1,1′,2,2′-Tetra­methyl-3,3′-(4-methoxy­benzyl­idene)di-1H-indole

Zhang, C.-L.; Ye, P.-P.; Du, Z.-Q.

doi:10.1107/S1600536809017759

organic compounds

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ISSN: 2056-9890

Volume 65| Part 6| June 2009| Page o1332

doi:10.1107/S1600536809017759

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1,1′,2,2′-Tetramethyl-3,3′-(4-methoxybenzylidene)di-1H-indole

Cai-Li Zhang,^a Ping-Ping Ye ^a and Zhi-Qiang Du ^a ^*

^aDepartment of Chemistry, Zhejiang University, Hangzhou 310027, People's Republic of China
^*Correspondence e-mail: duzq@zju.edu.cn

(Received 8 May 2009; accepted 12 May 2009; online 20 May 2009)

The title compound, C₂₈H₂₈N₂O, was prepared by condensation of 1,2-bimethylindole and 4-methoxybenzaldehyde. In the molecular structure, the plane of the non-fused benzene ring is twisted with respect to the planes of the two indole ring systems, exhibiting dihedral angles of 72.04 (7) and 72.24 (7)°, while the planes of the two indole ring systems are oriented at a dihedral angle of 87.05 (5)°. Neither hydrogen bonding nor π–π stacking is observed in the crystal structure.

Related literature

For general background to the physiological properties of indole derivatives, see: Poter et al. (1977 ); Sundberg (1996 ). For related structures, see: Chang et al. (1999 ); Ge et al. (1999 ); Morris & Andersen (1990 ); Azizian et al. (2007 ); Osawa & Namiki (1983 ). For the synthesis, see: Deb & Bhuyan (2006 ).

Experimental

Crystal data

C₂₈H₂₈N₂O
M_r = 408.52
Monoclinic, P 2₁ /n
a = 10.6647 (8) Å
b = 13.2088 (10) Å
c = 16.1494 (13) Å
β = 97.1740 (10)°
V = 2257.1 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 296 K
0.25 × 0.24 × 0.21 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: none
11505 measured reflections
3955 independent reflections
3196 reflections with I > 2σ(I)
R_int = 0.025

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.139
S = 0.83
3955 reflections
285 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: SMART (Bruker, 2004 ); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809017759/xu2523sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809017759/xu2523Isup2.hkl

checkCIF report

Comment top

Indole derivatives are found abundantly in a variety of natural plants and exhibit various physiological properties (Poter et al., 1977; Sundberg, 1996). Among them, bis-indolymethane derivatives are found to be kinds of potentially bioactive compounds (Chang et al., 1999; Ge et al., 1999). In recent years, the synthesis and application of bis-indolymethane derivatives have been widely studied (Osawa & Namiki, 1983; Morris & Andersen, 1990; Azizian et al., 2007). The title compound is one of bis-indolymethane derivatives. We report here its crystal structure.

The molecular structure of the title compound is shown in Fig. 1. The C2-benzene ring is twisted to the two indole rings with the dihedral angles of 72.04 (7)° and 72.24 (7)°, respectively. Two indole rings make a dihedral angle of 87.86 (3)° to each other. Neither hydrogen bonding nor π-π stacking is observed in the crystal structure.

Related literature top

For general background to thephysiological properties of indole derivatives, see: Poter et al. (1977); Sundberg (1996). For related structures, see: Chang et al. (1999); Ge et al. (1999); Morris & Andersen (1990); Azizian et al. (2007); Osawa & Namiki (1983). For the synthesis, see: Deb & Bhuyan (2006).

Experimental top

The title compound was prepared according to the procedure reported by Deb & Bhuyan (2006). 1,2-Bimethylindole (2.0 mmol) and p-methoxybenzaldehyde (1.0 mmol) were dissolved in methanol (5 ml). The solution was stirred at room temperature for 5 h, then the solvent was removed under vacuum and the crude product was purified by silica-gel flash column chromatography. Single crystals suitable for X-ray data collection were obtained by recrystallization from chloroform/hexane.

Computing details top

Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

Fig. 1. The molecular structure of (I) with 30% probability displacement ellipsoids.

