3,4,5-Trimeth­oxy-N-(2-methoxy­phen­yl)benzamide

Saeed, A.; Flörke, U.

doi:10.1107/S1600536809027974

organic compounds

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ISSN: 2056-9890

Volume 65| Part 8| August 2009| Page o1948

doi:10.1107/S1600536809027974

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3,4,5-Trimethoxy-N-(2-methoxyphenyl)benzamide

Aamer Saeed ^a ^* and Ulrich Flörke ^b

^aDepartment of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan, and ^bDepartment Chemie, Fakultät für Naturwissenschaften, Universität Paderborn, Warburgerstrasse 100, D-33098 Paderborn, Germany
^*Correspondence e-mail: aamersaeed@yahoo.com

(Received 13 July 2009; accepted 16 July 2009; online 22 July 2009)

In the title molecule, C₁₇H₁₉NO₅, the amide plane is oriented at an angle of 41.5 (3)° with respect to the 2-methoxybenzene ring. The three methoxy groups lie almost in the plane of the aromatic rings to which they are attached [C—O—C—C torsion angles of of 0.7 (4), −13.4 (4) and 3.1 (4)°], whereas the methoxy group at the 4-position of the 3,4,5-trimethoxybenzene ring is nearly perpendicularly oriented [C—O—C—C torsion angle of 103.9 (3)°]. In the crystal structure, intermolecular N—H⋯O hydrogen bonds link the molecules into chains along [001].

Related literature

The background of this work has been described in our earlier paper (Saeed et al. 2008 ). For a related structure, see: Parra et al. (2001 ).

Experimental

Crystal data

C₁₇H₁₉NO₅
M_r = 317.33
Orthorhombic, P c a 2₁
a = 7.409 (2) Å
b = 22.522 (6) Å
c = 9.681 (3) Å
V = 1615.4 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 120 K
0.50 × 0.44 × 0.20 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ) T_min = 0.953, T_max = 0.981
13253 measured reflections
2050 independent reflections
1902 reflections with I > 2σ(I)
R_int = 0.047

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.126
S = 1.13
2050 reflections
216 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1ⁱ	0.895 (10)	2.182 (14)	3.066 (4)	169 (4)
Symmetry code: (i) $[-x+{\script{1\over 2}}, y, z-{\script{1\over 2}}]$ .

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/S1600536809027974/wm2245sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809027974/wm2245Isup2.hkl

checkCIF report

Comment top

The background of this work has been described in our earlier paper (Saeed et al. 2008).

The molecular structure of the title compound (Fig. 1) is similar to that of ICULOH (Parra et al., 2001), but with 3,4,5-methoxy substitution of the benzamide ring. Methoxy groups O2, O3 and O5 lie almost in plane of the corresponding aromatic rings with torsion angles C8–O2–C7–C6 of 0.7 (4)°, C15–O3–C11–C10 of -13.4 (4)° and C17–O5–C13–C14 of 3.1 (4)°, respectively, whereas the O4-group is nearly perpendicular oriented with C16–O4–C12–C13 of 103.9 (3)°. The two aromatic planes make a dihedral angle of 67.66 (9)° and the angle between the amide group and the 2-methoxy benzene ring is 41.5 (3)°. In the cystal structure, intermolecular N–H···O hydrogen bonds (Table 1) link the molecules into infinite chains along the [001] direction (Fig. 2).

Related literature top

The background of this work has been described in our earlier paper (Saeed et al. 2008). For a related structure, see: Parra et al. (2001).

Experimental top

3,4,5-Trimethoxybenzoyl chloride (1 mmol) in CHCl₃ was treated with 2-methoxyaniline (3.5 mmol) under a nitrogen atmosphere at reflux conditions for 5 h. Upon cooling, the reaction mixture was diluted with CHCl₃ and washed consecutively with 1 M aq HCl and saturated aq NaHCO₃. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure. Crystallization of the residue in methanol afforded the title compound (84%) as white needles: Anal. calc. for C₁₇H₁₉NO₅: C 64.34, H 6.03, N 4.41%; found: C 64.31, H 6.09, N 4.34%

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. Molecular structure of title compound. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Crystal packing viewed along [100] with intermolecular hydrogen bonding pattern indicated as dashed lines. H-atoms not involved in hydrogen bonding are omitted.

