = 336
Triclinic, P1	D_x = 1.437 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.4130 (9) Å	Cell parameters from 25 reflections
b = 10.458 (2) Å	θ = 9–12°
c = 16.432 (3) Å	µ = 0.23 mm⁻¹
α = 87.79 (3)°	T = 298 K
β = 89.90 (3)°	Prism, colorless
γ = 80.48 (3)°	0.30 × 0.10 × 0.10 mm
V = 747.4 (3) Å³

Data collection top

Enraf–Nonius CAD-4 diffractometer	1685 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.048
Graphite monochromator	θ_max = 25.3°, θ_min = 1.2°
ω/2θ scans	h = 0→5
Absorption correction: ψ scan (North et al., 1968)	k = −12→12
T_min = 0.934, T_max = 0.977	l = −19→19
3108 measured reflections	3 standard reflections every 200 reflections
2724 independent reflections	intensity decay: 1%

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)] = 0.071	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.170	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.05P)² + P] where P = (F_o² + 2F_c²)/3
2724 reflections	(Δ/σ)_max < 0.001
208 parameters	Δρ_max = 0.35 e Å⁻³
0 restraints	Δρ_min = −0.25 e Å⁻³

Crystal data top

C₁₇H₁₃N₃O₂S	γ = 80.48 (3)°
M_r = 323.36	V = 747.4 (3) Å³
Triclinic, P1	Z = 2
a = 4.4130 (9) Å	Mo Kα radiation
b = 10.458 (2) Å	µ = 0.23 mm⁻¹
c = 16.432 (3) Å	T = 298 K
α = 87.79 (3)°	0.30 × 0.10 × 0.10 mm
β = 89.90 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1685 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.048
T_min = 0.934, T_max = 0.977	3 standard reflections every 200 reflections
3108 measured reflections	intensity decay: 1%
2724 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.071	0 restraints
wR(F²) = 0.170	H-atom parameters constrained
S = 1.04	Δρ_max = 0.35 e Å⁻³
2724 reflections	Δρ_min = −0.25 e Å⁻³
208 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
S	0.1838 (3)	0.34695 (12)	0.92472 (7)	0.0633 (4)
O1	0.6060 (10)	0.6024 (3)	0.5857 (2)	0.0916 (13)
O2	0.6987 (9)	0.7953 (3)	0.61531 (19)	0.0795 (11)
H2A	0.7614	0.7948	0.5683	0.119*
N1	1.0847 (10)	0.1910 (4)	0.5353 (2)	0.0737 (12)
N2	0.5470 (7)	0.2426 (3)	0.80536 (18)	0.0457 (8)
N3	0.5608 (9)	0.1325 (4)	0.9366 (2)	0.0597 (10)
C1	1.1506 (13)	0.0803 (5)	0.5789 (3)	0.0832 (17)
H1B	1.2665	0.0098	0.5544	0.100*
C2	0.9037 (14)	0.2874 (5)	0.5702 (3)	0.0819 (17)
H2B	0.8459	0.3649	0.5403	0.098*
C3	0.7973 (11)	0.2779 (4)	0.6488 (3)	0.0635 (13)
H3B	0.6757	0.3490	0.6713	0.076*
C4	0.8710 (10)	0.1634 (4)	0.6942 (2)	0.0506 (10)
C5	1.0591 (12)	0.0636 (5)	0.6570 (3)	0.0693 (14)
H5A	1.1230	−0.0148	0.6854	0.083*
