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Different packing motifs in the crystal structures of three mol­ecular salts containing the 2-amino-5-carb­­oxy­anilinium cation: C7H9N2O2+·Cl, C7H9N2O2+·Br and C7H9N2O2+·NO3·H2O

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aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
*Correspondence e-mail: w.harrison@abdn.ac.uk

Edited by C. Massera, Università di Parma, Italy (Received 27 February 2020; accepted 6 March 2020; online 13 March 2020)

The syntheses and crystal structures of three mol­ecular salts of protonated 3,4-di­amino­benzoic acid, viz. 2-amino-5-carb­oxy­anilinium chloride, C7H9N2O2+·Cl, (I), 2-amino-5-carb­oxy­anilinium bromide, C7H9N2O2+·Br, (II), and 2-amino-5-carb­oxy­anilinium nitrate monohydrate, C7H9N2O2+·NO3·H2O, (III), are described. The cation is protonated at the meta-N atom (with respect to the carb­oxy group) in each case. In the crystal of (I), carb­oxy­lic acid inversion dimers linked by pairwise O—H⋯O hydrogen bonds are seen and each N—H group forms a hydrogen bond to a chloride ion to result in (100) undulating layers of chloride ions bridged by the inversion dimers into a three-dimensional network. The extended structure of (II) features O—H⋯Br, N—H⋯Br and N—H⋯O hydrogen bonds: the last of these generates C(7) chains of cations. Overall, the packing in (II) features undulating (100) sheets of bromide ions alternating with the organic cations. Inter­molecular inter­actions in the crystal of (III) include O—H⋯O, O—H⋯(O,O), N—H⋯O, N—H⋯N and O—H⋯N links. The cations are linked into (001) sheets, and the nitrate ions and water mol­ecules form undulating chains. Taken together, alternating (001) slabs of organic cations plus anions/water mol­ecules result. Hirshfeld surfaces and fingerprint plots were generated to give further insight into the inter­molecular inter­actions in these structures. The crystal used for the data collection of (II) was twinned by rotation about [100] in reciprocal space in a 0.4896 (15):0.5104 (15) ratio.

1. Chemical context

The benzoate anion, C7H5O2 is a classic ligand in coordin­ation chemistry, with over 1500 crystal structures reported in the Cambridge Structural Database (version 5.40, updated to February 2020; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) for benzoate complexes of first-row transition metals alone. Functionalized benzoic acid derivatives add further structural variety: for example, –NH2 substituents at the ortho, meta and/or para positions of the benzene ring can form or accept hydrogen bonds with respect to nearby acceptor or donor groups and/or bond as Lewis bases to another metal ion (i.e. as a μ2-N,O or μ3-N,O,O bridging ligand). It should be noted that the presence of amine groups allows for protonation and the possible formation of mol­ecular salts with the amino­benzoic acid acting as the cation.

As part of our ongoing studies in this area (Khosa et al., 2015[Khosa, M. K., Wood, P. T., Humphreys, S. M. & Harrison, W. T. A. (2015). J. Struct. Chem. 56, 1130-1135.]), we now describe the syntheses and structures of three mol­ecular salts of protonated 3,4-di­amino­benzoic acid, viz. C7H9N2O2·Cl (I)[link], C7H9N2O2·Br (II)[link] and C7H9N2O2·NO3·H2O (III)[link]. Hirshfeld surface analyses have been performed to gain further insight into the inter­molecular inter­actions.

[Scheme 1]

2. Structural commentary

The contents of the asymmetric units of (I)[link] (Fig. 1[link]), (II)[link] (Fig. 2[link]) and (III)[link] (Fig. 3[link]) confirm them to be mol­ecular salts of 3,4-di­amino­benzoic acid (i.e. the C7H9N2O2+ 2-amino-5-carb­oxy­anilinium cation has been formed) and the appropriate strong acid (hydro­chloric acid, hydro­bromic acid and nitric acid, respectively); compound (III)[link] also includes a water mol­ecule of crystallization. The neutral organic mol­ecule (C7H8N2O2) is known to crystallize as a zwitterion (Rzaczyńska et al., 2000[Rzaczyńska, Z., Mrozek, R., Lenik, J., Sikorska, M. & Głowiak, T. (2000). J. Chem. Crystallogr. 30, 519-524.]) with nominal intra­molecular proton transfer from the carb­oxy­lic acid to the meta-N atom and presumably exists in the same form in solution, thus the formal acid–base reaction to form the title salts involves proton transfer from the strong acid to the –CO2 carboxyl­ate group of zwitterionic C7H8N2O2 to form a –CO2H carb­oxy­lic acid group; atom N1 remains protonated, to result in the C7H9N2O2+ cation.

[Figure 1]
Figure 1
The mol­ecular structure of (I)[link] showing 50% displacement ellipsoids. The N—H⋯Cl hydrogen bond is indicated by a double-dashed line.
[Figure 2]
Figure 2
The mol­ecular structure of (II)[link] showing 50% displacement ellipsoids. The N—H⋯Br hydrogen bond is indicated by a double-dashed line.
[Figure 3]
Figure 3
The mol­ecular structure of (III)[link] showing 50% displacement ellipsoids. The O—H⋯O hydrogen bonds are indicated by double-dashed lines.

The preference for the meta –NH2 group to be protonated in these salts compared to the para –NH2 group can be rationalized in terms of the potential loss of conjugation of the para-N-atom lone pair of electrons with the carb­oxy­lic acid grouping via the benzene ring, i.e., a small contribution of a quinoid (C=N+ containing) resonance form to the structure (Lai & Marsh, 1967[Lai, T. F. & Marsh, R. E. (1967). Acta Cryst. 22, 885-893.]): the mean bond lengths for C1—C2, C3—C4, C4—C5 and C1—C6 (single bonds in the quinoid structure) and C2—C3 and C5—C6 (double bonds) are 1.401/1.380, 1.400/1.381 and 1.403/1.373 Å for (I)[link], (II)[link] and (III)[link], respectively (global averages = 1.401/1.378 Å). These data compare very well to the equivalent values of 1.399/1.375 Å established over 50 years ago from Weissenberg data for p-amino­benzoic acid (Lai & Marsh, 1967[Lai, T. F. & Marsh, R. E. (1967). Acta Cryst. 22, 885-893.]).

This electronic effect is also no doubt reflected in the fact that the C4—N2 (para) bond in the title compounds is notably shorter than the C3—N1 (meta) bond [distances in (I)[link] = 1.378 (2) and 1.4640 (19), respectively; (II)[link] = 1.387 (6) and 1.468 (6); (III)[link] = 1.386 (5) and 1.457 (5) Å]. Even so, it may be noted that the bond-angle sums about N2 are 348.0, 340.4, and 339.2° for (I)[link], (II)[link] and (III)[link], respectively, suggesting a tendency towards sp3 hybridization (and presumably lone-pair localization) for the nitro­gen atom in each case: it also correlates with the fact that N2 accepts a hydrogen bond in the crystal of (III)[link] (vide infra).

