2,3,5,6-Tetra­methoxy­piperazine-1,4-dicarbaldehyde

Moosavi, S.M.; Taheri, A.

doi:10.1107/S1600536809035259

organic compounds

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ISSN: 2056-9890

Volume 65| Part 10| October 2009| Page o2338

doi:10.1107/S1600536809035259

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2,3,5,6-Tetramethoxypiperazine-1,4-dicarbaldehyde

Sayed Mojtaba Moosavi ^a and Amir Taheri ^a ^*

^aDepartment of Chemistry, Imam Hossein University, Tehran, Iran
^*Correspondence e-mail: amir.tahery1@gmail.com

(Received 24 August 2009; accepted 1 September 2009; online 5 September 2009)

The asymmetric unit of the title compound, C₁₀H₁₈N₂O₆, contains two halves of two independent centrosymmetric molecules with almost identical conformations. Weak intermolecular C—H⋯O hydrogen bonds consolidate the crystal packing.

Related literature

For details of the synthesis, see: Ferguson (1968a ,b ). For a closely related compound with acetyl substituents, see: Vedachalam et al. (1991 ). For anomeric interactions, see: Reed & Schleyer (1988 ). For glycoside structures, see: Schleifer et al. (1990 ).

Experimental

Crystal data

C₁₀H₁₈N₂O₆
M_r = 262.26
Monoclinic, P 2₁ /n
a = 14.331 (4) Å
b = 6.6044 (18) Å
c = 14.332 (4) Å
β = 114.800 (3)°
V = 1231.4 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 120 K
0.5 × 0.05 × 0.05 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1998 ) T_min = 0.980, T_max = 0.995
12344 measured reflections
2958 independent reflections
2242 reflections with I > 2σ(I)
R_int = 0.037

Refinement

R[F² > 2σ(F²)] = 0.059
wR(F²) = 0.127
S = 1.00
2958 reflections
168 parameters
H-atom parameters constrained
Δρ_max = 0.56 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5C⋯O6	0.96	2.53	3.260 (4)	133
C3—H3A⋯O1ⁱ	0.93	2.46	3.371 (3)	167
C8—H8A⋯O4ⁱⁱ	0.93	2.47	3.364 (4)	163
C10—H10B⋯O3ⁱⁱⁱ	0.96	2.60	3.208 (3)	122
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) $[-x+{\script{5\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iii) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 1998 ); cell refinement: SAINT-Plus (Bruker, 1998); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809035259/cv2606sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809035259/cv2606Isup2.hkl

checkCIF report

Comment top

The molecule of 1,4-diformyl-2,3,5,6-tetra-methoxypiperazine (Ferguson,1968a, b) (I), contains two formamyl groups in the two contrary-sides of the six-membered ring and four methoxy groups in the same axial situations. There are four asymmetric carbon atoms, S, S and R, R configuration which are mirror images of each other and diastereoisomer. The skeleton is symmetric by a central symmetry. The crystal contains two halves of two independent centrosymmetric molecules with almost identical conformations, which are comparable with similar molecule with acetyl substitutions (Vedachalam et al., 1991).

Despite the presence of six O and two N atoms carrying lone-pair electrons potentially are available for hydrogen-bond formation, there are, in fact, no powerful intramolecular C—H···N or C—H···O hydrogen bonds, rather some week C—H···O intermolecular interactions are observed (Table 1, Fig. 2).

The Properties of the anomeric effect in the infected system, n_O→σ*_C—Ninteractions are recognizable (Reed & Schleyer, 1988), The O—C bond is shorter than the C—N bond and the stability of gauche (axial) forms is definitely more than anti (equatorial) ones (Figure 1). This electron transfer results in lengthening the exocyclic anomeric C—O bonds, in the endocyclic contraction of the C—N bonds by increasing its double-bond character in the opening of the O—C—N angle as compared with its normal tetrahedral value. It can be considered that aa, ag and gg conformations of the C—O—C—N—C moieties, where a = anti (antiperiplanar) and g = gauche (synclinal) which aa and ag refer to equatorial and gg to axial. All of the Methoxy groups are in the gg conformations, comparable with gg in glycoside conformations that are more stable than aa, equatorial conformations (Schleifer et al., 1990). The acetyl groups as substitutions select axial positions than equatorials (Vedachalam et al., 1991).

