organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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Tetra­phenyl piperazine-1,4-diyldiphos­pho­nate

aDepartment of Chemistry, Ferdowsi University of Mashhad, Mashhad, 91779, Iran
*Correspondence e-mail: mehrdad_pourayoubi@yahoo.com

(Received 10 November 2010; accepted 17 November 2010; online 24 November 2010)

The mol­ecule of the title compound, C28H28N2O6P2, is organized around an inversion center located at the centre of the piperazine ring. Both piperazine N atoms are substituted by P(O)(OC6H5)2 phospho­ester groups. The P atoms display a slightly distorted tetra­hedral environment; the N atoms show some deviation from planarity. The O atoms of the P=O groups are involved in inter­molecular C—H⋯O hydrogen bonds, building R22(22) rings, in extended chains parallel to the a axis. C—H⋯π inter­actions involving the phenyl rings further stabilize the packing.

Related literature

For the physical properties of bis­phospho­ramidates, see: Nguyen & Kim (2008[Nguyen, C. & Kim, J. (2008). Polym. Degrad. Stabil. 93, 1037-1043.]). For related structures, see: Chen et al. (2007[Chen, X., Xiao, W. & Jiao, P. (2007). Acta Cryst. E63, o4271.]); Balakrishna et al. (2003[Balakrishna, M. S., George, P. P. & Mague, J. T. (2003). J. Chem. Res. pp. 576-577.], 2006[Balakrishna, M. S., George, P. P. & Mague, J. T. (2006). Phosphorus Sulfur Silicon Relat. Elem. 181, 141-146.]); Rodriguez i Zubiri et al. (2002[Rodriguez i Zubiri, M., Slawin, A. M. Z., Wainwright, M. & Woollins, J. D. (2002). Polyhedron, 21, 1729-1736.]). For hydrogen-bond motifs, see: Etter et al. (1990[Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256-262.]); Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C28H28N2O6P2

  • Mr = 550.46

  • Monoclinic, P 21 /n

  • a = 6.3117 (4) Å

  • b = 8.9530 (5) Å

  • c = 22.8630 (13) Å

  • β = 96.756 (1)°

  • V = 1282.99 (13) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.22 mm−1

  • T = 100 K

  • 0.55 × 0.40 × 0.20 mm

Data collection
  • Bruker APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.890, Tmax = 0.958

  • 14864 measured reflections

  • 3405 independent reflections

  • 3071 reflections with I > 2σ(I)

  • Rint = 0.025

Refinement
  • R[F2 > 2σ(F2)] = 0.032

  • wR(F2) = 0.089

  • S = 1.03

  • 3405 reflections

  • 172 parameters

  • H-atom parameters constrained

  • Δρmax = 0.51 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

Cg1 and Cg2 are the centroids of the C3–C8 and C11–C14 rings, respectively.

D—H⋯A D—H H⋯A DA D—H⋯A
C14—H14A⋯O1i 0.95 2.49 3.4327 (15) 172
C11—H11ACg1ii 0.95 2.74 3.3324 (12) 121
C7—H7ACg2iii 0.95 2.59 3.4099 (13) 145
Symmetry codes: (i) x+1, y, z; (ii) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]; (iii) x, y+1, z.

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEPIII (Burnett & Johnson, 1996[Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA.]), ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

The thermal behavior and flame retardancies of some bisphosphoramidates, with a P(O)XP(O) skeleton, such as the title compound have been investigated by Nguyen & Kim (2008). Here, we report the crystal structure of the title compound.

The molecule of the title compound is organized around inversion center located in the middle of the piperazine ring. Both the nitrogen atoms of the piperazine are substituted by the P(O)(OC6H5)2 phosphoester moieties (Fig. 1). The phosphorus atom has a distorted tetrahedral configuration with the bond angles in the range of 99.04 (4)° [O(2)–P(1)–O(3)] to 115.93 (5)° [O(1)–P(1)–O(2)]. As observed in related compounds containing piperazine ring substituted by phosphorus (Chen et al., 2007; Balakrishna et al., 2003, 2006; Rodriguez i Zubiri et al., 2002), the N atom shows some deviation from planarity, indeed it is 0.25 (1)Å above the C1, C2, P1 plane.