For each structure, the carb­oxy­lic acid group shows the expected clear distinction between the C7—O1H [(I) = 1.296 (2), (II)[link] = 1.326 (5), (III)[link] = 1.323 (6)Å] and C7=O2 [(I) = 1.252 (2), (II)[link] = 1.216 (5), (III)[link] = 1.232 (5) Å] bond lengths. The degree of twist of the –CO2H group with respect to the benzene ring is similar in the three salts [the angles between the mean planes passing through atoms C1–C6 and O1/O2/C7 are (I)[link] = 6.39 (16), (II)[link] = 0.5 (4), (III)[link] = 3.8 (5)°].

3. Supra­molecular features

In the crystal of (I)[link], the cations are connected into carb­oxy­lic acid inversion dimers via pairwise O—H⋯O hydrogen bonds (Table 1[link]), thereby generating classical R22(8) loops. All five N—H groups link to a nearby chloride ion: the H⋯Cl contacts from the protonated –N1H3+ moiety (mean = 2.35 Å) are substanti­ally shorter than those arising from the unprotonated –N2H2 group (mean = 2.70 Å). As a result, the chloride ion accepts five N—H⋯Cl bonds from four cations (one cation bonds from both N1 and N2) in an irregular geometry (Fig. 4[link]). The overall packing for (I)[link] results in corrugated (100) sheets of chloride ions bridged by the carb­oxy­lic acid dimers into a three-dimensional supra­molecular network (Fig. 5[link]).

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

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1O⋯O2i 0.74 (3) 1.88 (3) 2.6169 (18) 170 (3)
N1—H1N⋯Cl1ii 0.90 (2) 2.32 (2) 3.1578 (14) 153.4 (17)
N1—H2N⋯Cl1 0.91 (2) 2.25 (2) 3.1576 (15) 172.1 (18)
N1—H3N⋯Cl1iii 0.90 (2) 2.49 (2) 3.1722 (14) 132.9 (16)
N2—H4N⋯Cl1iv 0.86 (2) 2.72 (2) 3.2382 (15) 120.3 (17)
N2—H5N⋯Cl1iii 0.81 (2) 2.68 (2) 3.4852 (15) 176 (2)
Symmetry codes: (i) -x+1, -y+2, -z+1; (ii) [-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (iii) [x, -y+1, z+{\script{1\over 2}}]; (iv) [-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}].
[Figure 4]
Figure 4
Environment of the chloride ion in the structure of (I)[link] with N—H⋯Cl hydrogen bonds indicated by double-dashed lines. Symmetry codes: (i) [{1\over 2}] − x, y − [{1\over 2}], [{3\over 2}] − z; (ii) x, 1 − y, z − [{1\over 2}]; (iii) [{1\over 2}] − x, [{1\over 2}] + y, [{3\over 2}] − z.
[Figure 5]
Figure 5
The packing for (I)[link] viewed down [001]. The hydrogen bonds linking the carb­oxy­lic-acid inversion dimers are shown as double-dashed lines.

Rather than carb­oxy­lic acid inversion dimers, the packing for (II)[link] features O—H⋯Br hydrogen bonds as well as N—H⋯Br and N—H⋯O contacts (Table 2[link]). The bromide ion (Fig. 6[link]) is five-coordinated in an irregular geometry by four N—H⋯Br and one O—H⋯Br link arising from five different cations. The N1—H2N⋯O2 inter­action from the protonated –NH3+ group to the C=O bond of the carb­oxy­lic acid generates [010] C(7) chains of cations, with adjacent ions in the chain related by the 21 screw axis. When all the hydrogen bonds are considered together, the packing for (II)[link] can be described as a three-dimensional supra­molecular network of undulating (100) sheets of bromide ions alternating with the organic cations (Fig. 7[link]). A notably short C—H⋯O inter­action (H⋯O = 2.23 Å), which reinforces the C(7) chain of cations, is also observed.

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

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1O⋯Br1i 0.79 (7) 2.42 (7) 3.199 (3) 169 (6)
N1—H1N⋯Br1 0.73 (6) 2.70 (7) 3.404 (5) 163 (6)
N1—H2N⋯O2ii 0.90 (6) 1.90 (6) 2.787 (5) 168 (5)
N1—H3N⋯Br1iii 0.85 (6) 2.49 (6) 3.333 (5) 171 (5)
N2—H4N⋯Br1iv 0.81 (7) 2.98 (7) 3.705 (5) 150 (5)
N2—H5N⋯Br1v 0.82 (6) 2.98 (6) 3.513 (4) 125 (5)
C2—H2⋯O2ii 0.95 2.23 3.024 (5) 140
Symmetry codes: (i) -x+1, -y+1, -z; (ii) [-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iii) x, y, z+1; (iv) [-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (v) -x+2, -y+1, -z+1.
[Figure 6]
Figure 6
Environment of the bromide ion in the structure of (II)[link] with N—H⋯Br and O—H⋯Br hydrogen bonds indicated by double-dashed lines. Symmetry codes: (i) x, y, z − 1; (ii) 2 − x, 1 − y, 1 − z; (iii) 2 − x, [{1\over 2}] + y, [{1\over 2}] − z; (iv) 1 − x, 1 − y, −z.
[Figure 7]
Figure 7
The packing for (II)[link] viewed down [001].

The directional inter­molecular inter­actions in (III)[link] (Table 3[link]) include Oc—H⋯On, Ow—H⋯(On,On), N—H⋯Oc, N—H⋯N and N—H⋯On (c = carb­oxy­lic acid, n = nitrate, w = water) hydrogen bonds. The O atoms of the nitrate ion collectively accept four simple and one bifurcated hydrogen bond (Fig. 8[link]) from three cations and two water mol­ecules. As in (II)[link], an N1—H2N⋯O2 hydrogen bond in (III)[link] generates C(7) chains of cations propagating in [010] with adjacent ions related by the screw axis but an N1—H3N⋯N2 inter­action also occurs; by itself it leads to [100] C(5) chains with adjacent ions related by translation; together, (001) hydrogen-bonded sheets of cations arise. When the nitrate ion and water mol­ecules are taken together, undulating hydrogen-bonded chains propagating in the [010] direction arise. Collectively, the packing in (III)[link] (Fig. 9[link]) can be described as alternating (001) slabs of nitrate anions + water mol­ecules and organic cations arising from a three-dimensional supra­molecular network of hydrogen bonds.

Table 3
Hydrogen-bond geometry (Å, °) for (III)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1N⋯O6i 0.91 1.87 2.764 (5) 165
N1—H2N⋯O2ii 0.91 1.91 2.808 (5) 168
N1—H3N⋯N2iii 0.91 2.32 3.094 (6) 143
N1—H3N⋯O6iv 0.91 2.33 2.862 (5) 118
N2—H4N⋯O4i 0.91 (6) 2.07 (6) 2.972 (5) 169 (5)
N2—H5N⋯O5v 0.83 (6) 2.34 (7) 3.129 (5) 159 (6)
O1—H1O⋯O3 0.88 (6) 1.79 (6) 2.662 (5) 170 (6)
O6—H2O⋯O5 0.86 2.02 2.884 (5) 176
O6—H3O⋯O3vi 0.96 2.26 2.920 (5) 125
O6—H3O⋯O4vi 0.96 2.33 3.068 (5) 133
C2—H2⋯O2ii 0.95 2.54 3.285 (5) 135
Symmetry codes: (i) x-1, y, z-1; (ii) [-x+1, y-{\script{1\over 2}}, -z+1]; (iii) x+1, y, z; (iv) x, y, z-1; (v) [-x, y+{\script{1\over 2}}, -z+1]; (vi) [-x+2, y-{\script{1\over 2}}, -z+2].
[Figure 8]
Figure 8
Environment of the nitrate ion in the structure of (III)[link] with N—H⋯O and O—H⋯O hydrogen bonds indicated by double-dashed lines. Symmetry codes: (i) 1 + x, y, 1 + z; (ii) 2 − x, [{1\over 2}] + y, 2 − z; (iii) −x, y − [{1\over 2}]; 1 − z.
[Figure 9]
Figure 9
The packing for (III)[link] viewed down [100].

The three structures feature weak aromatic ππ stacking (Table 4[link]). In each case, infinite stacks of mol­ecules, with considerable slippage between adjacent benzene rings, arise: these stacks propagate in the [001], [001] and [100] directions for (I)[link], (II)[link] and (III)[link], respectively. A crystallographic c-glide generates the stacks in (I)[link] and (II)[link], whereas in (III)[link] adjacent mol­ecules are related by simple translation.

Table 4
Aromatic π–π stacking inter­actions in the title compounds

All inter­actions involve the C1–C6 benzene rings. CgCg is the centroid–centroid separation, α is the dihedral angle between the ring planes.

Compound CgCg (Å) α (°) slippage (Å) symmetry
(I) 3.8895 (9) 1.79 (7) 1.902 x, 1 − y, z − [{1\over 2}]
(I) 3.8895 (9) 1.79 (7) 1.822 x, 1 − y, z + [{1\over 2}]
(II) 3.736 (3) 1.5 (2) 2.035 x, [{1\over 2}] − y, z − [{1\over 2}]
(II) 3.736 (3) 1.5 (2) 1.954 x, [{1\over 2}] − y, z + [{1\over 2}]
(III) 3.890 (2) 0.0 (2) 2.105 x − 1, y, z
(III) 3.890 (2) 0.0 (2) 2.105 x + 1, y, z

4. Hirshfeld surface analyses

In order to gain further insight into the inter­molecular inter­actions in (I)[link], (II)[link] and (III)[link], their Hirshfeld surfaces and two-dimensional fingerprint plots were calculated using CrystalExplorer (Turner et al., 2017[Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). CrystalExplorer17. University of Western Australia. https://hirshfeldsurface.net.]) following the approach recently described by Tan et al. (2019[Tan, S. L., Jotani, M. M. & Tiekink, E. R. T. (2019). Acta Cryst. E75, 308-318.]). The Hirshfeld surfaces of the cations in (I)[link], (II)[link] and (III)[link] (see supplementary materials) show the expected red spots of varying intensity corresponding to close contacts resulting from the hydrogen bonds described above. The percentage contributions of the different type of contacts to the surfaces (Table 5[link]) call for some comment. Despite their different packing motifs, especially the presence of pairwise O—H⋯O hydrogen bonds in (I)[link] and O—H⋯Br and N—H⋯O inter­actions in (II)[link], the contact percentages for the C7H9N2O2+ cations in (I)[link] and (II)[link] are strikingly similar, being mostly within 1% of each other. It may be seen that H⋯H (van der Waals) contacts dominate, followed by H⋯X (X = Cl, Br), H⋯O (donor) and then O⋯H (acceptor), with other contacts playing a minor role. The contact percentage data for (III)[link] are decidedly different with H⋯O (donor) (32.2%) dominating and H⋯H (23.3%) relegated to second place, followed by O⋯H (acceptor) (12.6%). Despite the N—H⋯N hydrogen bond in (III)[link], the H⋯N contact percentages barely differ for the three compounds. The contact percentages for the anions in (I)[link] and (II)[link] (Table 5[link]) show them to be essentially `saturated' by their hydrogen bonds, despite the irregular coordination geometries.

Table 5
Hirshfeld fingerprint contact percentages for different inter­molecular inter­actions in the title compounds

Inter­action (I) (II) (III)
H⋯H 30.3 30.7 23.3
H⋯Xa 14.5 15.2
H⋯O (donor) 10.6 10.0 32.2
H⋯C 6.8 6.7 5.8
H⋯N 1.9 2.2 2.3
C⋯C 6.7 6.8 6.4
C⋯H 8.6 8.6 9.0
C⋯O 2.2 2.4 2.9
N⋯H 2.1 2.7 2.1
O⋯H (acceptor) 13.3 11.6 12.6
Xa⋯H 99.8 98.7
Note: (a) For (I)[link], X = Cl; for (II)[link] X = Br.

The fingerprint plot for the cation in (I)[link] (Fig. 10[link]) of outward (i.e. non-reciprocal) contacts shows three prominent features: the spike ending at (di, de) = (∼0.76, ∼1.36 Å) and extending backwards corresponds to the short inter­molecular H⋯Cl contacts associated with the N—H⋯Cl hydrogen bonds. The pronounced (0.65, 1.00 Å) feature equates with the H⋯O (donor) contact of the O—H⋯O hydrogen bond and that at (1.00, 0.65 Å) is associated with the H⋯O (acceptor) contact. The fingerprint plot for the cation in (II)[link] (Fig. 11[link]) shows the equivalent three spikes ending at (0.76, 1.45), (0.72, 1.08) and (1.06, 0.72 Å): the greater value of de for the first of these presumably reflects the larger size of the bromide ion in (II)[link] compared to the chloride ion in (I)[link]. The fingerprint plot for the cation in (III)[link] (Fig. 12[link]) naturally lacks the H⋯X (X = Cl, Br) features and has a more symmetric appearance, with the spike at (0.68, 1.02) equating to H⋯O (donor) and that at (1.08, 0.74 Å) equating to the O⋯H (acceptor) contact. The H⋯N (donor) contact is just perceptible as a shoulder-like feature terminating at (0.94, 1.30 Å) but mostly superimposed on the tail of the H⋯O spike. The `wing' like fingerprint plot for the chloride ion in (I)[link] (Fig. 13[link]) looks radically different to that of the cation (Fig. 10[link]) although the end-point at (1.38, 0.77 Å) of the sweeping feature corresponds well with the H⋯Cl contact for the cation. The fingerprint plot for the bromide ion in (II)[link] (Fig. 14[link]) with its sweeping feature terminating at (1.45, 0.77 Å) shows similar correspondence with the H⋯Br spike for the cation in (II)[link] (Fig. 11[link]).

[Figure 10]
Figure 10
Hirshfeld fingerprint plot for the C7H9N2O2+ cation in (I)[link].
[Figure 11]
Figure 11
Hirshfeld fingerprint plot for the C7H9N2O2+ cation in (II)[link].
[Figure 12]
Figure 12
Hirshfeld fingerprint plot for the C7H9N2O2+ cation in (III)[link].
[Figure 13]
Figure 13
Hirshfeld fingerprint plot for the chloride anion in (I)[link].
[Figure 14]
Figure 14
Hirshfeld fingerprint plot for the bromide anion in (II)[link].

5. Database survey

So far as we are aware, no mol­ecular salts containing the C7H9N2O2+ cation have been structurally characterized up to this point. A search of the Cambridge Structural Database (Version 5.40, updated to February 2020; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) yielded five complexes of the 3,4-di­amino­benzoate anion (i.e. C7H7N2O2) with sodium (CCDC refcode BEHJEE; Rzaczyńska et al., 2003[Rzaczyńska, Z., Bartyzel, A. & Głowiak, T. (2003). J. Coord. Chem. 56, 77-83.]), zinc (MIWSES; Fernández-Palacio et al., 2014[Fernández-Palacio, F., Restrepo, J., Gálvez, S., Gómez-Sal, P. & Mosquera, M. E. G. (2014). CrystEngComm, 16, 3376-3386.]), tin (XUPRUV and XUPSAC; Pruchnik et al., 2002[Pruchnik, F. P., Bańbuła, M., Ciunik, Z., Chojnacki, H., Latocha, M., Skop, B., Wilczok, T., Opolski, A., Wietrzyk, J. & Nasulewicz, A. (2002). Eur. J. Inorg. Chem. pp. 3214-3221.]) and neodymium (YENKOR; Rzaczyńska et al., 1994[Rzaczyńska, Z., Belskii, V. K. & Zavodnik, V. E. (1994). Polish J. Chem. 68, 1639-1647.]). As noted above, the structure of the zwitterionic free mol­ecule of C7H8N2O2 is known (VODWIU; Rzaczyńska et al., 2000[Rzaczyńska, Z., Mrozek, R., Lenik, J., Sikorska, M. & Głowiak, T. (2000). J. Chem. Crystallogr. 30, 519-524.]). Inter­estingly, the neutral, non-zwitterionic form of C7H8N2O2 has been co-crystallized with an organo-rhenium compound and other species (DONDUH; Davies et al., 2014[Davies, L. H., Kasten, B. B., Benny, P. D., Arrowsmith, R. L., Ge, H., Pascu, S. I., Botchway, S. W., Clegg, W., Harrington, R. W. & Higham, L. J. (2014). Chem. Commun. 50, 15503-15505.]). In VODWIU, the –CO2 group accepts several N—H⋯O hydrogen bonds while in DONDUH pairwise carb­oxy­lic-acid inversion dimers are formed. The different possible structures of the organic species are shown in Fig. 15[link].

[Figure 15]
Figure 15
Different structures based on 3,4-di­amino­benzoic acid: (a) neutral C7H8N2O2 mol­ecule as found in DONDUH; (b) zwitterion in VODWIU; (c) quinoid resonance form of the C7H9N2O2+ cation in the title compounds (see text and compare scheme 1); (d) C7H7N2O2 anion as found in the metal complexes noted in the text.

6. Synthesis and crystallization

Equimolar mixtures of 3,4-di­amino­benzoic acid and hydro­chloric acid (I)[link], hydro­bromic acid (II)[link] and nitric acid (III)[link] dissolved in water were deca­nted into petri dishes at room temperature and brown plates of (I)[link], pale-brown laths of (II)[link] and colourless slabs of (III)[link] formed as the water evaporated over the course of a few days. The IR spectra for 3,4-di­amino­benzoic acid, (I)[link], (II)[link] and (III)[link] are available as supporting information.

7. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 6[link]. For each structure, the N-bound H atoms were located in difference maps and their positions were freely refined. The C-bound H atoms were geometrically placed (C—H = 0.95 Å) and refined as riding atoms. The water H atoms in (III)[link] were located in difference maps and refined as riding atoms in their as-found relative locations. The constraint Uiso(H) = 1.2Ueq(carrier) was applied in all cases. The crystal used for the data collection of (II)[link] was twinned by rotation about [100] in reciprocal space in a 0.4896 (15):0.5104 (15) ratio and data merging was not performed (i.e. HKLF 5 refinement). The absolute structure of (III)[link] could not be determined based on the refinement reported here.

Table 6
Experimental details

  (I) (II) (III)
Crystal data
Chemical formula C7H9N2O2+·Cl C7H9N2O2+·Br C7H9N2O2+·NO3·H2O
Mr 188.61 233.07 233.19
Crystal system, space group Monoclinic, C2/c Monoclinic, P21/c Monoclinic, P21
Temperature (K) 100 100 100
a, b, c (Å) 28.0521 (6), 8.0469 (2), 7.2511 (2) 12.1190 (7), 11.0708 (5), 6.3795 (3) 3.8899 (3), 9.8238 (6), 12.5799 (9)
β (°) 91.309 (2) 103.047 (6) 98.673 (7)
V3) 1636.38 (7) 833.82 (8) 475.22 (6)
Z 8 4 2
Radiation type Mo Kα Mo Kα Mo Kα
μ (mm−1) 0.43 4.89 0.14
Crystal size (mm) 0.41 × 0.26 × 0.04 0.25 × 0.12 × 0.04 0.20 × 0.10 × 0.05
 
Data collection
Diffractometer Rigaku Mercury CCD Rigaku Mercury CCD Rigaku Mercury CCD
Absorption correction Gaussian (CrysAlis PRO; Rigaku, 2017[Rigaku (2017). CrysAlis PRO. Rigaku Inc., Tokyo, Japan.]) Multi-scan (CrysAlis PRO; Rigaku, 2017[Rigaku (2017). CrysAlis PRO. Rigaku Inc., Tokyo, Japan.]) Multi-scan (CrysAlis PRO; Rigaku, 2017[Rigaku (2017). CrysAlis PRO. Rigaku Inc., Tokyo, Japan.])
Tmin, Tmax 0.624, 1.000 0.538, 1.000 0.861, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 13456, 1865, 1765 3343, 3343, 3031 10770, 2157, 2100
Rint 0.035 ? 0.067
(sin θ/λ)max−1) 0.649 0.649 0.649
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.093, 1.13 0.036, 0.100, 1.14 0.058, 0.149, 1.15
No. of reflections 1865 3343 2157
No. of parameters 127 128 155
No. of restraints 0 0 1
H-atom treatment H atoms treated by a mixture of independent and constrained refinement H atoms treated by a mixture of independent and constrained refinement H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.45, −0.27 1.01, −0.70 0.48, −0.37
Computer programs: CrysAlis PRO (Rigaku, 2017[Rigaku (2017). CrysAlis PRO. Rigaku Inc., Tokyo, Japan.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2014/7 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ORTEP-3 for Windows (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

For all structures, data collection: CrysAlis PRO (Rigaku, 2017); cell refinement: CrysAlis PRO (Rigaku, 2017); data reduction: CrysAlis PRO (Rigaku, 2017); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: publCIF (Westrip, 2010).

2-Amino-5-carboxyanilinium chloride (I) top
Crystal data top
C7H9N2O2+·ClF(000) = 784
Mr = 188.61Dx = 1.531 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 28.0521 (6) ÅCell parameters from 8736 reflections
b = 8.0469 (2) Åθ = 2.9–30.1°
c = 7.2511 (2) ŵ = 0.43 mm1
β = 91.309 (2)°T = 100 K
V = 1636.38 (7) Å3Plate, brown
Z = 80.41 × 0.26 × 0.04 mm
Data collection top
Rigaku Mercury CCD
diffractometer
1765 reflections with I > 2σ(I)
ω scansRint = 0.035
Absorption correction: gaussian
(CrysAlisPRO; Rigaku, 2017)
θmax = 27.5°, θmin = 2.6°
Tmin = 0.624, Tmax = 1.000h = 3636
13456 measured reflectionsk = 1010
1865 independent reflectionsl = 99
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.031H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.093 w = 1/[σ2(Fo2) + (0.0434P)2 + 2.8134P]
where P = (Fo2 + 2Fc2)/3
S = 1.13(Δ/σ)max = 0.002
1865 reflectionsΔρmax = 0.45 e Å3
127 parametersΔρmin = 0.27 e Å3
0 restraints
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.42198 (5)0.7087 (2)0.6424 (2)0.0132 (3)
C20.37721 (5)0.7561 (2)0.7037 (2)0.0124 (3)
H20.36960.87040.71730.015*
C30.34405 (5)0.6353 (2)0.7443 (2)0.0115 (3)
C40.35376 (5)0.46541 (19)0.7258 (2)0.0118 (3)
C50.39962 (5)0.4200 (2)0.6688 (2)0.0132 (3)
H50.40770.30580.65860.016*
C60.43292 (6)0.5395 (2)0.6276 (2)0.0139 (3)
H60.46360.50670.58870.017*
C70.45674 (6)0.8354 (2)0.5858 (2)0.0150 (3)
N10.29675 (5)0.68573 (18)0.8047 (2)0.0126 (3)
H1N0.2945 (7)0.797 (3)0.818 (3)0.015*
H2N0.2748 (7)0.653 (3)0.717 (3)0.015*
H3N0.2895 (7)0.641 (3)0.914 (3)0.015*
N20.31909 (5)0.34702 (18)0.7525 (2)0.0158 (3)
H4N0.3282 (7)0.246 (3)0.768 (3)0.019*
H5N0.2970 (8)0.371 (3)0.817 (3)0.019*
O10.44480 (5)0.98914 (17)0.6117 (2)0.0226 (3)
H1O0.4634 (9)1.042 (3)0.570 (3)0.027*
O20.49517 (4)0.79238 (15)0.51547 (18)0.0203 (3)
Cl10.22232 (2)0.53660 (4)0.51641 (5)0.01266 (14)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0110 (7)0.0134 (8)0.0153 (7)0.0017 (6)0.0015 (5)0.0010 (6)
C20.0130 (7)0.0109 (7)0.0132 (7)0.0002 (6)0.0004 (5)0.0004 (6)
C30.0107 (7)0.0131 (7)0.0108 (7)0.0007 (6)0.0011 (5)0.0002 (6)
C40.0128 (7)0.0123 (8)0.0104 (7)0.0010 (5)0.0002 (5)0.0013 (5)
C50.0144 (7)0.0107 (7)0.0145 (7)0.0019 (6)0.0011 (5)0.0001 (6)
C60.0111 (7)0.0150 (8)0.0157 (8)0.0012 (6)0.0019 (6)0.0003 (6)
C70.0129 (7)0.0141 (8)0.0180 (8)0.0013 (6)0.0015 (6)0.0014 (6)
N10.0124 (6)0.0106 (7)0.0149 (7)0.0001 (5)0.0032 (5)0.0008 (5)
N20.0144 (7)0.0094 (7)0.0236 (7)0.0003 (5)0.0050 (5)0.0014 (6)
O10.0181 (6)0.0132 (6)0.0370 (8)0.0040 (5)0.0096 (5)0.0020 (5)
O20.0130 (5)0.0189 (6)0.0294 (7)0.0015 (5)0.0074 (5)0.0026 (5)
Cl10.0148 (2)0.0094 (2)0.0138 (2)0.00125 (12)0.00239 (14)0.00038 (12)
Geometric parameters (Å, º) top
C1—C21.395 (2)C5—H50.9500
C1—C61.401 (2)C6—H60.9500
C1—C71.475 (2)C7—O21.252 (2)
C2—C31.382 (2)C7—O11.296 (2)
C2—H20.9500N1—H1N0.90 (2)
C3—C41.401 (2)N1—H2N0.91 (2)
C3—N11.4640 (19)N1—H3N0.90 (2)
C4—N21.378 (2)N2—H4N0.86 (2)
C4—C51.408 (2)N2—H5N0.81 (2)
C5—C61.378 (2)O1—H1O0.74 (3)
C2—C1—C6119.38 (14)C5—C6—H6119.6
C2—C1—C7120.35 (15)C1—C6—H6119.6
C6—C1—C7120.22 (14)O2—C7—O1123.41 (15)
C3—C2—C1119.42 (15)O2—C7—C1120.19 (15)
C3—C2—H2120.3O1—C7—C1116.40 (14)
C1—C2—H2120.3C3—N1—H1N111.9 (13)
C2—C3—C4122.18 (14)C3—N1—H2N108.2 (12)
C2—C3—N1119.22 (14)H1N—N1—H2N108.3 (18)
C4—C3—N1118.59 (14)C3—N1—H3N112.1 (13)
N2—C4—C3121.45 (14)H1N—N1—H3N106.6 (19)
N2—C4—C5120.93 (15)H2N—N1—H3N109.6 (18)
C3—C4—C5117.53 (14)C4—N2—H4N117.6 (14)
C6—C5—C4120.72 (15)C4—N2—H5N118.0 (16)
C6—C5—H5119.6H4N—N2—H5N112 (2)
C4—C5—H5119.6C7—O1—H1O107.7 (19)
C5—C6—C1120.73 (14)
C6—C1—C2—C31.6 (2)C3—C4—C5—C62.0 (2)
C7—C1—C2—C3175.73 (14)C4—C5—C6—C10.3 (2)
C1—C2—C3—C40.1 (2)C2—C1—C6—C51.5 (2)
C1—C2—C3—N1178.67 (14)C7—C1—C6—C5175.82 (15)
C2—C3—C4—N2174.64 (15)C2—C1—C7—O2173.60 (15)
N1—C3—C4—N23.9 (2)C6—C1—C7—O23.7 (2)
C2—C3—C4—C51.9 (2)C2—C1—C7—O15.8 (2)
N1—C3—C4—C5179.57 (13)C6—C1—C7—O1176.96 (16)
N2—C4—C5—C6174.58 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1O···O2i0.74 (3)1.88 (3)2.6169 (18)170 (3)
N1—H1N···Cl1ii0.90 (2)2.32 (2)3.1578 (14)153.4 (17)
N1—H2N···Cl10.91 (2)2.25 (2)3.1576 (15)172.1 (18)
N1—H3N···Cl1iii0.90 (2)2.49 (2)3.1722 (14)132.9 (16)
N2—H4N···Cl1iv0.86 (2)2.72 (2)3.2382 (15)120.3 (17)
N2—H5N···Cl1iii0.81 (2)2.68 (2)3.4852 (15)176 (2)
Symmetry codes: (i) x+1, y+2, z+1; (ii) x+1/2, y+1/2, z+3/2; (iii) x, y+1, z+1/2; (iv) x+1/2, y1/2, z+3/2.
2-Amino-5-carboxyanilinium bromide (II) top
Crystal data top
C7H9N2O2+·BrF(000) = 464
Mr = 233.07Dx = 1.857 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 12.1190 (7) ÅCell parameters from 8521 reflections
b = 11.0708 (5) Åθ = 3.4–30.1°
c = 6.3795 (3) ŵ = 4.89 mm1
β = 103.047 (6)°T = 100 K
V = 833.82 (8) Å3Lath, pale brown
Z = 40.25 × 0.12 × 0.04 mm
Data collection top
Rigaku Mercury CCD
diffractometer
3031 reflections with I > 2σ(I)
ω scansθmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan
(CrysAlisPRO; Rigaku, 2017)
h = 1515
Tmin = 0.538, Tmax = 1.000k = 1414
3343 measured reflectionsl = 88
3343 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.100 w = 1/[σ2(Fo2) + (0.0423P)2 + 2.9863P]
where P = (Fo2 + 2Fc2)/3
S = 1.14(Δ/σ)max = 0.001
3343 reflectionsΔρmax = 1.01 e Å3
128 parametersΔρmin = 0.69 e Å3
0 restraints
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refined as a two-component twin

