Triphenylphosphine oxide-3-chlorobenzoic acid (1/1)

In the title compound, C₁₈H₁₅OP·C₇H₅ClO₂, the tri­phenyl­phosphine oxide molecule forms a single directed hydrogen bond with the 3-chloro­benzoic acid molecule, with an O...O=P distance of 2.607 (2) Å. The C-Cl and C=O bonds adopt a cisoid conformation in the 3-chloro­benzoic acid molecule.

S1. Comment

Triphenylphosphine oxide (TPPO) is a very useful molecule for hydrogen-bond model studies. Its bulky shape, its conformational flexibility via rotation of the phenyl rings about the P—C bonds and the electron-density concentration at the phosphoryl O atom make it ready to form strong, medium and weak hydrogen bonds of different types with various proton donors (Al-Farhan et al., 1990; Fuquen & Lechat, 1992; Baures, 1991). The hydrogen bond itself is of major interest in chemistry and biology. Because the hydrogen bond is sufficiently strong and directional, it is able to control and direct the structures of molecular assemblies. This control is both reliable and reproducible enough to be used in molecular recognition and crystal engineering (Desiraju & Steiner, 1999; Etter & Baures, 1988; Etter et al., 1986, 1990; Rebek et al., 1987, 1988). As part of our hydrogen-bond studies involving TPPO, the crystal structure determination of the title compound, (I), was undertaken and the results are presented here. \sch

Compound (I) is a 1:1 adduct between TPPO and 3-chlorobenzoic acid, linked by a single directed hydrogen bond [graph set D (Etter, 1990)]. A view of the adduct with the atom-numbering scheme is in Fig. 1 and selected geometric parameters are in Table 1.

The relevant distances and angles within the directed hydrogen-bond interaction are O2—H1 0.85 (3) and O1···O2 2.607 (2) Å, and O2—H1···O1 171 (3)°, C19—O2···O1 115.98 (15)° and P1—O1···O2 151.8 (1)°. As a result of the hydrogen bonding, the P1—O1 distance of 1.492 (2) Å is 0.013 Å longer than the P—O distance in free TPPO (Al-Farhan, 1992). The P1—O1 and O1···O2 values in (I) compare with the values of 1.492 (2) and 2.630 (4) Å (Fuquen & Lechat, 1992) and 1.496 (2) and 2.645 (2) Å (Gramstad et al., 1986) for the TPPO adducts with 4-nitrophenol and pentafluorophenol, respectively.

The dihedral angles between the TPPO phenyl rings, C1—C6/C7—C12, C1—C6/C13—C18 and C7—C12/C13—C18, are 70.3 (1), 66.2 (1) and 81.5 (1)°, respectively. The O—P—C—C torsion angles of the TPPO are 21.2 (2), 33.3 (2) and 74.8 (2)°, and these are distinctly different from the minimum-energy conformation (threefold symmetry and torsion angles of 40°) deduced from analysis of the observed conformations of a wide range of TPPO derivatives (Bye et al., 1982).

The significant structural change in 3-chlorobenzoic acid is that the C—Cl and C═O bonds have adopted a cisoid conformation in (I), whereas they are in a transoid conformation in the crystal structure of 3-chlorobenzoic acid (Gougoutas & Lessinger 1975). The dihedral angle between the plane of the benzene ring and that of the carboxylic acid group is 2.96 (35)°.

Examination of the structure with PLATON (Spek, 2003) showed that there were no solvent accessible voids in the crystal lattice of (I).

S2. Experimental

The title compound was prepared by mixing equimolar amounts of TPPO and 3-chlorobenzoic acid in CCl₄. Slow evaporation of the solvent afforded colourless crystals of (I) suitable for X-ray analysis.

S3. Refinement

H atoms were found in the difference Fourier map and were treated as riding atoms (C—H = 0.96 Å) with refinable isotropic displacement parameters, except for the H atom of the carboxylic acid group, which was allowed to refine freely.

Computing details

Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXL97.

Figures

Fig. 1. A view of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. The hydrogen bond is indicated by a dashed line.

