Tetra­phenyl piperazine-1,4-diyldiphos­pho­nate

Mehrdad Pourayoubi; Poorya Zargaran

doi:10.1107/S1600536810047860

. 2010 Nov 24;66(Pt 12):o3273–o3274. doi: 10.1107/S1600536810047860

Tetraphenyl piperazine-1,4-diyldiphosphonate

Mehrdad Pourayoubi ^a,^*, Poorya Zargaran ^a

PMCID: PMC3011784 PMID: 21589556

Abstract

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 R ₂ ²(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 ▶). 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

Crystal data

C₂₈H₂₈N₂O₆P₂
M _r = 550.46
Monoclinic,
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 ▶) T _min = 0.890, T _max = 0.958
14864 measured reflections
3405 independent reflections
3071 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.089
S = 1.03
3405 reflections
172 parameters
H-atom parameters constrained
Δρ_max = 0.51 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; 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.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810047860/dn2623sup1.cif

e-66-o3273-sup1.cif^{(16KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810047860/dn2623Isup2.hkl

e-66-o3273-Isup2.hkl^{(167KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

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	D⋯A	D—H⋯A
C14—H14A⋯O1ⁱ	0.95	2.49	3.4327 (15)	172
C11—H11A⋯Cg1ⁱⁱ	0.95	2.74	3.3324 (12)	121
C7—H7A⋯Cg2ⁱⁱⁱ	0.95	2.59	3.4099 (13)	145

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

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

supplementary crystallographic information

Comment

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 P═O 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).

Experimental

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, C_ortho), 125.11 (s), 129.90 (s), 150.07 p.p.m. (d, ²J(P,C) = 6.4 Hz, 4 C, C_ipso).