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Acta Crystallogr Sect E Struct Rep Online. 2009 April 1; 65(Pt 4): o828.
Published online 2009 March 25. doi:  10.1107/S1600536809009817
PMCID: PMC2968818

2,8-Dimethyl-10-p-tolyl-10H-phenoxaphosphine

Abstract

The title compound (systematic name: 3,6-dimethyl-10-p-tolyl-9-oxa-10-phosphaanthracene), C21H19OP, is a precursor for the preparation of a bidentate xanthene-based ligand, in which the dihedral angle between the toluene ring and the phenoxaphosphine ring system is 83.26 (3)°. The geometry at the P atom is pyramidal, resulting in a longer C—P bond length as compared to the two ring C—P bonds.

Related literature

For related structures based on the xanthene backbone, see: Marimuthu et al. (2008a [triangle],b [triangle],c [triangle]). For a related phenoxaphosphine compound, see: Mann et al. (1976 [triangle]). The title compound was synthesised by a modified literature method (Bronger et al., 2004 [triangle]). For other structurally related ligands, see: Levy et al. (1965 [triangle]); Seibold et al. (2008 [triangle]); Shau et al. (2002 [triangle]).

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Object name is e-65-0o828-scheme1.jpg

Experimental

Crystal data

  • C21H19OP
  • M r = 318.33
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-0o828-efi1.jpg
  • a = 10.9363 (3) Å
  • b = 11.6323 (3) Å
  • c = 14.0458 (4) Å
  • β = 111.532 (1)°
  • V = 1662.13 (8) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.17 mm−1
  • T = 173 K
  • 0.51 × 0.49 × 0.48 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: none
  • 29900 measured reflections
  • 4013 independent reflections
  • 3507 reflections with I > 2σ(I)
  • R int = 0.046

Refinement

  • R[F 2 > 2σ(F 2)] = 0.037
  • wR(F 2) = 0.108
  • S = 1.07
  • 4013 reflections
  • 211 parameters
  • H-atom parameters constrained
  • Δρmax = 0.37 e Å−3
  • Δρmin = −0.27 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT-Plus (Bruker, 2005 [triangle]); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809009817/rz2300sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809009817/rz2300Isup2.hkl

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

Acknowledgments

We thank Dr Manuel Fernandes for the data collection and acknowledge SASOL, THRIP and the University of KwaZulu-Natal for financial support.

supplementary crystallographic information

Comment

The title compound was prepared as part of an ongoing study of bidentate and tridentate xanthene-based ligands (Marimuthu et al. (2008a,b,c). Similar ligands have shown relative success for the Rh-catalysed hydroformylation of alkenes. The title compound is an example of a modified xanthene backbone where a phosphorous atom has been substituted into the central ring in order to investigate the electronic properties of the final target ligand when complexed to a metal centre. In addition, methyl groups are present on the outer rings in order to increase the solubility of a resulting catalyst. The outer rings of the phenoxaphosphine backbone are nearly coplanar (dihedral angle of 6.56 (2)°). This value is significantly different from the dihedral angle of 15° reported by Mann et al.(1976) for 10-phenylphenoxaphosphine, which was observed to have a boat-like conformation about the P—O axis. The C15—P1 bond length for the tolyl group is 1.835 (13) Å, which is longer than the C—P bond lengths of the backbone heterocycle (1.805 (13) and 1.809 (13) Å for C1—P1 and C12—P1, respectively). The longer C15—P1 bond length is due to the pyramidal geometry at the P atom. Hence, the C—P—C angles range from 98.0087 (6) to 101.04 (6)°. The ring of the toluene group is nearly perpendicular to the mean plane through the phenoxaphosphine backbone, forming a dihedral angle of 83.26 (3)°