Triphenylphosphine oxide-3-chlorobenzoic acid (1/1)

Crystal data

C18H15OP·C7H5ClO2	F(000) = 904
Mr = 434.83	Dx = 1.304 Mg m^−3
Monoclinic, P21/n	Melting point: 348 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 8.845 (1) Å	Cell parameters from 25 reflections
b = 16.101 (1) Å	θ = 17.4–17.5°
c = 16.029 (2) Å	µ = 0.27 mm^−1
β = 103.97 (1)°	T = 296 K
V = 2215.2 (4) Å^3	Plate, colourless
Z = 4	0.3 × 0.3 × 0.1 mm

Data collection

Siemens P4 diffractometer	Rint = 0.021
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 1.8°
Graphite monochromator	h = −1→10
θ/2θ scans	k = −1→19
5044 measured reflections	l = −19→18
3868 independent reflections	3 standard reflections every 200 reflections
3343 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.043	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.118	w = 1/[σ^2(Fo^2) + (0.0533P)^2 + 1.0553P] where P = (Fo^2 + 2Fc^2)/3
S = 1.02	(Δ/σ)max = 0.001
3868 reflections	Δρmax = 0.57 e Å^−3
295 parameters	Δρmin = −0.57 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.041 (2)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
P1	0.34344 (6)	0.87738 (3)	0.65724 (3)	0.04667 (18)
O1	0.3902 (2)	0.84066 (10)	0.58176 (10)	0.0660 (4)
C1	0.4022 (2)	0.81496 (12)	0.75300 (13)	0.0485 (5)
C2	0.3312 (3)	0.82171 (14)	0.82110 (14)	0.0599 (6)
H2	0.2477	0.8606	0.8181	0.074 (7)*
C3	0.3805 (3)	0.77250 (16)	0.89325 (15)	0.0703 (7)
H3	0.3311	0.7774	0.9402	0.095 (9)*
C4	0.4995 (3)	0.71688 (16)	0.89813 (16)	0.0739 (7)
H4	0.5335	0.6829	0.9484	0.079 (8)*
C5	0.5700 (3)	0.70997 (17)	0.83070 (17)	0.0790 (7)
H5	0.6531	0.6708	0.8341	0.106 (10)*
C6	0.5226 (3)	0.75863 (15)	0.75836 (15)	0.0641 (6)
H6	0.5729	0.7535	0.7118	0.078 (7)*
C7	0.4264 (2)	0.97959 (12)	0.67925 (13)	0.0477 (5)
C8	0.4705 (3)	1.01389 (15)	0.76057 (16)	0.0722 (7)
H8	0.4614	0.9821	0.8098	0.091 (9)*
C9	0.5280 (4)	1.09460 (17)	0.77092 (19)	0.0857 (8)
H9	0.5585	1.1184	0.8274	0.129 (13)*
C10	0.5414 (3)	1.13999 (17)	0.7013 (2)	0.0802 (8)
H10	0.5803	1.1958	0.7089	0.095 (9)*
C11	0.4998 (4)	1.10651 (17)	0.6212 (2)	0.0849 (8)
H11	0.5098	1.1387	0.5724	0.122 (12)*
C12	0.4430 (3)	1.02613 (15)	0.60986 (15)	0.0662 (6)
H12	0.4149	1.0026	0.5532	0.088 (8)*
C13	0.1352 (2)	0.88917 (12)	0.63849 (12)	0.0486 (5)
C14	0.0603 (2)	0.96473 (14)	0.61708 (14)	0.0579 (5)
H14	0.1202	1.0143	0.6159	0.068 (7)*
C15	−0.1013 (3)	0.96867 (18)	0.59736 (16)	0.0725 (7)
H15	−0.1532	1.0208	0.5815	0.094 (9)*
C16	−0.1871 (3)	0.8980 (2)	0.60047 (16)	0.0794 (8)
H16	−0.2987	0.9010	0.5874	0.087 (8)*
C17	−0.1143 (3)	0.8238 (2)	0.62194 (18)	0.0812 (8)
H17	−0.1751	0.7748	0.6241	0.115 (11)*
C18	0.0461 (3)	0.81838 (16)	0.64060 (16)	0.0692 (6)
H18	0.0962	0.7656	0.6550	0.088 (9)*
Cl1	0.85659 (12)	0.41131 (5)	0.46171 (8)	0.1153 (4)
O2	0.4212 (2)	0.71509 (12)	0.48453 (12)	0.0732 (5)
H1	0.409 (3)	0.752 (2)	0.5202 (19)	0.096 (10)*
