research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 72| Part 3| March 2016| Pages 407-411
doi:10.1107/S2056989016002942

Investigations of new potential photo-acid generators: crystal structures of 2-[(E)-2-phenyl­ethen­yl]phenol (ortho­rhom­bic polymorph) and (2E)-3-(2-bromo­phen­yl)-2-phenyl­prop-2-enoic acid

CROSSMARK_Color_square_no_text.svg
William T. A. Harrison,a* M. John Platera and Lee J. Yinb

aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland, and bDepartment of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
*Correspondence e-mail: w.harrison@abdn.ac.uk

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 5 February 2016; accepted 18 February 2016; online 24 February 2016)

The title compounds, C14H12O, (I), and C15H11BrO2, (II), were prepared and characterized as part of our studies of potential new photo-acid generators. In (I), which crystallizes in the ortho­rhom­bic space group Pca21, compared to P21/n for the previously known monoclinic polymorph [Cornella & Martin (2013[Cornella, J. & Martin, R. (2013). Org. Lett. 15, 6298-6301.]). Org. Lett. 15, 6298–6301], the dihedral angle between the aromatic rings is 4.35 (6)° and the OH group is disordered over two sites in a 0.795 (3):0.205 (3) ratio. In the crystal of (I), mol­ecules are linked by O—H⋯π inter­actions involving both the major and minor –OH disorder components, generating [001] chains as part of the herringbone packing motif. The asymmetric unit of (II) contains two mol­ecules with similar conformations (weighted r.m.s. overlay fit = 0.183 Å). In the crystal of (II), both mol­ecules form carboxyl­ate inversion dimers linked by pairs of O—H⋯O hydrogen bonds, generating R22(8) loops in each case. The dimers are linked by pairs of C—H⋯O hydrogen bonds to form [010] chains.

CCDC references: 1454393; 1454392

1. Chemical context

Photo-acid generators can be used as additives for creating patterns in a polymer film by irradiation through a mask followed by thermal development and base treatment (Ayothi et al., 2007[Ayothi, R., Yi, Y., Cao, H., Yueh, W., Putna, S. & Ober, C. K. (2007). Chem. Mater. 19, 1434-1444.]; Kudo et al., 2008[Kudo, H., Watanabe, D., Nishikubo, T., Maruyama, K., Shimizu, D., Kai, T., Shimokawa, T. & Ober, C. K. (2008). J. Mater. Chem. 18, 3588-3592.]; Steidl et al., 2009[Steidl, L., Jhaveri, S. J., Ayothi, R., Sha, J., McMullen, J. D., Ng, S. Y., Zipfel, W. R., Zentel, R. & Ober, C. K. (2009). J. Mater. Chem. 19, 505-513.]). The UV irradiation degrades a small amount of the photo-acid generator in exposed areas, which releases a catalytic amount of a strong acid (commonly triflic acid). This acid subsequently catalyses the degradation of the tert-butyl­carboxyl­ate groups of a polymer film in a thermal development step, releasing carb­oxy­lic acid groups and isobutene. Treatment with base then solubilizes and removes the degraded polymer film in exposed areas, thereby creating a positive resist image (Ito et al., 1994[Ito, H., Breyta, G., Hofer, D., Sooriyakumaran, R., Petrillo, K. & Seeger, D. (1994). J. Photopol. Sci. Technol. 7, 433-447.]).

We are exploring new types of organic structures as potential photo-acid generators, which might offer improvements over existing substances. Scheme 1[link] shows how substituted trans-stilbenes might act as photo-acid generators via sequential photochemical trans–cis isomerization and ring-closing reactions. It should be noted that the photochemical cyclization of stilbenes to phenanthenes in the presence of a hydrogen acceptor such as iodine or propyl­ene oxide is well known (Mallory & Mallory, 2005[Mallory, F. B. & Mallory, C. W. (2005). Org. React. 30, 1-456.]). However, in the absence of an oxidant, if a leaving group is present at the ring-closure site, as in structure 3, a rapid elimination of HX (structure 5) might occur via a stabilized carbocation inter­mediate 4. In the absence of an oxidant, the cyclized di­hydro-phenanthrene compound 6 will equilibrate back to cis-stilbene 2. Stilbenes can also undergo 2π + 2π photochemical cyclo­additions (Fulton & Dunitz, 1947[Fulton, J. D. & Dunitz, J. D. (1947). Nature, 160, 161-162.]; Shechter et al., 1963[Shechter, H., Link, W. J. & Tiers, G. V. D. (1963). J. Am. Chem. Soc. 85, 1601-1605.]), a possible competing reaction, but the mol­ecular structures and morphology may still favour the desired reaction to proceed in a thin film.

[Scheme 1]

As part of these studies, the syntheses and crystal structures of the title substituted stilbenes, (I)[link] and (II)[link], are now described [compound (II)[link] could also be described as a cinnamic acid derivative: the photochemical reactions of this family of compounds were reported by Schmidt (1971[Schmidt, G. M. J. (1971). Pure Appl. Chem. 27, 647-678.])]. Compound (I)[link] is an inter­mediate in the synthesis, whereas a close analogue of compound (II)[link] has already been shown to undergo photochemical cyclization to a phenanthrene with concomitant release of HCl (Geirsson & Kvaran, 2001[Geirsson, J. K. F. & Kvaran, Á. (2001). J. Photochem. Photobiol. A, 144, 175-177.]). A monoclinic polymorph (space group P21/n) of (I)[link] was reported recently (Cornella & Martin, 2013[Cornella, J. & Martin, R. (2013). Org. Lett. 15, 6298-6301.]) although its crystal structure was not described in detail.

[Scheme 2]

2. Structural commentary

Compound (I)[link] comprises one mol­ecule in the asymmetric unit (Fig. 1[link]), with the –OH group disordered over two sites in a 0.795 (3):0.205 (3) ratio. For the major disorder component, the Car—Car—O—H (ar = aromatic) torsion angle is 172°. The mol­ecule is close to planar and the dihedral angle between the aromatic rings is 4.35 (6)°. The bond lengths of the central unit [C6—C7 = 1.4703 (19); C7—C8 = 1.3407 (16); C8—C9 = 1.4720 (18) Å] are consistent with data from previous studies of similar compounds (Tirado-Rives et al., 1984[Tirado-Rives, J., Oliver, M. A., Fronczek, F. R. & Gandour, R. D. (1984). J. Org. Chem. 49, 1627-1634.]; Jungk et al., 1984[Jungk, S. J., Fronczek, F. R. & Gandour, R. D. (1984). Acta Cryst. C40, 1873-1875.]). In the monoclinic polymorph of (I)[link] (Cornella & Martin, 2013[Cornella, J. & Martin, R. (2013). Org. Lett. 15, 6298-6301.]), the asymmetric unit consists of a half-mol­ecule, which is completed by crystallographic inversion symmetry and therefore, of course, the aromatic rings are exactly coplanar: the OH group is statistically disordered by symmetry and the corresponding C—C—O—H torsion angle for the monoclinic phase is −175°.

[Figure 1]
Figure 1
The asymmetric unit of (I)[link], showing 50% displacement ellipsoids. Only the major disordered component for the OH group is shown (the minor component is attached to C14).

There are two mol­ecules in the asymmetric unit of (II)[link] (Fig. 2[link]). In the first (C1) mol­ecule, the dihedral angles between the carb­oxy­lic acid group and the phenyl and bromo­benzene rings are 61.52 (6) and 55.43 (5)°, respectively; the dihedral angle between the aromatic rings is 54.45 (5)°. The equivalent data for the second (C16) mol­ecule are 50.72 (6), 60.28 (5) and 61.48 (6)°, respectively. The C1 and C16 mol­ecules have a similar overall conformation with an r.m.s. deviation of 0.183 Å for the overlay fit for all non-hydrogen atoms. Otherwise, their bond lengths and bond angles are unexceptional and fall within the expected range of values.

[Figure 2]
Figure 2
The asymmetric unit of (II)[link], showing 50% displacement ellipsoids.

3. Supra­molecular features

The crystal of (I)[link] features O—H⋯π inter­actions as the main supra­molecular inter­action (Table 1[link]). The major disorder component (O1—H1O) generates [001] zigzag chains, as seen in Fig. 3[link]. The minor disorder component (O2—H2O) also forms [001] chains. There are also some possible very weak C—H⋯π inter­actions. The packing can be described as herringbone when viewed down [100] (Fig. 4[link]). The monoclinic polymorph (Cornella & Martin, 2013[Cornella, J. & Martin, R. (2013). Org. Lett. 15, 6298-6301.]) also features supra­molecular chains with the mol­ecules linked by O—H⋯π inter­actions but a different overall herringbone packing motif (Fig. 5[link]).

