Crystal structure of the co-crystal butyl­paraben–isonicotinamide (1/1)

Bhardwaj, R.M.; Yang, H.; Florence, A.J.

doi:10.1107/S2056989015023518

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Volume 72| Part 1| January 2016| Pages 53-55

doi:10.1107/S2056989015023518

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Crystal structure of the co-crystal butylparaben–isonicotinamide (1/1)

Rajni M. Bhardwaj,^a Huaiyu Yang ^a and Alastair J. Florence ^a ^*

^aStrathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, Scotland
^*Correspondence e-mail: alastair.florence@strath.ac.uk

Edited by V. V. Chernyshev, Moscow State University, Russia (Received 31 August 2015; accepted 7 December 2015; online 1 January 2016)

The title 1:1 co-crystal, C₁₁H₁₄O₃·C₆H₆N₂O [systematic name: butyl 4-hydroxybenzoate–isonicotinamide (1/1)], crystallizes with one molecule of butylparaben (BPN) and one molecule of isonicotinamide (ISN) in the asymmetric unit. In the crystal, BPN and ISN molecules form hydrogen-bonded (O—H⋯N and N—H⋯O) dimers of paired BPN and ISN molecules. These dimers are further connected to each other via N—H⋯O=C hydrogen bonds, creating ribbons in [011] which further stack along the a axis to form a layered structure with short C⋯C contacts of 3.285 (3) Å. Packing interactions within the crystal structure were assessed using PIXEL calculations.

Keywords: crystal structure; butylparaben; isonicotinamide; co-crystal; hydrogen bonding.

CCDC reference: 1440986

1. Chemical context

Butylparaben (butyl 4-hydroxybenzoate, BPN), a naturally derived preservative, is widely used in pharmaceutical products and cosmetics (Charnock & Finsrud, 2007 ), and generally considered to be safe (Hossaini et al., 2000 ). The solubility of BPN has been reported in various solvents (Yang & Rasmuson, 2010 ; 2012 ; 2013 ). Isonicotinamide (ISN) is a widely used coformer (Aakeröy et al., 2003 ) and is known to form hydrogen-bonded co-crystals with phenolic compounds (Vishweshwar et al., 2003 ; McKellar et al., 2014 ). The sample of butyl paraben–isonicotinamide (BPIN) co-crystals was isolated during an experimental co-crystal screening of BPN. The sample was identified as a novel form using multi-sample foil transmission X-ray powder diffraction analysis (Florence et al., 2003 ). A suitable sample for single crystal X-ray diffraction analysis was obtained from slow evaporation of 1:1 molar solution of BPN with ISN in ethanol at room temperature.

2. Structural commentary

The title co-crystal crystallizes with one molecule of BPN and a molecule of ISN in the asymmetric unit (Fig. 1). In the solid state, the BPN molecule exhibits a planar conformation with a fully extended trans zigzag butyl ester group.

Figure 1
A view of the molecular structure of the asymmetric unit of the title co-crystal, showing the atom labelling. Displacement ellipsoids are drawn at the 50% probability level.

3. Supramolecular features

The crystal structure is defined by hydrogen-bonded BPN–ISN–ISN–BPN dimers of paired BPN⋯ISN molecules connected via O—H⋯N hydrogen bonds (Fig. 2a). These BPN–ISN–ISN–BPN dimers are further connected to each other via N—H⋯O=C hydrogen-bonds extending the structure to form ribbons in [011]; see Fig. 2b and Table 1. These ribbons further stack along a axis to produce a layered structure (Fig. 3) which is stabilized by various van der Waals interactions and exhibits short C⋯C contacts of 3.285 (3) Å. PIXEL (Gavezzotti, 2002 ; 2003 ) calculations revealed that the largest contribution to crystal stabilization comes from the dispersion energy (E_d, −98.5 kJ mol⁻¹). The next greatest contribution comes from electrostatic (Coulombic) energy, (E_C, −67.3 kJ mol⁻¹) and then from polarization energy (E_p, −32.2 kJ mol⁻¹).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H3O⋯N2	0.95 (3)	1.79 (3)	2.721 (2)	165 (2)
N1—H1N⋯O1ⁱ	0.91 (2)	1.97 (2)	2.880 (2)	175.3 (15)
N1—H2N⋯O3ⁱⁱ	0.94 (2)	2.02 (2)	2.948 (2)	168.3 (18)
Symmetry codes: (i) -x-1, -y+3, -z+3; (ii) -x-1, -y+2, -z+2.