O3	0.6357 (2)	0.67806 (11)	0.58134 (12)	0.0778 (5)
C19	0.5432 (3)	0.66793 (13)	0.51304 (15)	0.0560 (5)
C20	0.5578 (3)	0.59818 (13)	0.45394 (14)	0.0563 (5)
C21	0.6842 (3)	0.54555 (14)	0.47894 (16)	0.0627 (6)
H21	0.7605	0.5553	0.5318	0.077 (8)*
C22	0.7000 (3)	0.47920 (15)	0.42779 (19)	0.0751 (7)
C23	0.5930 (4)	0.46471 (19)	0.3521 (2)	0.0895 (9)
H23	0.6060	0.4185	0.3166	0.113 (11)*
C24	0.4670 (4)	0.5164 (2)	0.32714 (18)	0.0913 (9)
H24	0.3914	0.5059	0.2742	0.124 (12)*
C25	0.4476 (3)	0.58414 (17)	0.37792 (15)	0.0734 (7)
H25	0.3594	0.6203	0.3604	0.055 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0548 (3)	0.0422 (3)	0.0465 (3)	0.0015 (2)	0.0191 (2)	0.0006 (2)
O1	0.0907 (11)	0.0575 (9)	0.0592 (9)	0.0057 (8)	0.0366 (8)	−0.0024 (7)
C1	0.0530 (11)	0.0421 (10)	0.0523 (11)	0.0010 (8)	0.0167 (9)	0.0005 (8)
C2	0.0692 (14)	0.0574 (13)	0.0586 (12)	0.0160 (11)	0.0263 (10)	0.0085 (10)
C3	0.0900 (17)	0.0700 (15)	0.0574 (13)	0.0151 (13)	0.0306 (12)	0.0126 (11)
C4	0.0927 (18)	0.0682 (15)	0.0588 (14)	0.0174 (14)	0.0146 (12)	0.0156 (12)
C5	0.0793 (17)	0.0773 (17)	0.0810 (17)	0.0328 (14)	0.0204 (13)	0.0155 (14)
C6	0.0651 (13)	0.0653 (14)	0.0669 (14)	0.0145 (11)	0.0256 (11)	0.0057 (11)
C7	0.0438 (10)	0.0474 (11)	0.0536 (11)	−0.0004 (8)	0.0153 (8)	0.0031 (9)
C8	0.0995 (19)	0.0598 (14)	0.0580 (13)	−0.0171 (13)	0.0205 (12)	0.0006 (11)
C9	0.112 (2)	0.0657 (16)	0.0769 (17)	−0.0263 (15)	0.0186 (16)	−0.0121 (13)
C10	0.0853 (18)	0.0582 (14)	0.099 (2)	−0.0243 (13)	0.0266 (15)	−0.0006 (14)
C11	0.103 (2)	0.0699 (17)	0.0860 (19)	−0.0249 (15)	0.0304 (16)	0.0172 (14)
C12	0.0756 (15)	0.0660 (14)	0.0582 (13)	−0.0153 (12)	0.0183 (11)	0.0071 (11)
C13	0.0537 (11)	0.0506 (11)	0.0412 (10)	−0.0058 (9)	0.0106 (8)	−0.0009 (8)
C14	0.0557 (12)	0.0567 (12)	0.0607 (12)	−0.0019 (10)	0.0130 (10)	0.0065 (10)
C15	0.0561 (13)	0.0851 (18)	0.0731 (15)	0.0078 (13)	0.0092 (11)	0.0094 (13)
C16	0.0496 (13)	0.122 (2)	0.0629 (14)	−0.0138 (15)	0.0058 (11)	0.0049 (15)
C17	0.0703 (16)	0.089 (2)	0.0784 (17)	−0.0343 (15)	0.0066 (13)	0.0040 (14)
C18	0.0699 (15)	0.0574 (14)	0.0757 (15)	−0.0152 (12)	0.0088 (12)	0.0014 (11)
Cl1	0.1304 (7)	0.0692 (5)	0.1693 (9)	0.0125 (4)	0.0811 (7)	−0.0007 (5)
O2	0.0890 (12)	0.0634 (10)	0.0681 (11)	0.0038 (9)	0.0208 (9)	−0.0075 (9)
O3	0.0728 (11)	0.0720 (11)	0.0843 (12)	−0.0093 (9)	0.0109 (9)	−0.0298 (9)
C19	0.0621 (13)	0.0477 (11)	0.0635 (13)	−0.0160 (10)	0.0260 (11)	−0.0040 (10)
C20	0.0718 (14)	0.0496 (11)	0.0557 (12)	−0.0197 (10)	0.0311 (10)	−0.0038 (9)
C21	0.0746 (15)	0.0520 (12)	0.0710 (14)	−0.0149 (11)	0.0362 (12)	−0.0041 (11)
C22	0.1019 (19)	0.0517 (13)	0.0901 (19)	−0.0135 (13)	0.0587 (16)	−0.0067 (12)
C23	0.134 (3)	0.0656 (16)	0.087 (2)	−0.0235 (18)	0.062 (2)	−0.0206 (15)
C24	0.125 (3)	0.097 (2)	0.0555 (15)	−0.034 (2)	0.0284 (16)	−0.0196 (15)
C25	0.0937 (19)	0.0722 (16)	0.0581 (14)	−0.0152 (14)	0.0255 (13)	−0.0016 (12)