Table 1
Hydrogen-bond geometry (Å, °) for (I)[link]

Cg1 and Cg2 are the centroids of rings C1–C6 and C9–C14, respectively.
D—H⋯A D—H H⋯A D⋯A D—H⋯A
O1—H1o⋯Cg2i 0.98 2.66 3.5028 (13) 144
O2—H2o⋯Cg1 0.91 2.74 3.646 (2) 179
C5—H5⋯Cg2ii 0.95 2.86 3.5337 (12) 129
C10—H10⋯Cg1iii 0.95 2.87 3.5742 (14) 132
C13—H13⋯Cg1iv 0.95 2.87 3.6015 (14) 135
Symmetry codes: (i) [-x+1, -y, z-{\script{1\over 2}}]; (ii) [x-{\script{1\over 2}}, -y+1, z]; (iii) [x+{\script{1\over 2}}, -y, z]; (iv) [-x+1, -y+1, z+{\script{1\over 2}}].
[Figure 3]
Figure 3
Part of a [001] chain of mol­ecules in the crystal of (I)[link], connected by O—H⋯π inter­actions (cyan lines).
[Figure 4]
Figure 4
The unit-cell packing in (I)[link], viewed approximately down [100]. The O—H⋯π inter­actions from both disordered components are shown as cyan lines.
[Figure 5]
Figure 5
The unit-cell packing in the monoclinic polymorph of C14H12O, viewed approximately down [000] (data from Cornella & Martin, 2013[Cornella, J. & Martin, R. (2013). Org. Lett. 15, 6298-6301.]). The O—H⋯π inter­actions are shown as cyan lines.

In the crystal of (II)[link], both mol­ecules (A and B) form carb­oxy­lic acid inversion dimers linked by pairs of O—H⋯O hydrogen bonds (Table 2[link]), which generate R22(8) loops in each case. The (A + A) and (B + B) dimers are in turn linked by pairs of C—H⋯O hydrogen bonds to generate [010] chains (Figs. 6[link] and 7[link]). This hydrogen-bond scheme is `balanced,' with both O1 and O3 accepting one O—H⋯O and one C—H⋯O hydrogen bond. The shortest Br⋯Br contact distance of 3.6504 (4) Å in the crystal of (II)[link] is slightly shorter than the van der Waals radius sum of 3.70 Å for two Br atoms (Bondi, 1964[Bondi, A. (1964). J. Phys. Chem. 68, 441-451.]).

Table 2
Hydrogen-bond geometry (Å, °) for (II)[link]

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O2—H2O⋯O1i 0.84 (2) 1.80 (2) 2.6402 (16) 174 (2)
O4—H4O⋯O3ii 0.81 (2) 1.84 (2) 2.6478 (16) 178 (2)
C5—H5⋯O3iii 0.95 2.42 3.323 (2) 158
C20—H20⋯O1iii 0.95 2.52 3.3072 (19) 141
Symmetry codes: (i) -x, -y+1, -z; (ii) -x+1, -y+1, -z+1; (iii) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].
[Figure 6]
Figure 6
Part of a [010] chain in the crystal of (II)[link], with O—H⋯O hydrogen bonds shown as yellow lines and C—H⋯O hydrogen bonds shown as cyan lines.
[Figure 7]
Figure 7
The unit-cell packing in (II)[link], viewed approximately down [010].

4. Database survey

A survey of the Cambridge Structural Database (Groom & Allen, 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]) (entries updated to 22 December 2015) revealed ten crystal structures of E-2-hy­droxy stilbenes with different substituents including (E)-1,2-bis­(2-hy­droxy­phen­yl)ethene (refcode CEYKUM; Tirado-Rives et al., 1984[Tirado-Rives, J., Oliver, M. A., Fronczek, F. R. & Gandour, R. D. (1984). J. Org. Chem. 49, 1627-1634.]), in which the mol­ecules are linked by O—H⋯O hydrogen bonds. Two substituted Z-isomers are also known. A total of 28 analogues of (II)[link] with different substituents to the aromatic rings were found in the same survey, including the parent compound, 2,3-di­phenyl­acrylic acid (refcode OJOFEZ; Fujihara et al., 2011[Fujihara, T., Xu, T., Semba, K., Terao, J. & Tsuji, Y. (2011). Angew. Chem. Int. Ed. 50, 523-527.]).

5. Synthesis and crystallization

Salicyl­aldehyde (0.2 g, 1.64 mmol) and benzyl­tri­phenyl­phospho­nium bromide (1.0 g, 2.31 mmol) in dry di­methyl­formamide (DMF) (30 ml) were treated with sodium methoxide powder (0.2 g, 3.70 mmol) and refluxed for 4 h (Mylona et al., 1986[Mylona, A., Nikokavouras, J. & Takakis, I. M. (1986). J. Chem. Res. pp. 433-433.]). The reaction mixture was then cooled, acidified with dilute aqueous HCl and extracted into CH2Cl2. The organic layer was washed twice with water to remove DMF, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography on silica gel. Hexane–diethyl ether (50:50) eluted the title compound (52 mg, 16%) as a white solid (m.p. 418–419 K), which was recrystallized from hexa­ne/diethyl ether solution to yield colourless slabs of (I)[link]; m/z 196.0886 (M+) C14H12O requires 196.0883. UV λmax(CHCl3)/nm 230 (log ∊ 4.30), 288 (4.39) and 315 (4.40). IR (νmax/cm−1) 3528s, 3019w, 2923w, 2852w, 1585s, 1498s, 1454s, 1332s, 1249s, 1195s, 1088s, 974vs, 845s, 752vs, 724vs, 691vs, 507vs. 1H NMR (400MHz, CDCl3) δ 5.07 (1H, s), 6.79 (1H, d, J = 8.0), 6.95 (1H, t, J = 7.4), 7.14 (2H, m), 7.25 (1H, t, J = 6.3), 7.35 (3H, m), 7.52 (3H, m). 13C NMR (99.5 MHz, CDCl3) δ 116.1, 121.3, 123.1, 124.8, 126.7, 127.3, 127.7, 128.8, 130.3, 137.7 and 153.1 (one resonance is missing).

2-Bromo­benzaldehyde (0.5 g, 2.70 mmol) and methyl phenyl­acetate (0.6 g, 4.0 mmol) in dry DMF (30 ml) were treated with sodium methoxide powder (0.3 g, 5.6 mmol) and refluxed for 4 h. The reaction mixture was then cooled, acidified with dilute aqueous HCl and extracted into CH2Cl2. The organic layer was washed twice with water to remove DMF, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography on silica gel. Hexane–diethyl ether (75:25) eluted (II)[link] (65 mg, 8%) as a colourless solid, which was recrystallized from hexa­ne/diethyl ether solution as colourless rods. The starting ester was evidently hydrolysed either during the reaction or at the work-up stage; m/z 300.9866 (M + H) C15H10O2Br requires 300.9870.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3[link]. Atom H1O in (I)[link] was located in a difference Fourier map and refined as riding in its as-found relative position with Uiso(H) = 1.2Ueq(O). The other H atoms were placed geometrically (C—H = 0.95 Å, O—H = 0.91 Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C,O). The O-bound H atoms in (II)[link] were located in a difference Fourier map and refined with Uiso(H) = 1.2Ueq(O). The C-bound H atoms were placed geometrically (C—H = 0.95 Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C).

Table 3
Experimental details

  (I) (II)
Crystal data
Chemical formula C14H12O C15H11BrO2
Mr 196.24 303.15
Crystal system, space group Orthorhombic, Pca21 Monoclinic, P21/n
Temperature (K) 100 100
a, b, c (Å) 11.6193 (8), 7.6800 (5), 11.3584 (8) 13.890 (1), 10.9048 (8), 17.8121 (10)
α, β, γ (°) 90, 90, 90 90, 106.064 (1), 90
V (Å3) 1013.58 (12) 2592.6 (3)
Z 4 8
Radiation type Mo Kα Mo Kα
μ (mm−1) 0.08 3.16
Crystal size (mm) 0.27 × 0.16 × 0.04 0.19 × 0.07 × 0.07
 
Data collection
Diffractometer Rigaku CCD Rigaku CCD
Absorption correction – Multi-scan (SADABS; Sheldrick, 2004[Sheldrick, G. M. (2004). SADABS. University of Göttingen, Germany.])
Tmin, Tmax – 0.585, 0.809
No. of measured, independent and observed [I > 2σ(I)] reflections 6984, 2271, 2132 31964, 5922, 5297
Rint 0.031 0.035
(sin θ/λ)max (Å−1) 0.649 0.650
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.091, 1.06 0.025, 0.063, 1.04
No. of reflections 2271 5922
No. of parameters 146 331
No. of restraints 1 0
H-atom treatment H-atom parameters constrained H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.19, −0.15 0.56, −0.74
Computer programs: CrystalClear (Rigaku, 2010[Rigaku (2010). CrystalClear. Rigaku Inc., Tokyo, Japan.]), SHELXS97 and SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and ATOMS (Dowty, 1999[Dowty, E. (1999). ATOMS. Shape Software, Kingsport, Tennessee, USA.]).