1,1',2,2'-Tetramethyl-3,3'-(4-methoxybenzylidene)di-1H-indole top

Crystal data top

C₂₈H₂₈N₂O	F(000) = 872
M_r = 408.52	D_x = 1.202 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6354 reflections
a = 10.6647 (8) Å	θ = 4.9–51.2°
b = 13.2088 (10) Å	µ = 0.07 mm⁻¹
c = 16.1494 (13) Å	T = 296 K
β = 97.174 (1)°	Prism, colorless
V = 2257.1 (3) Å³	0.25 × 0.24 × 0.21 mm
Z = 4

Data collection top

Bruker SMART CCD area-detector diffractometer	3196 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.025
Graphite monochromator	θ_max = 25.0°, θ_min = 2.0°
ϕ and ω scans	h = −12→12
11505 measured reflections	k = −15→15
3955 independent reflections	l = −19→19

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.139	H-atom parameters constrained
S = 0.83	w = 1/[σ²(F_o²) + (0.1047P)² + 0.8752P] where P = (F_o² + 2F_c²)/3
3955 reflections	(Δ/σ)_max < 0.001
285 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.22 e Å⁻³

Crystal data top

C₂₈H₂₈N₂O	V = 2257.1 (3) Å³
M_r = 408.52	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 10.6647 (8) Å	µ = 0.07 mm⁻¹
b = 13.2088 (10) Å	T = 296 K
c = 16.1494 (13) Å	0.25 × 0.24 × 0.21 mm
β = 97.174 (1)°