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.5791 (4)0.3232 (4)0.3020 (7)0.0114 (9)
C20.6253 (4)0.4394 (4)0.3348 (7)0.0105 (8)
H20.57810.50850.30350.013*
C30.7405 (4)0.4520 (4)0.4131 (7)0.0093 (8)
C40.8130 (4)0.3529 (4)0.4643 (7)0.0110 (9)
C50.7646 (4)0.2369 (4)0.4251 (7)0.0113 (9)
H50.81190.16770.45350.014*
C60.6494 (4)0.2226 (4)0.3460 (7)0.0122 (9)
H60.61810.14380.32160.015*
C70.4558 (4)0.3082 (4)0.2165 (7)0.0107 (9)
N10.7876 (4)0.5748 (3)0.4373 (8)0.0110 (8)
H1N0.816 (5)0.593 (5)0.352 (10)0.013*
H2N0.729 (5)0.627 (5)0.409 (9)0.013*
H3N0.815 (5)0.590 (5)0.569 (10)0.013*
N20.9285 (4)0.3686 (4)0.5425 (7)0.0155 (9)
H4N0.959 (5)0.304 (6)0.578 (9)0.019*
H5N0.951 (5)0.420 (6)0.635 (10)0.019*
O10.3992 (3)0.4115 (3)0.1817 (6)0.0167 (7)
H1O0.334 (6)0.400 (5)0.130 (10)0.020*
O20.4107 (3)0.2098 (3)0.1823 (6)0.0161 (7)
Br10.86980 (4)0.61815 (4)0.03325 (7)0.01281 (15)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.011 (2)0.009 (2)0.013 (2)0.0010 (16)0.0028 (17)0.0006 (16)
C20.013 (2)0.009 (2)0.010 (2)0.0014 (16)0.0034 (16)0.0008 (16)
C30.014 (2)0.005 (2)0.010 (2)0.0009 (16)0.0047 (17)0.0012 (16)
C40.013 (2)0.012 (2)0.008 (2)0.0008 (17)0.0021 (16)0.0011 (16)
C50.014 (2)0.011 (2)0.010 (2)0.0028 (17)0.0048 (17)0.0011 (17)
C60.016 (2)0.009 (2)0.012 (2)0.0017 (16)0.0033 (18)0.0015 (17)
C70.010 (2)0.011 (2)0.012 (2)0.0009 (16)0.0032 (17)0.0000 (17)
N10.0112 (19)0.0086 (18)0.013 (2)0.0019 (15)0.0034 (16)0.0003 (16)
N20.010 (2)0.015 (2)0.020 (2)0.0019 (17)0.0002 (16)0.0013 (17)
O10.0083 (16)0.0094 (15)0.029 (2)0.0007 (12)0.0025 (14)0.0008 (13)
O20.0118 (15)0.0097 (15)0.0247 (19)0.0020 (13)0.0001 (14)0.0012 (13)
Br10.0108 (2)0.0136 (2)0.0130 (2)0.00047 (18)0.00053 (16)0.00011 (17)
Geometric parameters (Å, º) top
C1—C61.391 (6)C5—H50.9500
C1—C21.400 (6)C6—H60.9500
C1—C71.479 (6)C7—O21.216 (5)
C2—C31.379 (6)C7—O11.326 (5)
C2—H20.9500N1—H1N0.73 (6)
C3—C41.398 (6)N1—H2N0.90 (6)
C3—N11.468 (5)N1—H3N0.85 (6)
C4—N21.387 (6)N2—H4N0.81 (7)
C4—C51.410 (6)N2—H5N0.82 (6)
C5—C61.383 (6)O1—H1O0.79 (7)
C6—C1—C2119.9 (4)C5—C6—H6119.9
C6—C1—C7120.4 (4)C1—C6—H6119.9
C2—C1—C7119.7 (4)O2—C7—O1123.2 (4)
C3—C2—C1119.1 (4)O2—C7—C1122.8 (4)
C3—C2—H2120.5O1—C7—C1114.0 (4)
C1—C2—H2120.5C3—N1—H1N114 (5)
C2—C3—C4122.4 (4)C3—N1—H2N107 (4)
C2—C3—N1118.1 (4)H1N—N1—H2N99 (6)
C4—C3—N1119.5 (4)C3—N1—H3N111 (4)
N2—C4—C3121.1 (4)H1N—N1—H3N122 (6)
N2—C4—C5121.6 (4)H2N—N1—H3N101 (5)
C3—C4—C5117.3 (4)C4—N2—H4N110 (4)
C6—C5—C4120.9 (4)C4—N2—H5N119 (5)
C6—C5—H5119.5H4N—N2—H5N111 (6)
C4—C5—H5119.5C7—O1—H1O111 (4)
C5—C6—C1120.3 (4)
C6—C1—C2—C30.7 (6)C3—C4—C5—C62.1 (7)
C7—C1—C2—C3179.5 (4)C4—C5—C6—C10.5 (7)
C1—C2—C3—C41.0 (7)C2—C1—C6—C51.0 (7)
C1—C2—C3—N1177.4 (4)C7—C1—C6—C5179.8 (4)
C2—C3—C4—N2179.9 (4)C6—C1—C7—O20.4 (7)
N1—C3—C4—N21.5 (7)C2—C1—C7—O2179.2 (4)
C2—C3—C4—C52.4 (7)C6—C1—C7—O1179.9 (4)
N1—C3—C4—C5176.0 (4)C2—C1—C7—O11.1 (6)
N2—C4—C5—C6179.6 (5)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1O···Br1i0.79 (7)2.42 (7)3.199 (3)169 (6)
N1—H1N···Br10.73 (6)2.70 (7)3.404 (5)163 (6)
N1—H2N···O2ii0.90 (6)1.90 (6)2.787 (5)168 (5)
N1—H3N···Br1iii0.85 (6)2.49 (6)3.333 (5)171 (5)
N2—H4N···Br1iv0.81 (7)2.98 (7)3.705 (5)150 (5)
N2—H5N···Br1v0.82 (6)2.98 (6)3.513 (4)125 (5)
C2—H2···O2ii0.952.233.024 (5)140
Symmetry codes: (i) x+1, y+1, z; (ii) x+1, y+1/2, z+1/2; (iii) x, y, z+1; (iv) x+2, y1/2, z+1/2; (v) x+2, y+1, z+1.
2-Amino-5-carboxyanilinium nitrate monohydrate (III) top
Crystal data top
C7H9N2O2+·NO3·H2OF(000) = 244
Mr = 233.19Dx = 1.630 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
a = 3.8899 (3) ÅCell parameters from 3653 reflections
b = 9.8238 (6) Åθ = 2.7–30.8°
c = 12.5799 (9) ŵ = 0.14 mm1
β = 98.673 (7)°T = 100 K
V = 475.22 (6) Å3Slab, colourless
Z = 20.20 × 0.10 × 0.05 mm
Data collection top
Rigaku Mercury CCD
diffractometer
2100 reflections with I > 2σ(I)
ω scansRint = 0.067
Absorption correction: multi-scan
(CrysAlisPRO; Rigaku, 2017)
θmax = 27.5°, θmin = 2.6°
Tmin = 0.861, Tmax = 1.000h = 55
10770 measured reflectionsk = 1212
2157 independent reflectionsl = 1616
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.058H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.149 w = 1/[σ2(Fo2) + (0.0747P)2 + 0.3934P]
where P = (Fo2 + 2Fc2)/3
S = 1.15(Δ/σ)max = 0.005
2157 reflectionsΔρmax = 0.48 e Å3
155 parametersΔρmin = 0.37 e Å3
1 restraint
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.2205 (11)0.5688 (5)0.4736 (3)0.0120 (8)
C20.2777 (10)0.4617 (5)0.4062 (3)0.0121 (8)
H20.42310.38800.43340.014*
C30.1240 (10)0.4617 (4)0.2997 (3)0.0120 (8)
C40.0999 (11)0.5677 (4)0.2573 (3)0.0124 (8)
C50.1462 (11)0.6769 (4)0.3255 (3)0.0128 (8)
H50.28780.75160.29820.015*
C60.0082 (11)0.6778 (4)0.4303 (3)0.0121 (8)
H60.02770.75300.47480.014*
