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In the title compound, NH
4+·C
10H
9O
3-, bimolecular layers of the anions are formed between layers of the cations. There are N-H
O hydrogen bonds between the ammonium ion and the carboxylate groups of the anions. In the crystal structure, the C=C moiety of the cinnamate ion makes an angle of 117.1 (2)° with that of the nearest neighbour, indicating that a pedal rotation is required before
-type [2+2]-photodimerization can take place, which is the predominant mode of the photochemistry of this compound.
Supporting information
CCDC reference: 243596
The title compound, (I), was prepared by dissolving 4-methoxycinnamic acid and concentrated aqueous ammonia (molar ratio 1:1) in warm aqueous methanol (Ito et al., 2003). Crystals of (I) were grown from a methanol solution (m.p. 448–451 K). The crystal specimen was coated with adhesive to avoid efflorescence.
All H atoms were located from difference syntheses, and their positional parameters were recalculated geometrically and fixed, with C—H = N—H = 0.95 Å and Uiso(H) = 1.2Ueq(parent atom). Please check added text.
Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999); cell refinement: WinAFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 2001); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: TEXSAN.
Crystal data top
NH4+·C10H9O3− | F(000) = 416 |
Mr = 195.22 | Dx = 1.248 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.7107 Å |
Hall symbol: -P 2ybc | Cell parameters from 25 reflections |
a = 22.077 (3) Å | θ = 10.2–13.6° |
b = 5.9332 (9) Å | µ = 0.09 mm−1 |
c = 7.9560 (8) Å | T = 298 K |
β = 94.76 (1)° | Plate, colourless |
V = 1038.5 (2) Å3 | 0.5 × 0.5 × 0.1 mm |
Z = 4 | |
Data collection top
Rigaku AFC-7R diffractometer | θmax = 27.5°, θmin = 2.8° |
ω scans | h = −28→28 |
2973 measured reflections | k = 0→7 |
2383 independent reflections | l = −10→4 |
1203 reflections with I > 2σ(I) | 3 standard reflections every 150 reflections |
Rint = 0.012 | intensity decay: 0.5% |
Refinement top
Refinement on F2 | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.047 | w = 1/[σ2(Fo2) + (0.0635P)2 + 0.0891P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.149 | (Δ/σ)max < 0.001 |
S = 1.01 | Δρmax = 0.18 e Å−3 |
2383 reflections | Δρmin = −0.19 e Å−3 |
127 parameters | |
Crystal data top
NH4+·C10H9O3− | V = 1038.5 (2) Å3 |
Mr = 195.22 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 22.077 (3) Å | µ = 0.09 mm−1 |
b = 5.9332 (9) Å | T = 298 K |
c = 7.9560 (8) Å | 0.5 × 0.5 × 0.1 mm |
β = 94.76 (1)° | |
Data collection top
Rigaku AFC-7R diffractometer | Rint = 0.012 |
2973 measured reflections | 3 standard reflections every 150 reflections |
2383 independent reflections | intensity decay: 0.5% |
1203 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.047 | 127 parameters |
wR(F2) = 0.149 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.18 e Å−3 |
2383 reflections | Δρmin = −0.19 e Å−3 |
Special details top
Refinement. Refinement using reflections with F2 > 0.0 σ(F2). The weighted R-factor (wR), goodness of fit (S) and R-factor (gt) are based on F, with F set to zero for negative F. The threshold expression of F2 > 2.0 σ(F2) is used only for calculating R-factor (gt). |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.07415 (7) | 0.4052 (3) | 0.3881 (2) | 0.0642 (5) | |