3,4,5-Trimethoxy-N-(2-methoxyphenyl)benzamide top

Crystal data top

C₁₇H₁₉NO₅	F(000) = 672
M_r = 317.33	D_x = 1.305 Mg m⁻³
Orthorhombic, Pca2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 887 reflections
a = 7.409 (2) Å	θ = 2.9–27.6°
b = 22.522 (6) Å	µ = 0.10 mm⁻¹
c = 9.681 (3) Å	T = 120 K
V = 1615.4 (7) Å³	Prism, colourless
Z = 4	0.50 × 0.44 × 0.20 mm

Data collection top

Bruker SMART APEX diffractometer	2050 independent reflections
Radiation source: sealed tube	1902 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.047
ϕ and ω scans	θ_max = 27.9°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −9→9
T_min = 0.953, T_max = 0.981	k = −29→25
13253 measured reflections	l = −12→12

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)] = 0.051	Hydrogen site location: difference Fourier map
wR(F²) = 0.126	H atoms treated by a mixture of independent and constrained refinement
S = 1.13	w = 1/[σ²(F_o²) + (0.0648P)² + 0.6933P] where P = (F_o² + 2F_c²)/3
2050 reflections	(Δ/σ)_max < 0.001
216 parameters	Δρ_max = 0.37 e Å⁻³
2 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₁₇H₁₉NO₅	V = 1615.4 (7) Å³
M_r = 317.33	Z = 4
Orthorhombic, Pca2₁	Mo Kα radiation
a = 7.409 (2) Å	µ = 0.10 mm⁻¹
b = 22.522 (6) Å	T = 120 K
c = 9.681 (3) Å	0.50 × 0.44 × 0.20 mm