Experimental

The synthesis of the title compound was modified from literature (Bronger et al. 2004). In an inert nitrogen atmosphere AlCl3 (2.5 g, 18.9 mmol) was added to p-tolylether (2.5 g, 12.6 mmol) in 9 ml phosphorous trichloride (PCl3). The reaction mixture was refluxed for 8 h at 358 K and thereafter the excess PCl3 was distilled off at 363 K. At this temperature, excess anhydrous toluene was added to the reaction mixture. The remaining PCl3 and toluene was distilled off at 383 K to afford an orange-red residue. The residue was again diluted with 15 ml of toluene and cooled to 273 K, followed by the dropwise addition of 3.6 ml pyridine to the mixture while stirring. After an hour, the resulting salts were filtered off and the yellow residue extracted with toluene. The solvent was removed in vacuo, and the crude product purified by filtration through a short plug of silica gel to yield 2.45 g of the title compound as an oil that solidified at room temperature. X-ray quality crystals were grown from a 2-propanol/dichloromethane (1:1 v/v) solution (Yield: 61%; m.p. 337 – 338 K). Spectroscopic analysis: 1H NMR: (400 MHz, C6D6, δ, p.p.m): 1.98 (s, 6H), 1.90 (s, 3H), 6.78 (d, 2H; J(H,H) = 7.2 Hz,), 6.85 (dd, 2H; CH; J(H,H) = 2.7, 1.7 Hz,), 7.09 (d, 2H; J(H,H) = 8.3 Hz,), 7.30 (dd, 2H; J(H,H) = 1.9, 1.6 Hz,), 7.39 (t, 2H, J(H,H)= 7.9 Hz). MS: m/z (%): 357.1 (M + K+) calculated = 357.1 for C21H19OPK+. FTIR: cm-1 = 3009(w), (CH), 2920(s), 1585(w), 1489(m), 1466(vs), 1385(s), 1295(s), 1265(vs), 1231(vs), 909(m).

Refinement

Non-H atoms were first refined isotropically followed by anisotropic refinement by full matrix least-squares calculations based on F2 using SHELXTL. All hydrogen atoms were first located in a difference Fourier map, then positioned geometrically and allowed to ride on their parent atoms, with C—H = 0.95 - 0.99 Å and with Uiso(H) = 1.2 Ueq(C) for aryl H or 1.5 Ueq(C) for alkyl H atoms.

Figures

Fig. 1.
The molecular structure of the title compound. Thermal ellipsoids are shown at the 50% probability level.

Crystal data

C21H19OPF(000) = 672
Mr = 318.33Dx = 1.272 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 8225 reflections
a = 10.9363 (3) Åθ = 2.3–28.4°
b = 11.6323 (3) ŵ = 0.17 mm1
c = 14.0458 (4) ÅT = 173 K
β = 111.532 (1)°Needle, colourless
V = 1662.13 (8) Å30.51 × 0.49 × 0.48 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer3507 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.046
graphiteθmax = 28.0°, θmin = 2.0°
[var phi] and ω scansh = −14→14
29900 measured reflectionsk = −15→15
4013 independent reflectionsl = −18→18

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.108H-atom parameters constrained
S = 1.07w = 1/[σ2(Fo2) + (0.0534P)2 + 0.586P] where P = (Fo2 + 2Fc2)/3
4013 reflections(Δ/σ)max = 0.040
211 parametersΔρmax = 0.37 e Å3
0 restraintsΔρmin = −0.27 e Å3

Special details

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)

