organic compounds
4-Carboxypyridin-1-ium 2,4,5-tricarboxybenzoate monohydrate
aDepartment of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249-0698, USA, and bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
*Correspondence e-mail: edward.tiekink@gmail.com
The title hydrated salt, C6H6NO2+·C10H5O8−·H2O, was isolated from the 1:1 cocrystallization of benzene-1,2,4,5-tetracarboxylic acid and isonicotinic acid in ethanol solution. In the crystal, the cation is close to planar [r.m.s. deviation = 0.085 Å for the nine fitted atoms; the C—C—C—O(carbonyl) torsion angle = −8.7 (4)°], but twists are evident in the anion, with all but the carboxylic acid group diagonally opposite the carboxylate group being significantly twisted out of the plane of the benzene ring [C—C—C—O(carbonyl) torsion angles = −118.1 (2), −157.6 (2), 4.3 (3) and 77.3 (3)°]. In the crystal, the ions and water molecules are consolidated into a three-dimensional architecture by O—H⋯O and N—H⋯O hydrogen bonding along with C—H⋯O interactions.
Related literature
For background to pharmaceutical co-crystals, see: Almarsson & Zaworotko (2004). For related co-crystallization studies on 1,2,4,5-benzenetetracarboxylic acid, see: Arman & Tiekink (2013a,b). For the structure of isonicotinic acid, see: Takusagawa & Shimada (1976). For the structure of the analogous salt formed from nicotinic acid, see: Dos Santos et al. (2012). For the calculation of pKa values, see: Chemaxon (2009).
Experimental
Crystal data
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Data collection: CrystalClear (Molecular Structure Corporation & Rigaku, 2005); cell CrystalClear; data reduction: CrystalClear; 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 DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
https://doi.org/10.1107/S1600536813016437/hb7093sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813016437/hb7093Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536813016437/hb7093Isup3.cml
Crystals of the title salt hydrate were harvested from an ethanol (10 ml) solution containing a 1:1 molar ratio of pyromellitic acid (Sigma-Aldrich; 6 mg) and isonicoinic acid (Sigma-Aldrich; 3 mg).
C-bound H-atoms were placed in calculated positions (C—H 0.95 Å) and were included in the
in the riding model approximation with Uiso(H) set to 1.2Ueq(C). The O—H and N—H atoms were located in difference maps and were refined with O—H = 0.84±0.01 Å and N—H = 0.88±0.01 Å, respectively, and with Uiso(H) = 1.5Ueq(O) and Uiso(H) = 1.2Ueq(N), respectively.Interest in co-crystallization experiments stems largely from potential applications in the pharmaceutical industry (Almarsson & Zaworotko, 2004). The title salt hydrate, (I), was isolated during an investigation of co-crystallization experiments with 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid; LH4) and various pyridyl derivatives (Arman & Tiekink, 2013a; Arman & Tiekink, 2013b).