Figure 2
Hydrogen bonds in the title compound: (a) hydrogen-bonded (thin grey lines) dimer of paired BPN⋯ISN molecules; (b) hydrogen-bonded (thin orange lines) ribbon of dimers extended in [011]. Atom colour code: C, N, O and H are grey, blue, red and white, respectively. Hydrogen atoms not involved in hydrogen bonding have been omitted for clarity.

Figure 3
A portion of the crystal packing showing the layered structure of the title co-crystal. H atoms have been omitted for clarity.

4. Database survey

The crystal structures of BPN (CSD refcode: UDOMIL) (Yang & Rasmuson, 2013) and its clathrate hydrate (CSD refcode: VOFKIL) have been reported in the literature (de Vries & Caira, 2008 ). In UDOMIL, the BPN molecule exhibits a planar conformation except for the terminal ethyl moiety of butyl ester group which is in a cis orientation with respect to the ester group.

5. Synthesis and crystallization

Plate shaped crystals were grown from the saturated 1:1 molar solution of BPN with ISN in ethanol by isothermal solvent evaporation at 298 K.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The N and O bound H atoms were located in a difference Fourier map and isotropically refined. The C-bound H atoms were placed in calculated positions and refined as riding atoms: C—H = 0.95–0.99 Å with U_iso(H) = 1.5U_eq(C) for methyl H atoms and = 1.2U_eq(C) for other H atoms.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₁H₁₄O₃·C₆H₆N₂O
M_r	316.35
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	150
a, b, c (Å)	5.6257 (6), 9.8661 (11), 14.3979 (15)
α, β, γ (°)	90.834 (7), 91.431 (7), 91.645 (7)
V (Å³)	798.47 (15)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.09
Crystal size (mm)	0.45 × 0.36 × 0.21

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2007 )
T_min, T_max	0.625, 0.745
No. of measured, independent and observed [I > 2σ(I)] reflections	10444, 3225, 2344
R_int	0.039
(sin θ/λ)_max (Å⁻¹)	0.627

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.116, 1.05
No. of reflections	3225
No. of parameters	221
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.27
Computer programs: APEX2 and SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), Mercury (Macrae et al., 2008 ), ORTEP-3 for Windows (Farrugia, 2012 ), enCIFer (Allen et al., 2004 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1440986

Crystal structure: contains datablock I. DOI: 10.1107/S2056989015023518/cv5494sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015023518/cv5494Isup2.hkl

Supporting information file. DOI: 10.1107/S2056989015023518/cv5494Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008) and ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010).

Butyl 4-hydroxybenzoate–isonicotinamide (1/1) top

Crystal data top

C₁₁H₁₄O₃·C₆H₆N₂O	Z = 2
M_r = 316.35	F(000) = 336
Triclinic, P1	D_x = 1.316 Mg m⁻³
a = 5.6257 (6) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.8661 (11) Å	Cell parameters from 4038 reflections
c = 14.3979 (15) Å	θ = 2.5–26.4°
α = 90.834 (7)°	µ = 0.09 mm⁻¹
β = 91.431 (7)°	T = 150 K
γ = 91.645 (7)°	Plate, colourless
V = 798.47 (15) Å³	0.45 × 0.36 × 0.21 mm

Data collection top

Bruker APEXII CCD diffractometer	3225 independent reflections
Radiation source: fine-focus sealed tube	2344 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.039
φ and ω scans	θ_max = 26.5°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −6→7
T_min = 0.625, T_max = 0.745	k = −12→12
10444 measured reflections	l = −18→18

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.045	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.116	w = 1/[σ²(F_o²) + (0.0482P)² + 0.3682P] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max = 0.001
3225 reflections	Δρ_max = 0.26 e Å⁻³
221 parameters	Δρ_min = −0.27 e Å⁻³

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
H1N	−0.623 (3)	1.480 (2)	1.4226 (13)	0.019 (5)*
H2N	−0.626 (4)	1.399 (2)	1.3256 (16)	0.035 (6)*
H3O	0.140 (5)	0.939 (3)	1.1807 (17)	0.054 (7)*
O4	0.1197 (2)	0.47988 (13)	0.82145 (8)	0.0227 (3)
O1	−0.2641 (2)	1.38157 (14)	1.49057 (9)	0.0275 (3)
N1	−0.5594 (3)	1.41555 (17)	1.38514 (11)	0.0238 (4)
O2	0.2637 (2)	0.88155 (15)	1.16227 (9)	0.0308 (4)
N2	−0.0392 (3)	1.05682 (16)	1.24155 (10)	0.0234 (4)
O3	−0.2134 (2)	0.59634 (14)	0.80166 (9)	0.0297 (3)
C13	−0.0315 (3)	0.57543 (19)	0.84578 (12)	0.0207 (4)
C7	0.2633 (3)	0.63083 (19)	0.97609 (12)	0.0220 (4)
H8	0.3619	0.5641	0.9542	0.026*
C6	−0.3631 (3)	1.35566 (18)	1.41440 (12)	0.0194 (4)
C12	0.0462 (3)	0.65243 (18)	0.93023 (12)	0.0190 (4)
C14	0.0586 (3)	0.40447 (19)	0.73615 (12)	0.0223 (4)
H15A	0.0438	0.4660	0.6845	0.027*
H15B	−0.0918	0.3552	0.7423	0.027*
C8	0.3330 (3)	0.7076 (2)	1.05364 (13)	0.0239 (4)
H9	0.4775	0.6920	1.0839	0.029*
C2	−0.0520 (3)	1.18936 (19)	1.38204 (13)	0.0234 (4)
H2	0.0162	1.2121	1.4399	0.028*
C10	−0.0302 (3)	0.83018 (19)	1.04128 (12)	0.0229 (4)
H11	−0.1290	0.8969	1.0631	0.027*
C16	0.2264 (3)	0.2420 (2)	0.62252 (13)	0.0242 (4)
H17A	0.0722	0.1955	0.6171	0.029*
H17B	0.2306	0.3126	0.5764	0.029*
C5	−0.3533 (3)	1.21153 (19)	1.26476 (12)	0.0213 (4)
H6	−0.4918	1.2498	1.2420	0.026*
C15	0.2548 (3)	0.30708 (19)	0.71924 (12)	0.0220 (4)
H16A	0.2511	0.2370	0.7658	0.026*
H16B	0.4075	0.3551	0.7248	0.026*
C1	−0.2580 (3)	1.25031 (18)	1.35125 (12)	0.0185 (4)
C9	0.1866 (3)	0.80852 (19)	1.08652 (12)	0.0221 (4)
C11	−0.0986 (3)	0.75279 (19)	0.96404 (12)	0.0223 (4)
H12	−0.2437	0.7680	0.9342	0.027*
C3	0.0504 (3)	1.0945 (2)	1.32551 (13)	0.0251 (4)
H3	0.1888	1.0544	1.3467	0.030*
C4	−0.2387 (3)	1.11486 (19)	1.21283 (13)	0.0240 (4)
H5	−0.3042	1.0892	1.1551	0.029*
C17	0.4194 (4)	0.1414 (2)	0.60224 (14)	0.0314 (5)
H18A	0.5725	0.1869	0.6068	0.047*
H18B	0.3946	0.1042	0.5407	0.047*
H18C	0.4130	0.0696	0.6465	0.047*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O4	0.0233 (7)	0.0256 (7)	0.0192 (7)	0.0096 (6)	−0.0068 (5)	−0.0082 (5)
O1	0.0308 (7)	0.0313 (8)	0.0203 (7)	0.0134 (6)	−0.0072 (6)	−0.0097 (6)
N1	0.0260 (9)	0.0268 (9)	0.0185 (8)	0.0106 (7)	−0.0047 (7)	−0.0089 (7)
O2	0.0272 (7)	0.0367 (8)	0.0279 (7)	0.0099 (6)	−0.0072 (6)	−0.0183 (6)
N2	0.0251 (8)	0.0230 (8)	0.0223 (8)	0.0055 (7)	0.0000 (6)	−0.0049 (7)
O3	0.0284 (7)	0.0376 (8)	0.0229 (7)	0.0145 (6)	−0.0098 (6)	−0.0089 (6)
C13	0.0215 (9)	0.0228 (10)	0.0181 (9)	0.0066 (8)	−0.0013 (7)	−0.0014 (8)
C7	0.0227 (9)	0.0230 (10)	0.0205 (9)	0.0081 (8)	−0.0021 (7)	−0.0043 (8)
C6	0.0209 (9)	0.0199 (9)	0.0173 (9)	0.0022 (8)	−0.0009 (7)	−0.0019 (7)
C12	0.0211 (9)	0.0195 (9)	0.0164 (9)	0.0033 (7)	−0.0010 (7)	−0.0006 (7)
C14	0.0257 (10)	0.0252 (10)	0.0157 (9)	0.0049 (8)	−0.0061 (7)	−0.0061 (8)
C8	0.0190 (9)	0.0311 (11)	0.0215 (9)	0.0076 (8)	−0.0060 (7)	−0.0061 (8)
C2	0.0234 (9)	0.0270 (10)	0.0195 (9)	0.0037 (8)	−0.0046 (7)	−0.0050 (8)
C10	0.0226 (9)	0.0241 (10)	0.0222 (9)	0.0090 (8)	0.0014 (7)	−0.0035 (8)
C16	0.0281 (10)	0.0246 (10)	0.0199 (9)	0.0060 (8)	−0.0034 (8)	−0.0053 (8)
C5	0.0234 (9)	0.0230 (10)	0.0176 (9)	0.0068 (8)	−0.0040 (7)	−0.0013 (8)
C15	0.0233 (9)	0.0232 (10)	0.0194 (9)	0.0062 (8)	−0.0042 (7)	−0.0027 (8)
C1	0.0200 (9)	0.0176 (9)	0.0179 (9)	0.0017 (7)	0.0009 (7)	−0.0015 (7)
C9	0.0239 (10)	0.0239 (10)	0.0184 (9)	0.0031 (8)	−0.0009 (7)	−0.0067 (8)
C11	0.0196 (9)	0.0276 (10)	0.0199 (9)	0.0079 (8)	−0.0037 (7)	−0.0010 (8)
C3	0.0225 (9)	0.0263 (10)	0.0265 (10)	0.0095 (8)	−0.0033 (8)	−0.0059 (8)
C4	0.0277 (10)	0.0269 (11)	0.0173 (9)	0.0055 (8)	−0.0029 (7)	−0.0058 (8)
C17	0.0348 (11)	0.0310 (11)	0.0287 (11)	0.0096 (9)	0.0016 (9)	−0.0062 (9)