Data collection top

Bruker SMART APEX diffractometer	2050 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	1902 reflections with I > 2σ(I)
T_min = 0.953, T_max = 0.981	R_int = 0.047
13253 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	2 restraints
wR(F²) = 0.126	H atoms treated by a mixture of independent and constrained refinement
S = 1.13	Δρ_max = 0.37 e Å⁻³
2050 reflections	Δρ_min = −0.20 e Å⁻³
216 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
O1	0.1314 (3)	0.22502 (9)	1.0268 (2)	0.0232 (5)
O2	−0.0063 (3)	0.16331 (10)	0.5858 (2)	0.0246 (5)
O3	0.7319 (3)	0.33720 (9)	0.7087 (2)	0.0258 (5)
O4	0.6652 (3)	0.43489 (9)	0.8620 (3)	0.0246 (5)
O5	0.4036 (3)	0.43643 (9)	1.0503 (3)	0.0263 (5)
N1	0.1909 (3)	0.19743 (11)	0.8055 (3)	0.0199 (5)
H1	0.232 (7)	0.2095 (18)	0.723 (3)	0.053 (13)*
C1	0.2067 (3)	0.23480 (13)	0.9166 (3)	0.0186 (6)
C2	0.0968 (3)	0.14253 (13)	0.8110 (3)	0.0189 (6)
C3	0.1076 (4)	0.10537 (14)	0.9251 (4)	0.0242 (6)
H3A	0.1804	0.1163	1.0018	0.029*
C4	0.0117 (4)	0.05177 (14)	0.9278 (4)	0.0285 (7)
H4A	0.0179	0.0268	1.0068	0.034*
C5	−0.0923 (4)	0.03511 (14)	0.8150 (4)	0.0294 (7)
H5A	−0.1575	−0.0012	0.8169	0.035*
C6	−0.1012 (4)	0.07152 (14)	0.6989 (4)	0.0270 (7)
H6A	−0.1718	0.0598	0.6217	0.032*
C7	−0.0069 (4)	0.12518 (13)	0.6956 (3)	0.0211 (6)
C8	−0.1114 (5)	0.14694 (18)	0.4675 (4)	0.0382 (9)
H8A	−0.0681	0.1089	0.4312	0.057*
H8B	−0.0996	0.1776	0.3961	0.057*
H8C	−0.2385	0.1432	0.4942	0.057*
C9	0.3260 (4)	0.28794 (12)	0.8974 (3)	0.0167 (5)
C10	0.4689 (4)	0.28683 (13)	0.8036 (3)	0.0183 (5)
H10A	0.4859	0.2532	0.7457	0.022*
C11	0.5872 (4)	0.33511 (13)	0.7945 (3)	0.0181 (5)
C12	0.5583 (4)	0.38548 (13)	0.8771 (3)	0.0204 (6)
C13	0.4143 (4)	0.38603 (12)	0.9724 (3)	0.0194 (6)
C14	0.2986 (4)	0.33723 (12)	0.9835 (3)	0.0190 (6)
H14A	0.2026	0.3374	1.0486	0.023*
C15	0.7858 (5)	0.28235 (14)	0.6464 (4)	0.0328 (8)
H15A	0.7979	0.2518	0.7179	0.049*
H15B	0.9019	0.2877	0.5995	0.049*
H15C	0.6945	0.2700	0.5790	0.049*
C16	0.8392 (5)	0.42964 (16)	0.9272 (5)	0.0367 (9)
H16A	0.8234	0.4255	1.0273	0.055*
H16B	0.9109	0.4652	0.9077	0.055*
H16C	0.9018	0.3946	0.8911	0.055*
C17	0.2685 (5)	0.43817 (14)	1.1558 (4)	0.0323 (7)
H17A	0.1487	0.4352	1.1135	0.048*
H17B	0.2779	0.4757	1.2067	0.048*
H17C	0.2865	0.4049	1.2195	0.048*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0229 (10)	0.0307 (11)	0.0159 (10)	−0.0039 (8)	0.0057 (9)	−0.0036 (9)
O2	0.0247 (11)	0.0311 (11)	0.0179 (10)	−0.0079 (9)	−0.0033 (8)	−0.0018 (9)
O3	0.0239 (10)	0.0295 (10)	0.0242 (12)	−0.0046 (9)	0.0100 (10)	−0.0015 (9)
O4	0.0241 (10)	0.0229 (11)	0.0268 (11)	−0.0044 (8)	0.0023 (9)	0.0033 (9)
O5	0.0285 (11)	0.0234 (10)	0.0270 (13)	−0.0027 (8)	0.0081 (10)	−0.0053 (9)
N1	0.0205 (11)	0.0271 (12)	0.0121 (11)	−0.0043 (9)	0.0007 (10)	−0.0019 (10)
C1	0.0142 (12)	0.0266 (14)	0.0150 (13)	0.0016 (10)	−0.0024 (10)	−0.0014 (11)
C2	0.0150 (12)	0.0240 (14)	0.0176 (14)	0.0001 (10)	0.0058 (11)	−0.0033 (12)
C3	0.0207 (14)	0.0289 (15)	0.0231 (16)	0.0044 (11)	0.0028 (12)	−0.0002 (12)
C4	0.0266 (15)	0.0269 (15)	0.0320 (18)	0.0057 (12)	0.0090 (14)	0.0062 (14)
C5	0.0242 (14)	0.0203 (14)	0.044 (2)	−0.0035 (11)	0.0069 (15)	−0.0030 (14)
C6	0.0223 (14)	0.0281 (15)	0.0307 (18)	−0.0025 (12)	0.0014 (13)	−0.0079 (13)
C7	0.0180 (13)	0.0242 (14)	0.0211 (15)	0.0006 (11)	0.0042 (11)	−0.0033 (12)
C8	0.0381 (19)	0.049 (2)	0.0276 (18)	−0.0158 (16)	−0.0144 (16)	0.0038 (17)
C9	0.0160 (12)	0.0243 (13)	0.0098 (12)	−0.0004 (10)	−0.0027 (10)	−0.0004 (10)
C10	0.0207 (12)	0.0245 (13)	0.0098 (12)	0.0018 (10)	−0.0005 (11)	−0.0018 (11)
C11	0.0163 (11)	0.0272 (14)	0.0107 (13)	0.0006 (10)	0.0026 (10)	0.0014 (11)
C12	0.0223 (13)	0.0218 (14)	0.0171 (14)	0.0000 (11)	−0.0036 (11)	0.0038 (11)
C13	0.0197 (13)	0.0228 (14)	0.0156 (14)	0.0015 (10)	−0.0031 (11)	0.0001 (12)
C14	0.0178 (12)	0.0275 (14)	0.0118 (12)	0.0025 (10)	−0.0008 (11)	−0.0007 (11)
C15	0.0301 (17)	0.0315 (15)	0.0368 (19)	−0.0044 (12)	0.0173 (16)	−0.0034 (16)
C16	0.0308 (17)	0.0338 (19)	0.045 (2)	−0.0093 (14)	−0.0069 (17)	0.0000 (16)
C17	0.0352 (17)	0.0316 (15)	0.0300 (18)	−0.0030 (14)	0.0107 (16)	−0.0127 (15)

