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Both the 1:1 and 2:1 mol­ecular adducts of 4-methyl­imidazole (4-MeIm) and terephthalic acid (H2TPA) are organic salts, viz. C4H7N2+·C8H5O4-, (I), and 2C4H7N2+·C8H4O42-, (II), respectively. The component ions in (I) are linked by N-H...O and O-H...O hydrogen bonds into continuous two-dimensional layers built from R64(32) hydrogen-bond motifs running parallel to the (100) plane. These adjacent two-dimensional layers are in turn linked by a combination of C-H...O, C-H...[pi] and [pi]-[pi] inter­actions into a three-dimensional network. In the crystal structure of (II), with the anion located on an inversion centre, only N-H...O hydrogen bonds result in two-dimensional layers built from R88(42) hydrogen-bond motifs running parallel to the (102) plane. Being similar to those in (I), these layers are also linked by means of C-H...O, C-H...[pi] and [pi]-[pi] inter­actions, forming a three-dimensional network. This study indicates that, on occasion, a change of the reactant concentration can exert a pivotal influence on the construction of supra­molecular structures based on hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108013024/sk3225sup1.cif
Contains datablocks global, I, II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108013024/sk3225Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108013024/sk3225IIsup3.hkl
Contains datablock II

CCDC references: 692665; 692666

Comment top

Terephthalic acid (H2TPA), a rod-like aromatic diacid, has often been used in the synthesis of metal–organic frameworks as a linker molecule (Serre et al., 2007; Mukherjee et al., 2004; Sun et al., 2000; Zakaria et al., 2001; Karanović et al., 2002; Damgaard Poulsen et al., 2006; Li et al., 1998). Recently, with the increase in interest in controlling the crystalline structures of organic-based solid-state materials, H2TPA is more and more employed in constructing supramolecular structures (Mei et al., 2007; Dale et al., 2004; Zhang & Chen, 2004; Lynch & Jones, 2004; Spencer et al., 2004; Devi & Muthiah, 2007). However, the experimental conditions employed (such as the solvent, temperature, crystallization method and counterions) can all have an important impact on the structure of the final assembly (She et al., 2008; Meng et al., 2007, 2008; Childs et al., 2007; Díaz et al., 2006). In this paper, we chose 4-methylimidazole (4-MeIm) acting as a proton-accepting candidate to study further the influence of its concentration on cocrystals and/or organic salt structures containing H2TPA. We obtained the title 1:1 and 2:1 binary molecular adducts, (I) and (II), respectively, and report their crystal structures here.

Compounds (I) and (II) crystallize in space groups P1 and P21/c, respectively. In (I), the H atom of one carboxylic acid group O atom is transferred to the imidazole N atom, while the other remains as the acid. The carboxylic acid and carboxylate groups are distinctly twisted away from the benzene ring, with dihedral angles of 21.9 (1) and 5.7 (1)°, respectively [Please check amended text - are angles in the right order?]. However, the imidazole ring makes a much larger dihedral angle of 60.6 (1)° with the benzene ring. The 4-MeIm+ and HTPA- component ions are joined together by two intermolecular N—H···O hydrogen bonds (Fig. 2, Table 1).

In contrast with (I), there is an inversion centre lying across the centre of the benzene ring of (II). Both carboxylic acid groups are deprotonated, with a carboxylate–benzene ring dihedral angle of 3.3 (1)° and an imidazole–benzene ring dihedral angle of 30.7 (1)°, roughly half of the corresponding values in (I). The component ions in (II) are linked together mainly by N—H···O hydrogen bonds (Fig. 3, Table 1).