xyzUiso*/Ueq
C10.59638 (12)1.06591 (11)0.15703 (10)0.0274 (3)
C20.53669 (13)1.05047 (12)0.22849 (10)0.0303 (3)
H20.54840.97910.26360.036*
C30.46153 (13)1.13388 (12)0.25049 (10)0.0313 (3)
C40.44183 (14)1.23579 (12)0.19518 (11)0.0361 (3)
H40.38801.29400.20690.043*
C50.49875 (14)1.25429 (12)0.12363 (11)0.0357 (3)
H50.48431.32470.08680.043*
C60.57734 (13)1.16977 (11)0.10547 (10)0.0289 (3)
C70.69900 (12)1.12246 (11)−0.00204 (10)0.0284 (3)
C80.73269 (14)1.16321 (12)−0.08200 (10)0.0340 (3)
H80.70921.2391−0.10710.041*
C90.80050 (14)1.09313 (13)−0.12506 (10)0.0347 (3)
H90.82461.1222−0.17890.042*
C100.83423 (13)0.98126 (12)−0.09135 (10)0.0310 (3)
C110.79734 (12)0.94259 (11)−0.01249 (10)0.0294 (3)
H110.81770.86570.01060.035*
C120.73184 (12)1.01137 (11)0.03436 (9)0.0264 (2)
C130.40629 (15)1.11516 (14)0.33266 (11)0.0399 (3)
H13A0.35531.04370.31900.060*
H13B0.34911.17980.33330.060*
H13C0.47841.10980.39930.060*
C140.90781 (15)0.90328 (14)−0.13659 (11)0.0387 (3)
H14A0.99810.8935−0.08780.058*
H14B0.90930.9371−0.20010.058*
H14C0.86410.8283−0.15150.058*
C150.85437 (13)0.98293 (12)0.24735 (9)0.0286 (3)
C160.94457 (15)0.89406 (13)0.28148 (11)0.0377 (3)
H160.92490.82090.24930.045*
C171.06328 (16)0.91088 (17)0.36216 (12)0.0474 (4)
H171.12460.84940.38370.057*
C181.09347 (15)1.01549 (17)0.41141 (11)0.0463 (4)
C191.00354 (15)1.10404 (16)0.37752 (11)0.0440 (4)
H191.02301.17670.41060.053*
C200.88574 (14)1.08866 (13)0.29636 (11)0.0358 (3)
H200.82581.15090.27390.043*
C211.22049 (18)1.0331 (2)0.50093 (13)0.0681 (6)
H21A1.25871.10740.49400.102*
H21B1.28210.97130.50240.102*
H21C1.20331.03220.56470.102*
O10.63326 (10)1.20048 (8)0.03575 (8)0.0356 (2)
P10.69921 (3)0.95166 (3)0.14160 (2)0.02660 (11)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.0250 (6)0.0274 (6)0.0299 (6)−0.0007 (5)0.0102 (5)−0.0010 (5)
C20.0298 (6)0.0307 (6)0.0311 (6)−0.0013 (5)0.0122 (5)0.0003 (5)
C30.0279 (6)0.0352 (7)0.0316 (6)−0.0036 (5)0.0119 (5)−0.0059 (5)
C40.0349 (7)0.0322 (7)0.0445 (8)0.0023 (5)0.0185 (6)−0.0054 (6)
C50.0383 (7)0.0273 (6)0.0439 (8)0.0038 (5)0.0179 (6)0.0021 (6)
C60.0287 (6)0.0280 (6)0.0313 (6)−0.0008 (5)0.0125 (5)0.0000 (5)
C70.0277 (6)0.0290 (6)0.0288 (6)−0.0008 (5)0.0105 (5)0.0001 (5)
C80.0373 (7)0.0331 (7)0.0332 (7)−0.0006 (5)0.0147 (6)0.0059 (5)
C90.0370 (7)0.0418 (8)0.0279 (6)−0.0051 (6)0.0150 (5)0.0011 (5)
C100.0295 (6)0.0372 (7)0.0267 (6)−0.0050 (5)0.0110 (5)−0.0063 (5)
C110.0308 (6)0.0289 (6)0.0279 (6)−0.0016 (5)0.0100 (5)−0.0026 (5)
C120.0263 (6)0.0285 (6)0.0239 (5)−0.0034 (5)0.0084 (5)−0.0013 (5)
C130.0402 (8)0.0469 (9)0.0385 (7)0.0005 (6)0.0214 (6)−0.0047 (6)
C140.0404 (8)0.0456 (8)0.0346 (7)−0.0017 (6)0.0190 (6)−0.0073 (6)
C150.0304 (6)0.0337 (6)0.0250 (6)0.0017 (5)0.0140 (5)0.0048 (5)
C160.0413 (8)0.0374 (7)0.0366 (7)0.0062 (6)0.0168 (6)0.0111 (6)
C170.0379 (8)0.0626 (10)0.0412 (8)0.0109 (7)0.0140 (7)0.0220 (8)
C180.0342 (7)0.0774 (12)0.0272 (7)−0.0079 (8)0.0111 (6)0.0112 (7)
C190.0416 (8)0.0588 (10)0.0334 (7)−0.0115 (7)0.0159 (6)−0.0083 (7)
C200.0350 (7)0.0398 (7)0.0338 (7)−0.0013 (6)0.0141 (6)−0.0030 (6)
C210.0400 (9)0.1219 (19)0.0356 (8)−0.0161 (10)0.0060 (7)0.0136 (10)
O10.0444 (6)0.0277 (5)0.0431 (5)0.0054 (4)0.0261 (5)0.0070 (4)
P10.02996 (18)0.02340 (17)0.02918 (18)0.00000 (12)0.01410 (14)0.00138 (12)

