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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 66| Part 12| December 2010| Page o3092
https://doi.org/10.1107/S1600536810044764

Tri­ethyl­ammonium 3,4-dihy­dr­oxy­benzoate

Li-Cai Zhua*

aSchool of Chemistry and Environment, South China Normal University, Guangzhou 510631, People's Republic of China
*Correspondence e-mail: licaizhu1977@yahoo.com.cn

(Received 26 October 2010; accepted 2 November 2010; online 6 November 2010)

In the title compound, C6H16N+·C7H5O4−, the hy­droxy groups of the 3,4-dihy­droxy­benzoate anion form O—H⋯O hydrogen bonds to the carboxyl­ate groups of two adjacent anions, generating layers propagating in the ac plane. The triethyl­ammonium cations lie between these layers, forming N—H⋯O hydrogen bonds to the carboxyl­ate groups of the anions. The structure is consolidated by weak inter­molecular C—H⋯O inter­actions.

Related literature

For the pharmacological activity of protocatechuic acid, see: Guan et al. (2006[Guan, S., Bao, Y. M., Jiang, B. & An, L. J. (2006). Eur. J. Pharmacol. 538, 73-79.]); Lin et al. (2009[Lin, C. Y., Huang, C. S., Huang, C. Y. & Yin, M. C. (2009). J. Agric. Food Chem. 57, 6661-6667.]); Yip et al. (2006[Yip, E. C. H., Chan, A. S. L., Pang, H., Tam, Y. K. & Wong, Y. H. (2006). Cell Biol. Toxicol. 22, 293-302.]). For related structures, see: Li et al. (2007[Li, J., Liang, Z.-P. & Guo, H.-M. (2007). Acta Cryst. E63, o2884.]); Mazurek et al. (2007[Mazurek, J., Dova, E. & Helmond, R. (2007). Acta Cryst. E63, o3289.]).

[Scheme 1]

Experimental

Crystal data

  • C6H16N+·C7H5O4−

  • Mr = 255.31

  • Orthorhombic, P b c a

  • a = 12.4341 (16) Å

  • b = 13.7227 (18) Å

  • c = 16.150 (2) Å

  • V = 2755.7 (6) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 296 K

  • 0.32 × 0.28 × 0.28 mm
Data collection

  • Bruker APEXII area-detector diffractometer

  • 13215 measured reflections

  • 2483 independent reflections

  • 1981 reflections with I > 2σ(I)

  • Rint = 0.028
Refinement

  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.107

  • S = 1.03

  • 2483 reflections

  • 172 parameters

  • 1 restraint

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.18 e Å−3

  • Δρmin = −0.13 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O3—H3⋯O2i 0.82 1.85 2.6574 (14) 166
O4—H4⋯O1ii 0.82 1.81 2.6321 (15) 178
C7—H7⋯O1ii 0.93 2.57 3.235 (2) 128
N1—H12⋯O2iii 0.92 1.87 2.776 (2) 170
C1—H1B⋯O3iv 0.97 2.57 3.409 (2) 145
C3—H3A⋯O1v 0.97 2.55 3.516 (2) 177
C3—H3B⋯O3vi 0.97 2.56 3.351 (2) 139
C10—H10⋯O4vii 0.93 2.38 3.222 (2) 150
Symmetry codes: (i) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (ii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (iii) [x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]; (iv) [-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (v) x-1, y+1, z; (vi) [x-{\script{1\over 2}}, y+1, -z+{\script{3\over 2}}]; (vii) [x+{\script{1\over 2}}, y, -z+{\script{3\over 2}}].

Data collection: APEX2 (Bruker, 2004[Bruker (2004). APEX2 and SMART. Bruker AXS Inc, Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2004[Bruker (2004). APEX2 and SMART. Bruker AXS Inc, Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536810044764/pv2348sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810044764/pv2348Isup2.hkl

checkCIF report


Comment top

Protocatechuic acid (3,4-dihydroxybenzoic acid) is one of the main secondary metabolites in the plant kingdom (Guan et al., 2006). Its derivatives possess diverse pharmacological activities (Lin et al., 2009; Yip et al., 2006). The molecular and crystal structure of the title compound is presented in this article.

