Bis(3,5-dimeth­oxy­phen­yl)phosphinic acid

Wei Cheng; Zhi-Qiang Feng; Jun-Mei Tang

doi:10.1107/S1600536811008440

. 2011 Mar 15;67(Pt 4):o896. doi: 10.1107/S1600536811008440

Bis(3,5-dimethoxyphenyl)phosphinic acid

Wei Cheng ^a,^*, Zhi-Qiang Feng ^b, Jun-Mei Tang ^a

PMCID: PMC3099812 PMID: 21754171

Abstract

In the crystal structure of the title compound, C₁₆H₁₉O₆P, intermolecular O—H⋯O interactions link the molecules into chains parallel to the b axis. These chains are linked by C—H⋯π and π–π interactions [centroid–centroid distance = 3.7307 (29) Å] into a three-dimensional network. The dihedral angle between the benzene rings is 73.5 (1)°. The C and O atoms of all four methoxy groups lie very close to the mean planes of their attached rings; the C atoms are 0.055 (2)–0.1038 (1) Å out of the mean plane of the attached rings.

Related literature

For standard bond lengths, see: Allen et al. (1987 ▶). For the synthesis of the title compound, see: Watson et al. (2006 ▶).

Experimental

Crystal data

C₁₆H₁₉O₆P
M _r = 338.28
Monoclinic,
a = 14.554 (3) Å
b = 7.7620 (16) Å
c = 14.634 (3) Å
β = 96.14 (3)°
V = 1643.7 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.20 mm⁻¹
T = 298 K
0.30 × 0.20 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.944, T _max = 0.981
3138 measured reflections
3014 independent reflections
2136 reflections with I > 2σ(I)
R _int = 0.032
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.162
S = 1.01
3014 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1985 ▶); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811008440/vm2080sup1.cif

e-67-0o896-sup1.cif^{(19.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811008440/vm2080Isup2.hkl

e-67-0o896-Isup2.hkl^{(147.9KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg2 is the centroid of the C7–C12 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5A⋯O6ⁱ	0.82	1.71	2.482 (3)	155
C14—H14B⋯Cg2ⁱⁱ	0.96	2.90	3.571 (4)	128

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

Acknowledgments

The authors thank the Center of Testing and Analysis, Nanjing University, for the support.

supplementary crystallographic information

Comment

The title compound, bis(3,5-dimethoxyphenyl)phosphinic acid (I) is an important intermediate for preparing metal phosphine complexes.

The molecular structure of (I) is shown in Fig. 1. The bond lengths and angles are within normal ranges (Allen et al., 1987).

The dihedral angle between ring 1 (C1—C6) and ring 2 (C7—C12) is 73.5 (1)°. The P atom is situated close to the best planes through the benzene rings (deviation P of -0.054 (1) and 0.014 (1) Å for ring 1 and 2, respectively).

The C and O atoms of all methoxy groups lie very close to the mean planes of their attached rings. The C13 and C14 atoms of methoxy groups are 0.064 (1) and 0.1038 (1) Å, respectively, out of the C1–C6 mean plane. The C15 and C16 atoms are 0.055 (2) and 0.096 (1) Å, respectively, out of the C7–C8 mean plane.

In the crystal structure, intermolecular O—H···O interactions link the molecules into chains parallel to the b-direction (Table 1, Fig. 2). These chains are linked by C—H···π (Table 1) and π—π interactions [distance Cg1···Cg1ⁱⁱ = 3.7307 (29) Å where Cg1 is the centroid of C1—C6; symmetry code ii: 2 - x,-y,1 - z] to give a three-dimensional network, which seems to be very effective in the stabilization of the crystal structure (Fig. 2).

Experimental

The title compound was synthesized by the reaction of dimethoxyphenyl bromide, t-BuLi, N,N-dimethylphosphoramic dichloride in aqueous HCl and THF (Watson et al., 2006). Crystals suitable for X-ray analysis were obtained by dissolving the title compound (50 mg) in ethyl acetate (10 ml) and evaporating the solvent slowly at room temperature for about 3 d.