Self-assembled supra­molecular sheet- and channel-type frameworks in the p-phenetidinium hydrogen phthalate and cyclo­hexyl­aminium hydrogen phthalate hemihydrate salts

The title compounds, p-phenetidinium hydrogen phthalate (or 4-eth­oxy­anilinium 2-carb­oxy­benzoate), C₈H₁₂NO⁺·C₈H₅O₄^-, (I), and cyclo­hexyl­aminium hydrogen phthalate hemihydrate (or cyclo­hexyl­aminium 2-carb­oxy­benzoate hemihydrate), C₆H₁₄N⁺·C₈H₅O₄^-·0.5H₂O, (II), form two- and one-dimensional supra­molecular networks, respectively. In (I), the anionic-cationic network consists of R₃²(6) and R₄⁴(16) hydrogen-bonded rings forming a two-dimensional sheet along the (001) plane. In (II), O-H...O hydrogen bonds connect the glide-related anions, generating a supramolecular chain running parallel to [001] to which the cations are linked to form one-dimensional channels along [001]. The solvent water mol­ecules, which reside on twofold axes, are trapped inside the mol­ecular channels by N-H...O and O-H...O hydrogen bonds.

S1. Comment

The physical and chemical properties of crystalline solids are characteristically dependant on the distribution or assembly of molecular components in the crystal structure (Ferrer et al., 2001). The predictable supramolecular self-organization of molecular components can be developed by the use of N—H···O, O—H···O, C—H···O and other weak intermolecular interactions, creating one-, two- and three-dimensional networks in crystalline solids (Ranganathan et al., 1999; Swift et al., 1998). Supramolecular assemblies based on carboxylic acid groups (–COOH) have been given prime importance because of their ability to form robust hydrogen bonds on their own and with several aza compounds (anilines, pyridines etc; MacDonald et al., 2000; Zhang & Chen, 2004). Phthalic acid is a good hydrogen-bond donor and acceptor and has been employed in constructing supramolecular architectures such as chains, sheets, ladders and ribbons (Ballabh et al., 2005; Thanigaimani et al., 2010; Dale et al., 2004). Phthalic acid is also important, as hydrogen phthalate anions are versatile building blocks in organic and organometallic crystal engineering (Braga et al., 1999), and the electro-optic properties of potassium hydrogen phthalate crystals reveal its use as a modulator (Kejalakshmy & Srinivasan 2003). As a continuation of our work to understand the hydrogen-bonded self-assembly of molecules in hydrogen phthalate salts (Jagan & Sivakumar 2009), we present here the crystal structure and supramolecular self-assembly of two hydrogen phthalate salts, (I) and (II).

The molecular structures of (I) and (II) (Figs. 1 and 2, respectively) crystallize in space groups P1 and Pbcn, respectively. In (I), the asymmetric unit contains one hydrogen phthalate anion and one p-phenetidinium cation [this is the first crystal structure reported for a p-phenetidine (4-ethoxyaniline) salt], whereas in (II) the asymmetric unit contains a hydrogen phthalate anion, a cyclohexylaminium cation and half a water molecule. The water molecule of (II) is positioned on the 2₁ screw axis (-x, y, 1/2 - z). In the hydrogen phthalate anion of (I), the COOH and COO^- groups are coplanar with the benzene ring and form an asymmetric intramolecular hydrogen bond (Küppers et al., 1985). The centred H atom in (I) (H2A) is 1.16 (3) and 1.22 (3) Å from atoms O2 and O3, respectively. This short intramolecular hydrogen-bond formation is responsible for the lengthening of the C1—C2 bond [C1—C2 = 1.4147 (18) Å; Janczak & Perpétuo, 2001]. The intramolecular hydrogen bond exerts a strain within the molecule, causing some displacement of the inner atoms O2 and O3 (Adiwidjaja & Küppers, 1978). This is evident from the dihedral angles between the least-squares plane of the benzene ring and the carboxy-carboxylate groups, 3.84 (11)° for O1/C7/O2 and 4.09 (11)° for O3/C8/O4. In (II), unlike (I), the COO^- and COOH groups are twisted from the benzene plane, making the COO^- group perpendicular with a dihedral angle of 89.76 (6)°, while the COOH group is slightly inclined with an angle of 7.64 (9)° (Kanai et al., 2005). The geometric parameters of the p-phenetidinium and cyclohexylaminium cations of (I) and (II) are consistent with the reported literature, although since (I) is the first salt reported for p-phenetidine, it was compared with the 4-methoxyanilinium cation (Ben Amor et al., 1995; Shahwar et al., 2009).

