p-Phenyl­enediamine and its dihydrate: two-dimensional isomorphism and mechanism of the dehydration process, and N—H...N and N—H...π inter­actions

p-Phenyl­enediamine can be obtained as the dihydrate, C₆H₈N₂·2H₂O, (I), and in its anhydrous form, C₆H₈N₂, (II). The asymmetric unit of (I) contains one half of the p-phenyl­ene­diamine mol­ecule lying about an inversion centre and two halves of water mol­ecules, one lying on a mirror plane and the other lying across a mirror plane. In (II), the asymmetric unit consists of one mol­ecule in a general position and two half mol­ecules located around inversion centres. In both structures, the p-phenyl­enediamine mol­ecules are arranged in layers stabilized by N—H...π inter­actions. The diamine layers in (I) are isostructural with half of the layers in (II). On dehydration, crystals of (I) transform to (II). Comparison of their crystal structures suggests the most plausible mechanism of the transformation process which requires, in addition to translational motion of the diamine mol­ecules, in-plane rotation of every fourth p-phenyl­enediamine mol­ecule by ca 60°. A search of the Cambridge Structural Database shows that the formation of hydrates by aromatic amines should be considered exceptional.

S1. Comment

p-Phenylenediamine is a popular reagent in organic and coordination chemistry. This compound is quite soluble in water but is generally known in its anhydrous form. In course of our work on cocrystal formation by aromatic diamines, aminophenols and diphenols, the previously unknown hydrated form of p-phenylenediamine emerged. To check whether formation of a hydrate by p-phenylenediamine can be considered exceptional among aromatic amines, recrystallizations of the two other phenylenediamine isomers from water have been carried out, always resulting in the known anhydrous forms. The crystal structures of the three (o-, m- and p-) anhydrous phenylenediamines have already been published (Betz et al., 2008; Poveteva & Zvonkova, 1975; Stalhandske, 1981), with two of them, the meta (Betz et al., 2008) and para (Poveteva & Zvonkova, 1975; Colapietro et al., 1985) isomers, showing high-Z' structures. The above observations prompted us to take a closer look at the structures of primary aromatic amines deposited in the Cambridge Structural Database (CSD, Version 5.31; Allen, 2002) and to analyse them from the point of view of hydrate formation. This paper, in addition to the crystal structure of p-phenylenediamine dihydrate, (I), reports the redetermination of the crystal structure of p-phenylenediamine, (II), at 130 K to provide more accurate positions of the amino H atoms.

The numbering scheme for (I) is shown in Fig. 1. The asymmetric unit contains one half of the p-phenylenediamine molecule, which is located around an inversion centre, and two halves of the water molecules. One water molecule has all its atoms on a mirror plane, whereas the other molecule lies across a mirror plane. The endocyclic bond angle at C1 of 118.17 (11)° is consistent with the electron-withdrawing character of the amino group. The water molecules are linked via O—H···O interactions into a C4 chain (Infantes & Motherwell, 2002), with one water molecule acting as a double donor and the other as a double acceptor of hydrogen bonding. p-Phenylenediamine molecules bridge these water chains by involving their amino groups as single donors and single acceptors in hydrogen bonding (Fig. 2a, Table 1). All these interactions generate a two-dimensional network of hydrogen bonds parallel to (010) and a three-dimensional network of hydrogen-bonded molecules (Fig. 2b). The p-phenylenediamine molecules in (I) are arranged via a herringbone motif into (010) layers. The amino H atom not involved in strong interactions with the water molecules forms an N—H···π interaction with an adjacent benzene ring, with an H···π distance of 2.48 (2) Å. Each benzene ring accepts two such interactions (Fig. 2c). It should be emphasized here that there is no direct hydrogen-bond interaction between the amino groups in (I). The crystals of (I) are unstable and in the air they lose the water molecules and are transformed into the known anhydrous form of p-phenylenediamine; this was confirmed by powder diffractograms of a partially-decomposed sample of (I).

The asymmetric unit of (II) contains one molecule in a general position (molecule A) and two halves of p-phenylenediamine molecules located on two different sets of inversion centres (molecules B and C) (Fig. 3). The endocyclic bond angles at atoms C1A, C4A, C1B and C1C are all significantly smaller than 120° [117.63 (10)–118.03 (10)°] and the C—N bond lengths are in the range 1.4064 (3)–1.4154 (13) Å. The four symmetry-independent primary amino groups are connected via N—H···N hydrogen bonds into a polymeric chain extending along [100] (Table 2, Fig. 4a), with each amino group acting as a single donor and a single acceptor in hydrogen bonding. These N—H···N interactions generate a three-dimensional network of p-phenylenediamine molecules (Fig. 4b). An alternative depiction of the crystal structure of (II) shows it to be composed of a set of two different (001) molecular layers, one layer composed solely of A molecules and the second one composed of centrosymmetric B and C molecules. The metric parameters of these layers [a = 8.3020 (2) Å, b = 5.8970 (1) Å and γ = 90°] resemble those of the (010) layers in (I) [a = 8.8599 (8) Å, c = 5.8952 (4) Å and β = 90°], and closer inspection of the two structures reveals that the layers of A molecules in (II) are virtually isostructural with the (010) layers of p-phenylenediamine molecules in (I), with the aromatic systems accepting two N—H···π interactions (Table 2). The layers of B and C molecules have a different structure, with the benzene ring of the C molecules accepting two N—H···π interactions from the N—H group of the B molecule, whereas the aromatic system of B is not involved in this type of interaction.

As indicated above, the dehydration process of (I) results in form (II) of p-phenylenediamine. Taking into account the extent of structural similarities between the two crystalline forms, we suggest a mechanism of transformation between the hydrated and anhydrous forms. In the most plausible mechanism that we can propose, the structure of every second (010) layer of p-phenylenediamine molecules in (I) remains unaltered by the dehydration process. When water molecules start to leave the crystal, hydrogen bonds are broken and the amino groups `seek' new donors and acceptors among the primary amino groups located on the surface of a neighbouring layer. The hydrogen-bond network of (I) cannot be fully reconstructed, as the number of NH₂ groups on the surface of the neighbouring layer is half the number of water molecules located in the interlayer space, and the acceptor–donor abilities of a primary amino group are different from those of water molecules. The proposed mechanism of dehydration of (I) is illustrated in Fig. 5. When the dehydration process begins, the stacks of B molecules running along the a axis move in the direction indicated by the arrow in Fig. 5 to replace two water molecules in a chain of hydrogen bonds with their NH₂ group. Because each water molecule occupies a special position of multiplicity 2 in the crystal structure, stoichiometrically this means a substitution of one water molecule per one amino group. This movement is accompanied by a concerted reorientation of the C molecules also arranged into stacks along the a axis. All C molecules within one stack rotate in the same direction by ca 60° around the axis approximately perpendicular to their aromatic ring plane. On this rearrangement, their NH₂ groups replace another pair of water molecules and a polymeric chain of N—H···N hydrogen bonds is formed, extending along the a axis and incorporating all amino groups as single donors and single acceptors. This mechanism requires substantial rearrangement of only 25% of the amine molecules in the crystal structure, whereas the remaining 75% of molecules undergo mainly translational motion. The above transformation should be seen as a cooperative structure reconstruction, with both events, translation and rotation of the diamine molecules, occurring at the same time.

In recent years, several papers dealing with the factors responsible for the formation of organic crystal hydrates have been published (Infantes & Motherwell, 2002; Infantes et al., 2003, 2007). The formation of the hydrate by p-phenylenediamine should be considered rather exceptional in the light of our survey of the CSD, which gave 80 structures of compounds with at least one primary amino group and with only C and H atoms in the remaining part of the molecule [C_nH_m(NH₂)_x]. Among these structures, 48 were formed by aromatic, 27 by aliphatic and four by vinyl amines, and one by a mixed aromatic/aliphatic amine. The same search requesting additionally the presence of a water molecule in the crystal structure gave 23 hydrates but only one of them was formed by an aromatic amine, with one molecule of water included per three tetraamine molecules (CSD refcode RARROS; Laliberté et al., 2005). The search shows that inclusion of water molecules in the crystal structures of primary aromatic mono- and polyamines is less feasible than in the case of their aliphatic analogues.