Supporting information

CCDC references: 1454393; 1454392

Crystal structure: contains datablocks I, II, global. DOI: 10.1107/S2056989016002942/su5278sup1.cif

Supporting information file. DOI: 10.1107/S2056989016002942/su5278Isup2.cml

Supporting information file. DOI: 10.1107/S2056989016002942/su5278IIsup3.cml

checkCIF report


Chemical context top

Photo-acid generators can be used as additives for creating patterns in a polymer film by irradiation through a mask followed by thermal development and base treatment (Ayothi et al., 2007; Kudo et al., 2008; Steidl et al., 2009). The UV irradiation degrades a small amount of the photo-acid generator in exposed areas, which releases a catalytic amount of a strong acid (commonly triflic acid). This acid subsequently catalyses the degradation of the tert-butyl­carboxyl­ate groups of a polymer film in a thermal development step, releasing carb­oxy­lic acid groups and isobutene. Treatment with base then solubilizes and removes the degraded polymer film in exposed areas, thereby creating a positive resist image (Ito et al., 1994).

We are exploring new types of organic structures as potential photo-acid generators, which might offer improvements over existing substances. Scheme 1 shows how substituted trans-stilbenes might act as photo-acid generators via sequential photochemical trans–cis isomerization and ring-closing reactions. It should be noted that the photochemical cyclization of stilbenes to phenanthenes in the presence of a hydrogen acceptor such as iodine or propyl­ene oxide is well known (Mallory & Mallory, 2005). However, in the absence of an oxidant, if a leaving group is present at the ring-closure site, as in structure 3, a rapid elimination of HX (structure 5) might occur via a stabilized carbocation inter­mediate 4. In the absence of an oxidant, the cyclized di­hydro-phenanthrene compound 6 will equilibrate back to cis-stilbene 2. Stilbenes can also undergo 2π + 2π photochemical cyclo­additions (Fulton & Dunitz, 1947; Shechter et al., 1963), a possible competing reaction, but the molecular structures and morphology may still favour the desired reaction to proceed in a thin film.

As part of these studies, the syntheses and crystal structures of the title substituted stilbenes, (I) and (II), are now described [compound (II) could also be described as a cinnamic acid derivative: the photochemical reactions of this family of compounds were reported by Schmidt (1971)]. Compound (I) is an inter­mediate in the synthesis, whereas a close analogue of compound (II) has already been shown to undergo photochemical cyclization to a phenanthrene with concomitant release of HCl (Geirsson & Kvaran, 2001). A monoclinic polymorph (space group P21/n) of (I) was reported recently (Cornella & Martin, 2013) although its crystal structure was not described in detail.

Structural commentary top

Compound (I) comprises one molecule in the asymmetric unit (Fig. 1), with the –OH group disordered over two sites in a 0.795 (3):0.205 (3) ratio. For the major disorder component, the Car—Car—O—H (ar = aromatic) torsion angle is 172°. The molecule is close to planar and the dihedral angle between the aromatic rings is 4.35 (6)°. The bond lengths of the central unit [C6—C7 = 1.4703 (19); C7—C8 = 1.3407 (16); C8—C9 = 1.4720 (18) Å] are consistent with data from previous studies of similar compounds (Tirado-Rives et al., 1984; Jungk et al., 1984). In the monoclinic polymorph of (I) (Cornella & Martin, 2013), the asymmetric unit consists of a half-molecule, which is completed by crystallographic inversion symmetry and therefore, of course, the aromatic rings are exactly coplanar: the OH group is statistically disordered by symmetry and the corresponding C—C—O—H torsion angle for the monoclinic phase is −175°.

There are two molecules in the asymmetric unit of (II) (Fig. 2). In the first (C1) molecule, the dihedral angles between the carb­oxy­lic acid group and the phenyl and bromo­benzene rings are 61.52 (6) and 55.43 (5)°, respectively; the dihedral angle between the aromatic rings is 54.45 (5)°. The equivalent data for the second (C16) molecule are 50.72 (6), 60.28 (5) and 61.48 (6)°, respectively. The C1 and C16 molecules have a similar overall conformation with an r.m.s. deviation of 0.183 Å for the overlay fit for all non-hydrogen atoms. Otherwise, their bond lengths and bond angles are unexceptional and fall within the expected range of values.

Supra­molecular features top

The crystal of (I) features O—H···π inter­actions as the main supra­molecular inter­action (Table 1). The major disorder component (O1—H1O) generates [001] zigzag chains, as seen in Fig. 3. The minor disorder component (O2—H2O) also forms [001] chains. There are also some possible very weak C—H···π inter­actions. The packing can be described as herringbone when viewed down [100] (Fig. 4). The monoclinic polymorph (Cornella & Martin, 2013) also features supra­molecular chains with the molecules linked by O—H···π inter­actions but a different overall herringbone packing motif (Fig. 5).

In the crystal of (II), both molecules (A and B) form carb­oxy­lic acid inversion dimers linked by pairs of O—H···O hydrogen bonds, which generate R22(8) loops in each case. The (A + A) and (B + B) dimers are in turn linked by pairs of C—H···O hydrogen bonds to generate [010] chains (Figs. 6 and 7). This hydrogen-bond scheme is `balanced,' with both O1 and O3 accepting one O—H···O and one C—H···O hydrogen bond. The shortest Br···Br contact distance of 3.6504 (4) Å in the crystal of (II) is slightly shorter than the van der Waals radius sum of 3.70 Å for two Br atoms (Bondi, 1964).

Database survey top

A survey of the Cambridge Structural Database (Groom & Allen, 2014) (entries updated to 22 December 2015) revealed ten crystal structures of E-2-hy­droxy stilbenes with different substituents including (E)-1,2-bis­(2-hy­droxy­phenyl)-ethene (refcode CEYKUM; Tirado-Rives et al., 1984), in which the molecules are linked by O—H···O hydrogen bonds. Two substituted Z-isomers are also known. A total of 28 analogues of (II) with different substituents to the aromatic rings were found in the same survey, including the parent compound, 2,3-di­phenyl­acrylic acid (refcode OJOFEZ; Fujihara et al., 2011).

Synthesis and crystallization top

Salicyl­aldehyde (0.2 g, 1.64 mmol) and benzyl­tri­phenyl­phospho­nium bromide (1.0 g, 2.31 mmol) in dry di­methyl­formamide (DMF) (30 ml) were treated with sodium methoxide powder (0.2 g, 3.70 mmol) and refluxed for 4 h (Mylona et al., 1986). The reaction mixture was then cooled, acidified with dilute aqueous HCl and extracted into CH2Cl2. The organic layer was washed twice with water to remove DMF, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography on silica gel. Hexane–di­ethyl ether (50:50) eluted the title compound (52 mg, 16%) as a white solid (m.p. 418–419 K), which was recrystallized from hexane/di­ethyl ether solution to yield colourless slabs of (I); m/z 196.0886 (M+) C14H12O requires 196.0883. UV λmax(CHCl3)/nm 230 (log ε 4.30), 288 (4.39) and 315 (4.40). IR (νmax/cm−1) 3528s, 3019w, 2923w, 2852w, 1585s, 1498s, 1454s, 1332s, 1249s, 1195s, 1088s, 974vs, 845s, 752vs, 724vs, 691vs, 507vs. 1H NMR (400 MHz, CDCl3) δ 5.07 (1H, s), 6.79 (1H, d, J = 8.0), 6.95 (1H, t, J = 7.4), 7.14 (2H, m), 7.25 (1H, t, J = 6.3), 7.35 (3H, m), 7.52 (3H, m). 13C NMR (99.5 MHz, CDCl3) δ 116.1, 121.3, 123.1, 124.8, 126.7, 127.3, 127.7, 128.8, 130.3, 137.7 and 153.1 (one resonance is missing).