The extensive supramolecular architectures exhibited by (I) and (II) are primarily formed by N—H···O and O—H···O hydrogen bonds and by the presence of C—H···O interactions (Tables 1 and 2). In (I), the hydrogen bonds N1—H1C···O4 and N1—H1A···O1ⁱ [symmetry code: (i) x, y + 1, z] link the hydrogen phthalate anions and p-phenetidinium cations to form a one-dimensional supramolecular chain extending infinitely along the [140] direction (Fig. 3). Similar one-dimensional chains are observed in the crystal structure of 1,4-phenylenediammonium bis(hydrogen phthalate) (Wang et al., 2007). Two N—H···O hydrogen bonds, N1—H1B···O4ⁱⁱ and N1—H1C···O1ⁱⁱⁱ [symmetry codes: (ii) x - 1, y, z; (iii) x - 1, y, z] connect the one-dimensional chains to form a two-dimensional supramolecular sheet extending parallel to the (001) plane. The (001) sheet shown in Fig. 4 is built from the infinite repetition of graph-set motifs of type R₃²(6) and R₄⁴(16) (Bernstein et al., 1995). The phenyl rings of both the anions and cations make angles of 61.93 and 76.71°, respectively, with the (001) plane. Inversion-related supramolecular sheets of anions and cations are further linked by C11—H11···O5^iv [symmetry code: (iv) -x, -y + 1, -z + 2] interactions with the formation of an R₂²(8) ring dimer, the centroid of which occupies the crystallographic inversion centre. The combination of N—H···O hydrogen bonds and C—H···O interactions generates a supramolecular sheet of thickness equal to the length of the c axis extending along the ab plane, as shown in Fig. 5.

In (II), the hydrogen phthalate anions alone form a one-dimensional chain running parallel to the [001] direction. The O1—H1A···O3ⁱ [symmetry code: (i) x, -y + 1, z + 1/2] hydrogen bond links the anions, forming a C(7) chain generated by the glide plane perpendicular to [010] whose glide component is (0, 0, 1/2), ending with an anionic substructure as shown in Fig. 6. The two antiparallel [001] chains are bridged by the cyclohexyl aminium cation through N1—H1C···O2 and N1—H1E···O4ⁱⁱ hydrogen bonds [symmetry code: (ii) -x + 1, -y + 1, -z + 1]. Interestingly, the bridging of the cations between the chains forms saddle-like cavities in which the solvent water molecules are located. The anions and cations form an extended self-assembled molecular channel along the [001] direction in which the trapped water molecules are located, separated by a distance of 5.97 Å (Fig. 7). The water molecules are bound to the molecular channel through O1W—H1W···O4, O1W—H1W···O2ⁱⁱⁱ [symmetry code: (iii) x + 1, -y + 1, z - 1/2] and N1—H1D···O1W hydrogen bonds, as illustrated. These water interactions, along with the bridging hydrogen bonds, form a variety of ring motifs [including R₄⁴(8), R₂³(8) and R₅³(10)], giving a self-assembled hydrogen-bonded network.

Since the above-described work is the continuation of our previously reported structures, a comparison of (I) and (II) with our previous structures of the 4-chloroanilinium, (III), 2-hydroxyanilinium, (IV), and 3-hydroxyanilinium, (V), hydrogen phthalates (Jagan & Sivakumar, 2009) is appropriate. In (II), the one-dimensional anionic supramolecular chain built from a C(7) motif is similar to the network observed in (III). It is of interest to note that in (II) and (III), adjacent hydrogen phthalate anions in the one-dimensional chain are symmetry related. As discussed above, the anions in (II) are generated by a c-glide, whereas in (III) they are generated by a 2₁ screw parallel to the b axis. The formation of this type of symmetry-related anionic network in hydrogen phthalate salts was investigated previously and studied by Langkilde et al. (2004). In the case of (I), (IV) and (V), the formation of short intramolecular O—H···O hydrogen bonds restricts the generation of the anionic one-dimensional chains observed in (II) and (III), and instead it forms one-dimensional chains built from alternating anions and cations linked through N—H···O and O—H···O hydrogen bonds, which further self-assemble to higher-dimensional supramolecular networks. In the closely related salt 1,4-phenylenediammonium bis(hydrogen phthalate) [Cambridge Structural Database (Version 5.3.1; Allen 2002; Macrae et al., 2008) refcode NEVKUV (Reference?)], the formation of a one-dimensional supramolecular chain is observed, as in (I). However, the presence of an NH₃ group instead of an ethoxy group in the para position results in the formation of an infinite three-dimensional network instead of the two-dimensional sheets seen in (I). Comparing the structures closely related to (II), the supramolecular architecture observed in the crystal structure of hexamethylenediamminium hydrogen phthalate dihydrate (CSD refcode CIZZIU; Jagannathan et al., 1984) shows the self-assembly of ions forming molecular channels in which the water molecules are trapped through hydrogen bonds, as in (II), whereas in piperazine-1,4-dium bis(orthohydrogen phthalate) dihydrate (CSD refcode VAJWUZ; Jin et al., 2003), the water molecules act as a bridge between the anionic–cationic one-dimensional networks and do not form channels. It is to be concluded that phthalates can form interesting tunable supramolecular self-assembled architecture like other organic salts, and the presence of weak C—H···O interactions demonstrates their importance in the molecular packing of phthalates.