The oxygen atom of PO group are involved in a C–H···O hydrogen bond building a R22(22) ring (Etter et al., 1990; Bernstein et al., 1995) (Table 1, Fig. 2). Furthermore, these rings are interconnected building infinite chains parallel to the a axis. C–H···π interactions involving the phenyl rings stabilize the packing (Table 1).

Related literature top

For the physical properties of bisphosphoramidates, see: Nguyen & Kim (2008). For related structures, see: Chen et al. (2007); Balakrishna et al. (2003, 2006); Rodriguez i Zubiri et al. (2002). For hydrogen-bond motifs, see: Etter et al. (1990); Bernstein et al. (1995).

Experimental top

To a solution of (C6H5O)2P(O)Cl in chloroform, a solution of piperazine and triethylamine (2:1:2 mole ratio) in chloroform was added at 273 K. After 4 h stirring, the solvent was removed and product was washed with distilled water and recrystallized from chloroform/n-heptane at room temperature. IR (KBr, cm-1): 3051.2, 2913.8, 2866.3, 1592.5, 1490.4, 1383.3, 1334.6, 1261.7, 1198.5, 1135.3, 1067.1, 1013.7, 969.8, 931.6, 776.8, 686.8. Raman (cm-1): 3066.5, 2526.4, 1593.0, 1469.5, 1452.2, 1265.1, 1218.8, 1168.7, 1157.1, 1024.0, 1006.6, 939.2, 771.4, 705.8, 617.1, 414.6, 262.2. 31P{1H} NMR (202.45 MHz, DMSO-d6, 300.0 K, H3PO4 external): -1.45 p.p.m. (s). 1H NMR (500.13 MHz, DMSO-d6, 300.0 K, TMS): 3.01 (s, 8H, CH2), 7.15–7.27 (m, 12H, Ar—H), 7.38–7.40 p.p.m. (m, 8H, Ar—H). 13C NMR (125.75 MHz, DMSO-d6, 300.0 K, TMS): 43.98 (d, 2(&3)J(P,C) = 3.5 Hz, 4 C), 119.94 (d, 3J(P,C) = 4.7 Hz, 8 C, Cortho), 125.11 (s), 129.90 (s), 150.07 p.p.m. (d, 2J(P,C) = 6.4 Hz, 4 C, Cipso).

Refinement top

H atoms were placed in calculated positions and included in the refinement in a riding-model approximation with C–H = 0.93–0.97 Å, and Uiso(H) = 1.2Ueq(C).

Structure description top

The thermal behavior and flame retardancies of some bisphosphoramidates, with a P(O)XP(O) skeleton, such as the title compound have been investigated by Nguyen & Kim (2008). Here, we report the crystal structure of the title compound.

The molecule of the title compound is organized around inversion center located in the middle of the piperazine ring. Both the nitrogen atoms of the piperazine are substituted by the P(O)(OC6H5)2 phosphoester moieties (Fig. 1). The phosphorus atom has a distorted tetrahedral configuration with the bond angles in the range of 99.04 (4)° [O(2)–P(1)–O(3)] to 115.93 (5)° [O(1)–P(1)–O(2)]. As observed in related compounds containing piperazine ring substituted by phosphorus (Chen et al., 2007; Balakrishna et al., 2003, 2006; Rodriguez i Zubiri et al., 2002), the N atom shows some deviation from planarity, indeed it is 0.25 (1)Å above the C1, C2, P1 plane.

The oxygen atom of PO group are involved in a C–H···O hydrogen bond building a R22(22) ring (Etter et al., 1990; Bernstein et al., 1995) (Table 1, Fig. 2). Furthermore, these rings are interconnected building infinite chains parallel to the a axis. C–H···π interactions involving the phenyl rings stabilize the packing (Table 1).

For the physical properties of bisphosphoramidates, see: Nguyen & Kim (2008). For related structures, see: Chen et al. (2007); Balakrishna et al. (2003, 2006); Rodriguez i Zubiri et al. (2002). For hydrogen-bond motifs, see: Etter et al. (1990); Bernstein et al. (1995).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular view with the atom labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.
[Figure 2] Fig. 2. Partial packing view showing the formation of dimer through C–H···O interactions. H bonds are shown as dashed lines. [Symmetry codes: (ii) x+1, y, z]
Tetraphenyl piperazine-1,4-diyldiphosphonate top
Crystal data top
C28H28N2O6P2F(000) = 576
Mr = 550.46Dx = 1.425 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 2258 reflections
a = 6.3117 (4) Åθ = 3–29°
b = 8.9530 (5) ŵ = 0.22 mm1
c = 22.8630 (13) ÅT = 100 K
β = 96.756 (1)°Plate, colourless
V = 1282.99 (13) Å30.55 × 0.40 × 0.20 mm
Z = 2
Data collection top
Bruker APEXII CCD area-detector
diffractometer
3405 independent reflections
Radiation source: fine-focus sealed tube3071 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
ω scansθmax = 29.0°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 88
Tmin = 0.890, Tmax = 0.958k = 1212
14864 measured reflectionsl = 3031
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.089H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0496P)2 + 0.567P]
where P = (Fo2 + 2Fc2)/3
3405 reflections(Δ/σ)max = 0.002
172 parametersΔρmax = 0.51 e Å3
0 restraintsΔρmin = 0.27 e Å3
Crystal data top
C28H28N2O6P2V = 1282.99 (13) Å3
Mr = 550.46Z = 2
Monoclinic, P21/nMo Kα radiation
a = 6.3117 (4) ŵ = 0.22 mm1
b = 8.9530 (5) ÅT = 100 K
c = 22.8630 (13) Å0.55 × 0.40 × 0.20 mm
β = 96.756 (1)°
Data collection top
Bruker APEXII CCD area-detector
diffractometer
3405 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
3071 reflections with I > 2σ(I)
Tmin = 0.890, Tmax = 0.958Rint = 0.025
14864 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0320 restraints
wR(F2) = 0.089H-atom parameters constrained
S = 1.03Δρmax = 0.51 e Å3
3405 reflectionsΔρmin = 0.27 e Å3
172 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
xyzUiso*/Ueq
P10.29408 (4)0.70141 (3)0.584588 (12)0.01226 (9)
O10.08499 (13)0.65211 (10)0.59873 (4)0.01722 (18)
O20.30060 (14)0.86102 (9)0.55434 (4)0.01595 (17)
O30.46851 (13)0.72855 (9)0.63989 (3)0.01431 (17)
N10.40456 (15)0.59125 (11)0.54033 (4)0.01435 (19)
C10.27230 (18)0.49056 (13)0.50046 (5)0.0154 (2)
H1A0.21680.54520.46420.019*
H1B0.14900.45570.51980.019*
C20.59794 (18)0.64262 (13)0.51554 (5)0.0159 (2)
H2A0.68520.70540.54480.019*
H2B0.55640.70390.48000.019*