2-Bromo­benzaldehyde (0.5 g, 2.70 mmol) and methyl phenyl­acetate (0.6 g, 4.0 mmol) in dry DMF (30 ml) were treated with sodium methoxide powder (0.3 g, 5.6 mmol) and refluxed for 4 h. The reaction mixture was then cooled, acidified with dilute aqueous HCl and extracted into CH2Cl2. The organic layer was washed twice with water to remove DMF, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography on silica gel. Hexane–di­ethyl ether (75:25) eluted (II) (65 mg, 8%) as a colourless solid, which was recrystallized from hexane/di­ethyl ether solution as colourless rods. The starting ester was evidently hydrolysed either during the reaction or at the work-up stage; m/z 300.9866 (M + H) C15H10O2Br requires 300.9870.

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 3. Atom H1O in (I) was located in a difference Fourier map and refined as riding in its as-found relative position with Uiso(H) = 1.2Ueq(O). The other H atoms were placed geometrically (C—H = 0.95 Å, O—H = 0.91 Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C,O). The O-bound H atoms in (II) were located in a difference Fourier map and refined with Uiso(H) = 1.2Ueq(O). The C-bound H atoms were placed geometrically (C—H = 0.95 Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C).

Structure description top

Photo-acid generators can be used as additives for creating patterns in a polymer film by irradiation through a mask followed by thermal development and base treatment (Ayothi et al., 2007; Kudo et al., 2008; Steidl et al., 2009). The UV irradiation degrades a small amount of the photo-acid generator in exposed areas, which releases a catalytic amount of a strong acid (commonly triflic acid). This acid subsequently catalyses the degradation of the tert-butyl­carboxyl­ate groups of a polymer film in a thermal development step, releasing carb­oxy­lic acid groups and isobutene. Treatment with base then solubilizes and removes the degraded polymer film in exposed areas, thereby creating a positive resist image (Ito et al., 1994).

We are exploring new types of organic structures as potential photo-acid generators, which might offer improvements over existing substances. Scheme 1 shows how substituted trans-stilbenes might act as photo-acid generators via sequential photochemical trans–cis isomerization and ring-closing reactions. It should be noted that the photochemical cyclization of stilbenes to phenanthenes in the presence of a hydrogen acceptor such as iodine or propyl­ene oxide is well known (Mallory & Mallory, 2005). However, in the absence of an oxidant, if a leaving group is present at the ring-closure site, as in structure 3, a rapid elimination of HX (structure 5) might occur via a stabilized carbocation inter­mediate 4. In the absence of an oxidant, the cyclized di­hydro-phenanthrene compound 6 will equilibrate back to cis-stilbene 2. Stilbenes can also undergo 2π + 2π photochemical cyclo­additions (Fulton & Dunitz, 1947; Shechter et al., 1963), a possible competing reaction, but the molecular structures and morphology may still favour the desired reaction to proceed in a thin film.

As part of these studies, the syntheses and crystal structures of the title substituted stilbenes, (I) and (II), are now described [compound (II) could also be described as a cinnamic acid derivative: the photochemical reactions of this family of compounds were reported by Schmidt (1971)]. Compound (I) is an inter­mediate in the synthesis, whereas a close analogue of compound (II) has already been shown to undergo photochemical cyclization to a phenanthrene with concomitant release of HCl (Geirsson & Kvaran, 2001). A monoclinic polymorph (space group P21/n) of (I) was reported recently (Cornella & Martin, 2013) although its crystal structure was not described in detail.

Compound (I) comprises one molecule in the asymmetric unit (Fig. 1), with the –OH group disordered over two sites in a 0.795 (3):0.205 (3) ratio. For the major disorder component, the Car—Car—O—H (ar = aromatic) torsion angle is 172°. The molecule is close to planar and the dihedral angle between the aromatic rings is 4.35 (6)°. The bond lengths of the central unit [C6—C7 = 1.4703 (19); C7—C8 = 1.3407 (16); C8—C9 = 1.4720 (18) Å] are consistent with data from previous studies of similar compounds (Tirado-Rives et al., 1984; Jungk et al., 1984). In the monoclinic polymorph of (I) (Cornella & Martin, 2013), the asymmetric unit consists of a half-molecule, which is completed by crystallographic inversion symmetry and therefore, of course, the aromatic rings are exactly coplanar: the OH group is statistically disordered by symmetry and the corresponding C—C—O—H torsion angle for the monoclinic phase is −175°.

There are two molecules in the asymmetric unit of (II) (Fig. 2). In the first (C1) molecule, the dihedral angles between the carb­oxy­lic acid group and the phenyl and bromo­benzene rings are 61.52 (6) and 55.43 (5)°, respectively; the dihedral angle between the aromatic rings is 54.45 (5)°. The equivalent data for the second (C16) molecule are 50.72 (6), 60.28 (5) and 61.48 (6)°, respectively. The C1 and C16 molecules have a similar overall conformation with an r.m.s. deviation of 0.183 Å for the overlay fit for all non-hydrogen atoms. Otherwise, their bond lengths and bond angles are unexceptional and fall within the expected range of values.

The crystal of (I) features O—H···π inter­actions as the main supra­molecular inter­action (Table 1). The major disorder component (O1—H1O) generates [001] zigzag chains, as seen in Fig. 3. The minor disorder component (O2—H2O) also forms [001] chains. There are also some possible very weak C—H···π inter­actions. The packing can be described as herringbone when viewed down [100] (Fig. 4). The monoclinic polymorph (Cornella & Martin, 2013) also features supra­molecular chains with the molecules linked by O—H···π inter­actions but a different overall herringbone packing motif (Fig. 5).

In the crystal of (II), both molecules (A and B) form carb­oxy­lic acid inversion dimers linked by pairs of O—H···O hydrogen bonds, which generate R22(8) loops in each case. The (A + A) and (B + B) dimers are in turn linked by pairs of C—H···O hydrogen bonds to generate [010] chains (Figs. 6 and 7). This hydrogen-bond scheme is `balanced,' with both O1 and O3 accepting one O—H···O and one C—H···O hydrogen bond. The shortest Br···Br contact distance of 3.6504 (4) Å in the crystal of (II) is slightly shorter than the van der Waals radius sum of 3.70 Å for two Br atoms (Bondi, 1964).

A survey of the Cambridge Structural Database (Groom & Allen, 2014) (entries updated to 22 December 2015) revealed ten crystal structures of E-2-hy­droxy stilbenes with different substituents including (E)-1,2-bis­(2-hy­droxy­phenyl)-ethene (refcode CEYKUM; Tirado-Rives et al., 1984), in which the molecules are linked by O—H···O hydrogen bonds. Two substituted Z-isomers are also known. A total of 28 analogues of (II) with different substituents to the aromatic rings were found in the same survey, including the parent compound, 2,3-di­phenyl­acrylic acid (refcode OJOFEZ; Fujihara et al., 2011).

Synthesis and crystallization top

Salicyl­aldehyde (0.2 g, 1.64 mmol) and benzyl­tri­phenyl­phospho­nium bromide (1.0 g, 2.31 mmol) in dry di­methyl­formamide (DMF) (30 ml) were treated with sodium methoxide powder (0.2 g, 3.70 mmol) and refluxed for 4 h (Mylona et al., 1986). The reaction mixture was then cooled, acidified with dilute aqueous HCl and extracted into CH2Cl2. The organic layer was washed twice with water to remove DMF, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography on silica gel. Hexane–di­ethyl ether (50:50) eluted the title compound (52 mg, 16%) as a white solid (m.p. 418–419 K), which was recrystallized from hexane/di­ethyl ether solution to yield colourless slabs of (I); m/z 196.0886 (M+) C14H12O requires 196.0883. UV λmax(CHCl3)/nm 230 (log ε 4.30), 288 (4.39) and 315 (4.40). IR (νmax/cm−1) 3528s, 3019w, 2923w, 2852w, 1585s, 1498s, 1454s, 1332s, 1249s, 1195s, 1088s, 974vs, 845s, 752vs, 724vs, 691vs, 507vs. 1H NMR (400 MHz, CDCl3) δ 5.07 (1H, s), 6.79 (1H, d, J = 8.0), 6.95 (1H, t, J = 7.4), 7.14 (2H, m), 7.25 (1H, t, J = 6.3), 7.35 (3H, m), 7.52 (3H, m). 13C NMR (99.5 MHz, CDCl3) δ 116.1, 121.3, 123.1, 124.8, 126.7, 127.3, 127.7, 128.8, 130.3, 137.7 and 153.1 (one resonance is missing).