Related literature

For related literature, see: Adiwidjaja & Küppers (1978); Allen (2002); Ballabh et al. (2005); Ben Amor, Soumhi, Ould Abdellahi & Jouini (1995); Bernstein et al. (1995); Braga et al. (1999); Dale et al. (2004); Ferrer et al. (2001); Jagan & Sivakumar (2009); Jagannathan et al. (1984); Janczak & Perpétuo (2001); Jin et al. (2003); Küppers et al. (1985); Kanai et al. (2005); Kejalakshmy & Srinivasan (2003); Langkilde et al. (2004); MacDonald et al. (2000); Macrae et al. (2008); Ranganathan et al. (1999); Shahwar et al. (2009); Swift et al. (1998); Thanigaimani et al. (2010); Wang et al. (2007); Zhang & Chen (2004).

S2. Experimental

Salt (I) was prepared by dissolving equimolar quantities of phthalic acid and p-phenetidine in methanol. The resulting solution was stirred well for 15 mins and was then left undisturbed in a test tube with the lid partially covered, for slow evaporation. Good diffraction-quality crystals were obtained after a few days. Salt (II) was prepared by mixing equimolar quantities of water and methonol solutions of cyclohexylamine and phthalic acid, respectively. The solution thus prepared was allowed to evaporate slowly and crystals were obtained.

S3. Refinement

In (I) and (II), the positions of the H atoms bound to N and O atoms were identified from difference electron-density maps, but were subsequently geometrically optimized, with O—H = 0.82 Å and N—H = 0.89 Å, and allowed to ride at the best staggered positions, with U_iso(H) = 1.5U_eq(O,N), except for atom O1 of (II), for which the O—H vector was allowed to rotate around the C—O bond, and the H atom associated with atom O2 of (I), which was identified from the difference electron-density peak and refined freely. H atoms bound to C atoms were treated as riding atoms, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C) for aromatic H, and C—H = 0.96 Å and U_iso(H) = 1.5U_eq(C) for methyl groups. The H atom associated with the water O atom of (II) was restrained to an O—H distance of 0.93 (1) Å.

Computing details

For both compounds, data collection: APEX2 (Bruker, 2004); cell refinement: APEX2 and SAINT (Bruker, 2004); data reduction: SAINT and XPREP (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level. The dashed line indicates the intermolecular hydrogen bond. [Please check added text]
	Fig. 2. The molecular structure of (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level. Dashed lines indicate the intermolecular hydrogen bonds. [Please check added text]
	Fig. 3. The extended supramolecular hydrogen-bonded one-dimensional chain in (I), viewed approximately along the [140] direction, showing the N1—H1C···O4 and N1—H1A···O1 linkages.
	Fig. 4. The two-dimensional sheet of anions and cations in (I), interlinked through N1—H1C···O4, N1—H1A···O1, N1—H1B···O4 and N1—H1C···O1 hydrogen bonds extending parallel to the (001) plane. H atoms not involved in these interactions have been omitted for clarity.
	Fig. 5. Part of the crystal structure of (I), showing the formation of the R2^2(8) ring of the C—H···O hydrogen-bonded dimer, which connects inversion-related (001) sheets, viewed along the a axis. H atoms not involved in these interactions have been omitted for clarity.
	Fig. 6. Part of the crystal structure of (II), showing the O1—H1A···O3 hydrogen-bond linkage between the [010] glide-related anions, forming an extended one-dimensional chain along the [001] direction.
	Fig. 7. The molecular packing in (II), showing the formation of [001] water channels holding the water molecules inside. Also shown is the trapping of water molecules through hydrogen bonds between the cavities, viewed along the b axis. H atoms not involved in these interactions have been omitted for clarity.

(I) 4-ethoxyanilinium 2-carboxybenzoate

Crystal data

C8H12NO^+·C8H5O4^−	Z = 2
Mr = 303.31	F(000) = 320
Triclinic, P1	Dx = 1.380 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 3.9983 (1) Å	Cell parameters from 9421 reflections
b = 9.2595 (2) Å	θ = 2.1–33.6°
c = 19.8227 (5) Å	µ = 0.10 mm^−1
α = 89.670 (1)°	T = 292 K
β = 84.947 (1)°	Block, colourless
γ = 86.708 (1)°	0.25 × 0.20 × 0.20 mm
V = 729.82 (3) Å^3

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer	3350 independent reflections
Radiation source: fine-focus sealed tube	2780 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
ω and ϕ scans	θmax = 27.5°, θmin = 1.0°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −5→5
Tmin = 0.905, Tmax = 0.980	k = −12→12
16579 measured reflections	l = −25→25

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.124	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0539P)^2 + 0.2188P] where P = (Fo^2 + 2Fc^2)/3
3350 reflections	(Δ/σ)max = 0.001
208 parameters	Δρmax = 0.20 e Å^−3
0 restraints	Δρmin = −0.18 e Å^−3