The asymmetric unit of the title compound contains a 3,4-dihydroxybenzoate anion and a triethylammonium cation (Fig. 1). The bond distances and angles in the title compound sgree with the corresponding bond distances and angles reported in related structures (Li et al., 2007; Mazurek et al., 2007). The carboxylate group O1/O2/C13 is oriented with respect to the benzene ring at 23.18 (6)°. The hydroxy groups of the anion form O—H···O hydrogen bonds to the carboxylate groups of two other anions (Table 1), generating two-dimensional layers. The triethylammonium cations lie between these layers, forming N—H···O hydrogen bonds to the carboxylate groups of the anions (Fig. 2). The structure is further consolidated by weak intermolecular interactions of the type C—H···O. (Table 1).

Related literature top

For the pharmacological activity of protocatechuic acid, see: Guan et al. (2006); Lin et al. (2009); Yip et al. (2006). For related structures, see: Li et al. (2007); Mazurek et al. (2007).

Experimental top

A mixture of protocatechuic acid (0.31 g, 2 mmol) and triethylamine (0.28 ml, 2 mmol) was stirred in methanol (20 ml) for 0.5 h at room temperature. After several days colourless block-like crystals, suitable for X-ray diffraction analysis, were obtained by slow evaporation of the solution.

Refinement top

H12 atom of triethylammonium cation was found from difference Fourier maps and refined isotropically with a restraint of N—H = 0.89 Å and Uiso(H) = 1.5Ueq(N). All other H atoms were positioned geometrically and refined as riding, with O—H = 0.82 Å and C—H = 0.93, 0.96 or 0.97 Å, for aryl, methyl and methylene type H atoms, respectively, with Uiso(H) = 1.2 or 1.5Ueq(C, O).

Structure description top

Protocatechuic acid (3,4-dihydroxybenzoic acid) is one of the main secondary metabolites in the plant kingdom (Guan et al., 2006). Its derivatives possess diverse pharmacological activities (Lin et al., 2009; Yip et al., 2006). The molecular and crystal structure of the title compound is presented in this article.

The asymmetric unit of the title compound contains a 3,4-dihydroxybenzoate anion and a triethylammonium cation (Fig. 1). The bond distances and angles in the title compound sgree with the corresponding bond distances and angles reported in related structures (Li et al., 2007; Mazurek et al., 2007). The carboxylate group O1/O2/C13 is oriented with respect to the benzene ring at 23.18 (6)°. The hydroxy groups of the anion form O—H···O hydrogen bonds to the carboxylate groups of two other anions (Table 1), generating two-dimensional layers. The triethylammonium cations lie between these layers, forming N—H···O hydrogen bonds to the carboxylate groups of the anions (Fig. 2). The structure is further consolidated by weak intermolecular interactions of the type C—H···O. (Table 1).

For the pharmacological activity of protocatechuic acid, see: Guan et al. (2006); Lin et al. (2009); Yip et al. (2006). For related structures, see: Li et al. (2007); Mazurek et al. (2007).

