(SP,SP)-(–)-(E)-1,2-Bis(methyl­phenyl­phosphino­yl)ethene

Butenschön, H.; Vinokurov, N.; Baumgardt, I.; Pietrusiewicz, K.M.

doi:10.1107/S1600536809004632

organic compounds

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ISSN: 2056-9890

Volume 65| Part 3| March 2009| Page o517

doi:10.1107/S1600536809004632

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(S_P,S_P)-(–)-(E)-1,2-Bis(methylphenylphosphinoyl)ethene

Holger Butenschön,^a ^* Nikolai Vinokurov,^a Ingmar Baumgardt ^a and K. Michal Pietrusiewicz ^b

^aInstitut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany, and ^bDepartment of Organic Chemistry, Maria Curie-Sklodowska-University Lublin, ul. Gliniana 33, Lublin, PL-20-614, Poland
^*Correspondence e-mail: holger.butenschoen@mbox.oci.uni-hannover.de

(Received 16 December 2008; accepted 9 February 2009; online 13 February 2009)

The title compound, C₁₆H₁₈O₂P₂, possesses two stereogenic P atoms and shows a distorted s–cis conformation of each O=P—C=C moiety. This has been suggested on the basis of the stereochemical result of 1,3-dipolar cycloadditions with nitrones and is now confirmed by the present crystal structure analysis. There are two crystallographically independent molecules in the asymmetric unit.

Related literature

For optically active P-stereogenic 1,2-diphosphinoethanes and diphosphane dioxides, see: Crepy & Imamoto (2003a ,b ); Glueck (2008 ); Knowles (1983 , 2002 ); Pietrusiewicz & Zablocka (1988 ); Demchuk et al. (2003 ); Vinokurov et al. (2006 ); Vinokurov, Garabatos-Perera et al. (2008 ) and Vinokurov, Pietrusiewicz et al. (2008 ). For the structures of (–)-(S_P)-methylphenylphosphine oxide and (+)-(R_P)-(tert-butylvinylphosphinoyl)benzene, see: Pietrusiewicz et al. (1991 ); Szmigielska et al. (2006 ). For the determination of the absolute configuration of the stereogenic centers for the title compound, see: Pietrusiewicz et al. (1984 , 1991) and Vinokurov, Pietrusiewicz et al. (2008).

Experimental

Crystal data

C₁₆H₁₈O₂P₂
M_r = 304.24
Monoclinic, P 2₁
a = 11.686 (5) Å
b = 5.5291 (15) Å
c = 24.132 (10) Å
β = 96.36 (5)°
V = 1549.7 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.28 mm⁻¹
T = 297 K
0.35 × 0.29 × 0.18 mm

Data collection

Stoe IPDS diffractometer
Absorption correction: multi-scan (Blessing, 1995 ) T_min = 0.927, T_max = 0.953
20851 measured reflections
6041 independent reflections
4640 reflections with I > 2σ(I)
R_int = 0.067

Refinement

R[F² > 2σ(F²)] = 0.041
wR(F²) = 0.097
S = 0.99
6041 reflections
361 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.19 e Å⁻³
Absolute structure: Flack (1983 ), 2656 Friedel pairs
Flack parameter: 0.01 (9)

Data collection: IPDS (Stoe & Cie, 1999 ); cell refinement: IPDS; data reduction: IPDS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ) and WinGX (Farrugia, 1999 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: enCIFer (Allen et al., 2004 ) and publCIF (Westrip, 2009 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809004632/jh2072sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809004632/jh2072Isup2.hkl

checkCIF report

Comment top

Optically active P-stereogenic 1,2-diphosphinoethanes constitute an important class of chiral bidentate ligands of great practical utility in the field of asymmetric catalysis (Crepy & Imamoto, 2003, Glueck, 2008, Knowles, 1983, 2002). The corresponding P-stereogenic diphosphane dioxides, which are the most direct precursors to such ligands, have recently been shown to be easily accessible through a simple conjugate addition of secondary phosphine oxides to the homochiral (–)-(S_P)-methylphenylphosphine oxide oxide (Pietrusiewicz & Zablocka, 1988). Recently, we reported on the synthesis of (S_P,S_P)-(–)-(E)-ethene-1,2-diylbis[methyl(phenyl)phosphine] dioxide (1) by the homo cross-metathesis reaction of (S)-methylphenylvinylphosphine oxide (Demchuk et al., 2003, Vinokurov et al., 2008, Vinokurov et al., 2006) and then studied the reactivity of 1 in 1,3-dipolar cycloadditions with acyclic nitrones to achieve new bidentate P-stereogenic phosphane ligands after stereospecific reduction (Vinokurov et al., 2008).