2-Bromo­benzaldehyde (0.5 g, 2.70 mmol) and methyl phenyl­acetate (0.6 g, 4.0 mmol) in dry DMF (30 ml) were treated with sodium methoxide powder (0.3 g, 5.6 mmol) and refluxed for 4 h. The reaction mixture was then cooled, acidified with dilute aqueous HCl and extracted into CH2Cl2. The organic layer was washed twice with water to remove DMF, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography on silica gel. Hexane–di­ethyl ether (75:25) eluted (II) (65 mg, 8%) as a colourless solid, which was recrystallized from hexane/di­ethyl ether solution as colourless rods. The starting ester was evidently hydrolysed either during the reaction or at the work-up stage; m/z 300.9866 (M + H) C15H10O2Br requires 300.9870.

Refinement details top

Crystal data, data collection and structure refinement details are summarized in Table 3. Atom H1O in (I) was located in a difference Fourier map and refined as riding in its as-found relative position with Uiso(H) = 1.2Ueq(O). The other H atoms were placed geometrically (C—H = 0.95 Å, O—H = 0.91 Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C,O). The O-bound H atoms in (II) were located in a difference Fourier map and refined with Uiso(H) = 1.2Ueq(O). The C-bound H atoms were placed geometrically (C—H = 0.95 Å) and refined as riding atoms with Uiso(H) = 1.2Ueq(C).