It is well known that both aliphatic and aromatic primary amines cocrystallize easily with a variety of mono- and dialcohols (Ermer & Eling 1994; Hanessian et al., 1994; Loehlin et al., 1998; Loehlin & Okasako, 2007), as predicted from the saturated hydrogen-bond principle introduced by Ermer & Eling (1994). In the complementary alcohol/amine system, the total number of donor H atoms matches the number of acceptor lone pairs, whereas primary amines alone show an excess of donor H atoms and a deficit of hydrogen-bond acceptors. The inclusion of self-complementary water molecules into the amine crystal structure leaves the unfavourable balance of donors and acceptors unchanged. However, on inclusion of water molecules into the crystal structures of aliphatic primary amines, stronger O—H···N and N—H···O hydrogen bonds can be formed substituting for weaker N—H···N interactions, and thus the enthalpic factor starts to play a promoting role in hydrate formation. In turn, primary aromatic amines are weak bases and have lower proton affinity. Thus, to accept a hydrogen bond their amine N atom has to adopt an sp³ hybridization at the expense of the conjugation energy of its lone pair with the aromatic ring π-system. Moreover, in aromatic amines the ratio of hydrogen-bond donors to acceptors is improved compared with aliphatic amines, as an aromatic ring with its electron-donating amine substituents becomes almost as good a hydrogen-bond accepting group as the aromatic amino group. Analysis of the intermolecular interactions in 48 aromatic amine structures in the CSD shows that N—H···π interactions are abundant and often competitive with respect to N—H···N hydrogen bonding. For example, 19 of the analysed structures show no N—H···N interactions, whereas only three of them do not have any short N—H···π contacts. By way of contrast, there is only one early structure (CSD refcode MTOLID; Fowweather, 1952) where N—H···N hydrogen bonds can be postulated but no N—H···π interactions are possible, given the arrangement of molecules within the crystal structure.

In the case of the anhydrous form of p-phenylenediamine, (II), only one N—H group of the four symmetry-independent NH₂ substituents is not involved in any of the specific interactions discussed above. However, cocrystallization of p-phenylenediamine with water molecules not only allows this molecule to adopt the packing mode in which stronger O—H···O, O—H···N and N—H···O interactions replace weaker N—H···N hydrogen bonds, but also all donors and all acceptors, including the electron-rich aromatic π system, contribute to the crystal stabilization energy. In our opinion, this is the explanation for this unusual case of a hydrate formation by an aromatic amine.

S2. Experimental

The hydrated form, (I), was obtained by slow evaporation of a water solution of p-phenylenediamine to give large colourless tabloid crystals. Crystals of (II) were obtained by evaporation of an ethanol–chloroform mixture (Solvent ratio?).

S3. Refinement

In (I), all H atoms were located in electron-density difference maps and freely refined (coordinates and isotropic displacement parameters). In (II), all H atoms were identified in difference Fourier maps but for refinement all C-bound H atoms were placed in calculated positions, with C—H = 0.93 Å, and refined as riding on their carrier atoms, with U_iso(H) = 1.2U_eq(C). All N-bound H atoms were freely refined (coordinates and isotropic displacement parameters).

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2007) for (I); CrysAlis PRO (Oxford Diffraction, 2009) for (II). Cell refinement: CrysAlis RED (Oxford Diffraction, 2007) for (I); CrysAlis PRO (Oxford Diffraction, 2009) for (II). Data reduction: CrysAlis RED (Oxford Diffraction, 2007) for (I); CrysAlis PRO (Oxford Diffraction, 2009) for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Only the asymmetric part of the unit cell is labelled (water molecules lie on mirror planes). Hydrogen bonds are shown as dashed lines.
	Fig. 2. The crystal structure of (I). Hydrogen bonds are shown as dotted lines. (a) The two-dimensional hydrogen-bond network formed by water molecules and primary amino groups. (b) A projection of the crystal structure along the a axis. (c) N—H···π interactions in the (010) layers of p-phenylenediamine molecules.
	Fig. 3. The molecular structure of (II), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. Only the asymmetric part of the unit cell is labelled. Hydrogen bonds are shown as dashed lines.
	Fig. 4. The crystal structure of (II). Hydrogen bonds are shown as dotted lines. (a) Chains of hydrogen bonds formed by primary amino groups. (b) A projection of the crystal structure along the a axis.
	Fig. 5. The proposed mechanism for the transformation of (I) into (II). One set of arrows show the direction of rotation of the C molecules, and the other set indicates pairs of water molecules replaced by the amino groups of the B molecules.