Although we have recently postulated the di-s-cis conformation of 1 as the reactive conformation in the thermal 1,3-dipolar cycloaddition, no experimental evidence with regard to the conformation of 1 has yet been reported. However, the structure of the related (–)-(S_P)-methylphenylphosphine oxide (Pietrusiewicz et al., 1991) and (+)-(R_P)-(tert-butylvinylphosphinoyl)benzene have recently been reported (Szmigielska et al., 2006). Herein, we describe the solid state structure of (S_P,S_P)-(–)-(E)-ethene-1,2-diylbis[methyl(phenyl)phosphine] dioxide (1), which has been obtained by a single-crystal X-ray structure analysis.

The molecular structure of 1 is displayed in Fig. 1. The absolute configuration of the stereogenic centers has not been determined crystallographically but is evident from that of the starting material (Pietrusiewicz et al., 1984, Pietrusiewicz et al., 1991) as well as from the crystal structure analysis of a cycloaddition product (Vinokurov et al., 2008). The largest substituents of each phosphorus atom are placed in the most distant zigzag positions, and the P1=O1 and P2=O2 dipoles are oriented in opposite directions relative to one another. The deviation from planarity of the O=P—C=C—P=O is reflected by the torsional angles given in Table 1.

As typical for compounds of type R₃P=O deformations of the tetrahedral environment of the P atoms cause an increase of the O—P—C and the simultaneous decrease of the C—P—C valency angles. The values observed fall in the range of 110.28 (15) - 115.80 (17)° and 101.69 (17) - 107.26 (15)° for P1 and, 110.87 (15)° - 114.73 (15)° and 102.42 (17) - 107.94 (14)° for P2, respectively.

DFT calculations show the observed conformation to be more stable than the corresponding di-s-trans conformation by 16.54 kJ/mol (TURBOMOLE 5.7 Method BP86/SV(P).

Related literature top

For optically active P-stereogenic 1,2-diphosphinoethanes and diphosphane dioxides see: Crepy & Imamoto (2003a,b), Glueck (2008), Knowles (1983, 2002), Pietrusiewicz & Zablocka (1988), Demchuk et al. (2003), Vinokurov et al. (2006), Vinokurov, Garabatos-Perera et al. (2008), Vinokurov, Pietrusiewicz et al. (2008). For the structures of (–)-(S_P)-methylphenylphosphine oxide and (+)-(R_P)-(tert-butylvinylphosphinoyl)benzene see: Pietrusiewicz et al. (1991) and Szmigielska et al. (2006). For the determination of the absolute configuration of the stereogenic centers for 1 see Pietrusiewicz et al. (1984, 1991) and Vinokurov, Pietrusiewicz et al. (2008).

Experimental top

For the preparation of (S_P,S_P)-(-)-(E)-1,2-bis(methylphenylphosphinoyl)ethene (1) see Vinokurov et al. (2006).

Computing details top

Data collection: IPDS (Stoe & Cie, 1999); cell refinement: IPDS (Stoe & Cie, 1999); data reduction: IPDS (Stoe & Cie, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and WinGX (Farrugia, 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: enCIFer (Allen, 2004) and publCIF (Westrip, 2009).

Figures top

Fig. 1. Structure of (1) in the crystal with atom labels and 50% probability displacement ellipsoids for non-H atoms.

