(E)-2-Methyl-5-(1-naphthyl­methyl)­cinnamic acid

The title compound, C₂₁H₁₈O₂, crystallized in the centrosymmetric space group P2₁/n with one mol­ecule in the asymmetric unit. There is a single hydrogen bond, with an O_donor...O_acceptor distance of 2.624 (2) Å, which forms a cyclic dimer about a center of symmetry. The carboxyl group O atoms are ordered, while the carboxyl-H atom is disordered. A single leading intermolecular C—H...O interaction has an H...O distance of 2.68 Å and a C—H...O angle of 178°; this interaction forms chains. Taken together with the hydrogen bond, it generates chains and rings. Structural comparisons are made with trans-cinnamic acid and with 4-methyl-trans-cinnamic acid.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1988); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1995); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: TEXSAN; molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: TEXSAN and PLATON (Spek, 1990).

(I)

Crystal data

C21H18O2	F(000) = 640
Mr = 302.37	Dx = 1.218 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 16.942 (1) Å	Cell parameters from 25 reflections
b = 5.932 (2) Å	θ = 13.2–17.4°
c = 17.265 (1) Å	µ = 0.08 mm^−1
β = 108.122 (5)°	T = 296 K
V = 1649.2 (5) Å^3	Cut column, colorless
Z = 4	0.38 × 0.19 × 0.15 mm

Data collection

Rigaku AFC5S diffractometer	Rint = 0.043
Radiation source: X-ray tube	θmax = 27.6°, θmin = 2.0°
Graphite monochromator	h = 0→22
ω scans	k = 0→7
3942 measured reflections	l = −22→21
3816 independent reflections	6 standard reflections every 150 reflections
1452 reflections with I > 2.00σI	intensity decay: +− 1.6 (average maximum relative intensity)

Refinement

Refinement on F^2	216 parameters
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.057	Weighting scheme based on measured s.u.'s 1/[σ^2cs + (0.004 I)^2]
wR(F^2) = 0.073	(Δ/σ)max = 0.0003
S = 1.36	Δρmax = 0.54 e Å^−3
3816 reflections	Δρmin = −0.49 e Å^−3

Special details

Experimental. The Laue group assignment, the systematic absences and the centrosymmetry indicated by the intensity statistics led to assignment of the space group uniquely as P2₁/n (No. 14); since refinement proceeded well, it was adopted. Fourier difference methods were used to locate initial H atom positions, excepting the carboxyl H atom, and these H atoms were refined. Refined C—H distances ranged from 0.92 (3) to 1.13 (3) Å, with mean value 1.02 (5) Å; their U_iso values ranged from 0.9 to 1.6 times the U_eq values of the attached C atoms. The H atoms, excepting the carboxyl H atom, H7 and H8 were then made canonical, with C—H = 0.98 Å and U_iso = 1.2 × U_eq of the attached C atom. In the later stages of refinement the extinction coefficient was predicted to be negative, so was not included in the model. The maximum peak in the final difference map occurs ~0.9 Å from O1, but not in a position to be interpretable as a carboxyl H atom, while the maximum negative peak occurs ~1.8 Å from C21 and 2.0 Å from C15 and C16.

Geometry. Table of Least-Squares Planes ——————————

————– Plane number 1 —————

Atoms Defining Plane Distance e.s.d. O1 (1) 0.0000 O2 (1) 0.0000 C9 (1) 0.0000

Mean deviation from plane is 0.0000 angstroms Chi-squared: 0.0

————– Plane number 2 —————

Atoms Defining Plane Distance e.s.d. C9 (1) 0.0228 0.0028 C8 (1) -0.0179 0.0029 C7 (1) -0.0219 0.0027 C1 (1) 0.0162 0.0023

Additional Atoms Distance H1 (1) 0.2052 H2 (1) 0.1776

Mean deviation from plane is 0.0197 angstroms Chi-squared: 209.3

Dihedral angles between least-squares planes plane plane angle 2 1 3.35

————– Plane number 3 —————

Atoms Defining Plane Distance e.s.d. C1 (1) -0.0066 0.0023 C2 (1) 0.0105 0.0025 C3 (1) -0.0040 0.0026 C4 (1) -0.0069 0.0026 C5 (1) 0.0081 0.0023 C6 (1) -0.0022 0.0023

Additional Atoms Distance C10 (1) 0.0204 C11 (1) 0.0421 C7 (1) -0.0100 C8 (1) -0.4658 C9 (1) -0.3400 O1 (1) 0.2345 O2 (1) -0.7880

Mean deviation from plane is 0.0064 angstroms Chi-squared: 44.6

Dihedral angles between least-squares planes plane plane angle 3 1 28.26 3 2 27.05

————– Plane number 4 —————

Atoms Defining Plane Distance e.s.d. C12 (1) -0.0267 0.0021 C13 (1) -0.0177 0.0023 C14 (1) 0.0205 0.0026 C15 (1) 0.0198 0.0027 C16 (1) -0.0252 0.0030 C17 (1) -0.0337 0.0032 C18 (1) 0.0138 0.0029 C19 (1) 0.0311 0.0025 C20 (1) 0.0138 0.0022 C21 (1) 0.0035 0.0024

Mean deviation from plane is 0.0206 angstroms Chi-squared: 817.0

Dihedral angles between least-squares planes plane plane angle 4 1 69.98 4 2 67.51 4 3 80.54

————– Plane number 5 —————

Atoms Defining Plane Distance e.s.d. C1 (2) 0.0066 0.0023 C2 (2) -0.0105 0.0025 C3 (2) 0.0040 0.0026 C4 (2) 0.0069 0.0026 C5 (2) -0.0081 0.0023 C6 (2) 0.0022 0.0023

Mean deviation from plane is 0.0064 angstroms Chi-squared: 44.6

Dihedral angles between least-squares planes plane plane angle 5 1 76.04 5 2 73.94 5 3 89.64 5 4 10.29

————– Plane number 6 —————

Atoms Defining Plane Distance e.s.d. C12 (1) -0.0077 0.0021 C13 (1) -0.0045 0.0023 C14 (1) 0.0129 0.0026 C15 (1) -0.0025 0.0027 C20 (1) 0.0173 0.0022 C21 (1) -0.0137 0.0024

Mean deviation from plane is 0.0098 angstroms Chi-squared: 122.6

Dihedral angles between least-squares planes plane plane angle 6 1 70.84 6 2 68.36 6 3 81.21 6 4 0.88 6 5 10.00

————– Plane number 7 —————

Atoms Defining Plane Distance e.s.d. C16 (1) 0.0015 0.0030 C17 (1) -0.0124 0.0032 C18 (1) 0.0077 0.0029 C19 (1) 0.0037 0.0025 C20 (1) -0.0089 0.0022 C21 (1) 0.0087 0.0024

Mean deviation from plane is 0.0071 angstroms Chi-squared: 48.7

Dihedral angles between least-squares planes plane plane angle 7 1 68.84 7 2 66.39 7 3 79.68 7 4 1.19 7 5 10.72 7 6 2.06

————– Plane number 8 —————

Atoms Defining Plane Distance e.s.d. C12 (2) 0.0267 0.0021 C13 (2) 0.0177 0.0023 C14 (2) -0.0205 0.0026 C15 (2) -0.0198 0.0027 C16 (2) 0.0252 0.0030 C17 (2) 0.0337 0.0032 C18 (2) -0.0138 0.0029 C19 (2) -0.0311 0.0025 C20 (2) -0.0138 0.0022 C21 (2) -0.0035 0.0024

Mean deviation from plane is 0.0206 angstroms Chi-squared: 817.0

Dihedral angles between least-squares planes plane plane angle 8 1 29.56 8 2 27.27 8 3 10.29 8 4 71.09 8 5 80.54 8 6 71.72 8 7 70.30

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.9432 (1)	−0.2712 (3)	0.4554 (1)	0.0926 (8)
O2	0.9084 (1)	−0.5568 (3)	0.5207 (1)	0.0887 (8)
C1	0.7230 (1)	0.0802 (4)	0.4483 (1)	0.0505 (8)
C2	0.6907 (1)	0.2399 (4)	0.3872 (1)	0.0561 (9)
C3	0.6215 (2)	0.3599 (5)	0.3882 (1)	0.065 (1)
C4	0.5852 (1)	0.3281 (5)	0.4489 (2)	0.0623 (9)
C5	0.6171 (1)	0.1754 (4)	0.5108 (1)	0.0502 (8)
C6	0.6854 (1)	0.0520 (4)	0.5093 (1)	0.0524 (8)
C7	0.7960 (2)	−0.0554 (5)	0.4502 (2)	0.061 (1)
C8	0.8160 (2)	−0.2541 (5)	0.4838 (2)	0.066 (1)
C9	0.8931 (2)	−0.3666 (5)	0.4859 (2)	0.066 (1)
C10	0.7284 (2)	0.2813 (5)	0.3200 (2)	0.085 (1)
C11	0.5786 (1)	0.1459 (4)	0.5782 (1)	0.0542 (8)
C12	0.6040 (1)	0.3214 (4)	0.6453 (1)	0.0469 (8)
C13	0.6612 (1)	0.4832 (5)	0.6471 (1)	0.0566 (9)
C14	0.6828 (2)	0.6481 (5)	0.7091 (2)	0.071 (1)
C15	0.6452 (2)	0.6509 (5)	0.7676 (2)	0.075 (1)
C16	0.5440 (2)	0.4906 (6)	0.8278 (2)	0.087 (1)
C17	0.4866 (2)	0.3328 (7)	0.8285 (2)	0.094 (1)
C18	0.4681 (2)	0.1594 (5)	0.7706 (2)	0.083 (1)
C19	0.5064 (2)	0.1532 (5)	0.7118 (1)	0.064 (1)
C20	0.5654 (1)	0.3179 (4)	0.7083 (1)	0.0505 (8)
C21	0.5853 (2)	0.4885 (5)	0.7685 (2)	0.0596 (9)
H1	0.9867	−0.3214	0.4626	0.111*	0.500
H2	0.9517	−0.6069	0.5278	0.106*	0.500
H3	0.5975	0.4700	0.3450	0.078*
H4	0.5358	0.4159	0.4478	0.075*
H6	0.7085	−0.0594	0.5523	0.063*
H7	0.834 (1)	0.011 (4)	0.425 (1)	0.064 (8)*
H8	0.782 (1)	−0.343 (4)	0.510 (1)	0.083 (9)*
H10C	0.7340	0.1377	0.2940	0.103*
H10A	0.7833	0.3503	0.3428	0.103*
H10B	0.6924	0.3827	0.2793	0.103*
H11A	0.5181	0.1523	0.5539	0.065*
H11B	0.5946	−0.0027	0.6029	0.065*
H13	0.6881	0.4856	0.6044	0.068*
H14	0.7253	0.7610	0.7097	0.086*
H15	0.6599	0.7675	0.8099	0.089*
H16	0.5570	0.6091	0.8695	0.104*
H17	0.4578	0.3398	0.8696	0.112*
H18	0.4276	0.0428	0.7722	0.100*
H19	0.4927	0.0319	0.6712	0.077*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.082 (1)	0.092 (2)	0.128 (2)	0.031 (1)	0.067 (1)	0.038 (1)
O2	0.075 (1)	0.065 (1)	0.139 (2)	0.025 (1)	0.052 (1)	0.030 (1)
C1	0.050 (2)	0.052 (2)	0.055 (2)	0.010 (1)	0.024 (1)	−0.001 (1)
C2	0.058 (2)	0.062 (2)	0.053 (2)	0.012 (2)	0.024 (1)	0.007 (2)
C3	0.067 (2)	0.070 (2)	0.061 (2)	0.025 (2)	0.023 (1)	0.015 (2)
C4	0.058 (2)	0.069 (2)	0.063 (2)	0.021 (2)	0.023 (2)	0.002 (2)
C5	0.052 (2)	0.053 (2)	0.050 (2)	0.004 (2)	0.022 (1)	−0.003 (1)
C6	0.053 (2)	0.049 (2)	0.056 (2)	0.009 (1)	0.018 (1)	0.003 (1)
C7	0.057 (2)	0.067 (2)	0.066 (2)	0.012 (2)	0.029 (2)	0.007 (2)
C8	0.057 (2)	0.064 (2)	0.088 (2)	0.019 (2)	0.037 (2)	0.009 (2)
C9	0.063 (2)	0.059 (2)	0.084 (2)	0.014 (2)	0.033 (2)	0.008 (2)
C10	0.096 (2)	0.099 (3)	0.075 (2)	0.025 (2)	0.046 (2)	0.018 (2)
C11	0.057 (2)	0.051 (2)	0.060 (2)	0.007 (1)	0.026 (1)	−0.005 (2)
C12	0.045 (2)	0.046 (2)	0.046 (2)	0.010 (1)	0.010 (1)	0.001 (1)
C13	0.051 (2)	0.060 (2)	0.056 (2)	0.003 (2)	0.014 (1)	0.002 (2)
C14	0.067 (2)	0.062 (2)	0.071 (2)	−0.007 (2)	0.002 (2)	−0.004 (2)
C15	0.081 (2)	0.072 (2)	0.060 (2)	0.002 (2)	0.006 (2)	−0.020 (2)
C16	0.099 (3)	0.107 (3)	0.056 (2)	0.024 (2)	0.026 (2)	−0.015 (2)
C17	0.100 (3)	0.132 (4)	0.062 (2)	0.024 (3)	0.044 (2)	0.004 (2)
C18	0.088 (2)	0.097 (3)	0.077 (2)	0.003 (2)	0.044 (2)	0.004 (2)
C19	0.074 (2)	0.067 (2)	0.061 (2)	0.004 (2)	0.033 (2)	−0.002 (2)
C20	0.052 (2)	0.051 (2)	0.048 (2)	0.016 (1)	0.015 (1)	0.002 (1)
C21	0.060 (2)	0.066 (2)	0.050 (2)	0.015 (2)	0.012 (1)	−0.006 (2)

Geometric parameters (Å, º)

O1—C9	1.263 (3)	C10—H10B	0.98
O1—H1	0.77	C11—C12	1.517 (3)
O2—C9	1.267 (3)	C11—H11A	0.98
O2—H2	0.77	C11—H11B	0.98
C1—C2	1.396 (3)	C12—C13	1.357 (3)
C1—C6	1.399 (3)	C12—C20	1.432 (3)
C1—C7	1.468 (3)	C13—C14	1.411 (3)
C2—C3	1.376 (3)	C13—H13	0.98
C2—C10	1.510 (3)	C14—C15	1.353 (3)
C3—C4	1.383 (3)	C14—H14	0.98
C3—H3	0.98	C15—C21	1.403 (3)
C4—C5	1.377 (3)	C15—H15	0.98
C4—H4	0.98	C16—C17	1.352 (4)
C5—C6	1.377 (3)	C16—C21	1.410 (3)
C5—C11	1.510 (3)	C16—H16	0.98
C6—H6	0.98	C17—C18	1.401 (4)
C7—C8	1.311 (3)	C17—H17	0.98
C7—H7	0.96 (2)	C18—C19	1.364 (3)
C8—C9	1.459 (3)	C18—H18	0.98
C8—H8	1.00 (2)	C19—C20	1.413 (3)
C10—H10C	0.98	C19—H19	0.98
C10—H10A	0.98	C20—C21	1.415 (3)
C9—O1—H1	119.6	C5—C11—H11A	108.1
C9—O2—H2	117.7	C5—C11—H11B	108.1
C2—C1—C6	119.1 (2)	C12—C11—H11A	108.1
C2—C1—C7	121.2 (2)	C12—C11—H11B	108.1
C6—C1—C7	119.7 (2)	H11A—C11—H11B	109.5
C1—C2—C3	118.5 (2)	C11—C12—C13	122.3 (2)
C1—C2—C10	122.1 (2)	C11—C12—C20	118.8 (2)
C3—C2—C10	119.4 (2)	C13—C12—C20	118.9 (2)
C2—C3—C4	121.3 (2)	C12—C13—C14	121.5 (2)
C2—C3—H3	119.3	C12—C13—H13	119.2
C4—C3—H3	119.4	C14—C13—H13	119.2
C3—C4—C5	121.2 (2)	C13—C14—C15	120.2 (3)
C3—C4—H4	119.4	C13—C14—H14	119.9
C5—C4—H4	119.4	C15—C14—H14	119.9
C4—C5—C6	117.7 (2)	C14—C15—C21	120.7 (3)
C4—C5—C11	121.0 (2)	C14—C15—H15	119.7
C6—C5—C11	121.4 (2)	C21—C15—H15	119.6
C1—C6—C5	122.2 (2)	C17—C16—C21	121.4 (3)
C1—C6—H6	118.9	C17—C16—H16	119.3
C5—C6—H6	118.9	C21—C16—H16	119.3
C1—C7—C8	127.0 (3)	C16—C17—C18	120.3 (3)
C1—C7—H7	116 (1)	C16—C17—H17	119.8
C8—C7—H7	117 (1)	C18—C17—H17	119.8
C7—C8—C9	121.8 (3)	C17—C18—C19	119.9 (3)
C7—C8—H8	125 (1)	C17—C18—H18	120.1
C9—C8—H8	113 (1)	C19—C18—H18	120.1
O1—C9—O2	122.2 (3)	C18—C19—C20	121.3 (3)
O1—C9—C8	119.9 (3)	C18—C19—H19	119.3
O2—C9—C8	117.9 (3)	C20—C19—H19	119.3
C2—C10—H10C	109.5	C12—C20—C19	122.6 (3)
C2—C10—H10A	109.5	C12—C20—C21	119.1 (2)
C2—C10—H10B	109.5	C19—C20—C21	118.2 (2)
H10C—C10—H10A	109.4	C15—C21—C16	121.7 (3)
H10C—C10—H10B	109.4	C15—C21—C20	119.4 (2)
H10A—C10—H10B	109.4	C16—C21—C20	118.8 (3)
C5—C11—C12	114.9 (2)
O1—C9—C8—C7	0.8 (5)	C11—C12—C13—C14	178.7 (2)
O2—C9—C8—C7	178.9 (3)	C11—C12—C20—C19	2.0 (3)
C1—C2—C3—C4	1.4 (4)	C11—C12—C20—C21	−176.5 (2)
C1—C6—C5—C4	1.0 (4)	C12—C13—C14—C15	−1.4 (4)
C1—C6—C5—C11	−178.7 (2)	C12—C20—C19—C18	−177.2 (2)
C1—C7—C8—C9	−176.2 (3)	C12—C20—C21—C15	−3.1 (4)
C2—C1—C6—C5	0.5 (4)	C12—C20—C21—C16	176.8 (2)
C2—C1—C7—C8	−155.1 (3)	C13—C12—C20—C19	−178.9 (2)
C2—C3—C4—C5	0.2 (4)	C13—C12—C20—C21	2.7 (3)
C3—C2—C1—C6	−1.7 (4)	C13—C14—C15—C21	1.1 (4)
C3—C2—C1—C7	179.2 (2)	C14—C13—C12—C20	−0.5 (4)
C3—C4—C5—C6	−1.3 (4)	C14—C15—C21—C16	−178.7 (3)
C3—C4—C5—C11	178.4 (2)	C14—C15—C21—C20	1.2 (4)
C4—C3—C2—C10	−179.7 (3)	C15—C21—C16—C17	−179.6 (3)
C4—C5—C11—C12	−80.7 (3)	C15—C21—C20—C19	178.4 (2)
C5—C6—C1—C7	179.7 (2)	C16—C17—C18—C19	−1.8 (5)
C5—C11—C12—C13	−4.2 (3)	C16—C21—C20—C19	−1.7 (4)
C5—C11—C12—C20	175.0 (2)	C17—C16—C21—C20	0.5 (5)
C6—C1—C2—C10	179.4 (2)	C17—C18—C19—C20	0.6 (5)
C6—C1—C7—C8	25.8 (4)	C18—C17—C16—C21	1.3 (5)
C6—C5—C11—C12	98.9 (3)	C18—C19—C20—C21	1.2 (4)
C7—C1—C2—C10	0.3 (4)