The 1:1 co-crystallization of pyromellitic acid and isonicotinic acid in an ethanol solution afforded a salt hydrate, (I), there being one complete molecule of the 4-carboxypyridin-1-ium cation, the hydroxy(2,4,5-tricarboxyphenyl)methanolate anion and a water molecule in the
Confirmation of protonation of isonicotinic acid during crystallization is found in the nature of hydrogen bonding involving the pyridinium cation (see below), and the widening of the C13—N1—C14 angle to 123.1 (2)° cf. 118.9 (2)° in the structure of isonicotinic acid itself (Takusagawa & Shimada, 1976). Further, the disparity in the C—O bond lengths of the carboxylic acid residue, Δ(C—O) = [(C—O)long - (C—O)short] = 0.10 Å, confirms that isonicotinic acid has been protonated at N1, rather than existing in a zwitterionic form, with equivalent C—O bonds. Complementing this evidence, in the anion, the Δ(C—O) value for the O1-carboxylate group is 0.01 Å, indicating considerable delocalization of electron density over the CO2 atoms, compared to values in the range 0.07 to 0.11 Å for the remaining carboxylic acids.In the cation, the carboxylic acid residue is approximately co-planar with the pyridyl ring to which it is attached as seen in the C12—C11—C16—O9 torsion angle of -8.7 (4)°. Indeed, the entire cation is approximately planar with the r.m.s. deviation = 0.085 Å for the nine fitted atoms. By contrast, anion is non-planar with the carboxylic acid diagonally opposite the carboxylate group being co-planar to the phenyl ring [C—C—C—O(carbonyl) torsion angle = 4.3 (3)°] but the remaining
and carboxylate residues deviate significantly [C—C—C—O(carbonyl) torsion angles =-118.1 (2), -157.6 (2) and 77.3 (3)°].The three-dimensional
of (I) is consolidated by O—H···O and N—H···O hydrogen bonding involving all three components of the structure; geometric parameters characterizing these are summarized in Table 1. Two distinct supramolecular aggregation patterns are clearly discerned, with the first of these being a tape along [1 0 0] comprising hydroxy(2,4,5-tricarboxyphenyl)methanolate anions, Fig. 2, which is sustained by centrosymmetric eight-membered {···O=COH}2 synthons involving the O3-carboxylic acid and orthogonal O6—H···O1 hydrogen bonds. A supramolecular chain containing alternating cations and anions is also found, Fig. 3. This is aligned along [1 0 - 1] and is stabilized by O10—H···O2 and N1—H···O5 hydrogen bonds. The aforementioned are connected into a supramolecular layer in the ac plane. As seen in Fig. 4, the centrosymmetrically related water molecules are bridged by carboxylate-O2 atoms to form an eight-membered {···HOH···O}2 ring. The water-O1w atom also accepts a hydrogen bond from the O8—H hydroxyl group. Also evident from the image in Fig. 4 is the critical role played by the trifurcated carboxylate-O2 atom in stabilizing the Several of the oxygen atoms not involved in formal hydrogen bonding