Special details

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

Refinement. Refinement of 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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.5447 (3)	−0.07535 (11)	0.66925 (6)	0.0574 (3)
O2	0.7096 (4)	0.09620 (14)	0.73046 (6)	0.0632 (4)
O3	0.7219 (4)	0.35266 (14)	0.73196 (6)	0.0649 (4)
O4	0.5698 (3)	0.54159 (12)	0.67375 (6)	0.0572 (3)
C1	0.4489 (3)	0.16250 (14)	0.62777 (6)	0.0328 (3)
C2	0.4582 (3)	0.31497 (14)	0.62863 (6)	0.0328 (3)
C3	0.3401 (4)	0.39166 (15)	0.57419 (7)	0.0411 (3)
H3	0.3417	0.4921	0.5744	0.049*
C4	0.2207 (4)	0.32474 (17)	0.51994 (8)	0.0457 (4)
H4	0.1485	0.3793	0.4839	0.055*
C5	0.2093 (4)	0.17726 (17)	0.51954 (8)	0.0457 (4)
H5	0.1274	0.1307	0.4835	0.055*
C6	0.3206 (4)	0.09863 (15)	0.57318 (7)	0.0407 (3)
H6	0.3092	−0.0014	0.5728	0.049*
C7	0.5737 (4)	0.05445 (15)	0.67927 (7)	0.0409 (3)
C8	0.5886 (4)	0.40934 (15)	0.68165 (7)	0.0407 (3)
O5	0.1981 (3)	0.70176 (12)	1.00074 (5)	0.0521 (3)
N1	0.0002 (4)	0.73246 (17)	0.72590 (6)	0.0488 (3)
H1A	−0.1184	0.8133	0.7167	0.085 (7)*
H1B	−0.1115	0.6563	0.7157	0.081 (7)*
H1C	0.1982	0.7300	0.7015	0.115 (10)*
C9	0.0534 (3)	0.72887 (16)	0.79811 (7)	0.0384 (3)
C10	−0.0213 (4)	0.60719 (17)	0.83524 (8)	0.0485 (4)
H10	−0.1052	0.5286	0.8146	0.058*
C11	0.0285 (5)	0.60233 (17)	0.90285 (8)	0.0497 (4)
H11	−0.0246	0.5207	0.9282	0.060*
C12	0.1578 (4)	0.71861 (15)	0.93348 (7)	0.0395 (3)
C13	0.2326 (4)	0.84003 (16)	0.89576 (7)	0.0433 (3)
H13	0.3195	0.9184	0.9160	0.052*
C14	0.1782 (4)	0.84523 (16)	0.82775 (8)	0.0445 (3)
H14	0.2261	0.9274	0.8023	0.053*
C15	0.3371 (4)	0.81501 (17)	1.03531 (8)	0.0471 (4)
H15A	0.1985	0.9039	1.0324	0.057*
H15B	0.5615	0.8315	1.0151	0.057*
C16	0.3494 (5)	0.7701 (2)	1.10753 (9)	0.0631 (5)
H16A	0.1265	0.7531	1.1269	0.095*
H16B	0.4395	0.8454	1.1323	0.095*
H16C	0.4903	0.6830	1.1099	0.095*
H2A	0.723 (6)	0.221 (3)	0.7325 (12)	0.086 (7)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0849 (9)	0.0316 (5)	0.0563 (7)	0.0004 (5)	−0.0121 (6)	0.0084 (5)
O2	0.1008 (10)	0.0470 (7)	0.0461 (7)	−0.0051 (6)	−0.0301 (6)	0.0107 (5)
O3	0.1041 (11)	0.0484 (7)	0.0475 (7)	−0.0101 (7)	−0.0326 (7)	−0.0040 (5)
O4	0.0744 (8)	0.0322 (6)	0.0671 (8)	−0.0032 (5)	−0.0171 (6)	−0.0094 (5)
C1	0.0356 (6)	0.0307 (6)	0.0315 (6)	−0.0004 (5)	0.0004 (5)	0.0013 (5)
C2	0.0344 (6)	0.0310 (6)	0.0326 (6)	−0.0012 (5)	−0.0004 (5)	−0.0012 (5)
C3	0.0483 (8)	0.0313 (7)	0.0438 (8)	0.0007 (6)	−0.0074 (6)	0.0047 (6)
C4	0.0510 (8)	0.0467 (8)	0.0405 (8)	0.0025 (7)	−0.0133 (6)	0.0082 (6)
C5	0.0494 (8)	0.0484 (8)	0.0409 (8)	−0.0030 (7)	−0.0133 (6)	−0.0057 (6)
C6	0.0477 (8)	0.0321 (7)	0.0426 (8)	−0.0038 (6)	−0.0047 (6)	−0.0034 (6)
C7	0.0502 (8)	0.0348 (7)	0.0367 (7)	0.0007 (6)	0.0001 (6)	0.0062 (6)
C8	0.0477 (8)	0.0356 (7)	0.0388 (7)	−0.0030 (6)	−0.0027 (6)	−0.0068 (6)
O5	0.0800 (8)	0.0434 (6)	0.0364 (6)	−0.0209 (5)	−0.0140 (5)	0.0037 (4)
N1	0.0482 (8)	0.0609 (9)	0.0383 (7)	0.0000 (6)	−0.0112 (6)	0.0000 (6)
C9	0.0382 (7)	0.0419 (7)	0.0351 (7)	0.0021 (6)	−0.0069 (5)	−0.0004 (6)
C10	0.0631 (10)	0.0393 (8)	0.0461 (8)	−0.0116 (7)	−0.0153 (7)	−0.0026 (6)
C11	0.0725 (11)	0.0361 (8)	0.0434 (8)	−0.0163 (7)	−0.0138 (7)	0.0051 (6)
C12	0.0471 (8)	0.0368 (7)	0.0356 (7)	−0.0055 (6)	−0.0071 (6)	0.0005 (5)
C13	0.0548 (9)	0.0360 (7)	0.0403 (8)	−0.0118 (6)	−0.0054 (6)	−0.0024 (6)
C14	0.0557 (9)	0.0378 (7)	0.0402 (8)	−0.0068 (6)	−0.0030 (6)	0.0055 (6)
C15	0.0567 (9)	0.0445 (8)	0.0420 (8)	−0.0121 (7)	−0.0087 (7)	−0.0043 (6)
C16	0.0843 (13)	0.0674 (12)	0.0418 (9)	−0.0207 (10)	−0.0188 (9)	0.0010 (8)