Data collection top

Bruker SMART CCD area-detector diffractometer	3196 reflections with I > 2σ(I)
11505 measured reflections	R_int = 0.025
3955 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.139	H-atom parameters constrained
S = 0.83	Δρ_max = 0.21 e Å⁻³
3955 reflections	Δρ_min = −0.22 e Å⁻³
285 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
N1	0.63286 (14)	0.32330 (11)	0.89904 (8)	0.0421 (4)
N2	0.23060 (12)	0.47645 (10)	0.62297 (8)	0.0358 (3)
O1	0.73808 (18)	0.09952 (13)	0.43460 (10)	0.0827 (5)
C1	0.54764 (14)	0.35901 (11)	0.67122 (9)	0.0316 (3)
H1	0.5937	0.4226	0.6671	0.038*
C2	0.59177 (14)	0.28915 (11)	0.60516 (9)	0.0334 (4)
C3	0.72045 (16)	0.27569 (12)	0.60290 (11)	0.0403 (4)
H3	0.7776	0.3097	0.6414	0.048*
C4	0.76556 (18)	0.21341 (14)	0.54521 (12)	0.0501 (5)
H4	0.8522	0.2066	0.5446	0.060*
C5	0.6831 (2)	0.16106 (14)	0.48826 (12)	0.0529 (5)
C6	0.5550 (2)	0.17324 (15)	0.48860 (12)	0.0544 (5)
H6	0.4984	0.1387	0.4502	0.065*
C7	0.51073 (17)	0.23765 (13)	0.54694 (11)	0.0435 (4)
H7	0.4240	0.2460	0.5464	0.052*
C8	0.6598 (4)	0.0526 (3)	0.36972 (17)	0.1146 (13)
H8A	0.7107	0.0159	0.3349	0.172*
H8B	0.6113	0.1031	0.3371	0.172*
H8C	0.6036	0.0066	0.3927	0.172*
C9	0.58732 (14)	0.32027 (11)	0.75930 (9)	0.0319 (3)
C10	0.62303 (14)	0.21961 (11)	0.78731 (10)	0.0317 (3)
C11	0.63396 (15)	0.12468 (12)	0.74924 (10)	0.0373 (4)
H11	0.6147	0.1177	0.6918	0.045*
C12	0.67336 (16)	0.04226 (12)	0.79772 (11)	0.0423 (4)
H12	0.6806	−0.0203	0.7724	0.051*
C13	0.70262 (16)	0.05046 (13)	0.88377 (11)	0.0446 (4)
H13	0.7297	−0.0065	0.9148	0.054*
C14	0.69222 (16)	0.14123 (14)	0.92376 (11)	0.0428 (4)
H14	0.7117	0.1467	0.9813	0.051*
C15	0.65141 (14)	0.22480 (12)	0.87502 (10)	0.0355 (4)
C16	0.59485 (15)	0.38016 (12)	0.82871 (10)	0.0377 (4)
C17	0.6468 (2)	0.35910 (17)	0.98459 (12)	0.0627 (6)
H17A	0.6664	0.3030	1.0218	0.094*
H17B	0.5693	0.3901	0.9960	0.094*
H17C	0.7139	0.4079	0.9926	0.094*
C18	0.5666 (2)	0.49042 (14)	0.83534 (13)	0.0561 (5)
H18A	0.6390	0.5245	0.8638	0.084*
H18B	0.4958	0.4992	0.8660	0.084*
H18C	0.5467	0.5185	0.7804	0.084*
C19	0.40945 (14)	0.38686 (11)	0.65659 (9)	0.0314 (3)
C20	0.30467 (14)	0.32631 (11)	0.67439 (9)	0.0325 (4)
C21	0.29216 (16)	0.22881 (12)	0.70659 (10)	0.0395 (4)
H21	0.3633	0.1891	0.7218	0.047*
C22	0.17413 (17)	0.19248 (14)	0.71551 (11)	0.0455 (4)
H22	0.1659	0.1277	0.7368	0.055*
C23	0.06594 (17)	0.25115 (15)	0.69312 (12)	0.0484 (4)
H23	−0.0130	0.2249	0.7000	0.058*
C24	0.07467 (16)	0.34710 (14)	0.66114 (11)	0.0438 (4)
H24	0.0028	0.3859	0.6458	0.053*
C25	0.19443 (15)	0.38423 (12)	0.65254 (9)	0.0339 (4)
C26	0.36095 (14)	0.47703 (11)	0.62486 (9)	0.0322 (3)
C27	0.14395 (17)	0.55850 (14)	0.59566 (12)	0.0477 (4)
H27A	0.0825	0.5654	0.6340	0.072*
H27B	0.1018	0.5437	0.5410	0.072*
H27C	0.1904	0.6206	0.5940	0.072*
C28	0.42723 (17)	0.56692 (13)	0.59485 (11)	0.0440 (4)
H28A	0.4049	0.6263	0.6240	0.066*
H28B	0.4025	0.5756	0.5361	0.066*
H28C	0.5169	0.5566	0.6051	0.066*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0508 (8)	0.0427 (8)	0.0313 (7)	0.0060 (6)	−0.0012 (6)	−0.0044 (6)
N2	0.0330 (7)	0.0350 (7)	0.0386 (7)	0.0063 (5)	0.0018 (6)	0.0039 (6)
O1	0.1152 (14)	0.0747 (11)	0.0624 (10)	0.0308 (10)	0.0278 (9)	−0.0145 (8)
C1	0.0315 (8)	0.0275 (8)	0.0353 (8)	−0.0008 (6)	0.0018 (6)	0.0037 (6)
C2	0.0382 (9)	0.0299 (8)	0.0324 (8)	0.0016 (6)	0.0052 (6)	0.0063 (6)
C3	0.0371 (9)	0.0382 (9)	0.0457 (10)	0.0028 (7)	0.0058 (7)	0.0039 (7)
C4	0.0499 (11)	0.0477 (11)	0.0557 (11)	0.0115 (8)	0.0177 (9)	0.0075 (9)
C5	0.0758 (14)	0.0434 (10)	0.0417 (10)	0.0161 (9)	0.0160 (9)	0.0026 (8)
C6	0.0690 (13)	0.0507 (11)	0.0416 (10)	0.0012 (9)	−0.0004 (9)	−0.0076 (8)
C7	0.0432 (9)	0.0474 (10)	0.0390 (9)	0.0005 (7)	0.0012 (7)	−0.0003 (8)
C8	0.173 (3)	0.112 (2)	0.0558 (15)	0.059 (2)	0.0022 (18)	−0.0304 (16)
C9	0.0294 (7)	0.0305 (8)	0.0347 (8)	0.0012 (6)	−0.0007 (6)	0.0008 (6)
C10	0.0281 (7)	0.0323 (8)	0.0339 (8)	0.0007 (6)	0.0008 (6)	0.0018 (6)
C11	0.0414 (9)	0.0336 (8)	0.0366 (9)	0.0005 (7)	0.0037 (7)	0.0017 (7)
C12	0.0446 (9)	0.0316 (8)	0.0514 (10)	0.0054 (7)	0.0089 (8)	0.0044 (7)
C13	0.0410 (9)	0.0411 (10)	0.0516 (11)	0.0064 (7)	0.0047 (8)	0.0156 (8)
C14	0.0398 (9)	0.0508 (10)	0.0366 (9)	0.0029 (8)	−0.0005 (7)	0.0085 (8)
C15	0.0337 (8)	0.0380 (9)	0.0338 (8)	0.0024 (7)	0.0001 (6)	0.0012 (7)
C16	0.0391 (9)	0.0338 (9)	0.0391 (9)	0.0042 (7)	0.0007 (7)	−0.0020 (7)
C17	0.0839 (15)	0.0651 (13)	0.0362 (10)	0.0102 (11)	−0.0041 (10)	−0.0105 (9)
C18	0.0727 (14)	0.0391 (10)	0.0550 (12)	0.0119 (9)	0.0018 (10)	−0.0095 (9)
C19	0.0324 (8)	0.0320 (8)	0.0294 (8)	0.0011 (6)	0.0024 (6)	0.0019 (6)
C20	0.0337 (8)	0.0337 (8)	0.0295 (8)	0.0006 (6)	0.0020 (6)	0.0000 (6)
C21	0.0385 (9)	0.0373 (9)	0.0416 (9)	−0.0008 (7)	0.0011 (7)	0.0051 (7)
C22	0.0453 (10)	0.0423 (10)	0.0485 (10)	−0.0090 (8)	0.0048 (8)	0.0065 (8)
C23	0.0375 (9)	0.0545 (11)	0.0536 (11)	−0.0099 (8)	0.0079 (8)	0.0008 (9)
C24	0.0338 (9)	0.0490 (10)	0.0481 (10)	0.0024 (7)	0.0030 (7)	−0.0022 (8)
C25	0.0340 (8)	0.0365 (8)	0.0309 (8)	0.0016 (6)	0.0025 (6)	−0.0013 (6)
C26	0.0335 (8)	0.0326 (8)	0.0305 (8)	0.0023 (6)	0.0036 (6)	0.0012 (6)
C27	0.0435 (10)	0.0446 (10)	0.0535 (11)	0.0141 (8)	0.0003 (8)	0.0048 (8)
C28	0.0461 (10)	0.0368 (9)	0.0492 (10)	0.0022 (7)	0.0069 (8)	0.0103 (7)