interactions participate in C—H···O interactions to consolidate the crystal packing, Fig. 5.While salt (I) was characterized from the 1:1 co-crystallization of LH4 with isonicoinic acid in an ethanol solution, the analogous experiment with nicotinic [NA] acid gave a salt of composition [NAH]2[LH2] (Dos Santos, et al., 2012). While protonation of NA is not surprising the fact that LH4 has been doubly deprotonated correlates nicely with the increased basicity of the nitrogen atom in NA cf. isonicotinic acid, i.e. calculated pKa = 4.19 and 2.35, respectively (Chemaxon, 2009).
For background to pharmaceutical co-crystals, see: Almarsson & Zaworotko (2004). For related co-crystallization studies on 1,2,4,5-benzenetetracarboxylic acid, see: Arman & Tiekink (2013a,b). For the structure of isonicotinic acid, see: Takusagawa & Shimada (1976). For the structure of the analogous salt formed from nicotinic acid, see: Dos Santos et al. (2012). For the calculation of pKa values, see: Chemaxon (2009).
Data collection: CrystalClear (Molecular Structure Corporation & Rigaku, 2005); cell
CrystalClear (Molecular Structure Corporation & Rigaku, 2005); data reduction: CrystalClear (Molecular Structure Corporation & Rigaku, 2005); 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 DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).Fig. 1. Molecular structures of (a) the 4-carboxypyridin-1-ium cation and (b) the hydroxy(2,4,5-tricarboxyphenyl)methanolate anion and water molecule (hydrogen bond shown as a dashed line) in (I), showing displacement ellipsoids at the 50% probability level. | |
Fig. 2. Supramolecular tape mediated by O—H···O hydrogen bonding between anions. The O—H···O hydrogen bonds are shown as orange dashed lines. | |
Fig. 3. Supramolecular chain mediated by N—H···O hydrogen bonding between cations and anions. The N—H···O hydrogen bonds are shown as blue dashed lines. | |
Fig. 4. Detail of the hydrogen bonding involving the trifurcated carboxylate-O2 atom and water molecule of solvation. | |
Fig. 5. Unit-cell contents in (I) viewed in projection down the c axis. The C—H···O interactions are shown as green dashed lines. |
C6H6NO2+·C10H5O8−·H2O | Z = 2 |
Mr = 395.27 | F(000) = 408 |
Triclinic, P1 | Dx = 1.580 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.724 (2) Å | Cell parameters from 3944 reflections |
b = 10.007 (2) Å | θ = 2.3–29.8° |
c = 10.755 (2) Å | µ = 0.14 mm−1 |
α = 99.56 (1)° | T = 98 K |
β = 114.667 (8)° | Block, colourless |
γ = 110.283 (9)° | 0.33 × 0.25 × 0.20 mm |
V = 830.7 (3) Å3 |
Rigaku AFC12K/SATURN724 diffractometer | 3414 independent reflections |
Radiation source: fine-focus sealed tube | 3200 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
ω scans | θmax = 26.5°, θmin = 2.3° |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | h = −11→12 |
Tmin = 0.807, Tmax = 1.000 | k = −12→12 |