Geometric parameters (Å, °)

C1—C61.3845 (18)C12—P11.8092 (13)
C1—C21.3953 (18)C13—H13A0.9800
C1—P11.8046 (13)C13—H13B0.9800
C2—C31.3780 (18)C13—H13C0.9800
C2—H20.9500C14—H14A0.9800
C3—C41.390 (2)C14—H14B0.9800
C3—C131.5021 (19)C14—H14C0.9800
C4—C51.379 (2)C15—C161.3873 (19)
C4—H40.9500C15—C201.390 (2)
C5—C61.3896 (19)C15—P11.8352 (13)
C5—H50.9500C16—C171.389 (2)
C6—O11.3784 (15)C16—H160.9500
C7—O11.3794 (16)C17—C181.379 (3)
C7—C81.3876 (18)C17—H170.9500
C7—C121.3876 (18)C18—C191.382 (3)
C8—C91.382 (2)C18—C211.507 (2)
C8—H80.9500C19—C201.383 (2)
C9—C101.388 (2)C19—H190.9500
C9—H90.9500C20—H200.9500
C10—C111.3858 (18)C21—H21A0.9800
C10—C141.4999 (19)C21—H21B0.9800
C11—C121.3901 (18)C21—H21C0.9800
C11—H110.9500
C6—C1—C2117.93 (12)H13A—C13—H13B109.5
C6—C1—P1124.10 (10)C3—C13—H13C109.5
C2—C1—P1117.92 (10)H13A—C13—H13C109.5
C3—C2—C1123.08 (12)H13B—C13—H13C109.5
C3—C2—H2118.5C10—C14—H14A109.5
C1—C2—H2118.5C10—C14—H14B109.5
C2—C3—C4117.25 (12)H14A—C14—H14B109.5
C2—C3—C13120.76 (13)C10—C14—H14C109.5
C4—C3—C13121.98 (13)H14A—C14—H14C109.5
C5—C4—C3121.42 (13)H14B—C14—H14C109.5
C5—C4—H4119.3C16—C15—C20118.26 (13)
C3—C4—H4119.3C16—C15—P1117.45 (11)
C4—C5—C6119.89 (13)C20—C15—P1124.28 (11)
C4—C5—H5120.1C15—C16—C17120.68 (15)
C6—C5—H5120.1C15—C16—H16119.7
O1—C6—C1125.24 (12)C17—C16—H16119.7
O1—C6—C5114.37 (12)C18—C17—C16120.93 (15)
C1—C6—C5120.38 (12)C18—C17—H17119.5
O1—C7—C8114.67 (12)C16—C17—H17119.5
O1—C7—C12124.88 (11)C17—C18—C19118.41 (14)
C8—C7—C12120.45 (12)C17—C18—C21121.11 (18)
C9—C8—C7119.82 (13)C19—C18—C21120.48 (19)
C9—C8—H8120.1C18—C19—C20121.14 (16)
C7—C8—H8120.1C18—C19—H19119.4
C8—C9—C10121.47 (12)C20—C19—H19119.4
C8—C9—H9119.3C19—C20—C15120.58 (15)
C10—C9—H9119.3C19—C20—H20119.7
C11—C10—C9117.27 (12)C15—C20—H20119.7
C11—C10—C14120.08 (13)C18—C21—H21A109.5
C9—C10—C14122.64 (12)C18—C21—H21B109.5
C10—C11—C12122.92 (12)H21A—C21—H21B109.5
C10—C11—H11118.5C18—C21—H21C109.5
C12—C11—H11118.5H21A—C21—H21C109.5
C7—C12—C11118.04 (12)H21B—C21—H21C109.5
C7—C12—P1124.12 (10)C6—O1—C7122.19 (10)
C11—C12—P1117.81 (10)C1—P1—C1298.00 (6)
C3—C13—H13A109.5C1—P1—C15100.87 (6)
C3—C13—H13B109.5C12—P1—C15101.04 (6)