C6	0.7669 (10)	0.1494 (4)	0.7790 (2)	0.0470 (10)
C7	0.4682 (9)	0.2307 (4)	0.8824 (2)	0.0462 (10)
C8	0.7742 (11)	0.0419 (4)	0.9077 (2)	0.0577 (12)
H8A	0.8544	−0.0276	0.9425	0.069*
C9	0.8839 (10)	0.0436 (4)	0.8303 (3)	0.0558 (11)
H9A	1.0315	−0.0232	0.8123	0.067*
C10	0.0460 (9)	0.4535 (4)	0.8386 (3)	0.0566 (11)
H10A	0.0430	0.4012	0.7912	0.068*
H10B	−0.1644	0.4929	0.8493	0.068*
C11	0.2261 (8)	0.5595 (4)	0.8179 (2)	0.0449 (9)
C12	0.3212 (9)	0.5779 (4)	0.7389 (2)	0.0448 (9)
H12A	0.2784	0.5227	0.6991	0.054*
C13	0.4809 (10)	0.6787 (4)	0.7186 (2)	0.0516 (11)
C14	0.5392 (10)	0.7623 (4)	0.7761 (2)	0.0516 (10)
H14A	0.6428	0.8305	0.7619	0.062*
C15	0.4440 (10)	0.7455 (4)	0.8553 (3)	0.0544 (11)
H15A	0.4859	0.8015	0.8948	0.065*
C16	0.2852 (10)	0.6446 (4)	0.8758 (3)	0.0575 (12)
H16A	0.2182	0.6343	0.9290	0.069*
C17	0.5941 (11)	0.6869 (4)	0.6328 (3)	0.0579 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S	0.0761 (8)	0.0604 (8)	0.0493 (7)	−0.0024 (6)	0.0165 (5)	0.0109 (5)
O1	0.161 (4)	0.067 (2)	0.0460 (19)	−0.016 (2)	0.026 (2)	−0.0079 (18)
O2	0.125 (3)	0.060 (2)	0.054 (2)	−0.019 (2)	0.0138 (19)	0.0092 (16)
N1	0.104 (3)	0.062 (3)	0.051 (2)	0.000 (2)	0.025 (2)	0.003 (2)
N2	0.056 (2)	0.0419 (19)	0.0373 (18)	−0.0057 (16)	0.0016 (15)	0.0116 (14)
N3	0.087 (3)	0.049 (2)	0.040 (2)	−0.006 (2)	−0.0012 (18)	0.0092 (17)
C1	0.119 (5)	0.054 (3)	0.067 (3)	0.015 (3)	0.027 (3)	0.000 (3)
C2	0.136 (5)	0.057 (3)	0.042 (3)	0.012 (3)	0.011 (3)	0.013 (2)
C3	0.091 (4)	0.048 (3)	0.047 (3)	0.002 (2)	0.010 (2)	0.005 (2)
C4	0.063 (3)	0.041 (2)	0.045 (2)	−0.002 (2)	−0.0035 (19)	0.0036 (18)
C5	0.094 (4)	0.054 (3)	0.051 (3)	0.013 (3)	0.017 (2)	0.011 (2)
C6	0.062 (3)	0.039 (2)	0.039 (2)	−0.007 (2)	−0.0010 (18)	0.0058 (17)
C7	0.056 (2)	0.041 (2)	0.041 (2)	−0.0115 (19)	0.0064 (18)	0.0108 (18)
C8	0.085 (3)	0.046 (3)	0.040 (2)	−0.007 (2)	−0.010 (2)	0.013 (2)
C9	0.074 (3)	0.037 (2)	0.052 (3)	0.004 (2)	−0.002 (2)	0.0017 (19)
C10	0.040 (2)	0.060 (3)	0.065 (3)	0.001 (2)	0.007 (2)	0.009 (2)
C11	0.033 (2)	0.046 (2)	0.051 (2)	0.0036 (17)	−0.0046 (17)	0.0045 (19)
C12	0.049 (2)	0.041 (2)	0.040 (2)	0.0058 (18)	−0.0048 (17)	0.0020 (17)
C13	0.064 (3)	0.040 (2)	0.044 (2)	0.011 (2)	−0.0021 (19)	0.0105 (19)
C14	0.065 (3)	0.039 (2)	0.048 (2)	0.000 (2)	0.001 (2)	0.0047 (19)
C15	0.069 (3)	0.043 (2)	0.049 (3)	−0.002 (2)	−0.006 (2)	−0.0028 (19)
C16	0.064 (3)	0.060 (3)	0.040 (2)	0.016 (2)	0.008 (2)	0.002 (2)
C17	0.074 (3)	0.044 (3)	0.050 (3)	0.005 (2)	0.001 (2)	0.010 (2)

