organic compounds 3-Hydroxybenzaldehyde

Transcription

1 organic compounds Acta Crystallographica Section C Crystal Structure Communications ISSN Hydroxybenzaldehyde J. A. PaixaÄo, a * A. Matos Beja, a M. Ramos Silva, a L. Alte da Veiga a and A. C. Serra b a Departamento de FõÂsica, Faculdade de CieÃncias e Tecnologia, Universidade de Coimbra, P-3000 Coimbra, Portugal, and b Departamento de QuõÂmica, Faculdade de CieÃncias e Tecnologia, Universidade de Coimbra, P-3000 Coimbra, Portugal Correspondence jap@pollux.fis.uc.pt Received 26 May 2000 Accepted 26 July 2000 mainly those involving a methoxy substituent (`vanilin'). The structures of o-vanilin (Iwasaki et al., 1976), isovanilin (Iwasaki, 1973) and vanilin-i (Velavan et al., 1995) have been reported. More recently, the crystal structures of three bromo derivatives of m-hydroxybenzaldehyde have been reported (Matos Beja et al., 1997, 1998, 2000). The average ring bond distance is (17) A Ê and the sum of the endocyclic bond angles is exactly 720, as expected for an unpuckered aromatic ring. However, the individual values of endocyclic angles ipso to the C1, C5 and C6 atoms deviate signi cantly from the ideal value of 120 by a maximum value of 1.4 (2) (angle ipso to C6). The benzene ring is planar to within A Ê, the weighted average torsion angle of the ring being 0.42 (14). Probably as a result of intermolecular interactions involving the aldehyde and hydroxyl groups of neighbouring molecules (see below), these two functional groups do not strictly lie in the plane of the ring. The aldehyde The title compound, C 7 H 6 O 2, forms in nite chains where the molecules are hydrogen bonded via the hydroxyl and aldehyde groups, with an OO distance of (3) A Ê. Interchain interactions are weak. The geometry of the ring differs from the ideal form due to the effect of the substituents. Ab initio (Hartree±Fock self-consistent eld±molecular orbital and density functional theory) calculations for the free molecule reproduce well the observed small distortions of the ring. In the crystal, the geometry deviates from the ideal C s symmetry of the free molecule, as given by the ab initio calculations. The aldehyde and hydroxyl groups are twisted around the single bonds which join them to the ring as a result of the intermolecular hydrogen-bond interactions. These are also responsible for an elongation of the hydroxy CÐOH bond compared with that calculated for the free molecule. Figure 1 ORTEPII (Johnson, 1976) plot of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Comment m-hydroxybenzaldehyde, (I), is an important precursor for the synthesis of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin, which is an intermediate in the preparation of the chlorine derivative, a compound already approved by WHO to be used as a photosensitizer in the photodynamic therapy of tumours (Bonnet, 1995). The structure of p-hydroxybenzaldehyde was determined by Iwasaki (1977), but those of m-hydroxybenzaldehyde (Fig. 1) and o-hydroxybenzaldehyde have not yet been reported. The latter is a liquid at room temperature, but the molecule exists as an isolated moiety in gossypol salicylaldehyde clathrate (Gdaniec et al., 1995). A limited number of derivatives of hydroxybenzaldehyde have been investigated, group is twisted around the single C1ÐC7 bond by 3.5 (2) and also slightly tilted out of the plane [deviations from the ring least-squares plane: C (3) and O (3) A Ê ]. There is also a small bend of the C1ÐC7 bond away from the carbonyl O1 atom, as can be seen from a comparison of the C6ÐC1ÐC7 [121.2 (2) ] and C2ÐC1ÐC7 [ (19) ] bond angles. This bend is similar to that observed in p- hydroxybenzaldehyde, but of opposite sign to those observed in the mono- and dibromo-substituted derivatives of the title compound (Matos Beja et al., 1997, 2000). The hydroxyl group is twisted around the C3ÐO2 bond, but the O2 atom is practically on the plane of the ring, the deviation from the least-squares plane being (4) A Ê. The molecules are hydrogen bonded via the hydroxyl and aldehyde groups, forming chains running along the c axis (Fig. 2). The pattern of hydrogen bonding is similar to that found in p-hydroxybenzaldehyde, where the molecules form in nite zigzag chains. Judging from the bond distances, the hydrogen bonding appears to be weaker in m-hydroxybenzaldehyde [O1O (3) A Ê ] compared with p-hydroxybenzaldehyde [O1O (5) A Ê ] # 2000 International Union of Crystallography Printed in Great Britain ± all rights reserved Acta Cryst. (2000). C56, 1348±1350