(S_P,S_P)-(-)-(E)-1,2-Bis(methylphenylphosphinoyl)ethene top

Crystal data top

C₁₆H₁₈O₂P₂	F(000) = 640
M_r = 304.24	D_x = 1.304 Mg m⁻³
Monoclinic, P2₁	Melting point: 511 K
Hall symbol: P 2yb	Mo Kα radiation, λ = 0.71073 Å
a = 11.686 (5) Å	Cell parameters from 8000 reflections
b = 5.5291 (15) Å	θ = 2.3–25.4°
c = 24.132 (10) Å	µ = 0.28 mm⁻¹
β = 96.36 (5)°	T = 297 K
V = 1549.7 (10) Å³	Plate, white
Z = 4	0.35 × 0.29 × 0.18 mm

Data collection top

Stoe IPDS diffractometer	6041 independent reflections
Radiation source: fine-focus sealed tube	4640 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.067
psi scans	θ_max = 26.0°, θ_min = 2.3°
Absorption correction: multi-scan (Blessing, 1995)	h = −14→14
T_min = 0.927, T_max = 0.953	k = −6→6
20851 measured reflections	l = −29→29

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.041	H-atom parameters constrained
wR(F²) = 0.097	w = 1/[σ²(F_o²) + (0.0482P)²] where P = (F_o² + 2F_c²)/3
S = 0.99	(Δ/σ)_max = 0.002
6041 reflections	Δρ_max = 0.37 e Å⁻³
361 parameters	Δρ_min = −0.19 e Å⁻³
1 restraint	Absolute structure: Flack (1983), 2656 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.01 (9)

Crystal data top

C₁₆H₁₈O₂P₂	V = 1549.7 (10) Å³
M_r = 304.24	Z = 4
Monoclinic, P2₁	Mo Kα radiation
a = 11.686 (5) Å	µ = 0.28 mm⁻¹
b = 5.5291 (15) Å	T = 297 K
c = 24.132 (10) Å	0.35 × 0.29 × 0.18 mm
β = 96.36 (5)°

Data collection top

Stoe IPDS diffractometer	6041 independent reflections
Absorption correction: multi-scan (Blessing, 1995)	4640 reflections with I > 2σ(I)
T_min = 0.927, T_max = 0.953	R_int = 0.067
20851 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.041	H-atom parameters constrained
wR(F²) = 0.097	Δρ_max = 0.37 e Å⁻³
S = 0.99	Δρ_min = −0.19 e Å⁻³
6041 reflections	Absolute structure: Flack (1983), 2656 Friedel pairs
361 parameters	Absolute structure parameter: 0.01 (9)
1 restraint