Geometric parameters (Å, º) top

S—C7	1.759 (4)	C5—H5A	0.9300
S—C10	1.809 (4)	C6—C9	1.393 (5)
O1—C17	1.191 (5)	C8—C9	1.360 (6)
O2—C17	1.314 (5)	C8—H8A	0.9300
O2—H2A	0.8200	C9—H9A	0.9300
N1—C2	1.327 (6)	C10—C11	1.496 (6)
N1—C1	1.327 (6)	C10—H10A	0.9700
N2—C7	1.318 (5)	C10—H10B	0.9700
N2—C6	1.341 (5)	C11—C12	1.379 (5)
N3—C8	1.323 (5)	C11—C16	1.382 (6)
N3—C7	1.344 (5)	C12—C13	1.392 (6)
C1—C5	1.358 (6)	C12—H12A	0.9300
C1—H1B	0.9300	C13—C14	1.365 (6)
C2—C3	1.380 (6)	C13—C17	1.499 (6)
C2—H2B	0.9300	C14—C15	1.381 (5)
C3—C4	1.378 (5)	C14—H14A	0.9300
C3—H3B	0.9300	C15—C16	1.390 (6)
C4—C5	1.383 (6)	C15—H15A	0.9300
C4—C6	1.476 (5)	C16—H16A	0.9300

C7—S—C10	103.54 (19)	C8—C9—H9A	121.3
C17—O2—H2A	109.5	C6—C9—H9A	121.3
C2—N1—C1	116.5 (4)	C11—C10—S	116.1 (3)
C7—N2—C6	115.9 (3)	C11—C10—H10A	108.3
C8—N3—C7	113.1 (3)	S—C10—H10A	108.3
N1—C1—C5	124.1 (4)	C11—C10—H10B	108.3
N1—C1—H1B	118.0	S—C10—H10B	108.3
C5—C1—H1B	118.0	H10A—C10—H10B	107.4
N1—C2—C3	123.0 (4)	C12—C11—C16	118.9 (4)
N1—C2—H2B	118.5	C12—C11—C10	120.0 (4)
C3—C2—H2B	118.5	C16—C11—C10	121.0 (4)
C4—C3—C2	120.1 (4)	C11—C12—C13	120.4 (4)
C4—C3—H3B	119.9	C11—C12—H12A	119.8
C2—C3—H3B	119.9	C13—C12—H12A	119.8
C3—C4—C5	116.3 (4)	C14—C13—C12	120.4 (4)
C3—C4—C6	122.1 (4)	C14—C13—C17	122.4 (4)
C5—C4—C6	121.6 (4)	C12—C13—C17	117.1 (4)
C1—C5—C4	119.9 (4)	C13—C14—C15	119.8 (4)
C1—C5—H5A	120.1	C13—C14—H14A	120.1
C4—C5—H5A	120.1	C15—C14—H14A	120.1
N2—C6—C9	120.2 (4)	C14—C15—C16	119.8 (4)
N2—C6—C4	117.1 (3)	C14—C15—H15A	120.1
C9—C6—C4	122.6 (4)	C16—C15—H15A	120.1
N2—C7—N3	128.7 (4)	C11—C16—C15	120.6 (4)
N2—C7—S	120.5 (3)	C11—C16—H16A	119.7
N3—C7—S	110.6 (3)	C15—C16—H16A	119.7
N3—C8—C9	124.3 (4)	O1—C17—O2	122.4 (4)
N3—C8—H8A	117.9	O1—C17—C13	124.5 (4)
C9—C8—H8A	117.9	O2—C17—C13	113.0 (4)
C8—C9—C6	117.5 (4)