Geometric parameters (Å, º)

P1—O1	1.492 (2)	C13—C14	1.388 (3)
P1—C1	1.803 (2)	C13—C18	1.391 (3)
P1—C7	1.802 (2)	C14—C15	1.389 (3)
P1—C13	1.803 (2)	C14—H14	0.9600
C1—C6	1.386 (3)	C15—C16	1.375 (4)
C1—C2	1.389 (3)	C15—H15	0.9600
C2—C3	1.383 (3)	C16—C17	1.361 (4)
C2—H2	0.9600	C16—H16	0.9600
C3—C4	1.370 (3)	C17—C18	1.381 (4)
C3—H3	0.9600	C17—H17	0.9600
C4—C5	1.377 (4)	C18—H18	0.9600
C4—H4	0.9600	Cl1—C22	1.745 (3)
C5—C6	1.378 (3)	C19—C20	1.495 (3)
C5—H5	0.9600	O2—C19	1.308 (3)
C6—H6	0.9600	O2—H1	0.85 (3)
C7—C12	1.378 (3)	O3—C19	1.209 (3)
C7—C8	1.382 (3)	C20—C21	1.383 (3)
C8—C9	1.391 (3)	C20—C25	1.383 (3)
C8—H8	0.9600	C21—C22	1.374 (3)
C9—C10	1.363 (4)	C21—H21	0.9600
C9—H9	0.9600	C22—C23	1.366 (4)
C10—C11	1.358 (4)	C23—C24	1.371 (5)
C10—H10	0.9600	C23—H23	0.9600
C11—C12	1.384 (4)	C24—C25	1.396 (4)
C11—H11	0.9600	C24—H24	0.9600
C12—H12	0.9600	C25—H25	0.9600
O1—P1—C1	112.96 (9)	C11—C12—H12	119.7
O1—P1—C7	109.93 (9)	C14—C13—C18	119.0 (2)
O1—P1—C13	112.25 (10)	C14—C13—P1	122.73 (16)
C1—P1—C7	108.81 (9)	C18—C13—P1	118.14 (17)
C1—P1—C13	105.88 (9)	C13—C14—C15	120.0 (2)
C7—P1—C13	106.73 (9)	C13—C14—H14	120.0
C6—C1—C2	119.29 (19)	C15—C14—H14	120.0
C2—C1—P1	122.23 (15)	C16—C15—C14	120.0 (3)
C6—C1—P1	118.48 (16)	C16—C15—H15	120.0
C3—C2—C1	120.1 (2)	C14—C15—H15	120.0
C3—C2—H2	120.0	C17—C16—C15	120.3 (2)
C1—C2—H2	120.0	C17—C16—H16	119.9
C4—C3—C2	120.4 (2)	C15—C16—H16	119.9
C4—C3—H3	119.8	C16—C17—C18	120.6 (2)
C2—C3—H3	119.8	C16—C17—H17	119.7
C3—C4—C5	119.7 (2)	C18—C17—H17	119.7
C3—C4—H4	120.2	C17—C18—C13	120.1 (2)
C5—C4—H4	120.2	C17—C18—H18	120.0
C4—C5—C6	120.8 (2)	C13—C18—H18	120.0
C4—C5—H5	119.6	C19—O2—H1	114 (2)
C6—C5—H5	119.6	O3—C19—O2	124.0 (2)
C5—C6—C1	119.8 (2)	O3—C19—C20	122.1 (2)
C5—C6—H6	120.1	O2—C19—C20	113.9 (2)
C1—C6—H6	120.1	C21—C20—C25	120.2 (2)
C12—C7—C8	118.9 (2)	C21—C20—C19	117.7 (2)
C8—C7—P1	123.93 (16)	C25—C20—C19	122.0 (2)
C12—C7—P1	117.15 (16)	C22—C21—C20	119.7 (3)
C7—C8—C9	119.8 (2)	C22—C21—H21	120.2