5233 measured reflections | l = −13→9 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.056 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.133 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.17 | w = 1/[σ2(Fo2) + (0.0449P)2 + 1.2826P] where P = (Fo2 + 2Fc2)/3 |
3414 reflections | (Δ/σ)max < 0.001 |
281 parameters | Δρmax = 0.34 e Å−3 |
8 restraints | Δρmin = −0.27 e Å−3 |
C6H6NO2+·C10H5O8−·H2O | γ = 110.283 (9)° |
Mr = 395.27 | V = 830.7 (3) Å3 |
Triclinic, P1 | Z = 2 |
a = 9.724 (2) Å | Mo Kα radiation |
b = 10.007 (2) Å | µ = 0.14 mm−1 |
c = 10.755 (2) Å | T = 98 K |
α = 99.56 (1)° | 0.33 × 0.25 × 0.20 mm |
β = 114.667 (8)° |
Rigaku AFC12K/SATURN724 diffractometer | 3414 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 3200 reflections with I > 2σ(I) |
Tmin = 0.807, Tmax = 1.000 | Rint = 0.020 |
5233 measured reflections |
R[F2 > 2σ(F2)] = 0.056 | 8 restraints |
wR(F2) = 0.133 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.17 | Δρmax = 0.34 e Å−3 |
3414 reflections | Δρmin = −0.27 e Å−3 |
281 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.1555 (2) | 0.6476 (2) | 0.60109 (18) | 0.0198 (4) | |
O2 | 0.3582 (2) | 0.80549 (19) | 0.83497 (17) | 0.0192 (4) | |
O3 | 0.3881 (2) | 0.53016 (19) | 0.85274 (17) | 0.0180 (4) | |
O4 | 0.6609 (2) | 0.56930 (19) | 0.94793 (17) | 0.0164 (3) | |
H4O | 0.642 (4) | 0.534 (4) | 1.008 (3) | 0.037 (9)* | |
O5 | 0.8655 (2) | 0.7742 (2) | 0.5022 (2) | 0.0235 (4) | |
O6 | 0.9197 (2) | 0.6410 (2) | 0.64907 (19) | 0.0210 (4) | |
H6O | 0.994 (4) | 0.643 (5) | 0.627 (5) | 0.076 (15)* | |
O7 | 0.6828 (2) | 0.98272 (19) | 0.46806 (18) | 0.0198 (4) | |
O8 | 0.5263 (2) | 0.7429 (2) | 0.29663 (18) | 0.0219 (4) | |
H8O | 0.542 (6) | 0.788 (5) | 0.240 (4) | 0.077 (15)* | |
O9 | 0.1620 (3) | 0.9309 (3) | −0.0204 (3) | 0.0409 (6) | |
O10 | 0.1966 (2) | 0.7184 (2) | −0.0264 (2) | 0.0251 (4) | |
H10O | 0.243 (4) | 0.751 (4) | −0.074 (3) | 0.039 (9)* | |
O1W | 0.6084 (2) | 0.8838 (2) | 0.1330 (2) | 0.0251 (4) | |
H1W | 0.645 (4) | 0.9798 (13) | 0.166 (3) | 0.042 (10)* | |
H2W | 0.549 (4) | 0.849 (3) | 0.0401 (11) | 0.058 (12)* | |
N1 | −0.0175 (3) | 0.7469 (2) | 0.3153 (2) | 0.0187 (4) | |
H1N | −0.054 (4) | 0.736 (4) | 0.378 (3) | 0.037 (9)* | |
C1 | 0.4428 (3) | 0.7087 (2) | 0.6751 (2) | 0.0129 (4) | |
C2 | 0.5480 (3) | 0.6444 (2) | 0.7461 (2) | 0.0126 (4) | |
C3 | 0.6741 (3) | 0.6448 (2) | 0.7146 (2) | 0.0127 (4) | |
H3 | 0.7450 | 0.6024 | 0.7630 | 0.015* | |
C4 | 0.6972 (3) | 0.7066 (2) | 0.6129 (2) | 0.0123 (4) | |
C5 | 0.5920 (3) | 0.7703 (2) | 0.5415 (2) | 0.0128 (4) | |
C6 | 0.4668 (3) | 0.7715 (2) | 0.5742 (2) | 0.0136 (4) | |
H6 | 0.3973 | 0.8155 | 0.5272 | 0.016* | |
C7 | 0.3075 (3) | 0.7199 (3) | 0.7072 (2) | 0.0138 (4) | |
C8 | 0.5237 (3) | 0.5753 (2) | 0.8532 (2) | 0.0134 (4) | |
C9 | 0.8360 (3) | 0.7090 (2) | 0.5826 (2) | 0.0131 (4) | |
C10 | 0.6099 (3) | 0.8443 (2) | 0.4328 (2) | 0.0132 (4) | |
C11 | 0.0918 (3) | 0.7909 (3) | 0.1229 (2) | 0.0171 (5) | |
C12 | 0.0210 (3) | 0.8792 (3) | 0.1604 (3) | 0.0202 (5) | |
H12 | 0.0106 | 0.9548 | 0.1194 | 0.024* | |
C13 | −0.0339 (3) | 0.8546 (3) | 0.2584 (3) | 0.0215 (5) | |
H13 | −0.0827 | 0.9131 | 0.2853 | 0.026* | |
C14 | 0.0488 (3) | 0.6591 (3) | 0.2804 (3) | 0.0199 (5) | |
H14 | 0.0573 | 0.5842 | 0.3229 | 0.024* | |
C15 | 0.1047 (3) | 0.6786 (3) | 0.1820 (3) | 0.0194 (5) | |
H15 | 0.1508 | 0.6169 | 0.1555 | 0.023* | |
C16 | 0.1542 (3) | 0.8213 (3) | 0.0175 (3) | 0.0222 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0155 (8) | 0.0324 (9) | 0.0186 (8) | 0.0140 (7) | 0.0122 (7) | 0.0092 (7) |
O2 | 0.0233 (9) | 0.0281 (9) | 0.0162 (8) | 0.0155 (7) | 0.0150 (7) | 0.0089 (7) |
O3 | 0.0172 (8) | 0.0267 (9) | 0.0195 (8) | 0.0122 (7) | 0.0138 (7) | 0.0133 (7) |
O4 | 0.0156 (8) | 0.0248 (8) | 0.0150 (8) | 0.0103 (7) | 0.0104 (7) | 0.0122 (7) |
O5 | 0.0293 (10) | 0.0366 (10) | 0.0315 (10) | 0.0243 (8) | 0.0261 (8) | 0.0242 (8) |
O6 | 0.0232 (9) | 0.0355 (10) | 0.0279 (9) | 0.0227 (8) | 0.0213 (8) | 0.0218 (8) |
O7 | 0.0232 (9) | 0.0193 (8) | 0.0222 (9) | 0.0103 (7) | 0.0146 (7) | 0.0108 (7) |
O8 | 0.0294 (9) | 0.0236 (9) | 0.0135 (8) | 0.0100 (8) | 0.0128 (7) | 0.0083 (7) |
O9 | 0.0678 (16) | 0.0473 (13) | 0.0561 (14) | 0.0395 (12) | 0.0537 (13) | 0.0393 (11) |
O10 | 0.0327 (10) | 0.0353 (10) | 0.0244 (9) | 0.0202 (9) | 0.0230 (8) | 0.0163 (8) |
O1W | 0.0305 (10) | 0.0285 (10) | 0.0195 (9) | 0.0134 (8) | 0.0150 (8) | 0.0113 (8) |
N1 | 0.0184 (10) | 0.0241 (10) | 0.0143 (9) | 0.0065 (8) | 0.0121 (8) | 0.0060 (8) |
C1 | 0.0124 (10) | 0.0155 (10) | 0.0121 (10) | 0.0061 (8) | 0.0083 (8) | 0.0034 (8) |
C2 | 0.0130 (10) | 0.0158 (10) | 0.0115 (10) | 0.0078 (8) | 0.0074 (8) | 0.0050 (8) |
C3 | 0.0129 (10) | 0.0156 (10) | 0.0133 (10) | 0.0081 (8) | 0.0081 (8) | 0.0065 (8) |
C4 | 0.0127 (10) | 0.0146 (10) | 0.0133 (10) | 0.0076 (8) | 0.0088 (8) | 0.0046 (8) |
C5 | 0.0136 (10) | 0.0155 (10) | 0.0102 (9) | 0.0067 (8) | 0.0070 (8) | 0.0045 (8) |
C6 | 0.0145 (10) | 0.0183 (10) | 0.0142 (10) | 0.0106 (9) | 0.0094 (9) | 0.0073 (8) |
C7 | 0.0178 (11) | 0.0191 (11) | 0.0156 (10) | 0.0123 (9) | 0.0129 (9) | 0.0111 (9) |
C8 | 0.0158 (10) | 0.0150 (10) | 0.0130 (10) | 0.0079 (8) | 0.0101 (9) | 0.0044 (8) |
C9 | 0.0127 (10) | 0.0190 (11) | 0.0133 (10) | 0.0088 (9) | 0.0098 (8) | 0.0066 (8) |
C10 | 0.0118 (10) | 0.0198 (11) | 0.0148 (10) | 0.0107 (9) | 0.0088 (8) | 0.0089 (9) |
C11 | 0.0172 (11) | 0.0208 (11) | 0.0147 (10) | 0.0075 (9) | 0.0104 (9) | 0.0064 (9) |
C12 | 0.0212 (12) | 0.0207 (11) | 0.0202 (11) | 0.0093 (10) | 0.0118 (10) | 0.0081 (9) |
C13 | 0.0213 (12) | 0.0244 (12) | 0.0220 (12) | 0.0117 (10) | 0.0138 (10) | 0.0057 (10) |
C14 | 0.0217 (12) | 0.0233 (12) | 0.0187 (11) | 0.0103 (10) | 0.0129 (10) | 0.0097 (9) |
C15 | 0.0218 (12) | 0.0255 (12) | 0.0187 (11) | 0.0140 (10) | 0.0135 (10) | 0.0098 (10) |
C16 | 0.0260 (13) | 0.0313 (13) | 0.0200 (11) | 0.0160 (11) | 0.0168 (10) | 0.0135 (10) |
O1—C7 | 1.260 (3) | C1—C2 | 1.418 (3) |
O2—C7 | 1.271 (3) | C1—C7 | 1.528 (3) |
O3—C8 | 1.234 (3) | C2—C3 | 1.400 (3) |
O4—C8 | 1.327 (3) | C2—C8 | 1.497 (3) |
O4—H4O | 0.845 (10) | C3—C4 | 1.401 (3) |
O5—C9 | 1.232 (3) | C3—H3 | 0.9500 |
O6—C9 | 1.303 (3) | C4—C5 | 1.415 (3) |
O6—H6O | 0.847 (10) | C4—C9 | 1.509 (3) |
O7—C10 | 1.219 (3) | C5—C6 | 1.404 (3) |
O8—C10 | 1.333 (3) | C5—C10 | 1.521 (3) |
O8—H8O | 0.846 (10) | C6—H6 | 0.9500 |
O9—C16 | 1.221 (3) | C11—C15 | 1.397 (3) |
O10—C16 | 1.323 (3) | C11—C12 | 1.398 (3) |
O10—H10O | 0.845 (10) | C11—C16 | 1.519 (3) |
O1W—H1W | 0.849 (10) | C12—C13 | 1.386 (3) |
O1W—H2W | 0.847 (10) | C12—H12 | 0.9500 |
N1—C13 | 1.347 (3) | C13—H13 | 0.9500 |
N1—C14 | 1.347 (3) | C14—C15 | 1.389 (3) |
N1—H1N | 0.885 (10) | C14—H14 | 0.9500 |
C1—C6 | 1.401 (3) | C15—H15 | 0.9500 |
C8—O4—H4O | 110 (2) | O2—C7—C1 | 117.70 (19) |
C9—O6—H6O | 111 (3) | O3—C8—O4 | 124.0 (2) |
C10—O8—H8O | 110 (3) | O3—C8—C2 | 122.2 (2) |
C16—O10—H10O | 106 (2) | O4—C8—C2 | 113.81 (18) |
H1W—O1W—H2W | 109.7 (16) | O5—C9—O6 | 124.6 (2) |
C13—N1—C14 | 123.1 (2) | O5—C9—C4 | 120.44 (19) |
C13—N1—H1N | 116 (2) | O6—C9—C4 | 114.93 (18) |
C14—N1—H1N | 121 (2) | O7—C10—O8 | 125.1 (2) |
C6—C1—C2 | 119.26 (19) | O7—C10—C5 | 121.98 (19) |
C6—C1—C7 | 117.27 (19) | O8—C10—C5 | 112.69 (18) |
C2—C1—C7 | 123.42 (19) | C15—C11—C12 | 120.4 (2) |
C3—C2—C1 | 119.65 (19) | C15—C11—C16 | 121.5 (2) |
C3—C2—C8 | 120.08 (19) | C12—C11—C16 | 118.1 (2) |
C1—C2—C8 | 120.27 (19) | C13—C12—C11 | 118.8 (2) |
C2—C3—C4 | 121.0 (2) | C13—C12—H12 | 120.6 |
C2—C3—H3 | 119.5 | C11—C12—H12 | 120.6 |
C4—C3—H3 | 119.5 | N1—C13—C12 | 119.5 (2) |
C3—C4—C5 | 119.42 (19) | N1—C13—H13 | 120.2 |
C3—C4—C9 | 120.37 (19) | C12—C13—H13 | 120.2 |
C5—C4—C9 | 120.19 (19) | N1—C14—C15 | 119.7 (2) |
C6—C5—C4 | 119.57 (19) | N1—C14—H14 | 120.2 |
C6—C5—C10 | 116.79 (19) | C15—C14—H14 | 120.2 |
C4—C5—C10 | 123.60 (19) | C14—C15—C11 | 118.5 (2) |
C5—C6—C1 | 121.1 (2) | C14—C15—H15 | 120.7 |
C5—C6—H6 | 119.5 | C11—C15—H15 | 120.7 |
C1—C6—H6 | 119.5 | O9—C16—O10 | 125.4 (2) |
O1—C7—O2 | 126.2 (2) | O9—C16—C11 | 121.5 (2) |
O1—C7—C1 | 116.06 (19) | O10—C16—C11 | 113.1 (2) |
C6—C1—C2—C3 | 0.1 (3) | C3—C2—C8—O4 | 23.1 (3) |
C7—C1—C2—C3 | −177.2 (2) | C1—C2—C8—O4 | −157.40 (19) |
C6—C1—C2—C8 | −179.41 (19) | C3—C4—C9—O5 | −174.1 (2) |
C7—C1—C2—C8 | 3.3 (3) | C5—C4—C9—O5 | 4.3 (3) |
C1—C2—C3—C4 | −0.6 (3) | C3—C4—C9—O6 | 4.6 (3) |
C8—C2—C3—C4 | 178.9 (2) | C5—C4—C9—O6 | −177.0 (2) |
C2—C3—C4—C5 | 0.3 (3) | C6—C5—C10—O7 | 77.3 (3) |
C2—C3—C4—C9 | 178.74 (19) | C4—C5—C10—O7 | −100.5 (3) |
C3—C4—C5—C6 | 0.4 (3) | C6—C5—C10—O8 | −97.4 (2) |
C9—C4—C5—C6 | −178.04 (19) | C4—C5—C10—O8 | 84.8 (3) |
C3—C4—C5—C10 | 178.15 (19) | C15—C11—C12—C13 | 0.8 (4) |
C9—C4—C5—C10 | −0.3 (3) | C16—C11—C12—C13 | −178.9 (2) |
C4—C5—C6—C1 | −0.9 (3) | C14—N1—C13—C12 | −0.7 (4) |
C10—C5—C6—C1 | −178.77 (19) | C11—C12—C13—N1 | 0.1 (4) |
C2—C1—C6—C5 | 0.6 (3) | C13—N1—C14—C15 | 0.3 (4) |
C7—C1—C6—C5 | 178.1 (2) | N1—C14—C15—C11 | 0.6 (4) |
C6—C1—C7—O1 | 64.6 (3) | C12—C11—C15—C14 | −1.2 (4) |
C2—C1—C7—O1 | −118.1 (2) | C16—C11—C15—C14 | 178.6 (2) |
C6—C1—C7—O2 | −112.4 (2) | C15—C11—C16—O9 | −171.1 (3) |
C2—C1—C7—O2 | 64.9 (3) | C12—C11—C16—O9 | 8.7 (4) |
C3—C2—C8—O3 | −157.6 (2) | C15—C11—C16—O10 | 9.1 (3) |
C1—C2—C8—O3 | 21.9 (3) | C12—C11—C16—O10 | −171.2 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4O···O3i | 0.84 (3) | 1.82 (3) | 2.654 (3) | 176 (3) |
O6—H6O···O1ii | 0.85 (5) | 1.69 (5) | 2.534 (3) | 174 (5) |
O8—H8O···O1W | 0.85 (5) | 1.79 (5) | 2.634 (3) | 171 (6) |
O10—H10O···O2iii | 0.85 (4) | 1.78 (4) | 2.625 (3) | 172 (4) |
N1—H1N···O5iv | 0.89 (4) | 1.86 (4) | 2.711 (3) | 160 (4) |
O1W—H1W···O2v | 0.85 (2) | 2.16 (2) | 2.957 (3) | 156 (3) |
O1W—H2W···O2iii | 0.85 (1) | 2.05 (2) | 2.853 (3) | 158 (4) |
C6—H6···O7v | 0.95 | 2.40 | 3.267 (3) | 151 |
C12—H12···O9vi | 0.95 | 2.35 | 3.179 (4) | 146 |
C14—H14···O6vii | 0.95 | 2.40 | 3.300 (4) | 159 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x+1, y, z; (iii) x, y, z−1; (iv) x−1, y, z; (v) −x+1, −y+2, −z+1; (vi) −x, −y+2, −z; (vii) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C6H6NO2+·C10H5O8−·H2O |
Mr | 395.27 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 98 |
a, b, c (Å) | 9.724 (2), 10.007 (2), 10.755 (2) |
α, β, γ (°) | 99.56 (1), 114.667 (8), 110.283 (9) |
V (Å3) | 830.7 (3) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.14 |
Crystal size (mm) | 0.33 × 0.25 × 0.20 |
Data collection | |
Diffractometer | Rigaku AFC12K/SATURN724 |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.807, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5233, 3414, 3200 |
Rint | 0.020 |
(sin θ/λ)max (Å−1) | 0.628 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.056, 0.133, 1.17 |
No. of reflections | 3414 |
No. of parameters | 281 |
No. of restraints | 8 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.34, −0.27 |
Computer programs: CrystalClear (Molecular Structure Corporation & Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4O···O3i | 0.84 (3) | 1.82 (3) | 2.654 (3) | 176 (3) |
O6—H6O···O1ii | 0.85 (5) | 1.69 (5) | 2.534 (3) | 174 (5) |
O8—H8O···O1W | 0.85 (5) | 1.79 (5) | 2.634 (3) | 171 (6) |
O10—H10O···O2iii | 0.85 (4) | 1.78 (4) | 2.625 (3) | 172 (4) |
N1—H1N···O5iv | 0.89 (4) | 1.86 (4) | 2.711 (3) | 160 (4) |
O1W—H1W···O2v | 0.848 (19) | 2.16 (2) | 2.957 (3) | 156 (3) |
O1W—H2W···O2iii | 0.846 (10) | 2.050 (19) | 2.853 (3) | 158 (4) |
C6—H6···O7v | 0.95 | 2.40 | 3.267 (3) | 151 |
C12—H12···O9vi | 0.95 | 2.35 | 3.179 (4) | 146 |
C14—H14···O6vii | 0.95 | 2.40 | 3.300 (4) | 159 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x+1, y, z; (iii) x, y, z−1; (iv) x−1, y, z; (v) −x+1, −y+2, −z+1; (vi) −x, −y+2, −z; (vii) −x+1, −y+1, −z+1. |
Acknowledgements
We gratefully thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR-MOHE/SC/12).