The carboxylic acid C—O bond lengths in both title compounds [C7—O1 = 1.275 (2), C7—O2 = 1.229 (2), C8—O3 = 1.210 (2) and C8—O4 = 1.310 (2) Å in (I); C4—O1 = 1.255 (2) and C4—O2 = 1.250 (2) Å in (II)] agree well with those tabulated by Allen et al. (1995) for a carboxylic acid group [1.305 (20) and 1.226 (20) Å] and/or for a carboxylate group [1.255 (10) Å] attached to a phenyl ring. The bond distances and angles in the 4-MeIm+ cation are also indicative of its protonation by drawing a comparison between (I), (II) and analogous compounds [Cambridge Structural Database, Version? (Allen, 2002; Macrae et al., 2006); refcodes AHIJUW (Gossman et al., 2002), FETDAK (Aakeröy et al., 2005), HISTPA (Mata et al., 2006), JAXMEB (Wang & Wei, 2005) and HILSAX (Tian, 2007)].

Although compounds (I) and (II) are both linked into their final three-dimensional networks by a combination of N—H···O, O—H···O, C—H···O hydrogen bonds and C—H···π and ππ interactions, the structural subunits are apparently different because of the concentration change of 4-MeIm. In (I), the supramolecular structure can be simply analyzed in terms of three substructures. Firstly, the HTPA- anions result in discrete one-dimensional C(8) (Bernstein et al., 1995) chains via an O4—H4···O1iii hydrogen bond [symmetry code: (iii) x, y, z + 1] running parallel to the [001] direction (Fig.2). Secondly, these adjacent [001] chains are linked together by 4-MeIm+ cations, forming two-dimensional layers built from R46(32) hydrogen-bond motifs which are parallel to the (100) plane (Fig. 2). If these R46(32) rings are regarded as the nodes of the resulting net, then this is of the (4,4) type (Batten & Robson, 1998). Finally, these neighbouring two-dimensional layers are assembled into a three-dimensional network by means of two C—H···O hydrogen bonds and two C—H···π interactions (Table 1), and ππ interactions. One of the ππ interactions occurs between centrosymmetrically related imidazole rings, with a ring centroid distance of 3.706 (2) Å, an interplanar spacing of 3.452 (2) Å and a ring offset of 1.348 (2) Å. However, the other one is stronger and is formed between strictly parallel benzene rings; the ring centroid separation is 3.569 (2) Å, with an interpanar spacing of 3.476 (2) Å and a ring offset of 0.807 (2) Å.

By comparison, the component ions in (II) are first linked by N1—H1A···O2viii [symmetry code: (iii) 1 - x,1/2 + y,3/2 - z] and N2—H2A···O1 hydrogen bonds, forming a two-dimensional layer built from centrosymmetric R88(42) hydrogen-bonded rings running parallel to the (102) plane (Fig. 3). According to the topology classification for nets, this is a (6,3) net, which is apparently larger than that in (I). These adjacent layers in (II) are in turn linked into a three-dimensional network by a combination of one C—H···O hydrogen bond and one C—H···π interaction (Table 1), and ππ interactions. The ππ interactions in (II) only occur between the strictly parallel imidazole rings, with a ring centroid distance of 3.665 (2) Å, an interplanar spacing of 3.302 (2) Å and a ring offset of 1.591 (2) Å.

Both title compounds should be regarded as organic salts according to the definitions of cocrystals and organic salts (Aakeröy & Salmon, 2005). We might find some reasons from the ΔpKa rule [ΔpKa = pKa(base) - pKa(acid); Childs et al., 2007; Bhogala et al., 2005] why cocrystallization of H2TPA and 4-MeIm from water yields the organic salt but not a cocrystal. It is generally accepted that reaction of an acid with a base will be expected to form a salt if ΔpKa is greater than 3 and will exclusively result in cocrystal formation if ΔpKa is less than 0. The pKa value of 4-MeIm is equal to 8.5 in aqueous solution at 303 K calculated using Advanced Chemistry Development Software running under Solaris (Advanced Chemistry Development, 2005). For H2TPA, pKa1 = 3.51 and pKa2 = 4.82. Both the ΔpKa1 (4.99) and ΔpKa2 (3.68) values are greater than 3, indicating that the 1:1 and 2:1 organic salts are available.

In conclusion, H2TPA is a good participant in hydrogen-bonding networks for the formation of acid–base molecular adducts. With the aim of gaining more insight into crystal engineering based on hydrogen bonds, further organic salts and/or cocrystals containing H2TPA are expected to obtained by means of the ΔpKa rule.

Experimental top

All reagents and solvents were used as obtained without further purification. Crystals of (I) were obtained by mixing equivalent molar quantities of 4-methylimidazole (0.2 mmol, 16.4 mg) and terephthalic acid (0.2 mmol, 33.2 mg) dissolved in water (10 ml). The mixture was stirred for 10 min at ambient temperature and then filtered. The resulting colourless solution was kept in air for one week. Colourless plate crystals of (I) suitable for single-crystal X-ray diffraction analysis were grown by slow evaporation of the solution at the bottom of the vessel. The crystals were filtered carefully, washed with distilled water and dried in air (yield 30%, 15.0 mg, based on the 1:1 organic salt).

Crystals of (II) were obtained by mixing 2:1 molar quantities of 4-methylimidazole (0.4 mmol, 32.8 mg) and terephthalic acid (0.2 mmol, 33.2 mg) in water (20 ml). The mixture was stirred for 30 min at ambient temperature and then filtered. The resulting colourless solution was kept in air for three weeks. Block colourless crystals of (II) suitable for single-crystal X-ray diffraction analysis were grown by slow evaporation of the solution at the bottom of the vessel. The crystals were filtered carefully, washed with distilled water and dried in air (yield 50%, 33.0 mg, based on the 2:1 organic salt).

Refinement top

For both compounds, H atoms bonded to C atoms were positioned geometrically, with C—H = 0.93 (aromatic) or 0.96 Å (methyl), and refined in riding mode, with Uiso(H) = 1.2Ueq(aromatic C) or 1.5Ueq(methyl C). H atoms bonded to N and O atoms were found in difference maps. N—H and O—H distances were refined freely (refined distances are given in Table 1), with Uiso(H) = 1.2Ueq(N) or 1.5Ueq(O).

Computing details top

For both compounds, data collection: SMART (Bruker, 2001); cell refinement: SMART (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. The molecular structures of (a) (I) and (b) (II), showing the atom-numbering schemes. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as dashed lines. [Symmetry code: (i) -x, -y, 2 - z.]
[Figure 2] Fig. 2. Part of the crystal structure of (I), showing the formation of the two-dimensional layer running parallel to the (100) plane. Hydrogen bonds are shown as dashed lines. For the sake of clarity, 4-MeIm+ cations and H atoms not involved in the motif have been omitted. [Symmetry codes: (ii) x, y - 1, z; (iii) x, y, z + 1.]
[Figure 3] Fig. 3. Part of the crystal structure of (II), showing the formation of the two-dimensional layer built from N—H···O hydrogen bonds. For the sake of clarity, H atoms not involved in the motif have been omitted. [Symmetry code: (viii) -x + 1, y + 1/2, -z + 3/2.]
(I) 4-methylimidazolium hydrogen terephthalate top
Crystal data top
C4H7N2+·C8H5O4Z = 2
Mr = 248.24F(000) = 260
Triclinic, P1Dx = 1.432 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.2649 (5) ÅCell parameters from 2409 reflections
b = 8.9459 (7) Åθ = 2.3–27.9°
c = 9.6844 (7) ŵ = 0.11 mm1
α = 75.406 (1)°T = 298 K
β = 72.731 (1)°Plate, colourless
γ = 77.966 (2)°0.30 × 0.10 × 0.04 mm
V = 575.52 (7) Å3
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2204 independent reflections
Radiation source: fine focus sealed Siemens Mo tube1820 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.021
0.3° wide ω exposures scansθmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1997)
h = 88
Tmin = 0.956, Tmax = 0.996k = 1111
5915 measured reflectionsl = 1011
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)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.156H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.1121P)2]
where P = (Fo2 + 2Fc2)/3
2204 reflections(Δ/σ)max < 0.001
173 parametersΔρmax = 0.25 e Å3
0 restraintsΔρmin = 0.29 e Å3
Crystal data top
C4H7N2+·C8H5O4γ = 77.966 (2)°
Mr = 248.24V = 575.52 (7) Å3
Triclinic, P1Z = 2
a = 7.2649 (5) ÅMo Kα radiation
b = 8.9459 (7) ŵ = 0.11 mm1
c = 9.6844 (7) ÅT = 298 K
α = 75.406 (1)°0.30 × 0.10 × 0.04 mm
β = 72.731 (1)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2204 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1997)
1820 reflections with I > 2σ(I)
Tmin = 0.956, Tmax = 0.996Rint = 0.021
5915 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.156H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.25 e Å3
2204 reflectionsΔρmin = 0.29 e Å3
173 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
C10.1846 (2)0.60860 (16)0.24746 (17)0.0301 (4)
C20.0813 (2)0.74895 (17)0.28407 (17)0.0321 (4)
H20.02210.82100.21670.039*
C30.0654 (2)0.78263 (17)0.41915 (17)0.0326 (4)
H30.00310.87710.44210.039*
C40.1525 (2)0.67416 (17)0.52099 (18)0.0301 (4)
C50.2507 (2)0.53242 (18)0.48622 (18)0.0332 (4)
H50.30630.45870.55470.040*
C60.2667 (2)0.49982 (17)0.35039 (18)0.0340 (4)
H60.33280.40450.32820.041*
C70.2108 (2)0.57179 (17)0.09894 (18)0.0323 (4)
C80.1396 (2)0.71605 (18)0.66356 (17)0.0337 (4)
C90.2188 (3)0.09526 (18)0.00584 (19)0.0399 (4)
H90.12710.08850.09680.048*
C100.4236 (2)0.03340 (18)0.19768 (19)0.0357 (4)
C110.4271 (2)0.18388 (19)0.1976 (2)0.0398 (4)
H110.50280.25160.27110.048*
C120.5354 (3)0.0689 (2)0.3029 (2)0.0547 (5)
H12A0.63120.01440.37900.082*
H12B0.44810.09690.34650.082*
H12C0.59910.16170.25120.082*
N10.2993 (2)0.21901 (15)0.07028 (17)0.0401 (4)
H10.278 (3)0.308 (2)0.032 (2)0.048*
N20.2900 (2)0.01884 (16)0.06859 (16)0.0369 (4)
H2A0.256 (3)0.116 (2)0.035 (2)0.044*
O10.19191 (18)0.68756 (12)0.00654 (12)0.0411 (4)
O20.2498 (2)0.43430 (13)0.08750 (14)0.0523 (4)
O30.0675 (2)0.84331 (14)0.69107 (14)0.0516 (4)
O40.2186 (2)0.60306 (14)0.75314 (13)0.0454 (4)
H40.203 (3)0.636 (2)0.845 (2)0.054*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0393 (8)0.0268 (8)0.0264 (9)0.0086 (6)0.0086 (7)0.0061 (6)
C20.0425 (9)0.0280 (8)0.0265 (9)0.0017 (6)0.0135 (7)0.0038 (6)
C30.0410 (9)0.0273 (8)0.0282 (9)0.0002 (6)0.0086 (7)0.0079 (6)
C40.0371 (8)0.0301 (8)0.0241 (8)0.0068 (6)0.0071 (6)0.0063 (6)
C50.0447 (9)0.0277 (8)0.0284 (9)0.0004 (6)0.0151 (7)0.0049 (6)
C60.0477 (9)0.0248 (8)0.0305 (9)0.0001 (6)0.0131 (7)0.0082 (6)
C70.0447 (9)0.0281 (8)0.0276 (9)0.0071 (6)0.0121 (7)0.0068 (6)
C80.0447 (9)0.0314 (8)0.0250 (9)0.0051 (7)0.0080 (7)0.0071 (7)
C90.0510 (10)0.0384 (9)0.0320 (10)0.0033 (7)0.0104 (8)0.0132 (7)
C100.0418 (9)0.0339 (8)0.0341 (10)0.0023 (7)0.0129 (7)0.0105 (7)
C110.0451 (9)0.0349 (9)0.0402 (11)0.0079 (7)0.0109 (8)0.0077 (7)
C120.0625 (12)0.0532 (11)0.0498 (13)0.0013 (9)0.0069 (9)0.0279 (10)
N10.0529 (9)0.0292 (7)0.0442 (9)0.0006 (6)0.0176 (7)0.0162 (6)
N20.0514 (8)0.0277 (7)0.0332 (8)0.0055 (6)0.0127 (6)0.0074 (6)
O10.0689 (8)0.0317 (6)0.0267 (7)0.0066 (6)0.0184 (6)0.0064 (5)
O20.0983 (11)0.0284 (6)0.0379 (8)0.0046 (6)0.0269 (7)0.0128 (6)
O30.0871 (10)0.0350 (7)0.0330 (8)0.0064 (6)0.0200 (7)0.0145 (5)
O40.0723 (9)0.0393 (7)0.0288 (7)0.0067 (6)0.0249 (6)0.0123 (6)
Geometric parameters (Å, º) top
C1—C61.385 (2)C8—O41.310 (2)
C1—C21.392 (2)C9—N11.309 (2)
C1—C71.505 (2)C9—N21.3260 (19)
C2—C31.382 (2)C9—H90.9300
C2—H20.9300C10—C111.352 (2)
C3—C41.395 (2)C10—N21.378 (2)
C3—H30.9300C10—C121.485 (2)
C4—C51.388 (2)C11—N11.370 (2)
C4—C81.492 (2)C11—H110.9300
C5—C61.385 (2)C12—H12A0.9600
C5—H50.9300C12—H12B0.9600
C6—H60.9300C12—H12C0.9600
C7—O21.2288 (18)N1—H10.932 (19)
C7—O11.2751 (18)N2—H2A0.907 (19)
C8—O31.2095 (19)O4—H40.98 (2)
C6—C1—C2119.12 (14)N1—C9—N2108.51 (15)
C6—C1—C7118.92 (13)N1—C9—H9125.7
C2—C1—C7121.95 (14)N2—C9—H9125.7
C3—C2—C1120.91 (15)C11—C10—N2105.41 (14)
C3—C2—H2119.5C11—C10—C12131.97 (16)
C1—C2—H2119.5N2—C10—C12122.58 (15)
C2—C3—C4119.68 (14)C10—C11—N1107.88 (15)
C2—C3—H3120.2C10—C11—H11126.1
C4—C3—H3120.2N1—C11—H11126.1
C5—C4—C3119.42 (14)C10—C12—H12A109.5
C5—C4—C8122.02 (15)C10—C12—H12B109.5
C3—C4—C8118.55 (14)H12A—C12—H12B109.5
C6—C5—C4120.53 (15)C10—C12—H12C109.5
C6—C5—H5119.7H12A—C12—H12C109.5
C4—C5—H5119.7H12B—C12—H12C109.5
C1—C6—C5120.29 (14)C9—N1—C11108.78 (13)
C1—C6—H6119.9C9—N1—H1121.4 (12)
C5—C6—H6119.9C11—N1—H1129.4 (12)
O2—C7—O1124.92 (14)C9—N2—C10109.41 (14)
O2—C7—C1118.34 (14)C9—N2—H2A123.1 (12)
O1—C7—C1116.73 (13)C10—N2—H2A127.4 (12)
O3—C8—O4123.84 (14)C7—O2—H1143.9 (6)
O3—C8—C4122.88 (15)C8—O4—H4109.5 (11)
O4—C8—C4113.25 (13)
C6—C1—C2—C32.1 (2)C5—C4—C8—O3174.27 (15)
C7—C1—C2—C3177.54 (13)C3—C4—C8—O34.7 (3)
C1—C2—C3—C40.6 (2)C5—C4—C8—O44.0 (2)
C2—C3—C4—C51.3 (2)C3—C4—C8—O4177.07 (13)
C2—C3—C4—C8177.66 (13)N2—C10—C11—N10.55 (19)
C3—C4—C5—C61.6 (2)C12—C10—C11—N1177.41 (18)
C8—C4—C5—C6177.35 (14)N2—C9—N1—C110.2 (2)
C2—C1—C6—C51.9 (2)C10—C11—N1—C90.2 (2)
C7—C1—C6—C5177.83 (14)N1—C9—N2—C100.59 (19)
C4—C5—C6—C10.0 (2)C11—C10—N2—C90.71 (19)
C6—C1—C7—O221.7 (2)C12—C10—N2—C9177.50 (17)
C2—C1—C7—O2158.63 (15)O1—C7—O2—H18.2 (11)
C6—C1—C7—O1157.80 (14)C1—C7—O2—H1172.4 (10)
C2—C1—C7—O121.9 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O20.932 (19)1.749 (19)2.6536 (17)162.7 (18)
O4—H4···O1i0.98 (2)1.59 (2)2.5657 (16)176.5 (19)
N2—H2A···O1ii0.907 (19)1.84 (2)2.7383 (17)168.0 (18)
C3—H3···O3iii0.932.533.2762 (19)138
C9—H9···O3iv0.932.273.155 (2)160
Symmetry codes: (i) x, y, z+1; (ii) x, y1, z; (iii) x, y+2, z+1; (iv) x, y+1, z+1.
(II) bis(4-methylimidazolium) terephthalate top
Crystal data top
2C4H7N2+·C8H4O42F(000) = 348
Mr = 330.34Dx = 1.341 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2847 reflections
a = 10.7759 (7) Åθ = 3.3–28.1°
b = 7.5608 (5) ŵ = 0.10 mm1
c = 10.3254 (7) ÅT = 296 K
β = 103.454 (1)°Block, colourless
V = 818.17 (9) Å30.36 × 0.30 × 0.10 mm
Z = 2
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
1860 independent reflections
Radiation source: fine focus sealed Siemens Mo tube1491 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
0.3° wide ω exposures scansθmax = 27.5°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1997)
h = 1114
Tmin = 0.945, Tmax = 0.990k = 99
8924 measured reflectionsl = 1313
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)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.151H atoms treated by a mixture of independent and constrained refinement
S = 1.08 w = 1/[σ2(Fo2) + (0.0899P)2 + 0.1197P]
where P = (Fo2 + 2Fc2)/3
1860 reflections(Δ/σ)max < 0.001
116 parametersΔρmax = 0.24 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
2C4H7N2+·C8H4O42V = 818.17 (9) Å3
Mr = 330.34Z = 2
Monoclinic, P21/cMo Kα radiation
a = 10.7759 (7) ŵ = 0.10 mm1
b = 7.5608 (5) ÅT = 296 K
c = 10.3254 (7) Å0.36 × 0.30 × 0.10 mm
β = 103.454 (1)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
1860 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1997)
1491 reflections with I > 2σ(I)
Tmin = 0.945, Tmax = 0.990Rint = 0.029
8924 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.151H atoms treated by a mixture of independent and constrained refinement
S = 1.08Δρmax = 0.24 e Å3
1860 reflectionsΔρmin = 0.21 e Å3
116 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
C10.11809 (13)0.04803 (19)0.97667 (14)0.0322 (3)
C20.09761 (15)0.0555 (2)1.10452 (15)0.0423 (4)
H20.16270.09261.17520.051*
C30.02051 (15)0.0074 (3)0.87335 (15)0.0433 (4)
H30.03370.01290.78760.052*
C40.24642 (14)0.0995 (2)0.95080 (15)0.0341 (4)
C50.64073 (16)0.3094 (2)1.03102 (16)0.0442 (4)
H50.67060.26901.11780.053*
C60.51308 (15)0.3646 (2)0.83893 (16)0.0451 (4)
H60.44090.36950.76910.054*
C70.70940 (14)0.3985 (2)0.95839 (16)0.0374 (4)
C80.84578 (17)0.4522 (3)0.9885 (2)0.0569 (5)
H8A0.87800.45871.08330.085*
H8B0.85340.56590.94980.085*
H8C0.89400.36670.95210.085*
N10.62720 (12)0.43310 (18)0.83836 (13)0.0387 (4)
H1A0.6463 (19)0.495 (3)0.780 (2)0.046*
N20.52027 (13)0.28898 (19)0.95533 (14)0.0443 (4)
H2A0.455 (2)0.230 (2)0.9814 (19)0.053*
O10.33403 (11)0.14222 (19)1.04883 (11)0.0516 (4)
O20.25708 (11)0.09877 (17)0.83280 (11)0.0480 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0270 (7)0.0371 (8)0.0353 (7)0.0042 (5)0.0128 (6)0.0010 (6)
C20.0296 (8)0.0648 (11)0.0337 (8)0.0135 (7)0.0099 (6)0.0078 (7)
C30.0342 (8)0.0686 (11)0.0307 (7)0.0117 (7)0.0150 (6)0.0065 (7)
C40.0281 (7)0.0372 (8)0.0405 (8)0.0035 (6)0.0149 (6)0.0017 (6)
C50.0377 (8)0.0494 (10)0.0475 (9)0.0013 (7)0.0140 (7)0.0095 (7)
C60.0283 (8)0.0572 (11)0.0485 (9)0.0011 (7)0.0064 (6)0.0119 (8)
C70.0294 (7)0.0398 (8)0.0436 (8)0.0017 (6)0.0100 (6)0.0011 (6)
C80.0320 (9)0.0675 (13)0.0689 (12)0.0090 (8)0.0075 (8)0.0051 (9)
N10.0333 (7)0.0490 (8)0.0365 (7)0.0044 (5)0.0135 (5)0.0007 (5)
N20.0341 (7)0.0479 (8)0.0560 (8)0.0086 (6)0.0204 (6)0.0003 (6)
O10.0311 (6)0.0797 (9)0.0459 (7)0.0199 (6)0.0131 (5)0.0080 (6)
O20.0368 (6)0.0721 (8)0.0411 (6)0.0052 (5)0.0210 (5)0.0015 (5)
Geometric parameters (Å, º) top
C1—C31.378 (2)C5—H50.9300
C1—C21.3893 (19)C6—N21.317 (2)
C1—C41.5189 (19)C6—N11.336 (2)
C2—C3i1.393 (2)C6—H60.9300
C2—H20.9300C7—N11.370 (2)
C3—C2i1.393 (2)C7—C81.486 (2)
C3—H30.9300C8—H8A0.9600
C4—O21.2501 (18)C8—H8B0.9600
C4—O11.2552 (19)C8—H8C0.9600
C5—C71.350 (2)N1—H1A0.82 (2)
C5—N21.359 (2)N2—H2A0.92 (2)
C3—C1—C2119.14 (13)N1—C6—H6125.9
C3—C1—C4120.26 (13)C5—C7—N1105.97 (14)
C2—C1—C4120.60 (13)C5—C7—C8131.54 (16)
C1—C2—C3i119.90 (14)N1—C7—C8122.47 (15)
C1—C2—H2120.0C7—C8—H8A109.5
C3i—C2—H2120.0C7—C8—H8B109.5
C1—C3—C2i120.96 (13)H8A—C8—H8B109.5
C1—C3—H3119.5C7—C8—H8C109.5
C2i—C3—H3119.5H8A—C8—H8C109.5
O2—C4—O1124.38 (13)H8B—C8—H8C109.5
O2—C4—C1117.65 (13)C6—N1—C7108.91 (13)
O1—C4—C1117.96 (13)C6—N1—H1A127.5 (14)
C7—C5—N2108.11 (15)C7—N1—H1A123.3 (14)
C7—C5—H5125.9C6—N2—C5108.73 (14)
N2—C5—H5125.9C6—N2—H2A125.9 (12)
N2—C6—N1108.28 (14)C5—N2—H2A125.4 (12)
N2—C6—H6125.9
C3—C1—C2—C3i0.1 (3)N2—C5—C7—N10.79 (19)
C4—C1—C2—C3i179.82 (15)N2—C5—C7—C8177.79 (18)
C2—C1—C3—C2i0.1 (3)N2—C6—N1—C70.36 (19)
C4—C1—C3—C2i179.83 (16)C5—C7—N1—C60.71 (18)
C3—C1—C4—O23.8 (2)C8—C7—N1—C6178.03 (16)
C2—C1—C4—O2176.41 (15)N1—C6—N2—C50.1 (2)
C3—C1—C4—O1177.13 (16)C7—C5—N2—C60.6 (2)
C2—C1—C4—O12.6 (2)
Symmetry code: (i) x, y, z+2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O2ii0.82 (2)1.90 (2)2.6968 (18)161.0 (19)
C6—H6···O1iii0.932.303.164 (2)154
N2—H2A···O10.92 (2)1.74 (2)2.6632 (17)171.8 (18)
N2—H2A···O20.92 (2)2.52 (2)3.1691 (18)127.3 (15)
Symmetry codes: (ii) x+1, y+1/2, z+3/2; (iii) x, y+1/2, z1/2.