Geometric parameters (Å, º) top

O1—C1	1.224 (4)	C6—H6A	0.9500
O2—C7	1.366 (4)	C8—H8A	0.9800
O2—C8	1.434 (4)	C8—H8B	0.9800
O3—C11	1.357 (3)	C8—H8C	0.9800
O3—C15	1.432 (4)	C9—C10	1.395 (4)
O4—C12	1.374 (4)	C9—C14	1.403 (4)
O4—C16	1.441 (4)	C10—C11	1.400 (4)
O5—C13	1.365 (4)	C10—H10A	0.9500
O5—C17	1.431 (4)	C11—C12	1.404 (4)
N1—C1	1.371 (4)	C12—C13	1.410 (4)
N1—C2	1.420 (4)	C13—C14	1.398 (4)
N1—H1	0.895 (10)	C14—H14A	0.9500
C1—C9	1.500 (4)	C15—H15A	0.9800
C2—C3	1.388 (4)	C15—H15B	0.9800
C2—C7	1.412 (4)	C15—H15C	0.9800
C3—C4	1.401 (5)	C16—H16A	0.9800
C3—H3A	0.9500	C16—H16B	0.9800
C4—C5	1.389 (5)	C16—H16C	0.9800
C4—H4A	0.9500	C17—H17A	0.9800
C5—C6	1.392 (5)	C17—H17B	0.9800
C5—H5A	0.9500	C17—H17C	0.9800
C6—C7	1.396 (4)

C7—O2—C8	117.3 (2)	C10—C9—C1	120.9 (2)
C11—O3—C15	116.7 (2)	C14—C9—C1	118.2 (2)
C12—O4—C16	113.8 (3)	C9—C10—C11	120.1 (3)
C13—O5—C17	117.3 (2)	C9—C10—H10A	119.9
C1—N1—C2	123.1 (2)	C11—C10—H10A	119.9
C1—N1—H1	119 (3)	O3—C11—C10	124.1 (3)
C2—N1—H1	118 (3)	O3—C11—C12	116.2 (2)
O1—C1—N1	122.3 (3)	C10—C11—C12	119.8 (3)
O1—C1—C9	121.4 (3)	O4—C12—C11	120.4 (3)
N1—C1—C9	116.3 (2)	O4—C12—C13	119.9 (3)
C3—C2—C7	119.7 (3)	C11—C12—C13	119.7 (3)
C3—C2—N1	121.8 (3)	O5—C13—C14	125.1 (3)
C7—C2—N1	118.6 (3)	O5—C13—C12	114.4 (2)
C2—C3—C4	120.3 (3)	C14—C13—C12	120.5 (3)
C2—C3—H3A	119.8	C13—C14—C9	119.1 (3)
C4—C3—H3A	119.8	C13—C14—H14A	120.4
C5—C4—C3	120.0 (3)	C9—C14—H14A	120.4
C5—C4—H4A	120.0	O3—C15—H15A	109.5
C3—C4—H4A	120.0	O3—C15—H15B	109.5
C4—C5—C6	120.1 (3)	H15A—C15—H15B	109.5
C4—C5—H5A	119.9	O3—C15—H15C	109.5
C6—C5—H5A	119.9	H15A—C15—H15C	109.5
C5—C6—C7	120.3 (3)	H15B—C15—H15C	109.5
C5—C6—H6A	119.8	O4—C16—H16A	109.5
C7—C6—H6A	119.8	O4—C16—H16B	109.5
O2—C7—C6	124.3 (3)	H16A—C16—H16B	109.5
O2—C7—C2	116.1 (2)	O4—C16—H16C	109.5
C6—C7—C2	119.6 (3)	H16A—C16—H16C	109.5
O2—C8—H8A	109.5	H16B—C16—H16C	109.5
O2—C8—H8B	109.5	O5—C17—H17A	109.5
H8A—C8—H8B	109.5	O5—C17—H17B	109.5
O2—C8—H8C	109.5	H17A—C17—H17B	109.5
H8A—C8—H8C	109.5	O5—C17—H17C	109.5
H8B—C8—H8C	109.5	H17A—C17—H17C	109.5
C10—C9—C14	120.7 (3)	H17B—C17—H17C	109.5