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
P1	0.30457 (7)	0.21685 (14)	0.97574 (3)	0.0353 (2)
P2	0.39031 (6)	−0.02618 (15)	1.14954 (3)	0.0346 (2)
O1	0.3363 (2)	0.4760 (5)	0.98268 (10)	0.0538 (6)
O2	0.3896 (2)	−0.2919 (4)	1.14004 (10)	0.0470 (6)
C1A	0.3199 (3)	0.0452 (6)	1.03959 (12)	0.0390 (7)
H1A	0.3089	−0.1213	1.0382	0.047*
C2A	0.3466 (3)	0.1518 (6)	1.08850 (12)	0.0377 (7)
H2A	0.3427	0.3193	1.0913	0.045*
C3A	0.2989 (3)	0.0536 (6)	1.20236 (11)	0.0379 (7)
C4A	0.2921 (4)	−0.1114 (7)	1.24450 (15)	0.0600 (10)
H4A	0.3340	−0.2545	1.2446	0.072*
C5A	0.2234 (5)	−0.0671 (11)	1.28698 (17)	0.0792 (14)
H5A	0.2188	−0.1808	1.3150	0.095*
C6A	0.1639 (4)	0.1403 (10)	1.28732 (19)	0.0741 (13)
H6A	0.1185	0.1701	1.3159	0.089*
C7A	0.1693 (4)	0.3089 (9)	1.2460 (2)	0.0704 (12)
H7A	0.1271	0.4512	1.2464	0.085*
C8A	0.2380 (3)	0.2673 (8)	1.20324 (15)	0.0531 (8)
H8A	0.2427	0.3827	1.1755	0.064*
C9A	0.5286 (3)	0.0957 (8)	1.17267 (15)	0.0557 (10)
H9A1	0.5606	0.0118	1.2056	0.083*
H9A2	0.5212	0.2645	1.1809	0.083*
H9A3	0.5784	0.0765	1.1439	0.083*
C10A	0.1564 (3)	0.1880 (6)	0.94567 (12)	0.0355 (7)
C11A	0.1106 (3)	0.3729 (7)	0.91121 (15)	0.0525 (9)
H11A	0.1567	0.5032	0.9036	0.063*
C12A	−0.0027 (4)	0.3649 (8)	0.88820 (19)	0.0639 (11)
H12A	−0.0319	0.4875	0.8643	0.077*
C13A	−0.0721 (3)	0.1788 (9)	0.90020 (18)	0.0625 (11)
H13A	−0.1492	0.1782	0.8856	0.075*
C14A	−0.0288 (3)	−0.0100 (9)	0.93402 (17)	0.0644 (11)
H14A	−0.0760	−0.1382	0.9417	0.077*
C15A	0.0867 (3)	−0.0058 (7)	0.95651 (13)	0.0490 (8)
H15A	0.1169	−0.1329	0.9788	0.059*
C16A	0.3893 (3)	0.0436 (8)	0.93298 (14)	0.0508 (9)
H16A	0.3879	0.1190	0.8971	0.076*
H16B	0.3583	−0.1170	0.9286	0.076*
H16C	0.4672	0.0355	0.9503	0.076*
P3	0.69714 (6)	0.45422 (16)	0.52266 (3)	0.03485 (19)
P4	0.61341 (7)	0.25487 (16)	0.34535 (3)	0.0377 (2)
O3	0.6815 (2)	0.7189 (5)	0.51686 (10)	0.0521 (6)
O4	0.6118 (2)	−0.0103 (5)	0.35230 (10)	0.0528 (6)
C1B	0.6767 (2)	0.2977 (6)	0.45711 (12)	0.0363 (7)
H1B	0.6813	0.1298	0.4570	0.044*
C2B	0.6553 (2)	0.4128 (6)	0.40913 (11)	0.0361 (7)
H2B	0.6621	0.5803	0.4085	0.043*
C3B	0.7090 (3)	0.3418 (6)	0.29501 (12)	0.0395 (7)
C4B	0.7920 (3)	0.1795 (7)	0.28267 (15)	0.0518 (9)
H4B	0.8021	0.0365	0.3029	0.062*
C5B	0.8607 (3)	0.2254 (9)	0.24069 (18)	0.0677 (11)
H5B	0.9151	0.1122	0.2324	0.081*
C6B	0.8484 (4)	0.4391 (9)	0.21121 (17)	0.0662 (11)
H6B	0.8953	0.4718	0.1834	0.079*
C7B	0.7671 (4)	0.6022 (8)	0.22304 (18)	0.0679 (12)
H7B	0.7576	0.7451	0.2027	0.082*
C8B	0.6986 (4)	0.5562 (7)	0.26523 (16)	0.0584 (10)
H8B	0.6449	0.6709	0.2736	0.070*
C9B	0.4772 (3)	0.3870 (7)	0.32300 (15)	0.0547 (10)
H9B1	0.4460	0.3149	0.2884	0.082*
H9B2	0.4864	0.5578	0.3179	0.082*
H9B3	0.4256	0.3595	0.3507	0.082*
C10B	0.8407 (3)	0.3773 (6)	0.55361 (12)	0.0345 (7)
C11B	0.9281 (3)	0.5428 (8)	0.54766 (15)	0.0542 (9)
H11B	0.9113	0.6854	0.5280	0.065*
C12B	1.0393 (3)	0.4980 (9)	0.57053 (19)	0.0678 (12)
H12B	1.0971	0.6092	0.5658	0.081*
C13B	1.0648 (3)	0.2913 (9)	0.60005 (18)	0.0650 (12)
H13B	1.1397	0.2632	0.6160	0.078*
C14B	0.9795 (3)	0.1226 (9)	0.60642 (17)	0.0634 (11)
H14B	0.9971	−0.0187	0.6265	0.076*
C15B	0.8674 (3)	0.1661 (7)	0.58256 (16)	0.0508 (9)
H15B	0.8103	0.0520	0.5862	0.061*
C16B	0.5972 (3)	0.3059 (8)	0.56197 (14)	0.0520 (9)
H16D	0.6010	0.3767	0.5984	0.078*
H16E	0.6161	0.1371	0.5653	0.078*
H16F	0.5207	0.3239	0.5433	0.078*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
P1	0.0399 (4)	0.0320 (5)	0.0331 (4)	−0.0040 (3)	0.0008 (3)	0.0008 (3)
P2	0.0375 (4)	0.0341 (5)	0.0315 (4)	−0.0016 (4)	0.0000 (3)	0.0002 (3)
O1	0.0653 (15)	0.0310 (14)	0.0615 (14)	−0.0135 (12)	−0.0088 (12)	0.0025 (12)
O2	0.0612 (14)	0.0282 (13)	0.0521 (12)	0.0006 (11)	0.0089 (11)	−0.0009 (10)
C1A	0.0425 (17)	0.0376 (17)	0.0362 (15)	−0.0016 (14)	0.0015 (13)	0.0010 (13)
C2A	0.0434 (17)	0.0346 (17)	0.0349 (15)	0.0013 (13)	0.0036 (13)	0.0025 (12)
C3A	0.0377 (16)	0.0416 (17)	0.0331 (14)	−0.0029 (14)	−0.0024 (12)	−0.0020 (13)
C4A	0.080 (3)	0.054 (3)	0.0479 (19)	0.0009 (19)	0.0144 (19)	0.0109 (16)
C5A	0.112 (4)	0.083 (4)	0.048 (2)	−0.004 (3)	0.032 (2)	0.006 (2)
C6A	0.074 (3)	0.086 (3)	0.068 (3)	−0.015 (3)	0.034 (2)	−0.016 (2)
C7A	0.056 (2)	0.067 (3)	0.092 (3)	0.002 (2)	0.024 (2)	−0.014 (2)
C8A	0.052 (2)	0.046 (2)	0.062 (2)	0.0021 (17)	0.0120 (16)	0.0027 (17)
C9A	0.045 (2)	0.070 (3)	0.0511 (19)	−0.0026 (18)	−0.0025 (16)	0.0010 (19)
C10A	0.0431 (16)	0.0322 (18)	0.0312 (13)	0.0015 (13)	0.0032 (12)	−0.0009 (12)
C11A	0.054 (2)	0.046 (2)	0.057 (2)	0.0032 (16)	−0.0003 (17)	0.0054 (16)
C12A	0.058 (2)	0.059 (3)	0.070 (3)	0.014 (2)	−0.014 (2)	0.002 (2)
C13A	0.043 (2)	0.070 (3)	0.071 (2)	0.0076 (19)	−0.0055 (18)	−0.024 (2)
C14A	0.051 (2)	0.077 (3)	0.066 (2)	−0.015 (2)	0.0072 (18)	−0.007 (2)
C15A	0.0511 (18)	0.045 (2)	0.0483 (17)	−0.0064 (16)	−0.0042 (14)	0.0050 (16)
C16A	0.0446 (19)	0.059 (2)	0.0503 (18)	−0.0003 (16)	0.0116 (15)	0.0019 (17)
P3	0.0352 (4)	0.0359 (5)	0.0330 (4)	0.0013 (4)	0.0018 (3)	−0.0026 (4)
P4	0.0410 (4)	0.0376 (5)	0.0345 (4)	−0.0042 (4)	0.0039 (3)	−0.0058 (4)
O3	0.0566 (15)	0.0390 (15)	0.0578 (14)	0.0047 (12)	−0.0064 (11)	−0.0032 (12)
O4	0.0715 (16)	0.0363 (15)	0.0538 (13)	−0.0085 (12)	0.0205 (12)	−0.0051 (11)
C1B	0.0320 (15)	0.0399 (19)	0.0369 (15)	−0.0027 (13)	0.0025 (12)	−0.0022 (13)
C2B	0.0339 (15)	0.0399 (19)	0.0346 (14)	0.0015 (13)	0.0040 (12)	−0.0015 (13)
C3B	0.0430 (17)	0.0439 (18)	0.0303 (14)	−0.0042 (14)	−0.0020 (13)	−0.0005 (13)
C4B	0.0444 (18)	0.052 (2)	0.059 (2)	0.0056 (16)	0.0084 (16)	0.0110 (17)
C5B	0.053 (2)	0.077 (3)	0.077 (3)	0.008 (2)	0.024 (2)	0.000 (3)
C6B	0.072 (3)	0.072 (3)	0.059 (2)	−0.017 (3)	0.027 (2)	0.002 (2)
C7B	0.095 (3)	0.054 (3)	0.058 (2)	−0.002 (2)	0.022 (2)	0.012 (2)
C8B	0.079 (3)	0.042 (2)	0.058 (2)	0.0048 (19)	0.0219 (19)	0.0017 (18)
C9B	0.0432 (18)	0.065 (3)	0.0533 (19)	0.0008 (17)	−0.0058 (15)	−0.0185 (18)
C10B	0.0341 (15)	0.0381 (18)	0.0310 (14)	0.0000 (12)	0.0027 (12)	−0.0041 (12)
C11B	0.0449 (19)	0.056 (2)	0.062 (2)	−0.0049 (16)	0.0059 (16)	0.0030 (18)
C12B	0.0373 (19)	0.078 (3)	0.087 (3)	−0.013 (2)	0.0034 (18)	−0.011 (3)
C13B	0.041 (2)	0.079 (3)	0.071 (2)	0.015 (2)	−0.0086 (17)	−0.025 (2)
C14B	0.057 (2)	0.067 (3)	0.062 (2)	0.018 (2)	−0.0108 (18)	−0.002 (2)
C15B	0.0440 (19)	0.047 (2)	0.060 (2)	0.0004 (15)	0.0014 (16)	0.0042 (17)
C16B	0.0427 (18)	0.067 (3)	0.0485 (19)	−0.0010 (17)	0.0128 (15)	0.0009 (17)