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Interest in co-crystallization experiments stems largely from potential applications in the pharmaceutical industry (Almarsson & Zaworotko, 2004). The title salt hydrate, (I), was isolated during an investigation of co-crystallization experiments with 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid; LH4) and various pyridyl derivatives (Arman & Tiekink, 2013a; Arman & Tiekink, 2013b).
The 1:1 co-crystallization of pyromellitic acid and isonicotinic acid in an ethanol solution afforded a salt hydrate, (I), there being one complete molecule of the 4-carboxypyridin-1-ium cation, the hydroxy(2,4,5-tricarboxyphenyl)methanolate anion and a water molecule in the asymmetric unit. Confirmation of protonation of isonicotinic acid during crystallization is found in the nature of hydrogen bonding involving the pyridinium cation (see below), and the widening of the C13—N1—C14 angle to 123.1 (2)° cf. 118.9 (2)° in the structure of isonicotinic acid itself (Takusagawa & Shimada, 1976). Further, the disparity in the C—O bond lengths of the carboxylic acid residue, Δ(C—O) = [(C—O)long - (C—O)short] = 0.10 Å, confirms that isonicotinic acid has been protonated at N1, rather than existing in a zwitterionic form, with equivalent C—O bonds. Complementing this evidence, in the anion, the Δ(C—O) value for the O1-carboxylate group is 0.01 Å, indicating considerable delocalization of electron density over the CO2 atoms, compared to values in the range 0.07 to 0.11 Å for the remaining carboxylic acids.
In the cation, the carboxylic acid residue is approximately co-planar with the pyridyl ring to which it is attached as seen in the C12—C11—C16—O9 torsion angle of -8.7 (4)°. Indeed, the entire cation is approximately planar with the r.m.s. deviation = 0.085 Å for the nine fitted atoms. By contrast, anion is non-planar with the carboxylic acid diagonally opposite the carboxylate group being co-planar to the phenyl ring [C—C—C—O(carbonyl) torsion angle = 4.3 (3)°] but the remaining carboxylic acids and carboxylate residues deviate significantly [C—C—C—O(carbonyl) torsion angles =-118.1 (2), -157.6 (2) and 77.3 (3)°].
The three-dimensional crystal structure of (I) is consolidated by O—H···O and N—H···O hydrogen bonding involving all three components of the structure; geometric parameters characterizing these are summarized in Table 1. Two distinct supramolecular aggregation patterns are clearly discerned, with the first of these being a tape along [1 0 0] comprising hydroxy(2,4,5-tricarboxyphenyl)methanolate anions, Fig. 2, which is sustained by centrosymmetric eight-membered {···O=COH}2 synthons involving the O3-carboxylic acid and orthogonal O6—H···O1 hydrogen bonds. A supramolecular chain containing alternating cations and anions is also found, Fig. 3. This is aligned along [1 0 - 1] and is stabilized by O10—H···O2 and N1—H···O5 hydrogen bonds. The aforementioned are connected into a supramolecular layer in the ac plane. As seen in Fig. 4, the centrosymmetrically related water molecules are bridged by carboxylate-O2 atoms to form an eight-membered {···HOH···O}2 ring. The water-O1w atom also accepts a hydrogen bond from the O8—H hydroxyl group. Also evident from the image in Fig. 4 is the critical role played by the trifurcated carboxylate-O2 atom in stabilizing the crystal structure. Several of the oxygen atoms not involved in formal hydrogen bonding interactions participate in C—H···O interactions to consolidate the crystal packing, Fig. 5.
While salt (I) was characterized from the 1:1 co-crystallization of LH4 with isonicoinic acid in an ethanol solution, the analogous experiment with nicotinic [NA] acid gave a salt of composition [NAH]2[LH2] (Dos Santos, et al., 2012). While protonation of NA is not surprising the fact that LH4 has been doubly deprotonated correlates nicely with the increased basicity of the nitrogen atom in NA cf. isonicotinic acid, i.e. calculated pKa = 4.19 and 2.35, respectively (Chemaxon, 2009).