In (I) via resonation of N-lone-pairs with pi-electrons of the carbonyl double-bond, N-pyramidalities (about 360°) are larger than natural forms (about 320°) at the same of molecule with acetyl substitutions (Vedachalam et al., 1991).

Related literature top

For details of the synthesis, see: Ferguson (1968a,b). For a closely related compound with acetyl substituents, see: Vedachalam et al. (1991). For anomeric interactions, see: Reed & Schleyer (1988). For glycoside structures, see: Schleifer et al. (1990).

Experimental top

1,4-Diformyltetrachloropiperazine (7.04 g,0.04 mol) (Ferguson, 1968a,b) were mixed with barium carbonate (78 g) and absolute methanol (32 ml, 0.79 mol) were added to the mixture and heated at 313 K for 3 h with stirring. The barium carbonate was filtered off and the methanol solution evaporated. The solid residue was extracted by 20 ml of hot chloroform and the extract evaporated to give white precipitation and washed with a little cold water and dried in oven by 303 K of temperature affording 1.83 g (70% yield) of (I). This solid was crystallized by hot mixture of methanol and benzene (m.p. 469 K). ¹HNMR (CDCl₃): δ_H 8.47 (s, 2H, CH), 5.29 (d, 2H, CH), 4.82 (d, 2H, CH), 3.21 (m, 12H,CH). ¹³C NMR (CDCl₃): δ_C165 (2CH), 83.4 (2CH), 79.1(2CH), 54.5 (6CH), 56.2 (6CH).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT-Plus (Bruker, 1998); data reduction: SAINT-Plus (Bruker, 1998); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. Two independent molecules of (I) showing the atomic numbering and 50% probability displacement ellipsoids [symmetry codes: (A) 1 - x, 1 - y , 1 - z; (B) 2 - x , 1 - y , 1 - z]. H atoms omitted for clarity.
	Fig. 2. A portion of the crystal packing viewed along crystallographic axis b. Dashed lines denote hydrogen bonds.

2,3,5,6-Tetramethoxypiperazine-1,4-dicarbaldehyde top

Crystal data top

C₁₀H₁₈N₂O₆	F(000) = 560
M_r = 262.26	D_x = 1.415 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1254 reflections
a = 14.331 (4) Å	θ = 2–25°
b = 6.6044 (18) Å	µ = 0.12 mm⁻¹
c = 14.332 (4) Å	T = 120 K
β = 114.800 (3)°	Needle, colourless
V = 1231.4 (6) Å³	0.5 × 0.05 × 0.05 mm
Z = 4

Data collection top

Bruker SMART 1000 CCD area-detector diffractometer	2958 independent reflections
Radiation source: fine-focus sealed tube	2242 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.037
ϕ and ω scans	θ_max = 28.0°, θ_min = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1998)	h = −18→18
T_min = 0.980, T_max = 0.995	k = −8→8
12344 measured reflections	l = −18→18

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)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.127	H-atom parameters constrained
S = 1.00	w = 1/[σ²(F_o²) + (0.0108P)² + 2.6266P] where P = (F_o² + 2F_c²)/3
2958 reflections	(Δ/σ)_max = 0.001
168 parameters	Δρ_max = 0.56 e Å⁻³
0 restraints	Δρ_min = −0.30 e Å⁻³

Crystal data top

C₁₀H₁₈N₂O₆	V = 1231.4 (6) Å³
M_r = 262.26	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 14.331 (4) Å	µ = 0.12 mm⁻¹
b = 6.6044 (18) Å	T = 120 K
c = 14.332 (4) Å	0.5 × 0.05 × 0.05 mm
β = 114.800 (3)°