C2—N1—C1—O1	−4.4 (4)	C1—C9—C10—C11	−175.1 (3)
C2—N1—C1—C9	174.0 (2)	C15—O3—C11—C10	−13.4 (4)
C1—N1—C2—C3	−39.8 (4)	C15—O3—C11—C12	167.1 (3)
C1—N1—C2—C7	141.6 (3)	C9—C10—C11—O3	178.4 (3)
C7—C2—C3—C4	−2.0 (4)	C9—C10—C11—C12	−2.0 (4)
N1—C2—C3—C4	179.4 (3)	C16—O4—C12—C11	−78.5 (4)
C2—C3—C4—C5	1.1 (5)	C16—O4—C12—C13	103.9 (3)
C3—C4—C5—C6	0.1 (5)	O3—C11—C12—O4	4.5 (4)
C4—C5—C6—C7	−0.5 (5)	C10—C11—C12—O4	−175.1 (3)
C8—O2—C7—C6	0.7 (4)	O3—C11—C12—C13	−177.9 (3)
C8—O2—C7—C2	−179.6 (3)	C10—C11—C12—C13	2.5 (4)
C5—C6—C7—O2	179.2 (3)	C17—O5—C13—C14	3.1 (4)
C5—C6—C7—C2	−0.4 (4)	C17—O5—C13—C12	−175.6 (3)
C3—C2—C7—O2	−178.0 (2)	O4—C12—C13—O5	−4.6 (4)
N1—C2—C7—O2	0.6 (4)	C11—C12—C13—O5	177.7 (3)
C3—C2—C7—C6	1.7 (4)	O4—C12—C13—C14	176.6 (3)
N1—C2—C7—C6	−179.7 (3)	C11—C12—C13—C14	−1.1 (4)
O1—C1—C9—C10	151.4 (3)	O5—C13—C14—C9	−179.5 (3)
N1—C1—C9—C10	−27.1 (4)	C12—C13—C14—C9	−0.8 (4)
O1—C1—C9—C14	−24.0 (4)	C10—C9—C14—C13	1.3 (4)
N1—C1—C9—C14	157.6 (2)	C1—C9—C14—C13	176.7 (2)
C14—C9—C10—C11	0.1 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.90 (1)	2.18 (1)	3.066 (4)	169 (4)

Symmetry code: (i) −x+1/2, y, z−1/2.

Experimental details

Crystal data
Chemical formula	C₁₇H₁₉NO₅
M_r	317.33
Crystal system, space group	Orthorhombic, Pca2₁
Temperature (K)	120
a, b, c (Å)	7.409 (2), 22.522 (6), 9.681 (3)
V (Å³)	1615.4 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.50 × 0.44 × 0.20

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004)
T_min, T_max	0.953, 0.981
No. of measured, independent and observed [I > 2σ(I)] reflections	13253, 2050, 1902
R_int	0.047
(sin θ/λ)_max (Å⁻¹)	0.658

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.126, 1.13
No. of reflections	2050
No. of parameters	216
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.37, −0.20

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1ⁱ	0.895 (10)	2.182 (14)	3.066 (4)	169 (4)

Symmetry code: (i) −x+1/2, y, z−1/2.

Acknowledgements

AS gratefully acknowledges a reasearch grant from Quaid-i-Azam University, Islamabad, under the URF project.

References

Bruker (2002). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Parra, R. D., Zeng, H., Zhu, J., Zheng, C., Zeng, X. C. & Gong, B. (2001). Chem. Eur. J. 7, 4352–4357. CrossRef PubMed CAS Google Scholar
Saeed, A., Khera, R. A., Abbas, N., Simpson, J. & Stanley, R. G. (2008). Acta Cryst. E64, o1976. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2004). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar