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The crystal structure of the title compound, C16H24IO3P, is composed of independent molecules, in which one of the phospho­nate ethoxy groups is disordered over two positions. The other ethoxy group lies sandwiched between two phenyl rings and, as a result, is ordered. This constrained environment also leads to two C—H...centroid interactions, one intra- and one intermolecular. Examination of the extended structure reveals the presence of chains of molecules held together by I...O interactions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104032913/av1218sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104032913/av1218Isup2.hkl
Contains datablock I

CCDC reference: 268118

Comment top

For the last three decades, there has been considerable interest in the synthesis and characterization of alkenylphosphonates, due to their wide range of applications as polymer additives, flame-retardants and intermediates for drugs, and as a useful tool in organic transformations (Minami & Motoyoshiya, 1992). However, very few vinylphosphonate structures have been characterized by X-ray crystallography to date. As part of an ongoing study of phosphoorganic biomolecules, we previously reported a facile procedure for the stereoselective preparation of alkenylphosphonates by carbocupration of 1-alkynylphosphonates in diethylether, followed by hydrolysis or reaction with various electrophiles (Cristau et al., 1994, 1997). Here, we report the structure of the title compound, (I), which has been determined by X-ray crystallographic methods.

The crystal structure of (I) is composed of independent molecules, in which the phosphonate ethoxy group facing the I atom is disordered over two orientations. In contrast, the other ethoxy group (atoms C13 and C14) does not exhibit disorder. This is due to restraints placed on it by the geometry of the molecule, in particular the arrangement of O atoms around the C1—P bond, leading to it facing the phenyl ring (Fig. 1). In addition, extrapolating the structure indicates that this ethoxy group is sandwiched between two phenyl rings (one intra- and one intermolecular), preventing disorder (Fig. 2). This constrained environment also leads to two C—H···π interactions. One of these acts in an intramolecular manner between the ethoxy group and the phenyl ring of the molecule [C14—H14C 0.96 Å, H14C···π 3.38 Å, C14—H14C···π 131° and C14···π 3.870 (7) Å]. The other C—H···π interaction occurs between the same ethoxy group and phenyl ring but as an intermolecular interaction [C14—H14B 0.96 Å, H14B···π 3.36 Å, C14—H14B···π 116° and C14···π 3.870 (7) Å; Fig. 2].

Despite the rotational restraint imposed by the double bond (C1C2), the deviations from zero in the torsion angles I—C1—C2—C3 [−6.7 (5)°] and P—C1—C2—C7 [−5.6 (5)°] indicate that there is some deviation from planarity around C1C2. This is most probably due to some steric interaction between I and C3, and P and C7.

Examining the crystal packing of (I) indicates that molecules related by the twofold screw axis are held together by an I···O interaction [I···O1 3.076 (3) Å, C1—I···O1 176.17 (12)° and I···O1—P 143.20 (16)°]. This leads to a chain of molecules running along the b axis (Fig. 3). While many examples of general I···O interactions can be found in the Cambridge Structural Database (CSD, Version 5.25, update 3 of July 2004; Allen, 2002), very few examples involving C—I···O—P interactions exist. A search of the CSD for an interaction between C—I and O—P yielded only 16 hits with I···O distances less than 4 Å. Only two of these have I···O distances less than 3.3 Å [2.921 Å in ICYGET10 (Reference?) and 2.941 Å in HXMIPX (Reference?)], and both structure determinations date back to the 1970's. In general, the effect of I···O interactions has not been widely discussed in the literature and is sufficiently rare that it is highlighted by current IUCr validation programs as an unlikely interaction. However, the effect of I···O interactions, together with other weak interactions, on the crystal packing of some iodo-nitroarenesulfonamides and iodo-nitroanilines has been discussed in detail by Kelly et al. (2002) and Garden et al. (2002).

Experimental top

The title compound was obtained as described previously by Cristau et al. (1997). Crystallization in Et2O/n-hexane yielded single crystals of (I) suitable for X-ray diffraction.

Refinement top

One of the phosphonate ethoxy groups exhibits orientational disorder and was refined over two positions using SADI and DFIX restraints. The final occupancy was 0.64 (1) for C15 and C16, and 0.36 (1) for C15B and C16B. H atoms were positioned geometrically and allowed to ride on their respective parent atoms, with C—H distances of 0.93 (aromatic CH), 0.97 (CH2) or 0.96 Å (CH3), and Uiso(H) equal to 1.2 (CH and CH2) or 1.5 (CH3) times Ueq of the parent atom.

Computing details top

Data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 1999); program(s) used to refine structure: SHELXTL; molecular graphics: PLATON (Spek, 2003) and SCHAKAL97 (Keller, 1997); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. A view of molecule of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown with arbitrary radii.
[Figure 2] Fig. 2. The weak C—H···π interactions in the structure of (I). The intra- and intermolecular C—H···π interactions are indicated by a hash (#) and a dollar sign ($), respectively. Molecules (A) and (B) are in the symmetry positions (1/2 + x, 1/2 − y, 1/2 + z) and (1 + x, y, 1 + z), respectively.
[Figure 3] Fig. 3. Part of the structure of (I), showing the chain of molecules held together by I···O interactions. I···O interactions are indicated by an asterix (*), while the intramolecular C—H···π interaction is indicated with a hash (#). Molecules (A), (B) and (C) are at the symmetry positions (1/2 − x, 1/2 + y, 3/2 − z), (x, 1 + y, z) and (1/2 − x, 3/2 + y, 3/2 − z), respectively.
Diethyl [(Z)-1-iodo-2-phenyl-1-hexenyl]phosphonate top
Crystal data top
C16H24IO3PF(000) = 848
Mr = 422.22Dx = 1.489 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 1006 reflections
a = 11.7324 (18) Åθ = 2.4–27.4°
b = 12.3985 (19) ŵ = 1.79 mm1
c = 13.228 (2) ÅT = 293 K
β = 101.817 (3)°Irregular, colourless
V = 1883.4 (5) Å30.48 × 0.42 × 0.26 mm
Z = 4
Data collection top
Bruker SMART CCD area-detector
diffractometer
3693 independent reflections
Radiation source: fine-focus sealed tube2988 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.019
ϕ and ω scansθmax = 26.0°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 1999)
h = 1314
Tmin = 0.480, Tmax = 0.653k = 1315
10404 measured reflectionsl = 1216
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.031H-atom parameters constrained
wR(F2) = 0.086 w = 1/[σ2(Fo2) + (0.0411P)2 + 1.3932P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max = 0.001
3693 reflectionsΔρmax = 0.70 e Å3
212 parametersΔρmin = 0.42 e Å3
57 restraintsExtinction correction: SHELXTL (Bruker, 1999), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0031 (4)
Crystal data top
C16H24IO3PV = 1883.4 (5) Å3
Mr = 422.22Z = 4
Monoclinic, P21/nMo Kα radiation
a = 11.7324 (18) ŵ = 1.79 mm1
b = 12.3985 (19) ÅT = 293 K
c = 13.228 (2) Å0.48 × 0.42 × 0.26 mm
β = 101.817 (3)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
3693 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 1999)
2988 reflections with I > 2σ(I)
Tmin = 0.480, Tmax = 0.653Rint = 0.019
10404 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.03157 restraints
wR(F2) = 0.086H-atom parameters constrained
S = 1.05Δρmax = 0.70 e Å3
3693 reflectionsΔρmin = 0.42 e Å3
212 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*/UeqOcc. (<1)
I0.27698 (2)0.178181 (18)0.656147 (19)0.06326 (13)
P0.40374 (9)0.04203 (8)0.76022 (7)0.0584 (2)
O10.3245 (3)0.0983 (2)0.8130 (2)0.0811 (8)
O20.5034 (2)0.1114 (2)0.7321 (2)0.0762 (8)
O30.4605 (3)0.0509 (3)0.8301 (3)0.1104 (12)
C10.3381 (3)0.0192 (3)0.6392 (3)0.0506 (7)
C20.3205 (3)0.0287 (3)0.5463 (2)0.0517 (7)
C30.2686 (4)0.0282 (3)0.4461 (3)0.0667 (10)
H3A0.30530.00140.39170.080*
H3B0.28480.10480.45380.080*
C40.1394 (4)0.0114 (3)0.4154 (3)0.0750 (11)
H4A0.12260.06510.41690.090*
H4B0.10180.04690.46520.090*
C50.0886 (4)0.0562 (4)0.3064 (4)0.0912 (14)
H5A0.12690.02090.25700.109*
H5B0.10580.13270.30530.109*
C60.0356 (5)0.0410 (5)0.2744 (5)0.122 (2)
H6A0.07370.06880.32660.183*
H6B0.06330.07870.21070.183*
H6C0.05240.03450.26460.183*
C70.3448 (3)0.1452 (3)0.5334 (3)0.0521 (8)
C80.4251 (4)0.1779 (3)0.4756 (3)0.0685 (10)
H80.46620.12650.44630.082*
C90.4443 (4)0.2865 (4)0.4614 (4)0.0865 (14)
H90.49930.30750.42370.104*
C100.3830 (4)0.3637 (4)0.5025 (4)0.0824 (12)
H100.39580.43650.49200.099*
C110.3031 (4)0.3327 (3)0.5589 (3)0.0724 (11)
H110.26160.38470.58690.087*
C120.2835 (3)0.2242 (3)0.5745 (3)0.0599 (9)
H120.22880.20420.61290.072*
C130.5489 (5)0.2053 (4)0.7904 (5)0.1054 (18)
H13A0.57180.18680.86300.126*
H13B0.48920.26050.78320.126*
C140.6483 (5)0.2460 (5)0.7537 (5)0.122 (2)
H14A0.70590.19020.75830.183*
H14B0.68090.30630.79530.183*
H14C0.62440.26850.68320.183*
C150.5622 (6)0.1068 (6)0.8245 (5)0.107 (3)0.642 (10)
H15A0.59100.07970.76570.128*0.642 (10)
H15B0.54240.18220.81120.128*0.642 (10)
C160.6548 (7)0.1009 (9)0.9137 (7)0.117 (4)0.642 (10)
H16A0.71980.14270.90210.175*0.642 (10)
H16B0.62840.12890.97260.175*0.642 (10)
H16C0.67820.02710.92630.175*0.642 (10)
C15B0.5569 (11)0.0557 (9)0.9104 (9)0.123 (6)0.358 (10)
H15C0.53260.03610.97370.147*0.358 (10)
H15D0.61250.00190.89810.147*0.358 (10)
C16B0.6157 (14)0.1589 (12)0.9260 (14)0.121 (6)0.358 (10)
H16D0.67250.15750.98950.182*0.358 (10)
H16E0.65360.17310.86960.182*0.358 (10)
H16F0.55980.21470.92930.182*0.358 (10)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
I0.0801 (2)0.04690 (16)0.06561 (19)0.00041 (11)0.02164 (13)0.00068 (10)
P0.0695 (6)0.0540 (5)0.0488 (5)0.0020 (4)0.0054 (4)0.0006 (4)
O10.100 (2)0.083 (2)0.0645 (17)0.0024 (16)0.0270 (15)0.0218 (15)
O20.0742 (17)0.0814 (19)0.0712 (17)0.0172 (15)0.0104 (14)0.0137 (15)
O30.129 (3)0.083 (2)0.099 (3)0.008 (2)0.026 (2)0.0217 (19)
C10.0580 (19)0.0449 (17)0.0508 (18)0.0039 (14)0.0152 (15)0.0023 (14)
C20.0543 (18)0.0545 (19)0.0488 (18)0.0044 (15)0.0159 (14)0.0045 (15)