Computing details top

For both compounds, data collection: CrystalClear (Rigaku, 2010); cell refinement: CrystalClear (Rigaku, 2010); data reduction: CrystalClear (Rigaku, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and ATOMS (Dowty, 1999); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of (I), showing 50% displacement ellipsoids. Only the major disordered component for the OH group is shown (the minor component is attached to C14).
[Figure 2] Fig. 2. The asymmetric unit of (II), showing 50% displacement ellipsoids.
[Figure 3] Fig. 3. Part of a [001] chain of molecules in the crystal of (I), connected by O—H···π interactions (cyan lines).
[Figure 4] Fig. 4. The unit-cell packing in (I), viewed approximately down [100]. The O—H···π interactions from both disordered components are shown as cyan lines.
[Figure 5] Fig. 5. The unit-cell packing in the monoclinic polymorph of C14H12O, viewed approximately down [000] (data from Cornella & Martin, 2013). The O—H···π interactions are shown as cyan lines.
[Figure 6] Fig. 6. Part of a [010] chain in the crystal of (II), with O—H···O hydrogen bonds shown as yellow lines and C—H···O hydrogen bonds shown as cyan lines.
[Figure 7] Fig. 7. The unit-cell packing in (II), viewed approximately down [010].
(I) 2-[(E)-2-Phenylethenyl]phenol top
Crystal data top
C14H12OF(000) = 416
Mr = 196.24Dx = 1.286 Mg m−3
Orthorhombic, Pca21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2acCell parameters from 7085 reflections
a = 11.6193 (8) Åθ = 2.5–27.5°
b = 7.6800 (5) ŵ = 0.08 mm−1
c = 11.3584 (8) ÅT = 100 K
V = 1013.58 (12) Å3Slab, colourless
Z = 40.27 × 0.16 × 0.04 mm
Data collection top
Rigaku CCD
diffractometer		2132 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.031
Graphite monochromatorθmax = 27.5°, θmin = 2.7°
ω scansh = −15→13
6984 measured reflectionsk = −9→8
2271 independent reflectionsl = −13→14
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.091H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0581P)2 + 0.0566P]
where P = (Fo2 + 2Fc2)/3
2271 reflections(Δ/σ)max < 0.001
146 parametersΔρmax = 0.19 e Å−3
1 restraintΔρmin = −0.15 e Å−3
Crystal data top
C14H12OV = 1013.58 (12) Å3
Mr = 196.24Z = 4
Orthorhombic, Pca21Mo Kα radiation
a = 11.6193 (8) ŵ = 0.08 mm−1
b = 7.6800 (5) ÅT = 100 K
c = 11.3584 (8) Å0.27 × 0.16 × 0.04 mm
Data collection top
Rigaku CCD
diffractometer		2132 reflections with I > 2σ(I)
6984 measured reflectionsRint = 0.031
2271 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0341 restraint
wR(F2) = 0.091H-atom parameters constrained
S = 1.06Δρmax = 0.19 e Å−3
2271 reflectionsΔρmin = −0.15 e Å−3
146 parameters
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.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
C10.30887 (12)0.13815 (16)0.08810 (11)0.0230 (3)
H10.36520.09290.03860.028*0.205 (3)
C20.19331 (12)0.12759 (16)0.05641 (11)0.0258 (3)
H20.17210.0723−0.01520.031*
C30.10941 (12)0.19707 (16)0.12852 (12)0.0249 (3)
H30.03070.18900.10670.030*
C40.14037 (12)0.27928 (17)0.23349 (12)0.0244 (3)
H40.08290.32800.28310.029*
C50.25559 (12)0.28929 (14)0.26490 (11)0.0222 (3)
H50.27590.34560.33640.027*
C60.34307 (12)0.21877 (16)0.19426 (10)0.0207 (3)
C70.46529 (12)0.22186 (16)0.22775 (11)0.0210 (3)
H70.51840.17010.17460.025*
C80.50832 (12)0.29131 (15)0.32669 (11)0.0219 (3)
H80.45500.34530.37860.026*
C90.62995 (11)0.29221 (15)0.36292 (11)0.0203 (3)
C100.71722 (12)0.21042 (16)0.29798 (11)0.0229 (3)
H100.69820.14980.22770.027*
C110.83100 (13)0.21675 (16)0.33495 (12)0.0259 (3)
H110.88920.16210.28930.031*
C120.86041 (12)0.30333 (17)0.43927 (13)0.0273 (3)
H120.93830.30730.46460.033*
C130.77504 (12)0.38320 (16)0.50516 (11)0.0265 (3)
H130.79430.44130.57630.032*
C140.66125 (13)0.37858 (16)0.46739 (11)0.0241 (3)
H140.60450.43400.51210.029*0.795 (3)
O10.39106 (10)0.07105 (15)0.01715 (10)0.0261 (3)0.795 (3)
H1O0.34920.0078−0.04430.031*0.795 (3)
O20.5932 (4)0.4523 (7)0.5351 (5)0.0305 (15)0.205 (3)
H2O0.63810.53650.56700.037*0.205 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0315 (7)0.0191 (5)0.0183 (6)−0.0012 (5)0.0010 (5)0.0000 (4)
C20.0358 (8)0.0207 (6)0.0208 (6)−0.0060 (5)−0.0057 (5)0.0003 (5)
C30.0259 (7)0.0222 (6)0.0266 (7)−0.0043 (5)−0.0061 (5)0.0043 (5)
C40.0255 (7)0.0231 (6)0.0246 (7)0.0004 (5)0.0012 (5)0.0001 (5)
C50.0270 (6)0.0207 (6)0.0190 (6)−0.0014 (5)−0.0005 (5)−0.0017 (5)
C60.0255 (6)0.0171 (5)0.0194 (6)−0.0026 (5)0.0011 (5)0.0005 (4)
C70.0245 (6)0.0204 (6)0.0180 (6)−0.0004 (5)0.0025 (5)−0.0005 (4)
C80.0240 (7)0.0207 (6)0.0208 (6)−0.0026 (5)0.0045 (5)−0.0022 (4)
C90.0260 (7)0.0182 (6)0.0166 (6)−0.0040 (5)−0.0001 (5)0.0025 (4)
C100.0275 (7)0.0213 (6)0.0199 (6)−0.0030 (5)0.0005 (5)0.0003 (4)
C110.0276 (7)0.0233 (6)0.0269 (7)−0.0001 (5)−0.0015 (5)0.0031 (5)
C120.0285 (7)0.0238 (7)0.0296 (8)−0.0056 (5)−0.0102 (6)0.0072 (5)
C130.0388 (8)0.0225 (6)0.0184 (6)−0.0084 (5)−0.0072 (6)0.0017 (5)
C140.0330 (7)0.0207 (6)0.0185 (6)−0.0038 (5)0.0014 (5)0.0001 (5)
O10.0247 (6)0.0328 (7)0.0209 (6)0.0027 (5)−0.0004 (4)−0.0101 (5)
O20.027 (3)0.035 (3)0.030 (3)−0.004 (2)0.003 (2)−0.014 (2)
Geometric parameters (Å, º) top
C1—O11.3517 (17)C8—H80.9500
C1—C21.3925 (18)C9—C101.4024 (17)
C1—C61.4126 (18)C9—C141.4073 (18)
C1—H10.9300C10—C111.388 (2)
C2—C31.381 (2)C10—H100.9500
C2—H20.9500C11—C121.401 (2)
C3—C41.3963 (19)C11—H110.9500
C3—H30.9500C12—C131.386 (2)
C4—C51.388 (2)C12—H120.9500
C4—H40.9500C13—C141.390 (2)
C5—C61.4036 (18)C13—H130.9500
C5—H50.9500C14—O21.240 (5)
C6—C71.4703 (19)C14—H140.9340
C7—C81.3407 (16)O1—H1O0.9794
C7—H70.9500O2—H2O0.9057
C8—C91.4720 (18)
O1—C1—C2120.33 (12)C7—C8—H8116.8
O1—C1—C6118.51 (12)C9—C8—H8116.8
C2—C1—C6121.17 (12)C10—C9—C14117.89 (12)
O1—C1—H10.7C10—C9—C8123.03 (11)
C2—C1—H1120.0C14—C9—C8119.08 (12)
C6—C1—H1118.8C11—C10—C9120.92 (12)
C3—C2—C1120.33 (11)C11—C10—H10119.5
C3—C2—H2119.8C9—C10—H10119.5
C1—C2—H2119.8C10—C11—C12120.32 (13)
C2—C3—C4119.97 (13)C10—C11—H11119.8
C2—C3—H3120.0C12—C11—H11119.8
C4—C3—H3120.0C13—C12—C11119.49 (13)
C5—C4—C3119.55 (13)C13—C12—H12120.3
C5—C4—H4120.2C11—C12—H12120.3
C3—C4—H4120.2C12—C13—C14120.18 (12)
C4—C5—C6122.03 (12)C12—C13—H13119.9
C4—C5—H5119.0C14—C13—H13119.9
C6—C5—H5119.0O2—C14—C13113.8 (3)
C5—C6—C1116.96 (12)O2—C14—C9125.0 (3)
C5—C6—C7123.05 (11)C13—C14—C9121.19 (13)
C1—C6—C7119.98 (11)C13—C14—H14119.4
C8—C7—C6125.69 (12)C9—C14—H14119.4
C8—C7—H7117.2C1—O1—H1O105.2
C6—C7—H7117.2C14—O2—H2O101.9
C7—C8—C9126.46 (12)
O1—C1—C2—C3−179.60 (12)C7—C8—C9—C10−3.09 (18)
C6—C1—C2—C30.32 (18)C7—C8—C9—C14176.96 (11)
C1—C2—C3—C40.36 (19)C14—C9—C10—C11−0.88 (17)
C2—C3—C4—C5−0.47 (19)C8—C9—C10—C11179.16 (12)
C3—C4—C5—C6−0.10 (19)C9—C10—C11—C120.94 (19)
C4—C5—C6—C10.74 (17)C10—C11—C12—C13−0.22 (19)
C4—C5—C6—C7−177.62 (12)C11—C12—C13—C14−0.54 (19)
O1—C1—C6—C5179.07 (11)C12—C13—C14—O2178.9 (3)
C2—C1—C6—C5−0.85 (17)C12—C13—C14—C90.59 (19)
O1—C1—C6—C7−2.52 (17)C10—C9—C14—O2−178.0 (3)
C2—C1—C6—C7177.56 (11)C8—C9—C14—O22.0 (4)
C5—C6—C7—C8−0.48 (19)C10—C9—C14—C130.12 (18)
C1—C6—C7—C8−178.79 (11)C8—C9—C14—C13−179.92 (11)
C6—C7—C8—C9178.55 (12)
Hydrogen-bond geometry (Å, º) top
Cg1 and Cg2 are the centroids of rings C1–C6 and C9–C14, respectively.
D—H···AD—HH···AD···AD—H···A
O1—H1o···Cg2i0.982.663.5028 (13)144
O2—H2o···Cg10.912.743.646 (2)179
C5—H5···Cg2ii0.952.863.5337 (12)129
C10—H10···Cg1iii0.952.873.5742 (14)132
C13—H13···Cg1iv0.952.873.6015 (14)135
Symmetry codes: (i) −x+1, −y, z−1/2; (ii) x−1/2, −y+1, z; (iii) x+1/2, −y, z; (iv) −x+1, −y+1, z+1/2.
(II) (2E)-3-(2-Bromophenyl)-2-phenylprop-2-enoic acid top
Crystal data top
C15H11BrO2F(000) = 1216
Mr = 303.15Dx = 1.553 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 30565 reflections
a = 13.890 (1) Åθ = 2.2–27.5°
b = 10.9048 (8) ŵ = 3.16 mm−1
c = 17.8121 (10) ÅT = 100 K
β = 106.064 (1)°Rod, colourless
V = 2592.6 (3) Å30.19 × 0.07 × 0.07 mm
Z = 8
Data collection top
Rigaku CCD
diffractometer		5922 independent reflections
Radiation source: fine-focus sealed tube5297 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.035
ω scansθmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)		h = −17→18
Tmin = 0.585, Tmax = 0.809k = −13→14
31964 measured reflectionsl = −22→23
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.025Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.063H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0335P)2 + 1.1714P]
where P = (Fo2 + 2Fc2)/3
5922 reflections(Δ/σ)max = 0.001
331 parametersΔρmax = 0.56 e Å−3
0 restraintsΔρmin = −0.74 e Å−3
Crystal data top
C15H11BrO2V = 2592.6 (3) Å3
Mr = 303.15Z = 8
Monoclinic, P21/nMo Kα radiation
a = 13.890 (1) ŵ = 3.16 mm−1
b = 10.9048 (8) ÅT = 100 K
c = 17.8121 (10) Å0.19 × 0.07 × 0.07 mm
β = 106.064 (1)°
Data collection top
Rigaku CCD
diffractometer		5922 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)		5297 reflections with I > 2σ(I)
Tmin = 0.585, Tmax = 0.809Rint = 0.035
31964 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0250 restraints
wR(F2) = 0.063H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.56 e Å−3
5922 reflectionsΔρmin = −0.74 e Å−3
331 parameters
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.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.18672 (11)0.20670 (14)0.33555 (9)0.0171 (3)
C20.21064 (12)0.11955 (16)0.39459 (9)0.0208 (3)
H20.24760.14190.44610.025*
C30.17974 (12)−0.00082 (16)0.37725 (10)0.0228 (3)
H30.1954−0.06140.41710.027*
C40.12604 (12)−0.03303 (16)0.30185 (10)0.0223 (3)
H40.1064−0.11580.28990.027*
C50.10111 (12)0.05592 (15)0.24394 (9)0.0206 (3)
H50.06320.03340.19280.025*
C60.13072 (11)0.17808 (15)0.25938 (9)0.0171 (3)