Geometric parameters (Å, º)

O1—C7	1.2329 (18)	N1—C9	1.4655 (18)
O2—C7	1.2649 (19)	N1—H1A	0.8900
O2—H2A	1.16 (3)	N1—H1B	0.8900
O3—C8	1.2686 (19)	N1—H1C	0.8900
O3—H2A	1.22 (3)	C9—C14	1.369 (2)
O4—C8	1.2325 (18)	C9—C10	1.375 (2)
C1—C6	1.387 (2)	C10—C11	1.372 (2)
C1—C2	1.4147 (18)	C10—H10	0.9300
C1—C7	1.5207 (19)	C11—C12	1.386 (2)
C2—C3	1.3908 (19)	C11—H11	0.9300
C2—C8	1.5164 (19)	C12—C13	1.379 (2)
C3—C4	1.378 (2)	C13—C14	1.385 (2)
C3—H3	0.9300	C13—H13	0.9300
C4—C5	1.369 (2)	C14—H14	0.9300
C4—H4	0.9300	C15—C16	1.493 (2)
C5—C6	1.377 (2)	C15—H15A	0.9700
C5—H5	0.9300	C15—H15B	0.9700
C6—H6	0.9300	C16—H16A	0.9600
O5—C12	1.3641 (17)	C16—H16B	0.9600
O5—C15	1.4213 (18)	C16—H16C	0.9600
C7—O2—H2A	112.7 (11)	H1B—N1—H1C	109.5
C8—O3—H2A	113.2 (11)	C14—C9—C10	120.78 (14)
C6—C1—C2	118.23 (12)	C14—C9—N1	120.09 (13)
C6—C1—C7	113.69 (12)	C10—C9—N1	119.13 (14)
C2—C1—C7	128.06 (12)	C11—C10—C9	119.68 (14)
C3—C2—C1	117.78 (12)	C11—C10—H10	120.2
C3—C2—C8	113.97 (12)	C9—C10—H10	120.2
C1—C2—C8	128.24 (12)	C10—C11—C12	120.27 (14)
C4—C3—C2	122.60 (13)	C10—C11—H11	119.9
C4—C3—H3	118.7	C12—C11—H11	119.9
C2—C3—H3	118.7	O5—C12—C13	125.13 (13)
C5—C4—C3	119.47 (14)	O5—C12—C11	115.27 (13)
C5—C4—H4	120.3	C13—C12—C11	119.60 (14)
C3—C4—H4	120.3	C12—C13—C14	119.97 (14)
C4—C5—C6	119.21 (14)	C12—C13—H13	120.0
C4—C5—H5	120.4	C14—C13—H13	120.0
C6—C5—H5	120.4	C9—C14—C13	119.70 (14)
C5—C6—C1	122.69 (13)	C9—C14—H14	120.2
C5—C6—H6	118.7	C13—C14—H14	120.2
C1—C6—H6	118.7	O5—C15—C16	107.63 (13)
O1—C7—O2	120.71 (14)	O5—C15—H15A	110.2
O1—C7—C1	118.31 (14)	C16—C15—H15A	110.2
O2—C7—C1	120.97 (13)	O5—C15—H15B	110.2
O4—C8—O3	121.02 (14)	C16—C15—H15B	110.2
O4—C8—C2	118.49 (13)	H15A—C15—H15B	108.5
O3—C8—C2	120.46 (13)	C15—C16—H16A	109.5
C12—O5—C15	118.56 (12)	C15—C16—H16B	109.5
C9—N1—H1A	109.5	H16A—C16—H16B	109.5
C9—N1—H1B	109.5	C15—C16—H16C	109.5
H1A—N1—H1B	109.5	H16A—C16—H16C	109.5
C9—N1—H1C	109.5	H16B—C16—H16C	109.5
H1A—N1—H1C	109.5
C6—C1—C2—C3	−0.52 (19)	C1—C2—C8—O4	−178.85 (14)
C7—C1—C2—C3	177.52 (13)	C3—C2—C8—O3	−175.82 (14)
C6—C1—C2—C8	−179.29 (13)	C1—C2—C8—O3	3.0 (2)
C7—C1—C2—C8	−1.3 (2)	C14—C9—C10—C11	0.2 (3)
C1—C2—C3—C4	−0.9 (2)	N1—C9—C10—C11	179.77 (15)
C8—C2—C3—C4	178.04 (14)	C9—C10—C11—C12	−0.9 (3)
C2—C3—C4—C5	1.5 (2)	C15—O5—C12—C13	−2.0 (2)
C3—C4—C5—C6	−0.6 (2)	C15—O5—C12—C11	178.50 (14)
C4—C5—C6—C1	−0.8 (2)	C10—C11—C12—O5	−179.75 (15)
C2—C1—C6—C5	1.4 (2)	C10—C11—C12—C13	0.7 (3)
C7—C1—C6—C5	−176.92 (14)	O5—C12—C13—C14	−179.43 (15)
C6—C1—C7—O1	−1.5 (2)	C11—C12—C13—C14	0.0 (2)
C2—C1—C7—O1	−179.58 (13)	C10—C9—C14—C13	0.6 (2)
C6—C1—C7—O2	177.22 (14)	N1—C9—C14—C13	−179.00 (14)
C2—C1—C7—O2	−0.9 (2)	C12—C13—C14—C9	−0.7 (2)
C3—C2—C8—O4	2.3 (2)	C12—O5—C15—C16	179.31 (15)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1^i	0.89	1.95	2.7766 (18)	153
N1—H1B···O4^ii	0.89	1.95	2.7996 (19)	160
N1—H1C···O1^iii	0.89	2.39	3.0264 (19)	129
C11—H11···O5^iv	0.93	2.58	3.5110 (19)	178
N1—H1C···O4	0.89	2.26	2.9193 (19)	130