O2 | 0.08615 (8) | 0.0385 (3) | 0.3536 (2) | 0.0701 (5) | |
O3 | 0.43479 (7) | 0.5709 (3) | 0.0988 (2) | 0.0644 (5) | |
N4 | −0.04784 (8) | 0.2175 (4) | 0.3864 (2) | 0.0568 (5) | |
C5 | 0.1042 (1) | 0.2386 (4) | 0.3474 (3) | 0.0491 (5) | |
C6 | 0.1654 (1) | 0.2690 (4) | 0.2850 (3) | 0.0550 (6) | |
C7 | 0.1962 (1) | 0.4557 (4) | 0.2913 (3) | 0.0507 (5) | |
C8 | 0.25828 (9) | 0.4886 (4) | 0.2389 (3) | 0.0473 (5) | |
C9 | 0.2871 (1) | 0.3276 (4) | 0.1451 (3) | 0.0546 (6) | |
C10 | 0.3454 (1) | 0.3592 (4) | 0.0998 (3) | 0.0558 (6) | |
C11 | 0.37689 (9) | 0.5540 (4) | 0.1498 (3) | 0.0487 (5) | |
C12 | 0.3492 (1) | 0.7146 (4) | 0.2421 (3) | 0.0564 (6) | |
C13 | 0.2904 (1) | 0.6816 (4) | 0.2843 (3) | 0.0558 (6) | |
C14 | 0.4679 (1) | 0.7694 (6) | 0.1426 (4) | 0.0807 (9) | |
H4A | −0.0717 | 0.3500 | 0.3686 | 0.0683* | |
H4B | −0.0612 | 0.1360 | 0.4792 | 0.0683* | |
H4C | −0.0064 | 0.2580 | 0.4098 | 0.0683* | |
H4D | −0.0521 | 0.1262 | 0.2880 | 0.0683* | |
H6 | 0.1834 | 0.1415 | 0.2368 | 0.0662* | |
H7 | 0.1769 | 0.5841 | 0.3340 | 0.0610* | |
H9 | 0.2660 | 0.1933 | 0.1118 | 0.0656* | |
H10 | 0.3640 | 0.2485 | 0.0349 | 0.0670* | |
H12 | 0.3706 | 0.8479 | 0.2768 | 0.0677* | |
H13 | 0.2715 | 0.7949 | 0.3463 | 0.0670* | |
H14A | 0.4479 | 0.8953 | 0.0892 | 0.0971* | |
H14B | 0.5077 | 0.7568 | 0.1064 | 0.0971* | |
H14C | 0.4704 | 0.7891 | 0.2614 | 0.0971* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0567 (10) | 0.066 (1) | 0.072 (1) | 0.0010 (9) | 0.0197 (8) | −0.0014 (9) |
O2 | 0.085 (1) | 0.063 (1) | 0.065 (1) | −0.0288 (10) | 0.0213 (9) | −0.0022 (9) |
O3 | 0.0415 (9) | 0.076 (1) | 0.077 (1) | −0.0068 (8) | 0.0153 (8) | 0.0018 (9) |
N4 | 0.052 (1) | 0.058 (1) | 0.063 (1) | −0.0008 (10) | 0.0135 (9) | 0.008 (1) |
C5 | 0.048 (1) | 0.059 (2) | 0.041 (1) | −0.015 (1) | 0.0059 (9) | 0.003 (1) |
C6 | 0.054 (1) | 0.051 (1) | 0.060 (1) | −0.004 (1) | 0.012 (1) | 0.001 (1) |
C7 | 0.051 (1) | 0.052 (1) | 0.049 (1) | −0.001 (1) | 0.0086 (9) | 0.002 (1) |
C8 | 0.043 (1) | 0.054 (1) | 0.045 (1) | −0.004 (1) | 0.0084 (9) | 0.002 (1) |
C9 | 0.052 (1) | 0.051 (1) | 0.061 (1) | −0.013 (1) | 0.005 (1) | −0.001 (1) |
C10 | 0.052 (1) | 0.054 (1) | 0.063 (1) | 0.000 (1) | 0.012 (1) | −0.003 (1) |
C11 | 0.040 (1) | 0.058 (1) | 0.049 (1) | −0.004 (1) | 0.0052 (9) | 0.008 (1) |
C12 | 0.051 (1) | 0.060 (1) | 0.060 (1) | −0.014 (1) | 0.011 (1) | −0.008 (1) |
C13 | 0.054 (1) | 0.056 (2) | 0.059 (1) | −0.006 (1) | 0.016 (1) | −0.006 (1) |
C14 | 0.054 (2) | 0.092 (2) | 0.098 (2) | −0.023 (2) | 0.019 (1) | 0.001 (2) |
Geometric parameters (Å, º) top
O1—C5 | 1.248 (3) | C8—C9 | 1.398 (3) |
O2—C5 | 1.255 (3) | C8—C13 | 1.379 (3) |
O3—C11 | 1.376 (3) | C9—C10 | 1.378 (3) |
O3—C14 | 1.415 (4) | C9—H9 | 0.950 |
N4—H4A | 0.951 | C10—C11 | 1.389 (3) |
N4—H4B | 0.950 | C10—H10 | 0.950 |
N4—H4C | 0.950 | C11—C12 | 1.376 (3) |
N4—H4D | 0.950 | C12—C13 | 1.383 (4) |
C5—C6 | 1.489 (3) | C12—H12 | 0.950 |
C6—C7 | 1.299 (3) | C13—H13 | 0.950 |
C6—H6 | 0.950 | C14—H14A | 0.950 |
C7—C8 | 1.478 (3) | C14—H14B | 0.950 |
C7—H7 | 0.949 | C14—H14C | 0.950 |
| | | |
C11—O3—C14 | 117.6 (2) | C8—C9—H9 | 119.2 |
H4A—N4—H4B | 109.4 | C10—C9—H9 | 119.2 |
H4A—N4—H4C | 109.5 | C9—C10—C11 | 119.6 (2) |
H4A—N4—H4D | 109.4 | C9—C10—H10 | 120.2 |
H4B—N4—H4C | 109.5 | C11—C10—H10 | 120.2 |
H4B—N4—H4D | 109.5 | O3—C11—C10 | 115.5 (2) |
H4C—N4—H4D | 109.5 | O3—C11—C12 | 124.8 (2) |
O1—C5—O2 | 124.2 (2) | C10—C11—C12 | 119.7 (2) |