Geometric parameters (Å, º) top

N1—C15	1.379 (2)	C12—H12	0.9300
N1—C16	1.380 (2)	C13—C14	1.373 (3)
N1—C17	1.450 (2)	C13—H13	0.9300
N2—C25	1.381 (2)	C14—C15	1.394 (2)
N2—C26	1.3867 (19)	C14—H14	0.9300
N2—C27	1.457 (2)	C16—C18	1.494 (2)
O1—C5	1.372 (2)	C17—H17A	0.9600
O1—C8	1.401 (4)	C17—H17B	0.9600
C1—C19	1.509 (2)	C17—H17C	0.9600
C1—C9	1.521 (2)	C18—H18A	0.9600
C1—C2	1.529 (2)	C18—H18B	0.9600
C1—H1	0.9800	C18—H18C	0.9600
C2—C7	1.375 (2)	C19—C26	1.372 (2)
C2—C3	1.389 (2)	C19—C20	1.432 (2)
C3—C4	1.374 (2)	C20—C21	1.401 (2)
C3—H3	0.9300	C20—C25	1.410 (2)
C4—C5	1.377 (3)	C21—C22	1.371 (2)
C4—H4	0.9300	C21—H21	0.9300
C5—C6	1.376 (3)	C22—C23	1.400 (3)
C6—C7	1.395 (3)	C22—H22	0.9300
C6—H6	0.9300	C23—C24	1.376 (3)
C7—H7	0.9300	C23—H23	0.9300
C8—H8A	0.9600	C24—C25	1.391 (2)
C8—H8B	0.9600	C24—H24	0.9300
C8—H8C	0.9600	C26—C28	1.493 (2)
C9—C16	1.366 (2)	C27—H27A	0.9600
C9—C10	1.440 (2)	C27—H27B	0.9600
C10—C11	1.408 (2)	C27—H27C	0.9600
C10—C15	1.413 (2)	C28—H28A	0.9600
C11—C12	1.376 (2)	C28—H28B	0.9600
C11—H11	0.9300	C28—H28C	0.9600
C12—C13	1.390 (3)

C15—N1—C16	108.65 (13)	N1—C15—C14	129.36 (15)
C15—N1—C17	125.05 (15)	N1—C15—C10	107.91 (13)
C16—N1—C17	126.26 (15)	C14—C15—C10	122.72 (15)
C25—N2—C26	108.65 (12)	C9—C16—N1	109.97 (14)
C25—N2—C27	124.55 (14)	C9—C16—C18	129.17 (16)
C26—N2—C27	126.80 (14)	N1—C16—C18	120.86 (15)
C5—O1—C8	118.2 (2)	N1—C17—H17A	109.5
C19—C1—C9	112.38 (12)	N1—C17—H17B	109.5
C19—C1—C2	114.70 (13)	H17A—C17—H17B	109.5
C9—C1—C2	112.06 (12)	N1—C17—H17C	109.5
C19—C1—H1	105.6	H17A—C17—H17C	109.5
C9—C1—H1	105.6	H17B—C17—H17C	109.5
C2—C1—H1	105.6	C16—C18—H18A	109.5
C7—C2—C3	117.22 (15)	C16—C18—H18B	109.5
C7—C2—C1	123.63 (14)	H18A—C18—H18B	109.5
C3—C2—C1	119.15 (14)	C16—C18—H18C	109.5
C4—C3—C2	121.69 (17)	H18A—C18—H18C	109.5
C4—C3—H3	119.2	H18B—C18—H18C	109.5
C2—C3—H3	119.2	C26—C19—C20	107.00 (13)
C5—C4—C3	120.34 (18)	C26—C19—C1	125.84 (14)
C5—C4—H4	119.8	C20—C19—C1	127.15 (13)
C3—C4—H4	119.8	C21—C20—C25	118.45 (14)
O1—C5—C4	115.59 (19)	C21—C20—C19	134.46 (14)
O1—C5—C6	125.1 (2)	C25—C20—C19	107.09 (13)
C4—C5—C6	119.35 (17)	C22—C21—C20	119.45 (16)
C5—C6—C7	119.62 (18)	C22—C21—H21	120.3
C5—C6—H6	120.2	C20—C21—H21	120.3
C7—C6—H6	120.2	C21—C22—C23	121.13 (17)
C2—C7—C6	121.77 (17)	C21—C22—H22	119.4
C2—C7—H7	119.1	C23—C22—H22	119.4
C6—C7—H7	119.1	C24—C23—C22	120.98 (16)
O1—C8—H8A	109.5	C24—C23—H23	119.5
O1—C8—H8B	109.5	C22—C23—H23	119.5
H8A—C8—H8B	109.5	C23—C24—C25	117.91 (16)
O1—C8—H8C	109.5	C23—C24—H24	121.0
H8A—C8—H8C	109.5	C25—C24—H24	121.0
H8B—C8—H8C	109.5	N2—C25—C24	130.18 (15)
C16—C9—C10	106.89 (13)	N2—C25—C20	107.76 (13)
C16—C9—C1	123.61 (14)	C24—C25—C20	122.07 (15)
C10—C9—C1	129.50 (14)	C19—C26—N2	109.49 (13)
C11—C10—C15	117.53 (14)	C19—C26—C28	129.77 (14)
C11—C10—C9	135.90 (15)	N2—C26—C28	120.74 (13)
C15—C10—C9	106.57 (13)	N2—C27—H27A	109.5
C12—C11—C10	119.50 (15)	N2—C27—H27B	109.5
C12—C11—H11	120.2	H27A—C27—H27B	109.5
C10—C11—H11	120.2	N2—C27—H27C	109.5
C11—C12—C13	121.45 (16)	H27A—C27—H27C	109.5
C11—C12—H12	119.3	H27B—C27—H27C	109.5
C13—C12—H12	119.3	C26—C28—H28A	109.5
C14—C13—C12	121.14 (16)	C26—C28—H28B	109.5
C14—C13—H13	119.4	H28A—C28—H28B	109.5
C12—C13—H13	119.4	C26—C28—H28C	109.5
C13—C14—C15	117.65 (16)	H28A—C28—H28C	109.5
C13—C14—H14	121.2	H28B—C28—H28C	109.5
C15—C14—H14	121.2

Experimental details

Crystal data
Chemical formula	C₂₈H₂₈N₂O
M_r	408.52
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	296
a, b, c (Å)	10.6647 (8), 13.2088 (10), 16.1494 (13)
β (°)	97.174 (1)
V (Å³)	2257.1 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.25 × 0.24 × 0.21

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	11505, 3955, 3196
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.139, 0.83
No. of reflections	3955
No. of parameters	285
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.22

Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Acknowledgements

The work was supported by the National Natural Science Foundation of China (grant No. 20376071).

References

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