Data collection top

Bruker SMART 1000 CCD area-detector diffractometer	2958 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1998)	2242 reflections with I > 2σ(I)
T_min = 0.980, T_max = 0.995	R_int = 0.037
12344 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.059	0 restraints
wR(F²) = 0.127	H-atom parameters constrained
S = 1.00	Δρ_max = 0.56 e Å⁻³
2958 reflections	Δρ_min = −0.30 e Å⁻³
168 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	0.67186 (15)	0.1494 (3)	0.66884 (16)	0.0354 (5)
O2	0.62334 (13)	0.7282 (3)	0.49476 (14)	0.0279 (4)
O3	0.55403 (13)	0.3233 (3)	0.39458 (14)	0.0291 (4)
O4	1.17420 (15)	0.1502 (3)	0.66699 (16)	0.0354 (5)
O5	0.99381 (14)	0.7197 (3)	0.62522 (15)	0.0311 (5)
O6	0.89855 (13)	0.3088 (3)	0.55478 (15)	0.0322 (5)
N1	0.59356 (15)	0.4210 (3)	0.56729 (16)	0.0237 (5)
N2	1.06918 (15)	0.4199 (4)	0.59207 (17)	0.0245 (5)
C1	0.58449 (18)	0.6410 (4)	0.5610 (2)	0.0239 (5)
H1A	0.6218	0.6977	0.6300	0.029*
C2	0.52907 (18)	0.2971 (4)	0.47925 (19)	0.0245 (5)
H2A	0.5365	0.1541	0.4993	0.029*
C3	0.66071 (19)	0.3326 (4)	0.6564 (2)	0.0260 (6)
H3A	0.7002	0.4165	0.7108	0.031*
C4	0.73438 (19)	0.7406 (5)	0.5418 (2)	0.0332 (7)
H4A	0.7577	0.7963	0.4934	0.050*
H4B	0.7628	0.6077	0.5618	0.050*
H4C	0.7563	0.8262	0.6013	0.050*
C5	0.6535 (2)	0.2490 (5)	0.4132 (2)	0.0360 (7)
H5A	0.6669	0.2731	0.3539	0.054*
H5B	0.6565	0.1063	0.4268	0.054*
H5C	0.7041	0.3176	0.4715	0.054*
C6	1.06031 (19)	0.6398 (4)	0.5843 (2)	0.0259 (6)
H6A	1.1287	0.6991	0.6214	0.031*
C7	0.98182 (18)	0.2938 (4)	0.5274 (2)	0.0268 (6)
H7A	1.0040	0.1522	0.5327	0.032*
C8	1.16039 (18)	0.3332 (4)	0.6578 (2)	0.0259 (6)
H8A	1.2143	0.4181	0.6972	0.031*
C9	1.0398 (2)	0.7262 (5)	0.7347 (2)	0.0384 (7)
H9A	0.9897	0.7693	0.7587	0.058*
H9B	1.0962	0.8199	0.7579	0.058*
H9C	1.0644	0.5939	0.7614	0.058*
C10	0.9185 (2)	0.2250 (6)	0.6521 (2)	0.0412 (8)
H10A	0.8587	0.2393	0.6657	0.062*
H10B	0.9753	0.2948	0.7041	0.062*
H10C	0.9351	0.0841	0.6526	0.062*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0309 (10)	0.0386 (13)	0.0360 (11)	0.0059 (9)	0.0134 (9)	0.0068 (9)
O2	0.0191 (8)	0.0373 (11)	0.0310 (10)	−0.0045 (8)	0.0141 (7)	0.0020 (8)
O3	0.0198 (8)	0.0421 (12)	0.0274 (9)	0.0021 (8)	0.0119 (7)	−0.0010 (9)
O4	0.0257 (9)	0.0393 (13)	0.0407 (12)	0.0066 (9)	0.0134 (9)	0.0067 (10)
O5	0.0205 (8)	0.0430 (12)	0.0334 (10)	0.0052 (8)	0.0148 (8)	−0.0060 (9)
O6	0.0167 (8)	0.0475 (13)	0.0341 (10)	0.0017 (8)	0.0124 (8)	0.0062 (9)
N1	0.0180 (9)	0.0285 (12)	0.0258 (11)	−0.0011 (8)	0.0103 (8)	0.0003 (9)
N2	0.0152 (9)	0.0295 (12)	0.0284 (11)	0.0010 (8)	0.0088 (8)	−0.0010 (9)
C1	0.0184 (11)	0.0290 (14)	0.0252 (12)	−0.0023 (10)	0.0099 (10)	−0.0007 (11)
C2	0.0177 (11)	0.0320 (15)	0.0256 (12)	−0.0008 (10)	0.0108 (10)	0.0005 (11)
C3	0.0184 (11)	0.0350 (16)	0.0260 (13)	0.0011 (11)	0.0107 (10)	0.0025 (11)
C4	0.0189 (12)	0.0384 (17)	0.0462 (17)	−0.0040 (11)	0.0175 (12)	−0.0005 (14)
C5	0.0220 (13)	0.0527 (19)	0.0379 (16)	0.0055 (13)	0.0172 (12)	−0.0032 (14)
C6	0.0171 (11)	0.0305 (15)	0.0312 (14)	0.0003 (10)	0.0112 (10)	−0.0049 (11)
C7	0.0172 (11)	0.0332 (15)	0.0313 (14)	0.0010 (10)	0.0113 (10)	−0.0033 (11)
C8	0.0153 (11)	0.0367 (16)	0.0275 (13)	0.0023 (10)	0.0107 (10)	0.0042 (12)
C9	0.0395 (16)	0.0463 (19)	0.0335 (15)	0.0073 (14)	0.0193 (13)	−0.0043 (14)
C10	0.0279 (14)	0.056 (2)	0.0452 (18)	0.0047 (14)	0.0203 (13)	0.0170 (16)