O1—C5—C6 | 120.5 (2) | C11—C12—C13 | 119.9 (2) |
O2—C5—C6 | 115.3 (2) | C11—C12—H12 | 120.0 |
C5—C6—C7 | 125.2 (2) | C13—C12—H12 | 120.0 |
C5—C6—H6 | 117.4 | C8—C13—C12 | 121.8 (2) |
C7—C6—H6 | 117.4 | C8—C13—H13 | 119.1 |
C6—C7—C8 | 126.6 (2) | C12—C13—H13 | 119.2 |
C6—C7—H7 | 116.7 | O3—C14—H14A | 109.4 |
C8—C7—H7 | 116.7 | O3—C14—H14B | 109.4 |
C7—C8—C9 | 122.3 (2) | O3—C14—H14C | 109.5 |
C7—C8—C13 | 120.3 (2) | H14A—C14—H14B | 109.5 |
C9—C8—C13 | 117.4 (2) | H14A—C14—H14C | 109.5 |
C8—C9—C10 | 121.5 (2) | H14B—C14—H14C | 109.5 |
| | | |
O1—C5—C6—C7 | 11.0 (3) | C8—C9—C10—C11 | 0.8 (4) |
O2—C5—C6—C7 | −169.5 (2) | C8—C13—C12—C11 | 1.1 (4) |
O3—C11—C10—C9 | −180.0 (2) | C9—C8—C13—C12 | −1.1 (3) |
O3—C11—C12—C13 | 179.0 (2) | C9—C10—C11—C12 | −0.8 (3) |
C5—C6—C7—C8 | 176.6 (2) | C10—C9—C8—C13 | 0.2 (3) |
C6—C7—C8—C9 | 12.5 (4) | C10—C11—O3—C14 | 178.2 (2) |
C6—C7—C8—C13 | −166.4 (2) | C10—C11—C12—C13 | −0.1 (3) |
C7—C8—C9—C10 | −178.8 (2) | C12—C11—O3—C14 | −0.9 (3) |
C7—C8—C13—C12 | 177.9 (2) | C12—C11—O3—C14 | −0.9 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H4A···O1i | 0.95 | 2.42 | 2.956 (3) | 115 |
N4—H4A···O2ii | 0.95 | 2.09 | 2.779 (3) | 128 |
N4—H4B···O2iii | 0.95 | 1.81 | 2.756 (3) | 176 |
N4—H4C···O1 | 0.95 | 2.00 | 2.913 (2) | 160 |
N4—H4C···O2 | 0.95 | 2.49 | 3.174 (3) | 129 |
N4—H4D···O1iv | 0.95 | 1.95 | 2.887 (3) | 168 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, y+1/2, −z+1/2; (iii) −x, −y, −z+1; (iv) −x, y−1/2, −z+1/2. |
Experimental details
Crystal data |
Chemical formula | NH4+·C10H9O3− |
Mr | 195.22 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 298 |
a, b, c (Å) | 22.077 (3), 5.9332 (9), 7.9560 (8) |
β (°) | 94.76 (1) |
V (Å3) | 1038.5 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.5 × 0.5 × 0.1 |
|
Data collection |
Diffractometer | Rigaku AFC-7R diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2973, 2383, 1203 |
Rint | 0.012 |
(sin θ/λ)max (Å−1) | 0.650 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.149, 1.01 |
No. of reflections | 2383 |
No. of parameters | 127 |
No. of restraints | ? |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.19 |
Selected geometric parameters (Å, º) topO1—C5 | 1.248 (3) | C6—C7 | 1.299 (3) |
O2—C5 | 1.255 (3) | C7—C8 | 1.478 (3) |
C5—C6 | 1.489 (3) | | |
| | | |
O1—C5—O2 | 124.2 (2) | O2—C5—C6 | 115.3 (2) |
O1—C5—C6 | 120.5 (2) | | |
| | | |
O1—C5—C6—C7 | 11.0 (3) | C6—C7—C8—C9 | 12.5 (4) |
C5—C6—C7—C8 | 176.6 (2) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N4—H4A···O1i | 0.95 | 2.42 | 2.956 (3) | 115 |
N4—H4A···O2ii | 0.95 | 2.09 | 2.779 (3) | 128 |
N4—H4B···O2iii | 0.95 | 1.81 | 2.756 (3) | 176 |
N4—H4C···O1 | 0.95 | 2.00 | 2.913 (2) | 160 |
N4—H4C···O2 | 0.95 | 2.49 | 3.174 (3) | 129 |
N4—H4D···O1iv | 0.95 | 1.95 | 2.887 (3) | 168 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, y+1/2, −z+1/2; (iii) −x, −y, −z+1; (iv) −x, y−1/2, −z+1/2. |