(I) p-phenylenedimamine dihydrate

Crystal data

C6H8N2·2H2O	F(000) = 312
Mr = 144.18	Dx = 1.220 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 2078 reflections
a = 8.8599 (8) Å	θ = 2.7–27.6°
b = 15.0248 (14) Å	µ = 0.09 mm^−1
c = 5.8952 (4) Å	T = 130 K
V = 784.76 (11) Å^3	Plate, pale pink
Z = 4	0.5 × 0.4 × 0.2 mm

Data collection

Kuma KM4CCD κ geometry diffractometer	830 independent reflections
Radiation source: fine-focus sealed tube	662 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.025
Detector resolution: 0 pixels mm^-1	θmax = 26.4°, θmin = 4.2°
ω scans	h = −10→11
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007)	k = −18→18
Tmin = 0.929, Tmax = 0.980	l = −7→6
3790 measured reflections

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)] = 0.032	Hydrogen site location: difference Fourier map
wR(F^2) = 0.086	All H-atom parameters refined
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0538P)^2 + 0.0295P] where P = (Fo^2 + 2Fc^2)/3
830 reflections	(Δ/σ)max = 0.001
75 parameters	Δρmax = 0.17 e Å^−3
0 restraints	Δρmin = −0.17 e Å^−3

Special details

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. 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
N1	0.28730 (11)	0.10580 (7)	0.76484 (18)	0.0202 (3)
H2N1	0.2198 (17)	0.0747 (10)	0.679 (2)	0.039 (4)*
H1N1	0.2388 (17)	0.1418 (10)	0.856 (3)	0.033 (4)*
C1	0.39237 (12)	0.05210 (7)	0.88402 (19)	0.0170 (3)
C2	0.43837 (13)	−0.03003 (8)	0.7984 (2)	0.0190 (3)
H2	0.3989 (13)	−0.0515 (8)	0.655 (2)	0.024 (3)*
C3	0.54413 (13)	−0.08137 (8)	0.9126 (2)	0.0191 (3)
H3	0.5743 (14)	−0.1379 (9)	0.850 (2)	0.021 (3)*
O1	0.35339 (14)	0.2500	0.4633 (2)	0.0230 (3)
H1O1	0.3431 (15)	0.2978 (11)	0.552 (3)	0.048 (5)*
O2	0.66776 (15)	0.2500	0.4291 (2)	0.0235 (3)
H2O2	0.712 (3)	0.2500	0.283 (4)	0.052 (7)*
H1O2	0.574 (3)	0.2500	0.421 (4)	0.056 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0202 (6)	0.0188 (5)	0.0215 (6)	0.0008 (5)	−0.0031 (5)	−0.0012 (4)
C1	0.0155 (6)	0.0176 (6)	0.0180 (6)	−0.0024 (5)	0.0019 (5)	0.0025 (5)
C2	0.0201 (6)	0.0207 (6)	0.0164 (6)	−0.0026 (5)	−0.0008 (5)	−0.0032 (5)
C3	0.0203 (6)	0.0163 (6)	0.0205 (7)	−0.0002 (5)	0.0023 (5)	−0.0041 (5)
O1	0.0267 (7)	0.0212 (7)	0.0209 (7)	0.000	0.0021 (5)	0.000
O2	0.0202 (7)	0.0261 (7)	0.0243 (7)	0.000	−0.0006 (6)	0.000

Geometric parameters (Å, º)