Geometric parameters (Å, º) top

O1—C3	1.224 (3)	C2—H2A	0.9800
O2—C1	1.409 (3)	C3—H3A	0.9300
O2—C4	1.447 (3)	C4—H4A	0.9600
O3—C2	1.412 (3)	C4—H4B	0.9600
O3—C5	1.423 (3)	C4—H4C	0.9600
O4—C8	1.223 (3)	C5—H5A	0.9600
O5—C6	1.414 (3)	C5—H5B	0.9600
O5—C9	1.425 (3)	C5—H5C	0.9600
O6—C7	1.408 (3)	C6—C7ⁱⁱ	1.519 (4)
O6—C10	1.414 (3)	C6—H6A	0.9800
N1—C3	1.367 (3)	C7—C6ⁱⁱ	1.519 (4)
N1—C1	1.458 (4)	C7—H7A	0.9800
N1—C2	1.462 (3)	C8—H8A	0.9300
N2—C8	1.375 (3)	C9—H9A	0.9600
N2—C6	1.458 (4)	C9—H9B	0.9600
N2—C7	1.465 (3)	C9—H9C	0.9600
C1—C2ⁱ	1.537 (3)	C10—H10A	0.9600
C1—H1A	0.9800	C10—H10B	0.9600
C2—C1ⁱ	1.537 (3)	C10—H10C	0.9600

C1—O2—C4	112.2 (2)	O3—C5—H5B	109.5
C2—O3—C5	113.0 (2)	H5A—C5—H5B	109.5
C6—O5—C9	112.8 (2)	O3—C5—H5C	109.5
C7—O6—C10	113.8 (2)	H5A—C5—H5C	109.5
C3—N1—C1	119.6 (2)	H5B—C5—H5C	109.5
C3—N1—C2	120.6 (2)	O5—C6—N2	113.1 (2)
C1—N1—C2	119.8 (2)	O5—C6—C7ⁱⁱ	106.9 (2)
C8—N2—C6	119.6 (2)	N2—C6—C7ⁱⁱ	110.5 (2)
C8—N2—C7	120.7 (2)	O5—C6—H6A	108.7
C6—N2—C7	119.6 (2)	N2—C6—H6A	108.7
O2—C1—N1	113.5 (2)	C7ⁱⁱ—C6—H6A	108.7
O2—C1—C2ⁱ	107.1 (2)	O6—C7—N2	112.5 (2)
N1—C1—C2ⁱ	109.9 (2)	O6—C7—C6ⁱⁱ	105.4 (2)
O2—C1—H1A	108.7	N2—C7—C6ⁱⁱ	111.1 (2)
N1—C1—H1A	108.7	O6—C7—H7A	109.3
C2ⁱ—C1—H1A	108.7	N2—C7—H7A	109.3
O3—C2—N1	112.1 (2)	C6ⁱⁱ—C7—H7A	109.3
O3—C2—C1ⁱ	104.8 (2)	O4—C8—N2	123.4 (3)
N1—C2—C1ⁱ	111.2 (2)	O4—C8—H8A	118.3
O3—C2—H2A	109.5	N2—C8—H8A	118.3
N1—C2—H2A	109.5	O5—C9—H9A	109.5
C1ⁱ—C2—H2A	109.5	O5—C9—H9B	109.5
O1—C3—N1	123.8 (3)	H9A—C9—H9B	109.5
O1—C3—H3A	118.1	O5—C9—H9C	109.5
N1—C3—H3A	118.1	H9A—C9—H9C	109.5
O2—C4—H4A	109.5	H9B—C9—H9C	109.5
O2—C4—H4B	109.5	O6—C10—H10A	109.5
H4A—C4—H4B	109.5	O6—C10—H10B	109.5
O2—C4—H4C	109.5	H10A—C10—H10B	109.5
H4A—C4—H4C	109.5	O6—C10—H10C	109.5
H4B—C4—H4C	109.5	H10A—C10—H10C	109.5
O3—C5—H5A	109.5	H10B—C10—H10C	109.5