C30.24646 (19)0.99346 (12)0.58193 (5)0.0141 (2)
C40.03688 (19)1.04226 (13)0.57405 (5)0.0174 (2)
H4A0.07170.98310.55310.021*
C50.0111 (2)1.18012 (14)0.59758 (6)0.0213 (2)
H5A0.15381.21570.59250.026*
C60.1478 (2)1.26566 (14)0.62831 (6)0.0224 (3)
H6A0.11421.36030.64360.027*
C70.3561 (2)1.21302 (14)0.63680 (6)0.0221 (3)
H7A0.46421.27090.65860.026*
C80.40715 (19)1.07579 (14)0.61346 (5)0.0181 (2)
H8A0.54941.03930.61910.022*
C90.51165 (18)0.61794 (12)0.68335 (5)0.0136 (2)
C100.36396 (19)0.58904 (13)0.72215 (5)0.0160 (2)
H10A0.22950.63800.71810.019*
C110.4174 (2)0.48638 (14)0.76736 (5)0.0190 (2)
H11A0.31760.46380.79410.023*
C120.6154 (2)0.41695 (14)0.77356 (5)0.0203 (2)
H12A0.65180.34860.80490.024*
C130.7607 (2)0.44750 (14)0.73384 (6)0.0204 (2)
H13A0.89570.39930.73800.025*
C140.70950 (18)0.54823 (13)0.68798 (5)0.0168 (2)
H14A0.80750.56880.66050.020*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
P10.01325 (14)0.01125 (14)0.01239 (14)0.00080 (10)0.00199 (10)0.00088 (9)
O10.0147 (4)0.0193 (4)0.0182 (4)0.0001 (3)0.0038 (3)0.0014 (3)
O20.0226 (4)0.0125 (4)0.0133 (4)0.0031 (3)0.0041 (3)0.0003 (3)
O30.0169 (4)0.0121 (4)0.0136 (4)0.0012 (3)0.0001 (3)0.0006 (3)
N10.0137 (4)0.0127 (4)0.0170 (5)0.0015 (3)0.0031 (3)0.0035 (3)
C10.0135 (5)0.0158 (5)0.0170 (5)0.0008 (4)0.0017 (4)0.0036 (4)
C20.0165 (5)0.0133 (5)0.0187 (5)0.0013 (4)0.0054 (4)0.0029 (4)
C30.0207 (5)0.0103 (5)0.0116 (5)0.0014 (4)0.0039 (4)0.0008 (4)
C40.0195 (5)0.0157 (5)0.0166 (5)0.0005 (4)0.0005 (4)0.0003 (4)
C50.0238 (6)0.0170 (6)0.0240 (6)0.0060 (5)0.0065 (5)0.0036 (5)
C60.0344 (7)0.0118 (5)0.0229 (6)0.0006 (5)0.0112 (5)0.0009 (4)
C70.0290 (6)0.0170 (6)0.0206 (6)0.0073 (5)0.0049 (5)0.0026 (4)
C80.0191 (5)0.0177 (6)0.0179 (5)0.0020 (4)0.0033 (4)0.0012 (4)
C90.0165 (5)0.0107 (5)0.0130 (5)0.0004 (4)0.0004 (4)0.0008 (4)
C100.0174 (5)0.0157 (5)0.0150 (5)0.0024 (4)0.0027 (4)0.0012 (4)
C110.0249 (6)0.0178 (5)0.0148 (5)0.0005 (5)0.0045 (4)0.0005 (4)
C120.0268 (6)0.0166 (6)0.0167 (5)0.0024 (5)0.0011 (5)0.0019 (4)
C130.0181 (5)0.0180 (6)0.0245 (6)0.0037 (4)0.0006 (5)0.0001 (5)
C140.0154 (5)0.0157 (5)0.0195 (5)0.0000 (4)0.0021 (4)0.0016 (4)
Geometric parameters (Å, º) top
P1—O11.4633 (9)C5—C61.3855 (19)
P1—O21.5901 (9)C5—H5A0.9500
P1—O31.5944 (8)C6—C71.3885 (19)
P1—N11.6275 (10)C6—H6A0.9500
O2—C31.4040 (13)C7—C81.3923 (17)
O3—C91.4066 (13)C7—H7A0.9500
N1—C11.4702 (14)C8—H8A0.9500
N1—C21.4783 (14)C9—C101.3847 (16)
C1—C2i1.5155 (16)C9—C141.3889 (16)
C1—H1A0.9900C10—C111.3946 (16)
C1—H1B0.9900C10—H10A0.9500
C2—C1i1.5155 (16)C11—C121.3880 (18)
C2—H2A0.9900C11—H11A0.9500
C2—H2B0.9900C12—C131.3913 (18)
C3—C41.3846 (16)C12—H12A0.9500
C3—C81.3855 (17)C13—C141.3919 (17)