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure showing the atomic-numbering scheme and displacement ellipsoids drawn at the 50% probability level.
[Figure 2] Fig. 2. The molecular packing showing the intermolecular hydrogen bonding interactions as dashed lines.
Triethylammonium 3,4-dihydroxybenzoate top
Crystal data top
C6H16N+·C7H5O4−F(000) = 1104
Mr = 255.31Dx = 1.231 Mg m−3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 4281 reflections
a = 12.4341 (16) Åθ = 2.5–27.2°
b = 13.7227 (18) ŵ = 0.09 mm−1
c = 16.150 (2) ÅT = 296 K
V = 2755.7 (6) Å3Block, colourless
Z = 80.32 × 0.28 × 0.28 mm
Data collection top
Bruker APEXII area-detector
diffractometer		1981 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.028
Graphite monochromatorθmax = 25.2°, θmin = 2.5°
φ and ω scansh = −14→14
13215 measured reflectionsk = −14→16
2483 independent reflectionsl = −16→19
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.037H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.107 w = 1/[σ2(Fo2) + (0.0515P)2 + 0.7195P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.001
2483 reflectionsΔρmax = 0.18 e Å−3
172 parametersΔρmin = −0.13 e Å−3
1 restraintExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0034 (5)
Crystal data top
C6H16N+·C7H5O4−V = 2755.7 (6) Å3
Mr = 255.31Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 12.4341 (16) ŵ = 0.09 mm−1
b = 13.7227 (18) ÅT = 296 K
c = 16.150 (2) Å0.32 × 0.28 × 0.28 mm
Data collection top
Bruker APEXII area-detector
diffractometer		1981 reflections with I > 2σ(I)
13215 measured reflectionsRint = 0.028
2483 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0371 restraint
wR(F2) = 0.107H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.18 e Å−3
2483 reflectionsΔρmin = −0.13 e Å−3
172 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
C60.3472 (2)0.97892 (16)0.41436 (15)0.0812 (7)
H6A0.38821.03810.41660.122*
H6B0.32850.96500.35790.122*
H6C0.38930.92630.43640.122*
C10.32649 (16)0.94605 (13)0.60034 (13)0.0677 (6)
H1A0.39190.92990.57060.081*
H1B0.28280.88760.60340.081*
C20.3554 (2)0.97807 (17)0.68702 (15)0.0893 (7)
H2A0.39891.03580.68440.134*
H2B0.39480.92710.71420.134*
H2C0.29080.99170.71750.134*
C30.16443 (13)1.05597 (13)0.59298 (13)0.0589 (5)
H3A0.13101.10400.55720.071*
H3B0.18201.08810.64480.071*
C50.24679 (17)0.99035 (14)0.46451 (14)0.0679 (6)
H5A0.20860.92870.46500.081*
H5B0.20081.03810.43780.081*
C40.08368 (18)0.97565 (17)0.61030 (18)0.0940 (8)
H4A0.06980.94010.56020.141*
H4B0.01791.00380.63020.141*
H4C0.11230.93220.65140.141*
C70.79526 (10)0.26562 (9)0.58103 (8)0.0290 (3)
H70.75030.27360.53550.035*
C120.90639 (10)0.26034 (9)0.56871 (8)0.0279 (3)
C130.95215 (10)0.27035 (9)0.48341 (8)0.0305 (3)
C100.92903 (11)0.24288 (10)0.71567 (9)0.0365 (3)
H100.97430.23540.76110.044*
C90.81903 (11)0.24855 (10)0.72768 (8)0.0323 (3)
C80.75071 (10)0.25922 (10)0.65907 (8)0.0303 (3)
C110.97267 (11)0.24818 (10)0.63692 (9)0.0342 (3)
H111.04670.24360.62980.041*
O11.04380 (8)0.23683 (9)0.47008 (7)0.0485 (3)
O20.89549 (8)0.31388 (7)0.42940 (6)0.0395 (3)
O30.77263 (8)0.24370 (8)0.80386 (6)0.0445 (3)
H30.81860.23090.83860.067*
O40.64348 (8)0.26312 (9)0.67366 (6)0.0479 (3)
H40.61100.26210.62950.072*
N10.26672 (11)1.02205 (10)0.55323 (10)0.0520 (4)
H120.3117 (15)1.0749 (13)0.5523 (12)0.078*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C60.0982 (17)0.0615 (13)0.0840 (15)0.0088 (12)0.0014 (13)−0.0160 (11)