2 organic compounds Hartree±Fock self-consistent eld±molecular orbital (SCF± MO) calculations of the isolated molecule were performed with the computer program GAMESS (Schmidt et al., 1993) and the density functional theory (DFT) calculations with the program DeFT2.2 (St-Amant et al., 1998). The atomic basis set used for the molecular orbital calculations was Pople's `triple split' 6-311G(d,p), which includes a set of p-polarization functions for the H atoms and a set of d-polarization functions for the C and O atoms. The Vosko±Wilk±Nusair local spindensity exchange and correlation functional (Vosko et al., 1980) was used in the DFT calculations. The orbital basis set chosen in this case was (10s,6p,1d/4s,1p)/[4s,3p,1d/2s,1p]. In both types of calculations, the convergence limit for SCF cycles was set to 10 8 and the maximum gradient at the end of the geometry optimization was 10 5 atomic units. At the end of the SCF±MO geometry optimization, a single point calculation of the total energy was performed using second-order Mùsser±Plesset perturbation theory (MP2) to partly account for correlation effects. In both the SCF±MO and DFT calculations, the equilibrium geometry of the molecule is very close to planar C s symmetry. The torsion angles involving atoms of the hydroxyl or aldehyde groups do not exceed 0.2. The agreement between the experimental bond lengths corrected for thermal motion and calculated bond lengths is better for the DFT than the SCF± MO calculations, the r.m.s. deviations from the experimental values being (SCF±MO) and A Ê (DFT). The absolute deviation for the DFT values never exceeds three s.u.'s, with the single exception of the C3ÐO2 bond, which is calculated by DFT as A Ê, a value signi cantly shorter than the observed bond distance [1.362 (3), (3) A Ê (corrected)]. However, the calculated value is in good agreement with the same bond distance measured in p-hydroxybenzaldehyde [1.357 (4) A Ê ; Iwasaki, 1977], in the dibromo derivative of the title compound [1.356 (5) A Ê ; Matos Beja et al., 1997] and in isovanilin (1.359 A Ê ; Iwasaki, 1973). Such a lengthening of the CÐOH bond is clearly related to the hydrogen bond involving the hydroxyl group. A similar lengthening is observed in phenols, where the CÐOH distances and their acid dissociation constants pk a are closely related (Andersen & Andersen, 1975). Both the SCF±MO and the DFT calculations reproduce the observed sign of the deviation of the endocyclic angles from 120, but the agreement is better for the SCF±MO results, for which all angles reproduce the observed values within two s.u.'s. However, both types of calculation give values for the exocyclic angles at C1 closer to 120 than those observed in the crystal (C6ÐC1ÐC7 SCF±MO , DFT ; C2ÐC1ÐC7 SCF±MO , DFT ). The difference can again be attributed to the intermolecular interactions between the aldehyde and hydroxyl groups of neighbouring molecules which also appear to be responsible for the small bend and twist of the aldehyde group. Experimental m-hydroxybenzaldehyde (Aldrich) was dissolved in a 1:1 mixture of ethanol and water. After a few weeks, small single crystals had grown from the solution. A single crystal of good quality was selected using Laue diffractograms. IR (KBr, cm 1 ): 3209 (m, br, OH), 1668 (s, CO), 1581 (s, CÐC aromatic), 1495 (m, CÐC aromatic), 1284 (s), 1250 (m), 1155 (m), 679 (m), 659 (m). Crystal data C 7 H 6 O 2 M r = Orthorhombic, Pna2 1 a = (7) A Ê b = (10) A Ê c = (7) A Ê V = (6) A Ê 3 Z =4 D x = Mg m 3 Data collection Enraf±Nonius CAD-4 diffractometer Pro le data from!±2 scans 5064 measured re ections 768 independent re ections 591 re ections with I > 2(I) R int = Re nement Re nement on F 2 R[F 2 >2(F 2 )] = wr(f 2 ) = S = re ections 88 parameters H-atom parameters constrained Mo K radiation Cell parameters from 25 re ections = 5.93±18.36 = mm 1 T = 293 (2) K Prism, colourless mm max = h = 26! 24 k = 5! 5 l = 10! 10 3 standard re ections frequency: 180 min intensity decay: 1.8% w = 1/[ 2 (F o 2 ) + (0.0415P) P] where P =(F o 2 +2F c 2 )/3 (/) max < max = 0.15 e A Ê 3 min = 0.14 e A Ê 3 Table 1 Selected geometric parameters (A Ê, ). Figure 2 Projection of the crystal structure on the ac plane showing the hydrogenbonding chains running along the c axis. O1ÐC (3) O2ÐC (3) C2ÐC1ÐC (2) C2ÐC1ÐC (19) C6ÐC1ÐC (2) C3ÐC2ÐC (2) O2ÐC3ÐC (2) O2ÐC3ÐC (2) C1ÐC (3) C4ÐC3ÐC (2) C5ÐC4ÐC (2) C6ÐC5ÐC (2) C5ÐC6ÐC (2) O1ÐC7ÐC (2) Acta Cryst. (2000). C56, 1348±1350 J. A. PaixaÄo et al. C 7 H 6 O