C30.087 (3)0.060 (2)0.052 (2)0.000 (2)0.0130 (18)0.0044 (17)
C40.086 (3)0.064 (2)0.071 (3)0.005 (2)0.006 (2)0.0004 (19)
C50.098 (3)0.077 (3)0.092 (3)0.005 (3)0.002 (3)0.017 (3)
C60.097 (4)0.101 (4)0.150 (5)0.006 (3)0.016 (4)0.040 (4)
C70.0559 (19)0.0551 (19)0.0455 (17)0.0007 (15)0.0109 (15)0.0026 (14)
C80.070 (2)0.073 (3)0.070 (2)0.0108 (19)0.029 (2)0.0089 (19)
C90.085 (3)0.084 (3)0.101 (4)0.007 (2)0.045 (3)0.022 (3)
C100.093 (3)0.063 (3)0.095 (3)0.005 (2)0.029 (3)0.019 (2)
C110.091 (3)0.054 (2)0.076 (3)0.007 (2)0.026 (2)0.0015 (18)
C120.066 (2)0.059 (2)0.061 (2)0.0003 (17)0.0256 (17)0.0021 (17)
C130.100 (4)0.085 (3)0.133 (5)0.026 (3)0.027 (3)0.041 (3)
C140.089 (3)0.119 (5)0.164 (6)0.036 (3)0.040 (4)0.061 (4)
C150.127 (6)0.098 (6)0.087 (5)0.049 (5)0.002 (4)0.008 (4)
C160.116 (6)0.124 (8)0.100 (6)0.046 (6)0.001 (5)0.006 (6)
C15B0.141 (11)0.132 (10)0.088 (9)0.068 (9)0.007 (9)0.029 (8)
C16B0.176 (13)0.097 (10)0.076 (8)0.044 (9)0.008 (9)0.023 (8)
Geometric parameters (Å, º) top
I—C12.125 (3)C8—H80.9300
P—O11.451 (3)C9—C101.373 (7)
P—O31.541 (3)C9—H90.9300
P—O21.557 (3)C10—C111.367 (6)
P—C11.797 (3)C10—H100.9300
O2—C131.438 (5)C11—C121.387 (5)
O3—C15B1.384 (5)C11—H110.9300
O3—C151.395 (4)C12—H120.9300
C1—C21.342 (5)C13—C141.443 (7)
C2—C71.489 (5)C13—H13A0.9700
C2—C31.515 (5)C13—H13B0.9700
C3—C41.501 (6)C14—H14A0.9600
C3—H3A0.9700C14—H14B0.9600
C3—H3B0.9700C14—H14C0.9600
C4—C51.547 (6)C15—C161.433 (5)
C4—H4A0.9700C15—H15A0.9700
C4—H4B0.9700C15—H15B0.9700
C5—C61.444 (7)C16—H16A0.9600
C5—H5A0.9700C16—H16B0.9600
C5—H5B0.9700C16—H16C0.9600
C6—H6A0.9600C15B—C16B1.448 (5)
C6—H6B0.9600C15B—H15C0.9700
C6—H6C0.9600C15B—H15D0.9700
C7—C81.390 (5)C16B—H16D0.9600
C7—C121.390 (5)C16B—H16E0.9600
C8—C91.385 (6)C16B—H16F0.9600
O1—P—O3108.2 (2)C10—C9—H9119.6
O1—P—O2115.87 (17)C8—C9—H9119.6
O3—P—O2107.62 (19)C11—C10—C9119.5 (4)
O1—P—C1115.64 (17)C11—C10—H10120.2
O3—P—C1105.80 (18)C9—C10—H10120.2
O2—P—C1103.07 (15)C10—C11—C12120.5 (4)
C13—O2—P122.2 (3)C10—C11—H11119.8
C15B—O3—C1556.4 (7)C12—C11—H11119.8
C15B—O3—P132.6 (5)C11—C12—C7120.6 (4)
C15—O3—P127.5 (4)C11—C12—H12119.7
C2—C1—P125.9 (3)C7—C12—H12119.7
C2—C1—I121.0 (3)O2—C13—C14109.8 (4)
P—C1—I112.95 (17)O2—C13—H13A109.7
C1—C2—C7122.5 (3)C14—C13—H13A109.7
C1—C2—C3123.6 (3)O2—C13—H13B109.7
C7—C2—C3113.8 (3)C14—C13—H13B109.7
C4—C3—C2112.0 (3)H13A—C13—H13B108.2
C4—C3—H3A109.2C13—C14—H14A109.5
C2—C3—H3A109.2C13—C14—H14B109.5
C4—C3—H3B109.2H14A—C14—H14B109.5
C2—C3—H3B109.2C13—C14—H14C109.5
H3A—C3—H3B107.9H14A—C14—H14C109.5
C3—C4—C5112.2 (4)H14B—C14—H14C109.5
C3—C4—H4A109.2O3—C15—C16116.3 (6)
C5—C4—H4A109.2O3—C15—H15A108.2
C3—C4—H4B109.2C16—C15—H15A108.2
C5—C4—H4B109.2O3—C15—H15B108.2
H4A—C4—H4B107.9C16—C15—H15B108.2
C6—C5—C4113.5 (5)H15A—C15—H15B107.4
C6—C5—H5A108.9C15—C16—H16A109.5
C4—C5—H5A108.9C15—C16—H16B109.5
C6—C5—H5B108.9H16A—C16—H16B109.5
C4—C5—H5B108.9C15—C16—H16C109.5
H5A—C5—H5B107.7H16A—C16—H16C109.5
C5—C6—H6A109.5H16B—C16—H16C109.5
C5—C6—H6B109.5O3—C15B—C16B115.9 (7)
H6A—C6—H6B109.5O3—C15B—H15C108.3
C5—C6—H6C109.5C16B—C15B—H15C108.3
H6A—C6—H6C109.5O3—C15B—H15D108.3
H6B—C6—H6C109.5C16B—C15B—H15D108.3
C8—C7—C12118.3 (3)H15C—C15B—H15D107.4
C8—C7—C2120.9 (3)C15B—C16B—H16D109.5
C12—C7—C2120.8 (3)C15B—C16B—H16E109.5
C9—C8—C7120.3 (4)H16D—C16B—H16E109.5
C9—C8—H8119.8C15B—C16B—H16F109.5
C7—C8—H8119.8H16D—C16B—H16F109.5
C10—C9—C8120.7 (4)H16E—C16B—H16F109.5
O1—P—O2—C1327.2 (5)C7—C2—C3—C482.5 (4)
O3—P—O2—C1393.9 (4)C2—C3—C4—C5172.3 (4)
C1—P—O2—C13154.6 (4)C3—C4—C5—C6179.8 (5)
O1—P—O3—C15B85.4 (10)C1—C2—C7—C8120.0 (4)
O2—P—O3—C15B40.5 (10)C3—C2—C7—C863.0 (4)
C1—P—O3—C15B150.2 (10)C1—C2—C7—C1263.3 (5)
O1—P—O3—C15161.4 (5)C3—C2—C7—C12113.7 (4)
O2—P—O3—C1535.5 (5)C12—C7—C8—C91.1 (6)
C1—P—O3—C1574.2 (5)C2—C7—C8—C9177.9 (4)
O1—P—C1—C288.5 (3)C7—C8—C9—C101.2 (7)
O3—P—C1—C2151.9 (3)C8—C9—C10—C110.7 (8)
O2—P—C1—C239.0 (3)C9—C10—C11—C120.1 (7)
O1—P—C1—I87.4 (2)C10—C11—C12—C70.1 (6)
O3—P—C1—I32.2 (2)C8—C7—C12—C110.6 (6)
O2—P—C1—I145.11 (17)C2—C7—C12—C11177.4 (4)
P—C1—C2—C75.6 (5)P—O2—C13—C14173.8 (4)
I—C1—C2—C7170.0 (2)C15B—O3—C15—C161.7 (10)
P—C1—C2—C3177.7 (3)P—O3—C15—C16119.2 (8)
I—C1—C2—C36.7 (5)C15—O3—C15B—C16B39.6 (14)
C1—C2—C3—C494.4 (4)P—O3—C15B—C16B152.1 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C14—H14C···Cg0.963.383.870 (7)131
C14—H14B···Cgi0.963.363.870 (7)116
Symmetry code: (i) x+1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC16H24IO3P
Mr422.22
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)11.7324 (18), 12.3985 (19), 13.228 (2)
β (°) 101.817 (3)
V3)1883.4 (5)
Z4
Radiation typeMo Kα
µ (mm1)1.79
Crystal size (mm)0.48 × 0.42 × 0.26
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 1999)
Tmin, Tmax0.480, 0.653
No. of measured, independent and
observed [I > 2σ(I)] reflections
10404, 3693, 2988
Rint0.019
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.086, 1.05
No. of reflections3693
No. of parameters212
No. of restraints57
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.70, 0.42

Computer programs: SMART-NT (Bruker, 1998), SAINT-Plus (Bruker, 1999), SAINT-Plus, SHELXTL (Bruker, 1999), SHELXTL, PLATON (Spek, 2003) and SCHAKAL97 (Keller, 1997).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C14—H14C···Cg0.963.383.870 (7)131
C14—H14B···Cgi0.963.363.870 (7)116
Symmetry code: (i) x+1/2, y+1/2, z+1/2.
 

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