Symmetry codes: (i) x−1, y+1, z; (ii) x−1, y, z; (iii) x, y+1, z; (iv) −x, −y+1, −z+2.

(II) cyclohexylaminium 2-carboxybenzoate hemihydrate

Crystal data

C6H14N^+·C8H5O4^−·0.5H2O	F(000) = 1176
Mr = 274.31	Dx = 1.306 Mg m^−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 7955 reflections
a = 16.9402 (4) Å	θ = 2.4–29.3°
b = 14.1463 (3) Å	µ = 0.10 mm^−1
c = 11.6407 (2) Å	T = 292 K
V = 2789.59 (10) Å^3	Block, colourless
Z = 8	0.30 × 0.25 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD area-detector diffractometer	4565 independent reflections
Radiation source: fine-focus sealed tube	2931 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.038
ω and ϕ scans	θmax = 31.3°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −24→18
Tmin = 0.911, Tmax = 0.981	k = −20→20
37264 measured reflections	l = −16→17

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.147	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0694P)^2 + 0.5135P] where P = (Fo^2 + 2Fc^2)/3
4565 reflections	(Δ/σ)max < 0.001
186 parameters	Δρmax = 0.27 e Å^−3
1 restraint	Δρmin = −0.26 e Å^−3

Special details

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

Refinement. Refinement of 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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.30734 (8)	0.58707 (7)	0.77506 (8)	0.0598 (3)
H1A	0.3038	0.5325	0.7983	0.090*
O2	0.34424 (8)	0.51570 (7)	0.61588 (8)	0.0592 (3)
O3	0.28629 (6)	0.56542 (7)	0.37369 (8)	0.0487 (3)
O4	0.41530 (6)	0.58414 (8)	0.39192 (9)	0.0506 (3)
C7	0.32563 (8)	0.58661 (8)	0.66795 (10)	0.0344 (3)
C1	0.32230 (7)	0.68098 (8)	0.61084 (9)	0.0304 (2)
C6	0.30866 (8)	0.76214 (9)	0.67534 (10)	0.0380 (3)
H6	0.3031	0.7573	0.7546	0.046*
C5	0.30321 (9)	0.84968 (10)	0.62357 (12)	0.0450 (3)
H5	0.2943	0.9034	0.6678	0.054*
C4	0.31103 (9)	0.85732 (10)	0.50637 (12)	0.0450 (3)
H4	0.3070	0.9161	0.4711	0.054*
C3	0.32487 (8)	0.77720 (9)	0.44084 (10)	0.0388 (3)
H3	0.3301	0.7826	0.3616	0.047*
C2	0.33096 (7)	0.68904 (8)	0.49213 (9)	0.0303 (2)
C8	0.34632 (8)	0.60557 (9)	0.41506 (9)	0.0351 (3)
N1	0.44252 (9)	0.38866 (9)	0.49025 (11)	0.0549 (4)
H1E	0.4901	0.3924	0.5222	0.069 (6)*
H1C	0.4096	0.4275	0.5265	0.084 (7)*
H1D	0.4457	0.4051	0.4166	0.103 (8)*
C9	0.41273 (9)	0.28972 (10)	0.49925 (12)	0.0446 (3)