Geometric parameters (Å, º) top

P1—O1	1.485 (3)	P3—O3	1.480 (3)
P1—C16A	1.786 (4)	P3—C16B	1.784 (3)
P1—C1A	1.801 (3)	P3—C1B	1.796 (3)
P1—C10A	1.809 (3)	P3—C10B	1.810 (3)
P2—O2	1.487 (3)	P4—O4	1.476 (3)
P2—C9A	1.782 (4)	P4—C9B	1.780 (4)
P2—C2A	1.798 (3)	P4—C2B	1.790 (3)
P2—C3A	1.806 (3)	P4—C3B	1.804 (3)
C1A—C2A	1.325 (4)	C1B—C2B	1.321 (4)
C1A—H1A	0.9300	C1B—H1B	0.9300
C2A—H2A	0.9300	C2B—H2B	0.9300
C3A—C4A	1.375 (5)	C3B—C4B	1.378 (5)
C3A—C8A	1.381 (5)	C3B—C8B	1.385 (5)
C4A—C5A	1.392 (6)	C4B—C5B	1.384 (5)
C4A—H4A	0.9300	C4B—H4B	0.9300
C5A—C6A	1.341 (7)	C5B—C6B	1.378 (7)
C5A—H5A	0.9300	C5B—H5B	0.9300
C6A—C7A	1.372 (7)	C6B—C7B	1.363 (6)
C6A—H6A	0.9300	C6B—H6B	0.9300
C7A—C8A	1.394 (5)	C7B—C8B	1.387 (5)
C7A—H7A	0.9300	C7B—H7B	0.9300
C8A—H8A	0.9300	C8B—H8B	0.9300
C9A—H9A1	0.9600	C9B—H9B1	0.9600
C9A—H9A2	0.9600	C9B—H9B2	0.9600
C9A—H9A3	0.9600	C9B—H9B3	0.9600
C10A—C11A	1.387 (5)	C10B—C15B	1.379 (5)
C10A—C15A	1.388 (5)	C10B—C11B	1.391 (5)
C11A—C12A	1.378 (6)	C11B—C12B	1.377 (5)
C11A—H11A	0.9300	C11B—H11B	0.9300
C12A—C13A	1.361 (6)	C12B—C13B	1.362 (7)
C12A—H12A	0.9300	C12B—H12B	0.9300
C13A—C14A	1.386 (6)	C13B—C14B	1.386 (6)
C13A—H13A	0.9300	C13B—H13B	0.9300
C14A—C15A	1.397 (5)	C14B—C15B	1.392 (5)
C14A—H14A	0.9300	C14B—H14B	0.9300
C15A—H15A	0.9300	C15B—H15B	0.9300
C16A—H16A	0.9600	C16B—H16D	0.9600
C16A—H16B	0.9600	C16B—H16E	0.9600
C16A—H16C	0.9600	C16B—H16F	0.9600