N1—C1	1.4182 (14)	C2—H2	0.969 (13)
N1—H2N1	0.912 (16)	C3—H3	0.965 (13)
N1—H1N1	0.877 (16)	O1—H1O1	0.894 (17)
C1—C2	1.3942 (16)	O2—H2O2	0.95 (3)
C1—C3^i	1.3957 (16)	O2—H1O2	0.83 (3)
C2—C3	1.3877 (17)
C1—N1—H2N1	114.4 (9)	C3—C2—H2	118.8 (7)
C1—N1—H1N1	111.6 (10)	C1—C2—H2	120.3 (7)
H2N1—N1—H1N1	109.7 (13)	C2—C3—C1^i	120.91 (11)
C2—C1—C3^i	118.17 (11)	C2—C3—H3	119.4 (7)
C2—C1—N1	121.07 (11)	C1^i—C3—H3	119.7 (7)
C3^i—C1—N1	120.73 (11)	H2O2—O2—H1O2	111 (2)
C3—C2—C1	120.92 (11)

Symmetry code: (i) −x+1, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N1···O2^ii	0.877 (16)	2.153 (17)	3.0120 (14)	166.1 (13)
O1—H1O1···N1^iii	0.894 (17)	1.978 (17)	2.8629 (13)	170.2 (14)
O2—H2O2···O1^iv	0.95 (3)	1.92 (3)	2.8383 (19)	164 (2)
O2—H1O2···O1	0.83 (3)	1.97 (3)	2.7925 (19)	169 (3)
N1—H2N1···Cg^v	0.912 (16)	2.48 (2)	3.383 (2)	169 (2)

Symmetry codes: (ii) x−1/2, y, −z+3/2; (iii) x, −y+1/2, z; (iv) x+1/2, y, −z+1/2; (v) −x+1/2, −y, z−1/2.

(II) p-phenylenediamine

Crystal data

C6H8N2	F(000) = 464
Mr = 108.14	Dx = 1.292 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 5671 reflections
a = 8.3020 (2) Å	θ = 2.9–29.6°
b = 5.8970 (1) Å	µ = 0.08 mm^−1
c = 22.7600 (5) Å	T = 130 K
β = 93.579 (2)°	Plate, colourless
V = 1112.09 (4) Å^3	0.45 × 0.4 × 0.25 mm
Z = 8

Data collection

Oxford Diffraction Xcalibur E diffractometer	2269 independent reflections
Radiation source: fine-focus sealed tube	1811 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 0 pixels mm^-1	θmax = 26.4°, θmin = 4.2°
ω scans	h = −10→10
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)	k = −7→7
Tmin = 0.973, Tmax = 0.980	l = −28→28
9761 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.031	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.082	w = 1/[σ^2(Fo^2) + (0.050P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
2269 reflections	Δρmax = 0.21 e Å^−3
178 parameters	Δρmin = −0.15 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.024 (3)