C70.3867 (11)0.5736 (4)0.5864 (3)0.0127 (8)
N10.1979 (10)0.3534 (4)0.2274 (3)0.0137 (8)
H1N0.00550.31980.19190.016*
H2N0.31740.28560.26610.016*
H3N0.32790.38710.17900.016*
N20.2843 (11)0.5597 (4)0.1542 (3)0.0167 (8)
H4N0.198 (16)0.524 (6)0.097 (5)0.020*
H5N0.358 (16)0.637 (6)0.136 (4)0.020*
O10.5752 (9)0.4650 (3)0.6185 (2)0.0182 (7)
H1O0.685 (15)0.469 (7)0.685 (5)0.022*
O20.3588 (8)0.6720 (3)0.6453 (2)0.0156 (7)
N30.9275 (9)0.4263 (4)0.8918 (3)0.0147 (8)
O30.9624 (10)0.4968 (4)0.8102 (3)0.0234 (8)
O41.0903 (8)0.4593 (4)0.9805 (2)0.0210 (7)
O50.7311 (10)0.3252 (4)0.8821 (3)0.0263 (8)
O60.6514 (8)0.2329 (3)1.0947 (3)0.0181 (7)
H2O0.66840.25661.02970.022*
H3O0.63280.13511.09760.022*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0129 (19)0.0080 (18)0.0155 (19)0.0052 (15)0.0033 (14)0.0015 (16)
C20.0105 (17)0.0076 (18)0.019 (2)0.0003 (16)0.0059 (14)0.0019 (16)
C30.0133 (19)0.0064 (18)0.0172 (19)0.0016 (17)0.0055 (14)0.0018 (16)
C40.015 (2)0.0084 (19)0.015 (2)0.0014 (16)0.0058 (15)0.0003 (17)
C50.015 (2)0.0044 (18)0.020 (2)0.0005 (16)0.0043 (15)0.0006 (17)
C60.0125 (19)0.0046 (17)0.021 (2)0.0010 (15)0.0076 (15)0.0000 (16)
C70.013 (2)0.0098 (19)0.015 (2)0.0043 (16)0.0020 (15)0.0000 (17)
N10.0137 (17)0.0123 (18)0.0148 (17)0.0055 (14)0.0014 (13)0.0014 (14)
N20.023 (2)0.0115 (18)0.0151 (18)0.0049 (15)0.0003 (14)0.0008 (15)
O10.0250 (17)0.0146 (16)0.0134 (14)0.0011 (14)0.0017 (12)0.0004 (13)
O20.0183 (16)0.0123 (15)0.0159 (14)0.0029 (12)0.0017 (11)0.0030 (13)
N30.0165 (17)0.0137 (18)0.0137 (17)0.0016 (14)0.0021 (13)0.0029 (14)
O30.0313 (19)0.0206 (17)0.0176 (16)0.0073 (14)0.0010 (13)0.0017 (14)
O40.0226 (16)0.0222 (18)0.0176 (15)0.0014 (14)0.0012 (12)0.0029 (13)
O50.032 (2)0.0202 (18)0.0268 (19)0.0136 (16)0.0056 (15)0.0046 (15)
O60.0214 (16)0.0113 (14)0.0223 (16)0.0000 (13)0.0061 (13)0.0008 (12)
Geometric parameters (Å, º) top
C1—C21.391 (6)C7—O11.323 (6)
C1—C61.410 (6)N1—H1N0.9100
C1—C71.469 (5)N1—H2N0.9100
C2—C31.382 (5)N1—H3N0.9100
C2—H20.9500N2—H4N0.91 (6)
C3—C41.409 (6)N2—H5N0.83 (6)
C3—N11.457 (5)O1—H1O0.88 (6)
C4—N21.386 (5)N3—O41.240 (5)
C4—C51.402 (6)N3—O51.247 (5)
C5—C61.363 (6)N3—O31.262 (5)
C5—H50.9500O6—H2O0.8625
C6—H60.9500O6—H3O0.9644
C7—O21.232 (5)
C2—C1—C6118.5 (4)O2—C7—O1123.0 (4)
C2—C1—C7121.7 (4)O2—C7—C1122.7 (4)
C6—C1—C7119.7 (4)O1—C7—C1114.3 (4)
C3—C2—C1120.3 (4)C3—N1—H1N109.5
C3—C2—H2119.8C3—N1—H2N109.5
C1—C2—H2119.8H1N—N1—H2N109.5
C2—C3—C4121.3 (4)C3—N1—H3N109.5
C2—C3—N1120.5 (4)H1N—N1—H3N109.5
C4—C3—N1118.2 (4)H2N—N1—H3N109.5
N2—C4—C5121.3 (4)C4—N2—H4N124 (4)
N2—C4—C3121.0 (4)C4—N2—H5N108 (4)
C5—C4—C3117.6 (4)H4N—N2—H5N107 (5)
C6—C5—C4121.2 (4)C7—O1—H1O115 (4)
C6—C5—H5119.4O4—N3—O5121.2 (4)
C4—C5—H5119.4O4—N3—O3119.0 (4)
C5—C6—C1121.0 (4)O5—N3—O3119.8 (4)
C5—C6—H6119.5H2O—O6—H3O108.8
C1—C6—H6119.5
C6—C1—C2—C31.1 (6)C3—C4—C5—C62.7 (6)
C7—C1—C2—C3178.4 (4)C4—C5—C6—C10.1 (6)
C1—C2—C3—C41.6 (6)C2—C1—C6—C51.8 (6)
C1—C2—C3—N1176.7 (4)C7—C1—C6—C5179.2 (4)
C2—C3—C4—N2172.5 (4)C2—C1—C7—O2174.8 (4)
N1—C3—C4—N29.2 (6)C6—C1—C7—O22.5 (6)
C2—C3—C4—C53.4 (6)C2—C1—C7—O13.7 (6)
N1—C3—C4—C5174.9 (4)C6—C1—C7—O1179.0 (4)
N2—C4—C5—C6173.3 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N···O6i0.911.872.764 (5)165
N1—H2N···O2ii0.911.912.808 (5)168
N1—H3N···N2iii0.912.323.094 (6)143
N1—H3N···O6iv0.912.332.862 (5)118
N2—H4N···O4i0.91 (6)2.07 (6)2.972 (5)169 (5)
N2—H5N···O5v0.83 (6)2.34 (7)3.129 (5)159 (6)
O1—H1O···O30.88 (6)1.79 (6)2.662 (5)170 (6)
O6—H2O···O50.862.022.884 (5)176
O6—H3O···O3vi0.962.262.920 (5)125
O6—H3O···O4vi0.962.333.068 (5)133
C2—H2···O2ii0.952.543.285 (5)135
Symmetry codes: (i) x1, y, z1; (ii) x+1, y1/2, z+1; (iii) x+1, y, z; (iv) x, y, z1; (v) x, y+1/2, z+1; (vi) x+2, y1/2, z+2.
Aromatic ππ stacking interactions in the title compounds top
All interactions involve the C1–C6 benzene rings. Cg···Cg is the centroid–centroid separation, α is the dihedral angle between the ring planes.
CompoundCg···Cg (Å)α (°)slippage (Å)symmetry
(I)3.8895 (9)1.79 (7)1.902x, 1 - y, z - 1/2
(I)3.8895 (9)1.79 (7)1.822x, 1 - y, z + 1/2
(II)3.736 (3)1.5 (2)2.035x, 1/2 - y, z - 1/2
(II)3.736 (3)1.5 (2)1.954x, 1/2 - y, z + 1/2
(III)3.890 (2)0.0 (2)2.105x - 1, y, z
(III)3.890 (2)0.0 (2)2.105x + 1, y, z
Hirshfeld fingerprint contact percentages for different intermolecular interactions in the title compounds top
Interaction(I)(II)(III)
H···H30.330.723.3
H···Xa14.515.2
H···O (donor)10.610.032.2
H···C6.86.75.8
H···N1.92.22.3
C···C6.76.86.4
C···H8.68.69.0
C···O2.22.42.9
N···H2.12.72.1
O···H (acceptor)13.311.612.6
Xa···H99.898.7
Note: (a) For (I), X = Cl; for (II) X = Br.
 

Acknowledgements

We thank the EPSRC National Crystallography Service (University of Southampton) for the intensity data collections.

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