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Organic solid-state reactions have the potential to control the stereoselectivity of chemical reactions. Ammonium salt formation is one way of designing the molecular arrangement of crystals (Ito et al., 1995; Ito & Olovsson, 1997; Ito, 1998). The photoreactivities of the ammonium and isopropylammonium salts of the fumaric acid dianion have been rationalized, based on their crystal structures (Hosomi et al., 1998). It is proposed that a small size or a planar structure of the amine is an important clue for converting photostable crystal packing into photodimerizable packing (Ito et al., 2003). In the present study, the structure of the ammonium salt of 4-methoxycinnamate, (I), has been determined in order to investigate the relationship between the crystal structure and its photoreactivity. The product in the solid-state photolysis of (I) is predominantly the β-type head-to-head dimer (Ito et al., 2003). \sch
Compound (I) consists of an ammonium cation and a p-methoxycinnamate anion (Fig. 1 and Table 1). The anions form bimolecular layers perpendicular to the a axis and the carboxylate groups are oriented on the outside, to form N—H···O hydrogen bonds with the ammonium cations (Fig. 2). This layer structure corresponds to the habit of the platelike crystals of (I) with a well developed (100) face. All the ammonium H atoms are connected to the carboxylate groups via hydrogen bonds (Table 2). Among them, atoms H4A and H4C are involved in bifurcated hydrogen bonds.
The close contact between the C6═C7 moieties in the crystal of (I) is C6···C6i or C6···C6ii of 3.984 (1) Å [symmetry codes: (i) x, 1/2 − y, 1/2 + z; (ii) x, 1/2 − y, z − 1/2]. However, the double bonds are not parallel to each other. Atoms C5 and C6 lie almost on the c-glide plane perpendicular to the b axis at y = 1/4, and the C5—C6═C7—C8 plane makes an angle of 75.9 (2)° with the glide plane (Fig. 3). Therefore, the C6═C7 bond axis makes an angle of 117.1 (2)° with the C6i═C7i axis, and the C7···C7i distance is 4.667 (3) Å. It seems that a pedal rotation of the cinnamate ion is required to achieve the parallel arrangement of the double bonds which is required before β-type [2 + 2]-photodimerization can take place. Pedal-like conformational changes and the dimerization of trans-cinnamamide in cocrystals with phthalic acid was previously reported by Ito et al. (2000) and was unambiguously proved by a partial single-crystal-to-single-crystal transformation (Ohba et al., 2001).
In the present study, the preliminary crystal structure of ammonium cinnamate, NH4+·C9H7O2−, (II), was also determined. Compound (II) was prepared by a similar method to (I) and colourless thin plate-like crystals were grown from a 2-propanol solution (m.p. 406–408 K). Crystal data for (II): monoclinic, space group P21/c, a = 20.033 (4) Å, b = 5.8741 (15) Å, c = 7.8681 (11) Å, β = 100.572 (14)°, V = 910.2 (3) Å3, Z = 4, Dx = 1.205 Mg m−3, R(F) = 0.066 for 560 reflections with I>2σ(I). Compound (II) consists of an ammonium cation and a cinnamate anion, and the arrangements of the ions and the N—H···O hydrogen bonds are similar to those in (I). It seems that a pedal rotation is also required in (II) before β-type [2 + 2]-photodimerization can take place. Bryan et al. (1963) reported the crystal structure of ammonium hydrogen dicinnamate, (III), which was prepared by dissolving cinnamic acid and concentrated aqueous ammonia (molar ratio 2:1) in warm ethanol. In (III), the hydrogen dicinnamate anion is centrosymmetric. The two cinnamate moieties are connected by a short O—H···O hydrogen bond around the inversion centre and form N—H···O hydrogen bonds with the ammonium cations. The hydrophobic and hydrophilic layers are stacked alternately, similar to the molecular packing of (I) and (II).