3 organic compounds Table 2 Hydrogen-bonding geometry (A Ê, ). DÐHA DÐH HA DA DÐHA O2ÐH2O1 i (3) 164 Symmetry code: (i) x; y; 1 z. The Friedel pairs were averaged because the structure does not contain any signi cant anomalous scatterer at the Mo K wavelength. A full unique set and their Friedel pairs were measured up to The ring H atoms and that of the aldehyde group were placed at idealized calculated geometries and re ned as riding using SHELXL97 defaults. The H atom of the hydroxyl group was located on a difference Fourier synthesis and the torsion angle around the CÐOH bond was re ned using the HFIX 147 instruction of SHELXL97. Examination of the crystal structure with PLATON (Spek, 1995) showed that there are no solvent-accessible voids in the crystal lattice. Data collection: CAD-4 Software (Enraf±Nonius, 1989); cell re nement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to re ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97. This work was supported by FundacËaÄo para a CieÃncia e para a Tecnologia (FCT). Supplementary data for this paper are available from the IUCr electronic archives (Reference: GD1106). Services for accessing these data are described at the back of the journal. References Andersen, E. K. & Andersen, I. G. K. (1975). Acta Cryst. B31, 387±390. Bonnet, R. (1995). Chem. Soc. Rev. 24, 19±33. Enraf±Nonius (1989). CAD-4 Software. Version 5.0. Enraf±Nonius, Delft, The Netherlands. Gdaniec, M., Talipov, S. A. & Ibragimov, B. T. (1995). Pol. J. Chem. 69, 1133± Iwasaki, F. (1973). Chem. Lett. pp. 227±228. Iwasaki, F. (1977). Acta Cryst. B33, 1646±1648. Iwasaki, F., Tanaka, I. & Aihara, A. (1976). Acta Cryst. B32, 1264±1266. Johnson, C. K. (1976). ORTEPII. Report ORNL Oak Ridge National Laboratory, Tennessee, USA. Matos Beja, A., PaixaÄo, J. A., Ramos Silva, M., Alte da Veiga, L., Rocha Gonsalves, A. M. d'a., Pereira, M. M. & Serra, A. C. (1997). Acta Cryst. C53, 494±496. Matos Beja, A., PaixaÄo, J. A., Ramos Silva, M., Alte da Veiga, L., Rocha Gonsalves, A. M. d'a., Pereira, M. M. & Serra, A. C. (1998). Z. Kristallogr. New Cryst. Struct. 213, 139±140. Matos Beja, A., PaixaÄo, J. A., Ramos Silva, M., Alte da Veiga, L., Rocha Gonsalves, A. M. d'a. & Serra, A. C. (2000). Acta Cryst. C56, 354±355. Schmidt, M. W., Baldridge, K. K., Boatz, J. A., Elbert, S. T., Gordon, M. S., Jensen, J. J., Koseki, S., Matsunaga, N., Nguyen, K. A., Su, S., Windus, T. L., Dupuis, M. & Montgomery, J. A. (1993). J. Comput. Chem. 14, 1347±1363. Sheldrick, G. M. (1990). Acta Cryst. A46, 467±473. Sheldrick, G. M. (1997). SHELXL97. University of GoÈttingen, Germany. Spek, A. L. (1997). HELENA. University of Utrecht, The Netherlands. Spek, A. L. (1995). PLATON. University of Utrecht, The Netherlands. St-Amant, A., Goh, S. K. & Gallant, R. T. (1998). DeFT2.2 Software Package. University of Ottawa, Ontario, Canada. Velavan, R., Sureshkumar, P., Sivakumar, K. & Natarajan, S. (1995). Acta Cryst. C51, 1131±1133. Vosko, H., Wilk, L. & Nusair, M. (1980). Can. J. Phys. 58, 1200± J. A. PaixaÄo et al. C 7 H 6 O 2 Acta Cryst. (2000). C56, 1348±1350