O1—P1—C16A	115.80 (17)	O3—P3—C16B	115.05 (17)
O1—P1—C1A	114.32 (15)	O3—P3—C1B	112.97 (15)
C16A—P1—C1A	101.69 (17)	C16B—P3—C1B	102.46 (17)
O1—P1—C10A	110.28 (15)	O3—P3—C10B	111.77 (15)
C16A—P1—C10A	106.75 (16)	C16B—P3—C10B	107.71 (16)
C1A—P1—C10A	107.26 (15)	C1B—P3—C10B	106.10 (14)
O2—P2—C9A	114.30 (18)	O4—P4—C9B	114.84 (18)
O2—P2—C2A	114.73 (15)	O4—P4—C2B	113.11 (15)
C9A—P2—C2A	102.42 (17)	C9B—P4—C2B	102.15 (16)
O2—P2—C3A	110.87 (15)	O4—P4—C3B	110.94 (15)
C9A—P2—C3A	105.85 (17)	C9B—P4—C3B	106.63 (18)
C2A—P2—C3A	107.94 (14)	C2B—P4—C3B	108.58 (15)
C2A—C1A—P1	121.3 (3)	C2B—C1B—P3	122.3 (3)
C2A—C1A—H1A	119.4	C2B—C1B—H1B	118.9
P1—C1A—H1A	119.4	P3—C1B—H1B	118.9
C1A—C2A—P2	120.2 (3)	C1B—C2B—P4	121.8 (3)
C1A—C2A—H2A	119.9	C1B—C2B—H2B	119.1
P2—C2A—H2A	119.9	P4—C2B—H2B	119.1
C4A—C3A—C8A	118.9 (3)	C4B—C3B—C8B	117.9 (3)
C4A—C3A—P2	116.6 (3)	C4B—C3B—P4	118.4 (3)
C8A—C3A—P2	124.5 (2)	C8B—C3B—P4	123.5 (3)
C3A—C4A—C5A	120.9 (4)	C3B—C4B—C5B	121.2 (4)
C3A—C4A—H4A	119.6	C3B—C4B—H4B	119.4
C5A—C4A—H4A	119.6	C5B—C4B—H4B	119.4
C6A—C5A—C4A	119.8 (4)	C6B—C5B—C4B	120.0 (4)
C6A—C5A—H5A	120.1	C6B—C5B—H5B	120.0
C4A—C5A—H5A	120.1	C4B—C5B—H5B	120.0
C5A—C6A—C7A	120.7 (4)	C7B—C6B—C5B	119.6 (3)
C5A—C6A—H6A	119.7	C7B—C6B—H6B	120.2
C7A—C6A—H6A	119.7	C5B—C6B—H6B	120.2
C6A—C7A—C8A	120.2 (4)	C6B—C7B—C8B	120.3 (4)
C6A—C7A—H7A	119.9	C6B—C7B—H7B	119.8
C8A—C7A—H7A	119.9	C8B—C7B—H7B	119.8
C3A—C8A—C7A	119.5 (4)	C3B—C8B—C7B	120.9 (4)
C3A—C8A—H8A	120.3	C3B—C8B—H8B	119.5
C7A—C8A—H8A	120.3	C7B—C8B—H8B	119.5
P2—C9A—H9A1	109.5	P4—C9B—H9B1	109.5
P2—C9A—H9A2	109.5	P4—C9B—H9B2	109.5
H9A1—C9A—H9A2	109.5	H9B1—C9B—H9B2	109.5
P2—C9A—H9A3	109.5	P4—C9B—H9B3	109.5
H9A1—C9A—H9A3	109.5	H9B1—C9B—H9B3	109.5
H9A2—C9A—H9A3	109.5	H9B2—C9B—H9B3	109.5
C11A—C10A—C15A	119.1 (3)	C15B—C10B—C11B	118.8 (3)
C11A—C10A—P1	117.6 (3)	C15B—C10B—P3	123.8 (3)
C15A—C10A—P1	123.2 (2)	C11B—C10B—P3	117.4 (3)
C12A—C11A—C10A	120.5 (4)	C12B—C11B—C10B	120.8 (4)
C12A—C11A—H11A	119.8	C12B—C11B—H11B	119.6
C10A—C11A—H11A	119.8	C10B—C11B—H11B	119.6
C13A—C12A—C11A	120.5 (4)	C13B—C12B—C11B	120.2 (4)
C13A—C12A—H12A	119.8	C13B—C12B—H12B	119.9
C11A—C12A—H12A	119.8	C11B—C12B—H12B	119.9
C12A—C13A—C14A	120.5 (4)	C12B—C13B—C14B	120.3 (4)
C12A—C13A—H13A	119.8	C12B—C13B—H13B	119.8
C14A—C13A—H13A	119.8	C14B—C13B—H13B	119.8
C13A—C14A—C15A	119.4 (4)	C13B—C14B—C15B	119.5 (4)
C13A—C14A—H14A	120.3	C13B—C14B—H14B	120.2
C15A—C14A—H14A	120.3	C15B—C14B—H14B	120.2
C10A—C15A—C14A	120.0 (4)	C10B—C15B—C14B	120.4 (4)
C10A—C15A—H15A	120.0	C10B—C15B—H15B	119.8
C14A—C15A—H15A	120.0	C14B—C15B—H15B	119.8
P1—C16A—H16A	109.5	P3—C16B—H16D	109.5
P1—C16A—H16B	109.5	P3—C16B—H16E	109.5
H16A—C16A—H16B	109.5	H16D—C16B—H16E	109.5
P1—C16A—H16C	109.5	P3—C16B—H16F	109.5
H16A—C16A—H16C	109.5	H16D—C16B—H16F	109.5
H16B—C16A—H16C	109.5	H16E—C16B—H16F	109.5