C2—N1—C1—C5	−3.9 (9)	N3—C8—C9—C6	1.3 (7)
C1—N1—C2—C3	2.9 (9)	N2—C6—C9—C8	−2.2 (6)
N1—C2—C3—C4	−1.9 (9)	C4—C6—C9—C8	179.0 (4)
C2—C3—C4—C5	1.6 (7)	C7—S—C10—C11	−84.7 (3)
C2—C3—C4—C6	178.9 (5)	S—C10—C11—C12	129.7 (3)
N1—C1—C5—C4	3.9 (9)	S—C10—C11—C16	−53.9 (5)
C3—C4—C5—C1	−2.5 (8)	C16—C11—C12—C13	1.6 (5)
C6—C4—C5—C1	−179.9 (5)	C10—C11—C12—C13	178.1 (4)
C7—N2—C6—C9	4.1 (6)	C11—C12—C13—C14	−1.5 (6)
C7—N2—C6—C4	−177.0 (4)	C11—C12—C13—C17	176.1 (4)
C3—C4—C6—N2	13.3 (6)	C12—C13—C14—C15	1.1 (6)
C5—C4—C6—N2	−169.5 (4)	C17—C13—C14—C15	−176.3 (4)
C3—C4—C6—C9	−167.9 (4)	C13—C14—C15—C16	−1.0 (6)
C5—C4—C6—C9	9.3 (7)	C12—C11—C16—C15	−1.4 (6)
C6—N2—C7—N3	−5.8 (6)	C10—C11—C16—C15	−177.8 (4)
C6—N2—C7—S	179.7 (3)	C14—C15—C16—C11	1.1 (6)
C8—N3—C7—N2	4.8 (7)	C14—C13—C17—O1	163.6 (5)
C8—N3—C7—S	179.7 (3)	C12—C13—C17—O1	−14.0 (7)
C10—S—C7—N2	4.9 (4)	C14—C13—C17—O2	−12.5 (6)
C10—S—C7—N3	−170.5 (3)	C12—C13—C17—O2	170.0 (4)
C7—N3—C8—C9	−2.2 (7)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···N1ⁱ	0.82	1.84	2.659 (5)	174
C10—H10B···Cg3ⁱⁱ	0.97	2.56	3.398 (5)	145

Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) x−1, y, z.

Experimental details

Crystal data
Chemical formula	C₁₇H₁₃N₃O₂S
M_r	323.36
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	4.4130 (9), 10.458 (2), 16.432 (3)
α, β, γ (°)	87.79 (3), 89.90 (3), 80.48 (3)
V (Å³)	747.4 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.23
Crystal size (mm)	0.30 × 0.10 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.934, 0.977
No. of measured, independent and observed [I > 2σ(I)] reflections	3108, 2724, 1685
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.601

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.071, 0.170, 1.04
No. of reflections	2724
No. of parameters	208
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.35, −0.25

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) and DIAMOND (Brandenburg, 1999), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···N1ⁱ	0.82	1.84	2.659 (5)	174.2
C10—H10B···Cg3ⁱⁱ	0.97	2.56	3.398 (5)	145

Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) x−1, y, z.

Acknowledgements

The authors are grateful for support from the China Postdoctoral Research Fund (20070411010) and the National Natural Science of Foundation of China (20801011).

References

Brandenburg, K. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008). Acta Cryst. E64, o794. Web of Science CSD CrossRef IUCr Journals Google Scholar
Enraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands. Google Scholar
Han, L., Huang, S.-S., Huang, Q.-B., Zhou, X.-M. & Diao, Y.-P. (2008). Acta Cryst. E64, o781. Web of Science CSD CrossRef IUCr Journals Google Scholar
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany. Google Scholar
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359. CrossRef IUCr Journals Web of Science Google Scholar
Raper, E. S. (1996). Coord. Chem. Rev. 153, 199–255. CrossRef CAS Web of Science Google Scholar
Raper, E. S. (1997). Coord. Chem. Rev. 165, 475–567. CrossRef CAS Web of Science Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar