Di-μ2-ethano­lato-octa­methyl­bis­(μ-4-methyl-5-sulfanyl­idene-4,5-dihydro-1H-1,2,4-triazol-1-ido-κ2N1:N2)di-μ3-oxido-tetra­tin(IV)

Najafi, E.; Amini, M.M.; Ng, S.W.

doi:10.1107/S1600536812047708

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 12| December 2012| Page m1545

doi:10.1107/S1600536812047708

Open

access

Di-μ₂-ethanolato-octamethylbis(μ-4-methyl-5-sulfanylidene-4,5-dihydro-1H-1,2,4-triazol-1-ido-κ²N¹:N²)di-μ₃-oxido-tetratin(IV)

Ezzatollah Najafi,^a Mostafa M. Amini ^a and Seik Weng Ng ^b ^*

^aDepartment of Chemistry, General Campus, Shahid Beheshti University, Tehran 1983963113, Iran, and ^bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 17 November 2012; accepted 20 November 2012; online 28 November 2012)

The tetranuclear title compound, [Sn₄(CH₃)₈(C₂H₅O)₂O₂(C₃H₄N₃S)₂], lies about a center of inversion; the molecule features a three-rung-staircase Sn₄O₄ core in which two Sn^IV atoms are bridged by the 4-methyl-5-sulfanylidene-4,5-dihydro-1H-1,2,4-triazol-1-ide group. The negatively charged N atom of the group binds to the terminal Sn^IV atom at a shorter distance [Sn—N = 2.240 (3) Å] compared with the neutral N atom that binds to the central Sn^IV atom [Sn← N = 2.641 (3) Å]. The terminal Sn^IV atom is five-coordinate in a cis-C₂SnNO₂ trigonal–bipyramidal geometry [C—Sn—C = 127.5 (2)°], whereas the central Sn^IV atom is six-coordinate in a C₂SnNO₃ skew-trazepoidal bipyramidal geometry [C—Sn—C = 145.0 (2)°].

Related literature

For the [Sn₂O(CH₃)₄(CH₃O)(C₃H₄N₃S)]₂ homolog, see: Najafi et al. (2011 ).

Experimental

Crystal data

[Sn₄(CH₃)₈(C₂H₅O)₂O₂(C₃H₄N₃S)₂]
M_r = 945.46
Monoclinic, P 2₁ /n
a = 9.3965 (4) Å
b = 17.8939 (7) Å
c = 9.9084 (4) Å
β = 103.036 (4)°
V = 1623.06 (11) Å³
Z = 2
Mo Kα radiation
μ = 3.20 mm⁻¹
T = 100 K
0.30 × 0.25 × 0.20 mm

Data collection

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012 ) T_min = 0.447, T_max = 0.567
15728 measured reflections
3743 independent reflections
3280 reflections with I > 2σ(I)
R_int = 0.037

Refinement

R[F² > 2σ(F²)] = 0.026
wR(F²) = 0.065
S = 1.04
3743 reflections
155 parameters
H-atom parameters constrained
Δρ_max = 0.75 e Å⁻³
Δρ_min = −0.67 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536812047708/bt6863sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812047708/bt6863Isup2.hkl

checkCIF report

Comment top

The title compound (Scheme I, Fig. 1), a distannoxane, was the unexpected product from an attempt at synthesizing a dimethyltin 4-methyl-4H-1,2,4-triazol-3-thiolate that possesses a tin-sulfur linkage. In the reaction of diorganotin oxides with organic acids (particularly carboxylic acids), tetranuclear distannoxanes are sometimes formed; these compounds have four organic groups. In the present reaction, two of the four organic groups are replaced by ethoxide groups.

Tetranuclear Sn₄O₂(CH₃)₈(C₂H₅O)₂(C₃H₄N₃S)₂ lies about a center-of-inversion; the molecule features a three-rung-staircase Sn₄O₄ core in which two Sn atoms are bridged by the C₃H₄N₃S triazolate group. The negatively-charged N atom of the group binds to the terminal Sn atom at a shorter distance [Sn–N 2.240 (3) Å] compared with the neutral N atom that binds to the central Sn atom [Sn←N 2.641 (3) Å]. The terminal Sn atom is five-coordinate in a cis-C₃SnNO trigonal bipyramid whereas the central Sn atom is six-coordinate in a C₂SnNO₃ skew-trazepoidal bipyramidal geometry.

Related literature top

For the [Sn₂O(CH₃)₄(CH₃O)(C₃H₄N₃S)]₂ homolog, see: Najafi et al. (2011).

Experimental top

Dimethyltin diisothiocyanate (1 mmol), 4-methyl-4H-1,2,4-triazole-3-thiol (1 mmol) and 1,10-phenanthroline (1 mmol) were loaded into a convection tube; several drops of triethylamine were added. The tube was filled with dry ethanol and kept at 333 K. Colorless crystals were collected from the side arm after several days.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of Sn₄O₂(CH₃)₈(C₂H₅O)₂(C₃H₄N₃S)₂ at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.

Di-µ₂-ethanolato-octamethylbis(µ-4-methyl-5-sulfanylidene-4,5-dihydro- 1H-1,2,4-triazolido-κ²N¹:N²)di-µ₃-oxido- tetratin(IV) top

Crystal data top

[Sn₄(CH₃)₈(C₂H₅O)₂O₂(C₃H₄N₃S)₂]	F(000) = 912
M_r = 945.46	D_x = 1.935 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 6388 reflections
a = 9.3965 (4) Å	θ = 2.9–27.5°
b = 17.8939 (7) Å	µ = 3.20 mm⁻¹
c = 9.9084 (4) Å	T = 100 K
β = 103.036 (4)°	Prism, colorless
V = 1623.06 (11) Å³	0.30 × 0.25 × 0.20 mm
Z = 2

Data collection top

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer	3743 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	3280 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.037
Detector resolution: 10.4041 pixels mm^-1	θ_max = 27.6°, θ_min = 2.9°
ω scan	h = −11→12
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012)	k = −23→21
T_min = 0.447, T_max = 0.567	l = −11→12
15728 measured reflections

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)] = 0.026	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.065	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0302P)² + 2.3203P] where P = (F_o² + 2F_c²)/3
3743 reflections	(Δ/σ)_max = 0.001
155 parameters	Δρ_max = 0.75 e Å⁻³
0 restraints	Δρ_min = −0.67 e Å⁻³

Crystal data top

[Sn₄(CH₃)₈(C₂H₅O)₂O₂(C₃H₄N₃S)₂]	V = 1623.06 (11) Å³
M_r = 945.46	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 9.3965 (4) Å	µ = 3.20 mm⁻¹
b = 17.8939 (7) Å	T = 100 K
c = 9.9084 (4) Å	0.30 × 0.25 × 0.20 mm
β = 103.036 (4)°

Data collection top

Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer	3743 independent reflections
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012)	3280 reflections with I > 2σ(I)
T_min = 0.447, T_max = 0.567	R_int = 0.037
15728 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.026	0 restraints
wR(F²) = 0.065	H-atom parameters constrained
S = 1.04	Δρ_max = 0.75 e Å⁻³
3743 reflections	Δρ_min = −0.67 e Å⁻³
155 parameters

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

	x	y	z	U_iso*/U_eq
Sn1	0.37077 (2)	0.436391 (12)	0.49959 (2)	0.01497 (7)
Sn2	0.70638 (2)	0.467990 (13)	0.80539 (2)	0.01507 (7)
S1	0.69104 (11)	0.33447 (6)	1.09067 (10)	0.0342 (2)
O1	0.5639 (2)	0.48179 (13)	0.6221 (2)	0.0182 (5)
O2	0.7909 (3)	0.55849 (14)	0.7058 (2)	0.0200 (5)
N1	0.4168 (3)	0.36557 (17)	0.7393 (3)	0.0224 (6)
N2	0.5475 (3)	0.37949 (17)	0.8347 (3)	0.0199 (6)
N3	0.4324 (3)	0.29205 (17)	0.9189 (3)	0.0233 (6)
C1	0.4547 (4)	0.3342 (2)	0.4438 (4)	0.0253 (8)
H1A	0.5373	0.3442	0.4012	0.038*
H1B	0.3782	0.3076	0.3777	0.038*
H1C	0.4877	0.3034	0.5268	0.038*
C2	0.2100 (4)	0.4864 (2)	0.5902 (4)	0.0265 (8)
H2A	0.2210	0.5408	0.5902	0.040*
H2B	0.2221	0.4686	0.6857	0.040*
H2C	0.1125	0.4727	0.5366	0.040*
C3	0.8781 (4)	0.3928 (2)	0.7987 (4)	0.0276 (8)
H3A	0.9637	0.4208	0.7859	0.041*
H3B	0.8469	0.3579	0.7214	0.041*
H3C	0.9034	0.3647	0.8858	0.041*
C4	0.6810 (4)	0.5344 (2)	0.9736 (3)	0.0247 (8)
H4A	0.7441	0.5785	0.9803	0.037*
H4B	0.7081	0.5054	1.0594	0.037*
H4C	0.5789	0.5504	0.9595	0.037*
C5	0.3523 (4)	0.3131 (2)	0.7935 (3)	0.0236 (7)
H5	0.2603	0.2921	0.7505	0.028*
C6	0.4001 (5)	0.2340 (2)	1.0099 (4)	0.0343 (9)
H6A	0.3039	0.2124	0.9699	0.051*
H6B	0.3999	0.2555	1.1008	0.051*
H6C	0.4747	0.1948	1.0204	0.051*
C7	0.5556 (4)	0.3356 (2)	0.9450 (3)	0.0212 (7)
C8	0.9254 (4)	0.5956 (2)	0.7578 (4)	0.0239 (7)
H8A	0.9841	0.5950	0.6864	0.029*
H8B	0.9809	0.5685	0.8400	0.029*
C9	0.9025 (5)	0.6751 (2)	0.7972 (5)	0.0381 (10)
H9A	0.9974	0.6990	0.8327	0.057*
H9B	0.8458	0.6758	0.8689	0.057*
H9C	0.8493	0.7024	0.7155	0.057*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sn1	0.01475 (12)	0.01498 (13)	0.01399 (11)	−0.00248 (8)	0.00072 (8)	0.00005 (8)
Sn2	0.01482 (12)	0.01626 (13)	0.01265 (11)	0.00072 (8)	−0.00002 (8)	−0.00025 (8)
S1	0.0269 (5)	0.0421 (6)	0.0294 (5)	0.0007 (4)	−0.0028 (4)	0.0170 (4)
O1	0.0186 (12)	0.0190 (12)	0.0146 (11)	−0.0030 (10)	−0.0011 (9)	0.0042 (9)
O2	0.0177 (12)	0.0203 (13)	0.0190 (12)	−0.0075 (10)	−0.0018 (9)	0.0009 (9)
N1	0.0239 (16)	0.0221 (16)	0.0198 (14)	−0.0062 (13)	0.0017 (11)	−0.0017 (11)
N2	0.0179 (14)	0.0235 (16)	0.0154 (13)	−0.0038 (12)	−0.0021 (10)	0.0026 (11)
N3	0.0275 (17)	0.0184 (16)	0.0251 (15)	−0.0027 (13)	0.0083 (12)	0.0011 (12)
C1	0.031 (2)	0.022 (2)	0.0214 (17)	0.0031 (16)	0.0031 (14)	−0.0010 (14)
C2	0.0229 (19)	0.036 (2)	0.0215 (17)	0.0055 (16)	0.0056 (14)	−0.0044 (15)
C3	0.0238 (19)	0.025 (2)	0.034 (2)	0.0090 (16)	0.0073 (15)	0.0025 (15)
C4	0.029 (2)	0.027 (2)	0.0198 (17)	−0.0050 (16)	0.0076 (14)	−0.0073 (14)
C5	0.0273 (19)	0.0212 (19)	0.0222 (17)	−0.0050 (15)	0.0056 (14)	−0.0048 (13)
C6	0.043 (2)	0.024 (2)	0.039 (2)	−0.0082 (18)	0.0167 (18)	0.0084 (16)
C7	0.0218 (18)	0.0180 (18)	0.0242 (17)	0.0023 (14)	0.0062 (13)	0.0017 (13)
C8	0.0184 (17)	0.025 (2)	0.0285 (18)	−0.0033 (15)	0.0049 (14)	−0.0017 (14)
C9	0.030 (2)	0.030 (2)	0.050 (3)	−0.0106 (18)	0.0016 (18)	−0.0093 (18)

Geometric parameters (Å, º) top

Sn1—O1ⁱ	2.076 (2)	C1—H1B	0.9800
Sn1—O1	2.106 (2)	C1—H1C	0.9800
Sn1—C1	2.114 (4)	C2—H2A	0.9800
Sn1—C2	2.121 (4)	C2—H2B	0.9800
Sn1—O2ⁱ	2.250 (2)	C2—H2C	0.9800
Sn1—N1	2.641 (3)	C3—H3A	0.9800
Sn2—O1	2.013 (2)	C3—H3B	0.9800
Sn2—C4	2.105 (3)	C3—H3C	0.9800
Sn2—C3	2.114 (4)	C4—H4A	0.9800
Sn2—O2	2.140 (2)	C4—H4B	0.9800
Sn2—N2	2.240 (3)	C4—H4C	0.9800
S1—C7	1.695 (4)	C5—H5	0.9500
O1—Sn1ⁱ	2.076 (2)	C6—H6A	0.9800
O2—C8	1.418 (4)	C6—H6B	0.9800
O2—Sn1ⁱ	2.250 (2)	C6—H6C	0.9800
N1—C5	1.297 (5)	C8—C9	1.503 (6)
N1—N2	1.393 (4)	C8—H8A	0.9900
N2—C7	1.334 (4)	C8—H8B	0.9900
N3—C5	1.353 (4)	C9—H9A	0.9800
N3—C7	1.371 (5)	C9—H9B	0.9800
N3—C6	1.452 (5)	C9—H9C	0.9800
C1—H1A	0.9800

O1ⁱ—Sn1—O1	74.55 (9)	H1A—C1—H1C	109.5
O1ⁱ—Sn1—C1	106.36 (12)	H1B—C1—H1C	109.5
O1—Sn1—C1	99.22 (12)	Sn1—C2—H2A	109.5
O1ⁱ—Sn1—C2	106.31 (13)	Sn1—C2—H2B	109.5
O1—Sn1—C2	101.36 (12)	H2A—C2—H2B	109.5
C1—Sn1—C2	144.96 (16)	Sn1—C2—H2C	109.5
O1ⁱ—Sn1—O2ⁱ	70.95 (8)	H2A—C2—H2C	109.5
O1—Sn1—O2ⁱ	145.49 (9)	H2B—C2—H2C	109.5
C1—Sn1—O2ⁱ	90.83 (12)	Sn2—C3—H3A	109.5
C2—Sn1—O2ⁱ	88.04 (12)	Sn2—C3—H3B	109.5
O1ⁱ—Sn1—N1	148.36 (9)	H3A—C3—H3B	109.5
O1—Sn1—N1	73.83 (9)	Sn2—C3—H3C	109.5
C1—Sn1—N1	79.92 (12)	H3A—C3—H3C	109.5
C2—Sn1—N1	79.00 (12)	H3B—C3—H3C	109.5
O2ⁱ—Sn1—N1	140.66 (9)	Sn2—C4—H4A	109.5
O1—Sn2—C4	118.29 (13)	Sn2—C4—H4B	109.5
O1—Sn2—C3	114.01 (12)	H4A—C4—H4B	109.5
C4—Sn2—C3	127.46 (15)	Sn2—C4—H4C	109.5
O1—Sn2—O2	74.44 (9)	H4A—C4—H4C	109.5
C4—Sn2—O2	93.32 (12)	H4B—C4—H4C	109.5
C3—Sn2—O2	95.86 (13)	N1—C5—N3	111.5 (3)
O1—Sn2—N2	82.92 (9)	N1—C5—H5	124.3
C4—Sn2—N2	95.66 (13)	N3—C5—H5	124.3
C3—Sn2—N2	95.15 (14)	N3—C6—H6A	109.5
O2—Sn2—N2	157.27 (9)	N3—C6—H6B	109.5
Sn2—O1—Sn1ⁱ	112.77 (11)	H6A—C6—H6B	109.5
Sn2—O1—Sn1	141.62 (12)	N3—C6—H6C	109.5
Sn1ⁱ—O1—Sn1	105.45 (9)	H6A—C6—H6C	109.5
C8—O2—Sn2	125.4 (2)	H6B—C6—H6C	109.5
C8—O2—Sn1ⁱ	132.4 (2)	N2—C7—N3	106.8 (3)
Sn2—O2—Sn1ⁱ	101.70 (9)	N2—C7—S1	126.7 (3)
C5—N1—N2	105.8 (3)	N3—C7—S1	126.4 (3)
C5—N1—Sn1	136.2 (2)	O2—C8—C9	111.7 (3)
N2—N1—Sn1	117.7 (2)	O2—C8—H8A	109.3
C7—N2—N1	109.2 (3)	C9—C8—H8A	109.3
C7—N2—Sn2	127.3 (2)	O2—C8—H8B	109.3
N1—N2—Sn2	123.4 (2)	C9—C8—H8B	109.3
C5—N3—C7	106.7 (3)	H8A—C8—H8B	108.0
C5—N3—C6	128.2 (3)	C8—C9—H9A	109.5
C7—N3—C6	125.1 (3)	C8—C9—H9B	109.5
Sn1—C1—H1A	109.5	H9A—C9—H9B	109.5
Sn1—C1—H1B	109.5	C8—C9—H9C	109.5
H1A—C1—H1B	109.5	H9A—C9—H9C	109.5
Sn1—C1—H1C	109.5	H9B—C9—H9C	109.5

C4—Sn2—O1—Sn1ⁱ	88.55 (16)	O1ⁱ—Sn1—N1—N2	−9.0 (3)
C3—Sn2—O1—Sn1ⁱ	−86.31 (16)	O1—Sn1—N1—N2	−6.9 (2)
O2—Sn2—O1—Sn1ⁱ	3.23 (10)	C1—Sn1—N1—N2	95.9 (3)
N2—Sn2—O1—Sn1ⁱ	−178.81 (13)	C2—Sn1—N1—N2	−112.3 (3)
C4—Sn2—O1—Sn1	−96.9 (2)	O2ⁱ—Sn1—N1—N2	174.7 (2)
C3—Sn2—O1—Sn1	88.2 (2)	C5—N1—N2—C7	−1.2 (4)
O2—Sn2—O1—Sn1	177.8 (2)	Sn1—N1—N2—C7	−176.1 (2)
N2—Sn2—O1—Sn1	−4.3 (2)	C5—N1—N2—Sn2	−177.7 (2)
O1ⁱ—Sn1—O1—Sn2	−174.8 (3)	Sn1—N1—N2—Sn2	7.5 (3)
C1—Sn1—O1—Sn2	−70.2 (2)	O1—Sn2—N2—C7	−179.2 (3)
C2—Sn1—O1—Sn2	81.3 (2)	C4—Sn2—N2—C7	−61.3 (3)
O2ⁱ—Sn1—O1—Sn2	−175.41 (15)	C3—Sn2—N2—C7	67.2 (3)
N1—Sn1—O1—Sn2	6.38 (19)	O2—Sn2—N2—C7	−174.1 (3)
O1ⁱ—Sn1—O1—Sn1ⁱ	0.0	O1—Sn2—N2—N1	−3.4 (3)
C1—Sn1—O1—Sn1ⁱ	104.54 (13)	C4—Sn2—N2—N1	114.5 (3)
C2—Sn1—O1—Sn1ⁱ	−103.98 (14)	C3—Sn2—N2—N1	−117.0 (3)
O2ⁱ—Sn1—O1—Sn1ⁱ	−0.7 (2)	O2—Sn2—N2—N1	1.7 (4)
N1—Sn1—O1—Sn1ⁱ	−178.86 (13)	N2—N1—C5—N3	0.3 (4)
O1—Sn2—O2—C8	−175.8 (3)	Sn1—N1—C5—N3	173.6 (2)
C4—Sn2—O2—C8	65.7 (3)	C7—N3—C5—N1	0.7 (4)
C3—Sn2—O2—C8	−62.5 (3)	C6—N3—C5—N1	−178.0 (4)
N2—Sn2—O2—C8	178.9 (3)	N1—N2—C7—N3	1.7 (4)
O1—Sn2—O2—Sn1ⁱ	−2.81 (9)	Sn2—N2—C7—N3	177.9 (2)
C4—Sn2—O2—Sn1ⁱ	−121.28 (13)	N1—N2—C7—S1	−177.6 (3)
C3—Sn2—O2—Sn1ⁱ	110.52 (13)	Sn2—N2—C7—S1	−1.3 (5)
N2—Sn2—O2—Sn1ⁱ	−8.1 (3)	C5—N3—C7—N2	−1.5 (4)
O1ⁱ—Sn1—N1—C5	178.2 (3)	C6—N3—C7—N2	177.3 (3)
O1—Sn1—N1—C5	−179.7 (4)	C5—N3—C7—S1	177.8 (3)
C1—Sn1—N1—C5	−76.9 (4)	C6—N3—C7—S1	−3.4 (5)
C2—Sn1—N1—C5	75.0 (4)	Sn2—O2—C8—C9	−112.7 (3)
O2ⁱ—Sn1—N1—C5	1.9 (4)	Sn1ⁱ—O2—C8—C9	76.5 (4)

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	[Sn₄(CH₃)₈(C₂H₅O)₂O₂(C₃H₄N₃S)₂]
M_r	945.46
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	9.3965 (4), 17.8939 (7), 9.9084 (4)
β (°)	103.036 (4)
V (Å³)	1623.06 (11)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	3.20
Crystal size (mm)	0.30 × 0.25 × 0.20

Data collection
Diffractometer	Agilent SuperNova (Dual, Cu at zero, Atlas) diffractometer
Absorption correction	Multi-scan (CrysAlis PRO; Agilent, 2012)
T_min, T_max	0.447, 0.567
No. of measured, independent and observed [I > 2σ(I)] reflections	15728, 3743, 3280
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.651

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.026, 0.065, 1.04
No. of reflections	3743
No. of parameters	155
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.75, −0.67

Computer programs: CrysAlis PRO (Agilent, 2012), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2010).

Acknowledgements

We thank Shahid Beheshti University and the Ministry of Higher Education of Malaysia (grant No. UM.C/HIR/MOHE/SC/12) for supporting this study.

References

Agilent (2012). CrysAlis PRO. Agilent Technologies, Yarnton, England. Google Scholar
Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
Najafi, E., Amini, M. M. & Ng, S. W. (2011). Acta Cryst. E67, m242. 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
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. 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.