H9	0.3565	0.2889	0.4796	0.049 (4)*
C10	0.42251 (11)	0.25645 (11)	0.62178 (12)	0.0557 (4)
H10A	0.3906	0.2954	0.6723	0.067*
H10B	0.4773	0.2632	0.6447	0.067*
C11	0.39769 (12)	0.15372 (13)	0.63358 (18)	0.0711 (5)
H11A	0.4087	0.1321	0.7110	0.085*
H11B	0.3413	0.1485	0.6207	0.085*
C12	0.44090 (12)	0.09176 (11)	0.54878 (17)	0.0634 (5)
H12A	0.4967	0.0913	0.5674	0.076*
H12B	0.4214	0.0275	0.5550	0.076*
C13	0.43001 (12)	0.12609 (12)	0.42745 (16)	0.0653 (5)
H13A	0.3748	0.1211	0.4063	0.078*
H13B	0.4603	0.0865	0.3756	0.078*
C14	0.45672 (10)	0.22788 (11)	0.41546 (12)	0.0505 (4)
H14A	0.5130	0.2321	0.4301	0.061*
H14B	0.4470	0.2496	0.3377	0.061*
O1W	0.5000	0.45258 (14)	0.2500	0.0636 (4)
H1W	0.4587 (12)	0.4943 (16)	0.244 (3)	0.143 (11)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.1021 (10)	0.0400 (6)	0.0371 (5)	0.0102 (6)	0.0198 (5)	0.0092 (4)
O2	0.1049 (9)	0.0306 (5)	0.0422 (5)	0.0093 (6)	0.0121 (5)	0.0007 (4)
O3	0.0497 (6)	0.0504 (6)	0.0459 (5)	−0.0005 (5)	−0.0029 (4)	−0.0189 (4)
O4	0.0450 (6)	0.0488 (6)	0.0579 (6)	0.0031 (5)	0.0113 (5)	−0.0129 (4)
C7	0.0399 (7)	0.0306 (6)	0.0328 (5)	0.0010 (5)	0.0014 (5)	0.0021 (4)
C1	0.0329 (6)	0.0267 (6)	0.0317 (5)	0.0013 (5)	0.0005 (4)	−0.0005 (4)
C6	0.0454 (8)	0.0343 (6)	0.0343 (5)	0.0027 (5)	0.0008 (5)	−0.0053 (5)
C5	0.0542 (9)	0.0294 (6)	0.0515 (7)	0.0056 (6)	−0.0012 (6)	−0.0080 (5)
C4	0.0546 (9)	0.0279 (6)	0.0526 (7)	0.0023 (6)	−0.0070 (6)	0.0056 (5)
C3	0.0470 (8)	0.0341 (6)	0.0352 (5)	−0.0010 (6)	−0.0023 (5)	0.0057 (5)
C2	0.0310 (6)	0.0289 (6)	0.0311 (5)	−0.0004 (5)	−0.0004 (4)	−0.0012 (4)
C8	0.0441 (7)	0.0325 (6)	0.0286 (5)	0.0028 (5)	0.0043 (5)	0.0010 (4)
N1	0.0772 (10)	0.0368 (7)	0.0505 (7)	0.0080 (6)	−0.0044 (7)	−0.0005 (5)
C9	0.0450 (8)	0.0362 (7)	0.0525 (7)	0.0063 (6)	−0.0047 (6)	−0.0036 (5)
C10	0.0717 (11)	0.0466 (9)	0.0488 (7)	0.0068 (8)	0.0130 (7)	−0.0019 (6)
C11	0.0713 (12)	0.0553 (10)	0.0867 (12)	0.0035 (9)	0.0269 (10)	0.0138 (9)
C12	0.0647 (11)	0.0362 (8)	0.0891 (13)	0.0004 (8)	0.0045 (9)	0.0011 (8)
C13	0.0757 (12)	0.0462 (9)	0.0740 (11)	0.0026 (9)	−0.0085 (9)	−0.0184 (8)
C14	0.0568 (9)	0.0493 (9)	0.0453 (7)	0.0065 (7)	−0.0028 (6)	−0.0085 (6)
O1W	0.0627 (11)	0.0686 (12)	0.0594 (9)	0.000	0.0032 (8)	0.000

Geometric parameters (Å, º)