Geometric parameters (Å, º) top

O4—C13	1.336 (2)	C12—C11	1.391 (2)
O4—C14	1.455 (2)	C14—C15	1.506 (2)
O1—C6	1.238 (2)	C8—C9	1.395 (2)
N1—C6	1.330 (2)	C2—C3	1.379 (2)
O2—C9	1.354 (2)	C2—C1	1.387 (2)
N2—C4	1.334 (2)	C10—C11	1.380 (3)
N2—C3	1.341 (2)	C10—C9	1.392 (3)
O3—C13	1.215 (2)	C16—C17	1.523 (3)
C13—C12	1.475 (2)	C16—C15	1.528 (2)
C7—C8	1.382 (3)	C5—C4	1.387 (2)
C7—C12	1.397 (2)	C5—C1	1.388 (2)
C6—C1	1.514 (2)

C13—O4—C14	115.95 (13)	C3—C2—C1	118.97 (17)
C4—N2—C3	117.20 (15)	C11—C10—C9	120.08 (16)
O3—C13—O4	122.73 (16)	C17—C16—C15	112.76 (15)
O3—C13—C12	123.99 (16)	C4—C5—C1	118.94 (16)
O4—C13—C12	113.28 (14)	C14—C15—C16	110.66 (15)
C8—C7—C12	120.73 (16)	C2—C1—C5	118.09 (16)
O1—C6—N1	123.13 (16)	C2—C1—C6	117.54 (16)
O1—C6—C1	118.87 (15)	C5—C1—C6	124.37 (15)
N1—C6—C1	117.99 (16)	O2—C9—C10	122.75 (16)
C11—C12—C7	118.73 (16)	O2—C9—C8	117.70 (16)
C11—C12—C13	118.87 (15)	C10—C9—C8	119.55 (16)
C7—C12—C13	122.38 (15)	C10—C11—C12	120.95 (17)
O4—C14—C15	107.55 (14)	N2—C3—C2	123.48 (17)
C7—C8—C9	119.96 (17)	N2—C4—C5	123.31 (17)

C14—O4—C13—O3	2.3 (3)	O1—C6—C1—C2	−1.0 (3)
C14—O4—C13—C12	−177.25 (15)	N1—C6—C1—C2	179.41 (18)
C8—C7—C12—C11	0.0 (3)	O1—C6—C1—C5	179.42 (18)
C8—C7—C12—C13	178.19 (18)	N1—C6—C1—C5	−0.2 (3)
O3—C13—C12—C11	2.0 (3)	C11—C10—C9—O2	179.70 (18)
O4—C13—C12—C11	−178.52 (16)	C11—C10—C9—C8	−0.4 (3)
O3—C13—C12—C7	−176.20 (19)	C7—C8—C9—O2	−179.54 (17)
O4—C13—C12—C7	3.3 (3)	C7—C8—C9—C10	0.6 (3)
C13—O4—C14—C15	177.62 (16)	C9—C10—C11—C12	0.1 (3)
C12—C7—C8—C9	−0.4 (3)	C7—C12—C11—C10	0.1 (3)
O4—C14—C15—C16	−170.00 (15)	C13—C12—C11—C10	−178.09 (17)
C17—C16—C15—C14	−179.45 (17)	C4—N2—C3—C2	−0.4 (3)
C3—C2—C1—C5	0.6 (3)	C1—C2—C3—N2	−0.2 (3)
C3—C2—C1—C6	−179.01 (17)	C3—N2—C4—C5	0.7 (3)
C4—C5—C1—C2	−0.4 (3)	C1—C5—C4—N2	−0.3 (3)
C4—C5—C1—C6	179.21 (17)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H3O···N2	0.95 (3)	1.79 (3)	2.721 (2)	165 (2)
N1—H1N···O1ⁱ	0.91 (2)	1.97 (2)	2.880 (2)	175.3 (15)
N1—H2N···O3ⁱⁱ	0.94 (2)	2.02 (2)	2.948 (2)	168.3 (18)

Symmetry codes: (i) −x−1, −y+3, −z+3; (ii) −x−1, −y+2, −z+2.

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