C10.0641 (12)0.0484 (10)0.0906 (15)0.0088 (9)−0.0025 (11)0.0114 (10)
C20.113 (2)0.0760 (15)0.0786 (15)0.0189 (14)−0.0120 (14)0.0185 (12)
C30.0446 (9)0.0473 (10)0.0848 (14)0.0007 (8)0.0011 (9)0.0004 (9)
C50.0733 (13)0.0496 (10)0.0807 (14)−0.0091 (9)−0.0151 (11)−0.0100 (9)
C40.0598 (13)0.0760 (15)0.146 (2)−0.0169 (11)0.0156 (15)0.0058 (15)
C70.0235 (7)0.0362 (7)0.0274 (7)−0.0005 (5)−0.0044 (5)−0.0015 (5)
C120.0244 (7)0.0295 (6)0.0296 (7)−0.0005 (5)0.0010 (5)−0.0004 (5)
C130.0259 (7)0.0350 (7)0.0307 (7)−0.0020 (5)0.0008 (6)−0.0019 (6)
C100.0293 (7)0.0508 (9)0.0295 (7)0.0009 (6)−0.0083 (6)0.0011 (6)
C90.0326 (7)0.0384 (7)0.0261 (7)−0.0026 (6)0.0008 (6)0.0001 (5)
C80.0222 (6)0.0381 (7)0.0307 (7)−0.0027 (5)0.0005 (6)−0.0015 (6)
C110.0207 (6)0.0447 (8)0.0372 (8)0.0010 (6)−0.0014 (6)0.0007 (6)
O10.0295 (6)0.0745 (8)0.0414 (6)0.0125 (5)0.0099 (5)0.0059 (5)
O20.0382 (6)0.0515 (6)0.0290 (5)0.0071 (5)0.0002 (4)0.0011 (4)
O30.0392 (6)0.0692 (7)0.0251 (5)0.0010 (5)0.0019 (4)0.0036 (5)
O40.0215 (5)0.0881 (9)0.0340 (6)−0.0020 (5)0.0028 (4)−0.0031 (6)
N10.0448 (8)0.0357 (7)0.0756 (10)−0.0022 (6)−0.0041 (7)0.0009 (7)
Geometric parameters (Å, º) top
C6—C51.496 (3)C4—H4B0.9600
C6—H6A0.9600C4—H4C0.9600
C6—H6B0.9600C7—C81.3795 (18)
C6—H6C0.9600C7—C121.3979 (18)
C1—N11.490 (2)C7—H70.9300
C1—C21.511 (3)C12—C111.386 (2)
C1—H1A0.9700C12—C131.4968 (19)
C1—H1B0.9700C13—O11.2476 (17)
C2—H2A0.9600C13—O21.2705 (16)
C2—H2B0.9600C10—C91.384 (2)
C2—H2C0.9600C10—C111.385 (2)
C3—N11.499 (2)C10—H100.9300
C3—C41.517 (3)C9—O31.3606 (17)
C3—H3A0.9700C9—C81.4039 (19)
C3—H3B0.9700C8—O41.3551 (16)
C5—N11.518 (3)C11—H110.9300
C5—H5A0.9700O3—H30.8200
C5—H5B0.9700O4—H40.8200
C4—H4A0.9600N1—H120.916 (15)
C5—C6—H6A109.5C3—C4—H4C109.5
C5—C6—H6B109.5H4A—C4—H4C109.5
H6A—C6—H6B109.5H4B—C4—H4C109.5
C5—C6—H6C109.5C8—C7—C12121.57 (12)
H6A—C6—H6C109.5C8—C7—H7119.2
H6B—C6—H6C109.5C12—C7—H7119.2
N1—C1—C2112.85 (16)C11—C12—C7118.75 (12)
N1—C1—H1A109.0C11—C12—C13121.11 (12)
C2—C1—H1A109.0C7—C12—C13120.12 (12)
N1—C1—H1B109.0O1—C13—O2124.15 (13)
C2—C1—H1B109.0O1—C13—C12118.18 (12)
H1A—C1—H1B107.8O2—C13—C12117.67 (11)
C1—C2—H2A109.5C9—C10—C11120.88 (13)
C1—C2—H2B109.5C9—C10—H10119.6
H2A—C2—H2B109.5C11—C10—H10119.6
C1—C2—H2C109.5O3—C9—C10122.90 (12)
H2A—C2—H2C109.5O3—C9—C8117.53 (12)
H2B—C2—H2C109.5C10—C9—C8119.56 (13)
N1—C3—C4114.51 (16)O4—C8—C7123.47 (12)
N1—C3—H3A108.6O4—C8—C9117.53 (12)
C4—C3—H3A108.6C7—C8—C9119.00 (12)
N1—C3—H3B108.6C10—C11—C12120.22 (12)
C4—C3—H3B108.6C10—C11—H11119.9
H3A—C3—H3B107.6C12—C11—H11119.9
C6—C5—N1113.88 (16)C9—O3—H3109.5
C6—C5—H5A108.8C8—O4—H4109.5
N1—C5—H5A108.8C1—N1—C3114.97 (15)
C6—C5—H5B108.8C1—N1—C5111.29 (14)
N1—C5—H5B108.8C3—N1—C5110.78 (14)
H5A—C5—H5B107.7C1—N1—H12105.0 (13)
C3—C4—H4A109.5C3—N1—H12106.2 (13)
C3—C4—H4B109.5C5—N1—H12108.1 (12)
H4A—C4—H4B109.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O2i0.821.852.6574 (14)166
O4—H4···O1ii0.821.812.6321 (15)178
C7—H7···O1ii0.932.573.235 (2)128
N1—H12···O2iii0.921.872.776 (2)170
C1—H1B···O3iv0.972.573.409 (2)145
C3—H3A···O1v0.972.553.516 (2)177
C3—H3B···O3vi0.972.563.351 (2)139
C10—H10···O4vii0.932.383.222 (2)150
Symmetry codes: (i) x, −y+1/2, z+1/2; (ii) x−1/2, −y+1/2, −z+1; (iii) x−1/2, −y+3/2, −z+1; (iv) −x+1, y+1/2, −z+3/2; (v) x−1, y+1, z; (vi) x−1/2, y+1, −z+3/2; (vii) x+1/2, y, −z+3/2.