C6—C1—C2—C3−0.7 (2)C20—C15—C16—C17−0.3 (2)
P1—C1—C2—C3176.68 (10)P1—C15—C16—C17−179.07 (11)
C1—C2—C3—C42.4 (2)C15—C16—C17—C181.1 (2)
C1—C2—C3—C13−176.31 (13)C16—C17—C18—C19−1.0 (2)
C2—C3—C4—C5−2.1 (2)C16—C17—C18—C21178.23 (14)
C13—C3—C4—C5176.57 (13)C17—C18—C19—C200.1 (2)
C3—C4—C5—C60.2 (2)C21—C18—C19—C20−179.10 (14)
C2—C1—C6—O1177.32 (12)C18—C19—C20—C150.6 (2)
P1—C1—C6—O10.09 (19)C16—C15—C20—C19−0.5 (2)
C2—C1—C6—C5−1.29 (19)P1—C15—C20—C19178.12 (11)
P1—C1—C6—C5−178.52 (10)C1—C6—O1—C710.4 (2)
C4—C5—C6—O1−177.21 (13)C5—C6—O1—C7−170.89 (12)
C4—C5—C6—C11.5 (2)C8—C7—O1—C6171.17 (12)
O1—C7—C8—C9179.10 (12)C12—C7—O1—C6−9.1 (2)
C12—C7—C8—C9−0.6 (2)C6—C1—P1—C12−8.60 (12)
C7—C8—C9—C101.1 (2)C2—C1—P1—C12174.17 (10)
C8—C9—C10—C11−0.1 (2)C6—C1—P1—C1594.34 (12)
C8—C9—C10—C14−179.98 (13)C2—C1—P1—C15−82.90 (11)
C9—C10—C11—C12−1.45 (19)C7—C12—P1—C19.72 (12)
C14—C10—C11—C12178.41 (12)C11—C12—P1—C1−172.23 (10)
O1—C7—C12—C11179.45 (12)C7—C12—P1—C15−93.08 (12)
C8—C7—C12—C11−0.86 (19)C11—C12—P1—C1584.97 (11)
O1—C7—C12—P1−2.50 (19)C16—C15—P1—C1159.40 (10)
C8—C7—C12—P1177.19 (10)C20—C15—P1—C1−19.24 (12)
C10—C11—C12—C71.94 (19)C16—C15—P1—C12−100.12 (11)
C10—C11—C12—P1−176.23 (10)C20—C15—P1—C1281.24 (12)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RZ2300).

References

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  • Bruker (2005). APEX2 and SAINT-Plus Bruker AXS Inc., Madison, Wisconsin, USA.
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  • Mann, F. G., Millar, I. T., Powell, M. & Watkin, D. J. (1976). J. Chem. Soc. Perkin Trans. 2, pp. 1383–1384.
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  • Marimuthu, T., Bala, M. D. & Friedrich, H. B. (2008b). Acta Cryst. E64, o772. [PMC free article] [PubMed]
  • Marimuthu, T., Bala, M. D. & Friedrich, H. B. (2008c). Acta Cryst. E64, o1984–o1985.
  • Seibold, S., Schafer, A., Lohstroh, W., Walter, O. & Doring, M. (2008). J. Appl. Polym. Sci.108, 264–271.
  • Shau, M. D., Lin, C. W., Yang, W. H. & Lin, H. R. (2002). J. Appl. Polym. Sci.84, 950–961.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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