C4—O2—C1—N1	−78.1 (3)	C9—O5—C6—N2	77.0 (3)
C4—O2—C1—C2ⁱ	160.4 (2)	C9—O5—C6—C7ⁱⁱ	−161.1 (2)
C3—N1—C1—O2	110.9 (3)	C8—N2—C6—O5	−111.3 (2)
C2—N1—C1—O2	−70.5 (3)	C7—N2—C6—O5	70.6 (3)
C3—N1—C1—C2ⁱ	−129.1 (2)	C8—N2—C6—C7ⁱⁱ	128.9 (2)
C2—N1—C1—C2ⁱ	49.4 (3)	C7—N2—C6—C7ⁱⁱ	−49.1 (3)
C5—O3—C2—N1	66.7 (3)	C10—O6—C7—N2	−67.6 (3)
C5—O3—C2—C1ⁱ	−172.6 (2)	C10—O6—C7—C6ⁱⁱ	171.2 (3)
C3—N1—C2—O3	−114.5 (3)	C8—N2—C7—O6	113.5 (3)
C1—N1—C2—O3	67.0 (3)	C6—N2—C7—O6	−68.5 (3)
C3—N1—C2—C1ⁱ	128.5 (2)	C8—N2—C7—C6ⁱⁱ	−128.7 (2)
C1—N1—C2—C1ⁱ	−50.0 (3)	C6—N2—C7—C6ⁱⁱ	49.4 (3)
C1—N1—C3—O1	178.7 (2)	C6—N2—C8—O4	−178.6 (2)
C2—N1—C3—O1	0.2 (4)	C7—N2—C8—O4	−0.5 (4)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5C···O6	0.96	2.53	3.260 (4)	133
C3—H3A···O1ⁱⁱⁱ	0.93	2.46	3.371 (3)	167
C8—H8A···O4^iv	0.93	2.47	3.364 (4)	163
C10—H10B···O3^v	0.96	2.60	3.208 (3)	122

Symmetry codes: (iii) −x+3/2, y+1/2, −z+3/2; (iv) −x+5/2, y+1/2, −z+3/2; (v) x+1/2, −y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formula	C₁₀H₁₈N₂O₆
M_r	262.26
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	120
a, b, c (Å)	14.331 (4), 6.6044 (18), 14.332 (4)
β (°)	114.800 (3)
V (Å³)	1231.4 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.12
Crystal size (mm)	0.5 × 0.05 × 0.05

Data collection
Diffractometer	Bruker SMART 1000 CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1998)
T_min, T_max	0.980, 0.995
No. of measured, independent and observed [I > 2σ(I)] reflections	12344, 2958, 2242
R_int	0.037
(sin θ/λ)_max (Å⁻¹)	0.660

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.059, 0.127, 1.00
No. of reflections	2958
No. of parameters	168
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.56, −0.30

Computer programs: SMART (Bruker, 1998), SAINT-Plus (Bruker, 1998), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5C···O6	0.96	2.53	3.260 (4)	133
C3—H3A···O1ⁱ	0.93	2.46	3.371 (3)	167
C8—H8A···O4ⁱⁱ	0.93	2.47	3.364 (4)	163
C10—H10B···O3ⁱⁱⁱ	0.96	2.60	3.208 (3)	122

Symmetry codes: (i) −x+3/2, y+1/2, −z+3/2; (ii) −x+5/2, y+1/2, −z+3/2; (iii) x+1/2, −y+1/2, z+1/2.

Acknowledgements

We thank the Chemistry Group of Imam Hossain University for their cooperation.

References

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