C70.10814 (12)0.27030 (14)0.19619 (9)0.0177 (3)
H70.16150.32210.19230.021*
C80.01866 (11)0.28748 (14)0.14364 (8)0.0156 (3)
C90.01101 (11)0.37744 (14)0.07944 (9)0.0153 (3)
C10−0.07591 (11)0.22525 (14)0.14608 (9)0.0158 (3)
C11−0.10312 (12)0.21984 (15)0.21603 (9)0.0203 (3)
H11−0.06350.26050.26120.024*
C12−0.18786 (13)0.15528 (16)0.21964 (10)0.0234 (3)
H12−0.20570.15170.26740.028*
C13−0.24673 (12)0.09582 (16)0.15388 (10)0.0239 (3)
H13−0.30350.04970.15700.029*
C14−0.22209 (12)0.10418 (15)0.08346 (10)0.0213 (3)
H14−0.26330.06590.03790.026*
C15−0.13720 (12)0.16852 (15)0.07977 (9)0.0177 (3)
H15−0.12070.17390.03160.021*
O1−0.06993 (8)0.41209 (10)0.03689 (6)0.0185 (2)
O20.09775 (8)0.41647 (11)0.07169 (7)0.0204 (2)
H2O0.0845 (15)0.471 (2)0.0373 (12)0.024*
Br10.230078 (13)0.370757 (16)0.360313 (9)0.02454 (6)
C160.88556 (12)0.19354 (15)0.43750 (9)0.0194 (3)
C170.94766 (12)0.10532 (16)0.41971 (10)0.0234 (3)
H171.01580.12360.42400.028*
C180.90912 (13)−0.00957 (16)0.39570 (10)0.0249 (4)
H180.9510−0.07080.38350.030*
C190.80940 (13)−0.03570 (15)0.38943 (10)0.0227 (3)
H190.7834−0.11510.37390.027*
C200.74767 (12)0.05462 (15)0.40597 (9)0.0204 (3)
H200.67910.03640.40030.025*
C210.78410 (11)0.17179 (15)0.43077 (9)0.0173 (3)
C220.72086 (12)0.26361 (14)0.45511 (9)0.0179 (3)
H220.75250.31130.49980.021*
C230.62358 (12)0.28762 (14)0.42138 (9)0.0169 (3)
C240.57101 (12)0.37778 (14)0.45901 (9)0.0172 (3)
C250.56263 (12)0.23498 (14)0.34604 (9)0.0173 (3)
C260.59428 (12)0.24671 (15)0.27832 (9)0.0203 (3)
H260.65400.29060.28010.024*
C270.53886 (13)0.19457 (16)0.20854 (10)0.0234 (3)
H270.56110.20240.16290.028*
C280.45100 (14)0.13098 (15)0.20517 (10)0.0249 (4)
H280.41370.09450.15750.030*
C290.41787 (13)0.12096 (15)0.27187 (10)0.0239 (3)
H290.35770.07790.26980.029*
C300.47260 (12)0.17383 (15)0.34140 (10)0.0201 (3)
H300.44870.16850.38640.024*
O30.48613 (8)0.41328 (11)0.42624 (6)0.0207 (2)
O40.62187 (9)0.41561 (11)0.52942 (6)0.0207 (2)
H4O0.5877 (16)0.467 (2)0.5428 (12)0.025*
Br20.942911 (13)0.350346 (17)0.471076 (12)0.03017 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0130 (7)0.0176 (7)0.0209 (7)−0.0002 (6)0.0049 (6)0.0010 (6)
C20.0144 (7)0.0290 (9)0.0184 (7)0.0024 (6)0.0034 (6)0.0036 (6)
C30.0168 (7)0.0269 (9)0.0254 (8)0.0037 (6)0.0071 (6)0.0107 (7)
C40.0187 (8)0.0179 (8)0.0308 (9)0.0006 (6)0.0075 (7)0.0030 (6)
C50.0175 (7)0.0228 (8)0.0207 (8)0.0006 (6)0.0039 (6)0.0007 (6)
C60.0131 (7)0.0200 (8)0.0181 (7)0.0014 (6)0.0041 (6)0.0013 (6)
C70.0180 (7)0.0179 (8)0.0176 (7)−0.0003 (6)0.0055 (6)−0.0008 (6)
C80.0171 (7)0.0156 (7)0.0152 (7)0.0002 (6)0.0061 (6)0.0000 (5)
C90.0156 (7)0.0164 (7)0.0147 (7)−0.0006 (6)0.0056 (6)−0.0020 (5)
C100.0147 (7)0.0160 (7)0.0174 (7)0.0027 (6)0.0057 (6)0.0029 (6)
C110.0192 (8)0.0246 (8)0.0171 (7)0.0031 (6)0.0053 (6)0.0023 (6)
C120.0214 (8)0.0298 (9)0.0224 (8)0.0042 (7)0.0117 (7)0.0068 (7)
C130.0184 (8)0.0239 (9)0.0320 (9)−0.0010 (6)0.0112 (7)0.0063 (7)
C140.0188 (8)0.0202 (8)0.0247 (8)−0.0009 (6)0.0057 (6)−0.0010 (6)
C150.0184 (7)0.0180 (7)0.0179 (7)0.0013 (6)0.0070 (6)0.0008 (6)
O10.0147 (5)0.0218 (6)0.0185 (5)0.0001 (4)0.0036 (4)0.0037 (4)
O20.0143 (5)0.0249 (6)0.0224 (6)0.0001 (4)0.0058 (4)0.0086 (5)
Br10.02498 (9)0.02182 (9)0.02174 (9)−0.00288 (6)−0.00199 (6)−0.00055 (6)
C160.0192 (7)0.0187 (8)0.0193 (7)−0.0005 (6)0.0040 (6)0.0007 (6)
C170.0173 (8)0.0286 (9)0.0248 (8)0.0035 (7)0.0069 (6)0.0019 (7)
C180.0243 (9)0.0246 (9)0.0276 (9)0.0090 (7)0.0100 (7)0.0008 (7)
C190.0270 (8)0.0168 (8)0.0261 (8)0.0010 (6)0.0103 (7)−0.0001 (6)
C200.0197 (8)0.0213 (8)0.0219 (8)−0.0003 (6)0.0085 (6)0.0026 (6)
C210.0174 (7)0.0204 (8)0.0146 (7)0.0019 (6)0.0051 (6)0.0028 (6)
C220.0188 (7)0.0182 (8)0.0177 (7)−0.0008 (6)0.0070 (6)0.0002 (6)
C230.0187 (7)0.0158 (7)0.0186 (7)−0.0005 (6)0.0091 (6)0.0011 (6)
C240.0181 (7)0.0171 (7)0.0180 (7)−0.0016 (6)0.0079 (6)0.0015 (6)
C250.0184 (7)0.0150 (7)0.0192 (7)0.0030 (6)0.0063 (6)−0.0001 (6)
C260.0200 (8)0.0202 (8)0.0222 (8)0.0016 (6)0.0085 (6)0.0007 (6)
C270.0274 (9)0.0240 (9)0.0205 (8)0.0034 (7)0.0097 (7)−0.0004 (6)
C280.0294 (9)0.0211 (8)0.0224 (8)0.0012 (7)0.0044 (7)−0.0052 (6)
C290.0227 (8)0.0196 (8)0.0297 (9)−0.0033 (6)0.0077 (7)−0.0029 (7)
C300.0219 (8)0.0180 (8)0.0228 (8)0.0005 (6)0.0099 (6)−0.0003 (6)
O30.0174 (5)0.0240 (6)0.0207 (5)0.0026 (5)0.0052 (4)−0.0035 (5)
O40.0193 (6)0.0233 (6)0.0195 (5)0.0049 (5)0.0054 (4)−0.0045 (5)
Br20.02001 (9)0.02494 (10)0.04386 (12)−0.00432 (6)0.00599 (8)−0.00679 (7)
Geometric parameters (Å, º) top
C1—C21.388 (2)C16—C171.386 (2)
C1—C61.400 (2)C16—C211.401 (2)
C1—Br11.9002 (16)C16—Br21.9111 (16)
C2—C31.389 (2)C17—C181.383 (3)
C2—H20.9500C17—H170.9500
C3—C41.389 (2)C18—C191.388 (2)
C3—H30.9500C18—H180.9500
C4—C51.388 (2)C19—C201.390 (2)
C4—H40.9500C19—H190.9500
C5—C61.399 (2)C20—C211.400 (2)
C5—H50.9500C20—H200.9500
C6—C71.477 (2)C21—C221.474 (2)
C7—C81.346 (2)C22—C231.344 (2)
C7—H70.9500C22—H220.9500
C8—C91.488 (2)C23—C251.489 (2)
C8—C101.490 (2)C23—C241.490 (2)
C9—O11.2287 (18)C24—O31.2247 (19)
C9—O21.3205 (18)C24—O41.3236 (19)
C10—C151.395 (2)C25—C301.399 (2)
C10—C111.400 (2)C25—C261.399 (2)
C11—C121.388 (2)C26—C271.390 (2)
C11—H110.9500C26—H260.9500
C12—C131.390 (3)C27—C281.390 (2)
C12—H120.9500C27—H270.9500
C13—C141.391 (2)C28—C291.392 (2)
C13—H130.9500C28—H280.9500
C14—C151.389 (2)C29—C301.387 (2)
C14—H140.9500C29—H290.9500
C15—H150.9500C30—H300.9500
O2—H2O0.84 (2)O4—H4O0.81 (2)
C2—C1—C6122.28 (15)C17—C16—C21122.53 (15)
C2—C1—Br1118.35 (12)C17—C16—Br2117.43 (12)
C6—C1—Br1119.36 (12)C21—C16—Br2120.03 (12)
C1—C2—C3118.96 (15)C18—C17—C16119.17 (15)
C1—C2—H2120.5C18—C17—H17120.4
C3—C2—H2120.5C16—C17—H17120.4
C4—C3—C2120.28 (15)C17—C18—C19120.21 (15)
C4—C3—H3119.9C17—C18—H18119.9
C2—C3—H3119.9C19—C18—H18119.9
C5—C4—C3119.91 (16)C18—C19—C20119.86 (16)
C5—C4—H4120.0C18—C19—H19120.1
C3—C4—H4120.0C20—C19—H19120.1
C4—C5—C6121.33 (15)C19—C20—C21121.55 (15)
C4—C5—H5119.3C19—C20—H20119.2
C6—C5—H5119.3C21—C20—H20119.2
C5—C6—C1117.21 (14)C20—C21—C16116.66 (15)
C5—C6—C7120.64 (14)C20—C21—C22121.33 (14)
C1—C6—C7122.06 (14)C16—C21—C22121.80 (15)
C8—C7—C6125.82 (14)C23—C22—C21127.45 (15)
C8—C7—H7117.1C23—C22—H22116.3
C6—C7—H7117.1C21—C22—H22116.3
C7—C8—C9118.81 (14)C22—C23—C25125.33 (14)
C7—C8—C10124.62 (14)C22—C23—C24118.99 (14)
C9—C8—C10116.54 (13)C25—C23—C24115.63 (13)
O1—C9—O2122.81 (14)O3—C24—O4122.96 (14)
O1—C9—C8122.37 (13)O3—C24—C23121.41 (14)
O2—C9—C8114.82 (13)O4—C24—C23115.63 (13)
C15—C10—C11118.89 (14)C30—C25—C26118.78 (14)
C15—C10—C8120.92 (13)C30—C25—C23120.85 (13)
C11—C10—C8120.17 (14)C26—C25—C23120.37 (14)
C12—C11—C10120.26 (15)C27—C26—C25120.34 (15)
C12—C11—H11119.9C27—C26—H26119.8
C10—C11—H11119.9C25—C26—H26119.8
C11—C12—C13120.41 (15)C26—C27—C28120.33 (15)
C11—C12—H12119.8C26—C27—H27119.8
C13—C12—H12119.8C28—C27—H27119.8
C12—C13—C14119.68 (15)C27—C28—C29119.73 (16)
C12—C13—H13120.2C27—C28—H28120.1
C14—C13—H13120.2C29—C28—H28120.1
C15—C14—C13119.96 (16)C30—C29—C28120.04 (16)
C15—C14—H14120.0C30—C29—H29120.0
C13—C14—H14120.0C28—C29—H29120.0
C14—C15—C10120.74 (14)C29—C30—C25120.73 (15)
C14—C15—H15119.6C29—C30—H30119.6
C10—C15—H15119.6C25—C30—H30119.6
C9—O2—H2O106.5 (14)C24—O4—H4O106.9 (14)
C6—C1—C2—C31.3 (2)C21—C16—C17—C18−1.2 (3)
Br1—C1—C2—C3−179.76 (12)Br2—C16—C17—C18179.57 (13)
C1—C2—C3—C40.2 (2)C16—C17—C18—C190.1 (3)
C2—C3—C4—C5−1.5 (2)C17—C18—C19—C201.2 (3)
C3—C4—C5—C61.3 (2)C18—C19—C20—C21−1.5 (2)
C4—C5—C6—C10.2 (2)C19—C20—C21—C160.4 (2)
C4—C5—C6—C7176.79 (14)C19—C20—C21—C22−174.34 (15)
C2—C1—C6—C5−1.5 (2)C17—C16—C21—C200.9 (2)
Br1—C1—C6—C5179.60 (11)Br2—C16—C21—C20−179.89 (11)
C2—C1—C6—C7−178.07 (14)C17—C16—C21—C22175.67 (15)
Br1—C1—C6—C73.0 (2)Br2—C16—C21—C22−5.1 (2)
C5—C6—C7—C848.0 (2)C20—C21—C22—C23−41.2 (2)
C1—C6—C7—C8−135.58 (17)C16—C21—C22—C23144.30 (17)
C6—C7—C8—C9−174.75 (14)C21—C22—C23—C25−7.6 (3)
C6—C7—C8—C107.3 (2)C21—C22—C23—C24175.15 (14)
C7—C8—C9—O1−168.38 (15)C22—C23—C24—O3171.51 (15)
C10—C8—C9—O19.7 (2)C25—C23—C24—O3−6.0 (2)
C7—C8—C9—O211.9 (2)C22—C23—C24—O4−8.7 (2)
C10—C8—C9—O2−169.98 (13)C25—C23—C24—O4173.74 (13)
C7—C8—C10—C15−131.17 (17)C22—C23—C25—C30125.69 (17)
C9—C8—C10—C1550.8 (2)C24—C23—C25—C30−57.0 (2)
C7—C8—C10—C1147.0 (2)C22—C23—C25—C26−54.8 (2)
C9—C8—C10—C11−131.04 (15)C24—C23—C25—C26122.57 (16)
C15—C10—C11—C122.3 (2)C30—C25—C26—C27−2.3 (2)
C8—C10—C11—C12−175.92 (15)C23—C25—C26—C27178.17 (15)
C10—C11—C12—C13−0.3 (3)C25—C26—C27—C280.5 (2)
C11—C12—C13—C14−1.9 (3)C26—C27—C28—C290.8 (3)
C12—C13—C14—C152.0 (3)C27—C28—C29—C30−0.3 (3)
C13—C14—C15—C100.0 (2)C28—C29—C30—C25−1.6 (3)
C11—C10—C15—C14−2.1 (2)C26—C25—C30—C292.9 (2)
C8—C10—C15—C14176.04 (14)C23—C25—C30—C29−177.60 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O1i0.84 (2)1.80 (2)2.6402 (16)174 (2)
O4—H4O···O3ii0.81 (2)1.84 (2)2.6478 (16)178 (2)
C5—H5···O3iii0.952.423.323 (2)158
C20—H20···O1iii0.952.523.3072 (19)141
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y+1, −z+1; (iii) −x+1/2, y−1/2, −z+1/2.
Hydrogen-bond geometry (Å, º) for (I) top
Cg1 and Cg2 are the centroids of rings C1–C6 and C9–C14, respectively.
D—H···AD—HH···AD···AD—H···A
O1—H1o···Cg2i0.982.663.5028 (13)144
O2—H2o···Cg10.912.743.646 (2)179
C5—H5···Cg2ii0.952.863.5337 (12)129
C10—H10···Cg1iii0.952.873.5742 (14)132
C13—H13···Cg1iv0.952.873.6015 (14)135
Symmetry codes: (i) −x+1, −y, z−1/2; (ii) x−1/2, −y+1, z; (iii) x+1/2, −y, z; (iv) −x+1, −y+1, z+1/2.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O1i0.84 (2)1.80 (2)2.6402 (16)174 (2)
O4—H4O···O3ii0.81 (2)1.84 (2)2.6478 (16)178 (2)
C5—H5···O3iii0.952.423.323 (2)158
C20—H20···O1iii0.952.523.3072 (19)141
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, −y+1, −z+1; (iii) −x+1/2, y−1/2, −z+1/2.