C3A—P2—C2A—C1A	−125.9 (7)	O1—P1—C1A—C2A	6.2 (4)
P1—C1A—C2A—P2	−167.1 (5)	O2—P2—C2A—C1A	−1.8 (4)
C16A—P1—C1A—C2A	131.7 (2)	P1—C1A—C2A—P2	−167.2 (2)

Experimental details

Crystal data
Chemical formula	C₁₆H₁₈O₂P₂
M_r	304.24
Crystal system, space group	Monoclinic, P2₁
Temperature (K)	297
a, b, c (Å)	11.686 (5), 5.5291 (15), 24.132 (10)
β (°)	96.36 (5)
V (Å³)	1549.7 (10)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.28
Crystal size (mm)	0.35 × 0.29 × 0.18

Data collection
Diffractometer	Stoe IPDS diffractometer
Absorption correction	Multi-scan (Blessing, 1995)
T_min, T_max	0.927, 0.953
No. of measured, independent and observed [I > 2σ(I)] reflections	20851, 6041, 4640
R_int	0.067
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.097, 0.99
No. of reflections	6041
No. of parameters	361
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.37, −0.19
Absolute structure	Flack (1983), 2656 Friedel pairs
Absolute structure parameter	0.01 (9)

Computer programs: IPDS (Stoe & Cie, 1999), SHELXS97 (Sheldrick, 2008) and WinGX (Farrugia, 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), enCIFer (Allen, 2004) and publCIF (Westrip, 2009).

Selected geometric parameters (Å, º) top

P1—O1	1.485 (3)	P2—C2A	1.798 (3)
P1—C1A	1.801 (3)	C1A—C2A	1.325 (4)
P2—O2	1.487 (3)

O1—P1—C16A	115.80 (17)	O2—P2—C2A	114.73 (15)
O1—P1—C1A	114.32 (15)	C2A—C1A—P1	121.3 (3)
O2—P2—C9A	114.30 (18)	C1A—C2A—P2	120.2 (3)

C3A—P2—C2A—C1A	−125.9 (7)	O1—P1—C1A—C2A	6.2 (4)
P1—C1A—C2A—P2	−167.1 (5)	O2—P2—C2A—C1A	−1.8 (4)
C16A—P1—C1A—C2A	131.7 (2)	P1—C1A—C2A—P2	−167.2 (2)

Acknowledgements

This research was kindly supported by the Gottlieb Daimler and Karl Benz Foundation (doctoral fellowship to NV) and by the Deutsche Forschungsgemeinschaft.

References

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