C7—C8—H8	120.1	C20—C21—H21	120.2
C9—C8—H8	120.1	C23—C22—C21	120.9 (3)
C10—C9—C8	120.3 (3)	C23—C22—Cl1	119.8 (2)
C10—C9—H9	119.8	C21—C22—Cl1	119.3 (2)
C8—C9—H9	119.8	C22—C23—C24	119.7 (3)
C11—C10—C9	120.2 (2)	C22—C23—H23	120.1
C11—C10—H10	119.9	C24—C23—H23	120.1
C9—C10—H10	119.9	C23—C24—C25	120.6 (3)
C10—C11—C12	120.2 (2)	C23—C24—H24	119.7
C10—C11—H11	119.9	C25—C24—H24	119.7
C12—C11—H11	119.9	C20—C25—C24	118.8 (3)
C7—C12—C11	120.5 (2)	C20—C25—H25	120.6
C7—C12—H12	119.7	C24—C25—H25	120.6
O1—P1—C1—C6	21.2 (2)	O1—P1—C13—C14	−101.20 (18)
C7—P1—C1—C6	−101.17 (19)	C7—P1—C13—C14	19.3 (2)
C13—P1—C1—C6	144.43 (18)	C1—P1—C13—C14	135.12 (17)
O1—P1—C1—C2	−158.94 (18)	O1—P1—C13—C18	74.8 (2)
C7—P1—C1—C2	78.7 (2)	C7—P1—C13—C18	−164.68 (17)
C13—P1—C1—C2	−35.7 (2)	C1—P1—C13—C18	−48.86 (19)
C6—C1—C2—C3	−0.1 (3)	C18—C13—C14—C15	−0.6 (3)
P1—C1—C2—C3	−179.94 (19)	P1—C13—C14—C15	175.36 (17)
C1—C2—C3—C4	0.0 (4)	C13—C14—C15—C16	1.1 (4)
C2—C3—C4—C5	−0.1 (4)	C14—C15—C16—C17	−0.7 (4)
C3—C4—C5—C6	0.2 (4)	C15—C16—C17—C18	−0.2 (4)
C4—C5—C6—C1	−0.3 (4)	C16—C17—C18—C13	0.7 (4)
C2—C1—C6—C5	0.2 (4)	C14—C13—C18—C17	−0.3 (3)
P1—C1—C6—C5	−179.9 (2)	P1—C13—C18—C17	−176.4 (2)
O1—P1—C7—C12	33.3 (2)	O3—C19—C20—C21	−1.4 (3)
C1—P1—C7—C12	157.50 (17)	O2—C19—C20—C21	179.63 (18)
C13—P1—C7—C12	−88.66 (18)	O3—C19—C20—C25	176.6 (2)
O1—P1—C7—C8	−148.1 (2)	O2—C19—C20—C25	−2.4 (3)
C1—P1—C7—C8	−23.9 (2)	C25—C20—C21—C22	0.1 (3)
C13—P1—C7—C8	89.9 (2)	C19—C20—C21—C22	178.17 (19)
C12—C7—C8—C9	1.0 (4)	C20—C21—C22—C23	0.4 (3)
P1—C7—C8—C9	−177.5 (2)	C20—C21—C22—Cl1	−177.95 (16)
C7—C8—C9—C10	−0.1 (5)	C21—C22—C23—C24	−0.7 (4)
C8—C9—C10—C11	−0.6 (5)	Cl1—C22—C23—C24	177.6 (2)
C9—C10—C11—C12	0.3 (5)	C22—C23—C24—C25	0.5 (4)
C8—C7—C12—C11	−1.3 (4)	C21—C20—C25—C24	−0.3 (3)
P1—C7—C12—C11	177.3 (2)	C19—C20—C25—C24	−178.3 (2)
C10—C11—C12—C7	0.7 (4)	C23—C24—C25—C20	0.0 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1···O1	0.85 (3)	1.76 (3)	2.607 (2)	171 (3)