Experimental details

(I)(II)
Crystal data
Chemical formulaC14H12OC15H11BrO2
Mr196.24303.15
Crystal system, space groupOrthorhombic, Pca21Monoclinic, P21/n
Temperature (K)100100
a, b, c (Å)11.6193 (8), 7.6800 (5), 11.3584 (8)13.890 (1), 10.9048 (8), 17.8121 (10)
α, β, γ (°)90, 90, 9090, 106.064 (1), 90
V (Å3)1013.58 (12)2592.6 (3)
Z48
Radiation typeMo KαMo Kα
µ (mm−1)0.083.16
Crystal size (mm)0.27 × 0.16 × 0.040.19 × 0.07 × 0.07
Data collection
DiffractometerRigaku CCDRigaku CCD
Absorption correction–Multi-scan
(SADABS; Sheldrick, 2004)
Tmin, Tmax–0.585, 0.809
No. of measured, independent and
observed [I > 2σ(I)] reflections		6984, 2271, 2132 31964, 5922, 5297
Rint0.0310.035
(sin θ/λ)max (Å−1)0.6490.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.091, 1.06 0.025, 0.063, 1.04
No. of reflections22715922
No. of parameters146331
No. of restraints10
H-atom treatmentH-atom parameters constrainedH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.19, −0.150.56, −0.74

Computer programs: CrystalClear (Rigaku, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and ATOMS (Dowty, 1999).

 

Acknowledgements

We thank the EPSRC National Crystallography Service (University of Southampton) for the X-ray data collections and the National Mass Spectrometry Service (University of Swansea) for the high-resolution mass-spectroscopic data.

References

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ISSN: 2056-9890
Volume 72| Part 3| March 2016| Pages 407-411
doi:10.1107/S2056989016002942
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