C4—C51.3937 (17)C13—H13A0.9500
C4—H4A0.9500C14—H14A0.9500
O1—P1—O2115.93 (5)C6—C5—H5A119.7
O1—P1—O3115.30 (5)C4—C5—H5A119.7
O2—P1—O399.04 (4)C5—C6—C7120.00 (11)
O1—P1—N1114.71 (5)C5—C6—H6A120.0
O2—P1—N1103.85 (5)C7—C6—H6A120.0
O3—P1—N1106.20 (5)C6—C7—C8120.27 (12)
C3—O2—P1122.92 (7)C6—C7—H7A119.9
C9—O3—P1120.74 (7)C8—C7—H7A119.9
C1—N1—C2112.78 (9)C3—C8—C7118.71 (11)
C1—N1—P1120.23 (8)C3—C8—H8A120.6
C2—N1—P1118.91 (7)C7—C8—H8A120.6
N1—C1—C2i110.39 (9)C10—C9—C14122.29 (11)
N1—C1—H1A109.6C10—C9—O3119.68 (10)
C2i—C1—H1A109.6C14—C9—O3117.89 (10)
N1—C1—H1B109.6C9—C10—C11118.39 (11)
C2i—C1—H1B109.6C9—C10—H10A120.8
H1A—C1—H1B108.1C11—C10—H10A120.8
N1—C2—C1i109.99 (9)C12—C11—C10120.49 (11)
N1—C2—H2A109.7C12—C11—H11A119.8
C1i—C2—H2A109.7C10—C11—H11A119.8
N1—C2—H2B109.7C11—C12—C13119.99 (11)
C1i—C2—H2B109.7C11—C12—H12A120.0
H2A—C2—H2B108.2C13—C12—H12A120.0
C4—C3—C8121.97 (11)C12—C13—C14120.44 (11)
C4—C3—O2119.17 (10)C12—C13—H13A119.8
C8—C3—O2118.76 (10)C14—C13—H13A119.8
C3—C4—C5118.47 (11)C9—C14—C13118.39 (11)
C3—C4—H4A120.8C9—C14—H14A120.8
C5—C4—H4A120.8C13—C14—H14A120.8
C6—C5—C4120.55 (12)
Symmetry code: (i) x+1, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of the C3–C8 and C11–C14 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C14—H14A···O1ii0.952.493.4327 (15)172
C11—H11A···Cg1iii0.952.743.3324 (12)121
C7—H7A···Cg2iv0.952.593.4099 (13)145
Symmetry codes: (ii) x+1, y, z; (iii) x+1/2, y1/2, z+3/2; (iv) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC28H28N2O6P2
Mr550.46
Crystal system, space groupMonoclinic, P21/n
Temperature (K)100
a, b, c (Å)6.3117 (4), 8.9530 (5), 22.8630 (13)
β (°) 96.756 (1)
V3)1282.99 (13)
Z2
Radiation typeMo Kα
µ (mm1)0.22
Crystal size (mm)0.55 × 0.40 × 0.20
Data collection
DiffractometerBruker APEXII CCD area-detector
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.890, 0.958
No. of measured, independent and
observed [I > 2σ(I)] reflections
14864, 3405, 3071
Rint0.025
(sin θ/λ)max1)0.682
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.089, 1.03
No. of reflections3405
No. of parameters172
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.51, 0.27

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of the C3–C8 and C11–C14 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C14—H14A···O1i0.952.493.4327 (15)171.6
C11—H11A···Cg1ii0.952.743.3324 (12)121.1
C7—H7A···Cg2iii0.952.593.4099 (13)144.8
Symmetry codes: (i) x+1, y, z; (ii) x+1/2, y1/2, z+3/2; (iii) x, y+1, z.
 

Acknowledgements

Support of this investigation by Ferdowsi University of Mashhad is gratefully acknowledged.

References

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