Experimental details

Crystal data
Chemical formulaC6H16N+·C7H5O4−
Mr255.31
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)296
a, b, c (Å)12.4341 (16), 13.7227 (18), 16.150 (2)
V (Å3)2755.7 (6)
Z8
Radiation typeMo Kα
µ (mm−1)0.09
Crystal size (mm)0.32 × 0.28 × 0.28
Data collection
DiffractometerBruker APEXII area-detector
Absorption correction–
No. of measured, independent and
observed [I > 2σ(I)] reflections		13215, 2483, 1981
Rint0.028
(sin θ/λ)max (Å−1)0.599
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.107, 1.03
No. of reflections2483
No. of parameters172
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.18, −0.13

Computer programs: APEX2 (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3···O2i0.821.852.6574 (14)166.1
O4—H4···O1ii0.821.812.6321 (15)177.6
C7—H7···O1ii0.932.573.235 (2)128.4
N1—H12···O2iii0.921.872.776 (2)169.5
C1—H1B···O3iv0.972.573.409 (2)144.5
C3—H3A···O1v0.972.553.516 (2)176.6
C3—H3B···O3vi0.972.563.351 (2)139.3
C10—H10···O4vii0.932.383.222 (2)149.8
Symmetry codes: (i) x, −y+1/2, z+1/2; (ii) x−1/2, −y+1/2, −z+1; (iii) x−1/2, −y+3/2, −z+1; (iv) −x+1, y+1/2, −z+3/2; (v) x−1, y+1, z; (vi) x−1/2, y+1, −z+3/2; (vii) x+1/2, y, −z+3/2.
 

Acknowledgements

The author acknowledges South China Normal University for supporting this work.

References

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ISSN: 2056-9890
Volume 66| Part 12| December 2010| Page o3092
https://doi.org/10.1107/S1600536810044764
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