4 supporting information supporting information [ 3-Hydroxybenzaldehyde J. A. Paixão, A. Matos Beja, M. Ramos Silva, L. Alte da Veiga and A. C. Serra Computing details Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: HELENA (Spek, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97. m-hydroxybenzaldehyde Crystal data C 7 H 6 O 2 M r = Orthorhombic, Pna2 1 Hall symbol: P 2c -2n a = (7) Å b = (1) Å c = (7) Å V = (6) Å 3 Z = 4 Data collection Enraf-Nonius CAD-4 diffractometer Radiation source: fine-focus sealed tube Graphite monochromator profile data from ω 2θ scans 5064 measured reflections 768 independent reflections 591 reflections with I > 2σ(I) Refinement Refinement on F 2 Least-squares matrix: full R[F 2 > 2σ(F 2 )] = wr(f 2 ) = S = reflections 88 parameters 1 restraint Primary atom site location: structure-invariant direct methods F(000) = 256 D x = Mg m 3 Mo Kα radiation, λ = Å Cell parameters from 25 reflections θ = µ = 0.10 mm 1 T = 293 K Prism, colourless mm R int = θ max = 29.9, θ min = 5.4 h = k = 5 5 l = standard reflections every 180 min intensity decay: 1.8% Secondary atom site location: difference Fourier map Hydrogen site location: inferred from neighbouring sites H-atom parameters constrained w = 1/[σ 2 (F o2 ) + (0.0415P) P] where P = (F o 2 + 2F c2 )/3 (Δ/σ) max < Δρ max = 0.15 e Å 3 Δρ min = 0.14 e Å 3 sup-1

5 supporting information Special details 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 F 2 against ALL reflections. The weighted R-factor wr and goodness of fit S are based on F 2, conventional R-factors R are based on F, with F set to zero for negative F 2. The threshold expression of F 2 > σ(f 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 ) x y z U iso */U eq O (11) (7) (2) (6) O (10) (6) (2) (5) H (2) (9) (6) 0.087* C (11) (6) (3) (5) C (13) (6) (3) (5) H2A * C (12) (6) (3) (5) C (12) (6) (3) (5) H * C (12) (6) (3) (6) H * C (11) (6) (3) (5) H * C (13) (7) (3) (6) H (15) (7) (4) 0.055* Atomic displacement parameters (Å 2 ) U 11 U 22 U 33 U 12 U 13 U 23 O (12) (18) (8) (11) (8) (10) O (10) (14) (8) (11) (8) (9) C (10) (10) (10) (9) (9) (10) C (9) (12) (11) (10) (9) (10) C (11) (13) (10) (10) (9) (10) C (10) (13) (12) (11) (9) (10) C (10) (14) (14) (10) (10) (12) C (10) (13) (12) (9) (9) (10) C (11) (16) (11) (11) (10) (12) Geometric parameters (Å, º) O1 C (3) C3 C (3) O2 C (3) C4 C (3) O2 H (4) C4 H C1 C (3) C5 C (4) C1 C (3) C5 H sup-2

6 supporting information C1 C (3) C6 H C2 C (4) C7 H (3) C2 H2A C3 O2 H2 102 (3) C5 C4 H C2 C1 C (2) C3 C4 H C2 C1 C (19) C6 C5 C (2) C6 C1 C (2) C6 C5 H C3 C2 C (2) C4 C5 H C3 C2 H2A C5 C6 C (2) C1 C2 H2A C5 C6 H O2 C3 C (2) C1 C6 H O2 C3 C (2) O1 C7 C (2) C4 C3 C (2) O1 C7 H (18) C5 C4 C (2) C1 C7 H (18) C6 C1 C2 C3 0.2 (3) C3 C4 C5 C6 0.7 (4) C7 C1 C2 C (2) C4 C5 C6 C1 0.5 (4) C1 C2 C3 O (2) C2 C1 C6 C5 0.3 (3) C1 C2 C3 C4 0.4 (3) C7 C1 C6 C (2) O2 C3 C4 C (2) C2 C1 C7 O (3) C2 C3 C4 C5 0.7 (3) C6 C1 C7 O1 3.8 (4) Hydrogen-bond geometry (Å, º) D H A D H H A D A D H A O2 H2 O1 i 0.89 (4) 1.85 (5) (3) 164 (4) Symmetry code: (i) x, y, z+1. sup-3