Experimental details

(I)(II)
Crystal data
Chemical formulaC4H7N2+·C8H5O42C4H7N2+·C8H4O42
Mr248.24330.34
Crystal system, space groupTriclinic, P1Monoclinic, P21/c
Temperature (K)298296
a, b, c (Å)7.2649 (5), 8.9459 (7), 9.6844 (7)10.7759 (7), 7.5608 (5), 10.3254 (7)
α, β, γ (°)75.406 (1), 72.731 (1), 77.966 (2)90, 103.454 (1), 90
V3)575.52 (7)818.17 (9)
Z22
Radiation typeMo KαMo Kα
µ (mm1)0.110.10
Crystal size (mm)0.30 × 0.10 × 0.040.36 × 0.30 × 0.10
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Bruker SMART APEX CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1997)
Multi-scan
(SADABS; Sheldrick, 1997)
Tmin, Tmax0.956, 0.9960.945, 0.990
No. of measured, independent and
observed [I > 2σ(I)] reflections
5915, 2204, 1820 8924, 1860, 1491
Rint0.0210.029
(sin θ/λ)max1)0.6170.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.156, 1.07 0.048, 0.151, 1.08
No. of reflections22041860
No. of parameters173116
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.25, 0.290.24, 0.21

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2003).

Geometry of hydrogen bonds and C—H···π interactions in the title compounds (Å, °) top
D—H···AD—HH···AD···AD—H···A
(I)
N1—H1···O20.93 (2)1.749 (19)2.6536 (17)162.7 (18)
N2—H2A···O1ii0.98 (2)1.59 (2)2.5657 (16)176.5 (19)
O4—H4···O1iii0.98 (2)1.59 (2)2.5657 (16)176.5 (19)
C3—H3···O3iv0.932.533.2762 (19)138
C9—H9···O3v0.932.273.155 (2)160
C2—H2···Cg1vi0.932.963.744 (2)143
C11—H11···Cg2vii0.932.603.429 (2)149
(II)
N1—H1A···O2viii0.82 (2)1.90 (2)2.6968 (18)161.0 (19)
N2—H2A···O10.92 (2)1.74 (2)2.6632 (17)171.8 (18)
C6—H6···O1ix0.932.303.164 (2)154
C8—H8C···Cg3x0.963.003.791 (2)141
Symmetry codes: (ii) x, y-1, z; (iii) x, y, z+1; (iv) -x, -y+2, -z+1; (v) -x, -y+1, -z+1; (vi) -x,1-y,-z; (vii) 1-x, 1-y, -z; (viii) -x+1, y+1/2, -z+3/2; (ix) x, -y+1/2, z-1/2; (ix) 1-x,-y, 2-z. Cg1 is the centroid defined by atoms N1/N2/C9–C11 in (I); Cg2 and Cg3 are the centroids defined by the benzene C atoms in (I) and (II), respectively.
 

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