O1—C7	1.2848 (14)	N1—H1D	0.8900
O1—H1A	0.8200	C9—C14	1.507 (2)
O2—C7	1.2137 (15)	C9—C10	1.511 (2)
O3—C8	1.2604 (16)	C9—H9	0.9800
O4—C8	1.2369 (16)	C10—C11	1.519 (2)
C7—C1	1.4925 (16)	C10—H10A	0.9700
C1—C6	1.3912 (16)	C10—H10B	0.9700
C1—C2	1.3943 (15)	C11—C12	1.509 (3)
C6—C5	1.3803 (19)	C11—H11A	0.9700
C6—H6	0.9300	C11—H11B	0.9700
C5—C4	1.375 (2)	C12—C13	1.505 (3)
C5—H5	0.9300	C12—H12A	0.9700
C4—C3	1.3862 (19)	C12—H12B	0.9700
C4—H4	0.9300	C13—C14	1.516 (2)
C3—C2	1.3866 (17)	C13—H13A	0.9700
C3—H3	0.9300	C13—H13B	0.9700
C2—C8	1.5055 (16)	C14—H14A	0.9700
N1—C9	1.4916 (19)	C14—H14B	0.9700
N1—H1E	0.8900	O1W—H1W	0.918 (10)
N1—H1C	0.8900
C7—O1—H1A	109.5	N1—C9—H9	108.9
O2—C7—O1	123.47 (12)	C14—C9—H9	108.9
O2—C7—C1	121.78 (10)	C10—C9—H9	108.9
O1—C7—C1	114.75 (10)	C9—C10—C11	110.67 (14)
C6—C1—C2	119.01 (11)	C9—C10—H10A	109.5
C6—C1—C7	120.27 (10)	C11—C10—H10A	109.5
C2—C1—C7	120.71 (10)	C9—C10—H10B	109.5
C5—C6—C1	121.06 (11)	C11—C10—H10B	109.5
C5—C6—H6	119.5	H10A—C10—H10B	108.1
C1—C6—H6	119.5	C12—C11—C10	111.24 (14)
C4—C5—C6	119.82 (12)	C12—C11—H11A	109.4
C4—C5—H5	120.1	C10—C11—H11A	109.4
C6—C5—H5	120.1	C12—C11—H11B	109.4
C5—C4—C3	119.87 (12)	C10—C11—H11B	109.4
C5—C4—H4	120.1	H11A—C11—H11B	108.0
C3—C4—H4	120.1	C13—C12—C11	111.52 (15)
C4—C3—C2	120.74 (11)	C13—C12—H12A	109.3
C4—C3—H3	119.6	C11—C12—H12A	109.3
C2—C3—H3	119.6	C13—C12—H12B	109.3
C3—C2—C1	119.50 (11)	C11—C12—H12B	109.3
C3—C2—C8	117.50 (10)	H12A—C12—H12B	108.0
C1—C2—C8	123.00 (10)	C12—C13—C14	110.88 (13)
O4—C8—O3	124.65 (12)	C12—C13—H13A	109.5
O4—C8—C2	119.03 (11)	C14—C13—H13A	109.5
O3—C8—C2	116.21 (11)	C12—C13—H13B	109.5
C9—N1—H1E	109.5	C14—C13—H13B	109.5
C9—N1—H1C	109.5	H13A—C13—H13B	108.1
H1E—N1—H1C	109.5	C9—C14—C13	110.13 (14)
C9—N1—H1D	109.5	C9—C14—H14A	109.6
H1E—N1—H1D	109.5	C13—C14—H14A	109.6
H1C—N1—H1D	109.5	C9—C14—H14B	109.6
N1—C9—C14	109.38 (13)	C13—C14—H14B	109.6
N1—C9—C10	108.75 (12)	H14A—C14—H14B	108.1
C14—C9—C10	112.07 (12)
O2—C7—C1—C6	−173.41 (13)	C7—C1—C2—C8	−1.82 (18)
O1—C7—C1—C6	6.64 (18)	C3—C2—C8—O4	88.00 (15)
O2—C7—C1—C2	8.1 (2)	C1—C2—C8—O4	−92.42 (15)
O1—C7—C1—C2	−171.88 (12)	C3—C2—C8—O3	−88.33 (15)
C2—C1—C6—C5	0.36 (19)	C1—C2—C8—O3	91.25 (15)
C7—C1—C6—C5	−178.19 (13)	N1—C9—C10—C11	−176.44 (13)
C1—C6—C5—C4	0.3 (2)	C14—C9—C10—C11	−55.39 (19)
C6—C5—C4—C3	−0.4 (2)	C9—C10—C11—C12	54.1 (2)
C5—C4—C3—C2	0.0 (2)	C10—C11—C12—C13	−55.4 (2)
C4—C3—C2—C1	0.6 (2)	C11—C12—C13—C14	56.7 (2)
C4—C3—C2—C8	−179.80 (13)	N1—C9—C14—C13	177.26 (13)
C6—C1—C2—C3	−0.78 (18)	C10—C9—C14—C13	56.57 (18)
C7—C1—C2—C3	177.76 (12)	C12—C13—C14—C9	−56.7 (2)
C6—C1—C2—C8	179.65 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O3^i	0.82	1.67	2.4696 (14)	166
N1—H1E···O4^ii	0.89	1.92	2.7983 (19)	170
O1W—H1W···O2^iii	0.92 (1)	2.45 (2)	3.0985 (13)	128 (2)
N1—H1C···O2	0.89	1.97	2.8531 (17)	175
O1W—H1W···O4	0.92 (1)	2.26 (3)	2.8726 (16)	124 (2)
N1—H1D···O1W	0.89	2.25	3.0963 (14)	159

Symmetry codes: (i) x, −y+1, z+1/2; (ii) −x+1, −y+1, −z+1; (iii) x, −y+1, z−1/2.