Special details

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. 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
N1A	0.57581 (11)	0.45945 (17)	0.82638 (4)	0.0215 (2)
H1NA	0.5144 (16)	0.529 (2)	0.8523 (6)	0.031 (3)*
H2NA	0.5189 (16)	0.353 (2)	0.8054 (6)	0.037 (4)*
N2A	0.91283 (11)	1.05625 (17)	0.68371 (4)	0.0200 (2)
H3NA	0.9730 (15)	1.157 (2)	0.7049 (5)	0.030 (3)*
H4NA	0.9729 (15)	0.980 (2)	0.6591 (6)	0.028 (3)*
C1A	0.65567 (11)	0.61057 (18)	0.78992 (4)	0.0172 (2)
C2A	0.69894 (11)	0.82793 (18)	0.80938 (4)	0.0174 (2)
H2A	0.6684	0.8770	0.8459	0.021*
C3A	0.78648 (12)	0.97219 (18)	0.77534 (4)	0.0172 (2)
H3A	0.8145	1.1156	0.7896	0.021*
C4A	0.83318 (11)	0.90546 (18)	0.72000 (4)	0.0161 (2)
C5A	0.79023 (11)	0.68827 (17)	0.70053 (4)	0.0174 (2)
H5A	0.8209	0.6392	0.6640	0.021*
C6A	0.70242 (12)	0.54375 (18)	0.73467 (4)	0.0178 (2)
H6A	0.6744	0.4003	0.7205	0.021*
N1B	0.34805 (11)	0.68514 (18)	0.92084 (4)	0.0235 (2)
H1NB	0.2984 (16)	0.578 (3)	0.9388 (6)	0.041 (4)*
H2NB	0.2804 (16)	0.739 (2)	0.8914 (6)	0.037 (4)*
C1B	0.41969 (12)	0.84520 (18)	0.96075 (4)	0.0182 (2)
C2B	0.45712 (12)	0.78883 (19)	1.01944 (4)	0.0197 (2)
H2B	0.4290	0.6464	1.0330	0.024*
C3B	0.46460 (12)	1.05970 (18)	0.94198 (5)	0.0192 (2)
H3B	0.4417	1.1018	0.9030	0.023*
N1C	0.88623 (12)	0.2537 (2)	0.89997 (4)	0.0268 (3)
H1NC	0.9007 (16)	0.103 (3)	0.9030 (6)	0.044 (4)*
H2NC	0.7847 (17)	0.297 (2)	0.8867 (6)	0.040 (4)*
C1C	0.93977 (12)	0.37346 (19)	0.95096 (4)	0.0199 (3)
C2C	1.06434 (12)	0.28966 (19)	0.98880 (5)	0.0218 (3)
H2C	1.1087	0.1483	0.9815	0.026*
C3C	0.87718 (12)	0.58587 (19)	0.96296 (5)	0.0217 (3)
H3C	0.7945	0.6454	0.9381	0.026*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1A	0.0212 (5)	0.0220 (5)	0.0214 (5)	−0.0040 (4)	0.0028 (4)	−0.0003 (4)
N2A	0.0201 (5)	0.0221 (5)	0.0179 (5)	−0.0034 (4)	0.0012 (4)	−0.0007 (4)
C1A	0.0124 (5)	0.0200 (6)	0.0189 (5)	0.0011 (4)	−0.0017 (4)	0.0023 (4)
C2A	0.0168 (5)	0.0211 (6)	0.0140 (5)	0.0024 (4)	−0.0003 (4)	−0.0027 (4)
C3A	0.0175 (5)	0.0149 (5)	0.0187 (5)	0.0009 (4)	−0.0028 (4)	−0.0025 (4)
C4A	0.0123 (5)	0.0188 (6)	0.0169 (5)	0.0019 (4)	−0.0025 (4)	0.0009 (4)
C5A	0.0156 (5)	0.0218 (6)	0.0144 (5)	0.0035 (4)	−0.0010 (4)	−0.0027 (4)
C6A	0.0162 (5)	0.0159 (5)	0.0207 (6)	0.0013 (4)	−0.0037 (4)	−0.0029 (4)
N1B	0.0252 (5)	0.0247 (5)	0.0202 (5)	−0.0039 (4)	−0.0013 (4)	−0.0001 (4)
C1B	0.0149 (5)	0.0216 (6)	0.0183 (5)	0.0007 (4)	0.0024 (4)	−0.0019 (4)
C2B	0.0189 (5)	0.0197 (5)	0.0208 (6)	0.0002 (4)	0.0041 (4)	0.0024 (4)
C3B	0.0185 (5)	0.0245 (6)	0.0147 (5)	0.0025 (4)	0.0016 (4)	0.0023 (4)
N1C	0.0259 (5)	0.0337 (7)	0.0209 (5)	−0.0077 (5)	0.0016 (4)	−0.0077 (5)
C1C	0.0195 (5)	0.0251 (6)	0.0158 (5)	−0.0083 (4)	0.0056 (4)	−0.0018 (4)
C2C	0.0210 (5)	0.0200 (6)	0.0251 (6)	−0.0026 (4)	0.0061 (4)	−0.0002 (5)
C3C	0.0190 (5)	0.0271 (6)	0.0191 (5)	−0.0031 (4)	0.0007 (4)	0.0035 (5)

Geometric parameters (Å, º)

N1A—C1A	1.4111 (14)	N1B—C1B	1.4151 (14)
N1A—H1NA	0.902 (13)	N1B—H1NB	0.869 (15)
N1A—H2NA	0.905 (15)	N1B—H2NB	0.904 (14)
N2A—C4A	1.4065 (13)	C1B—C2B	1.3925 (14)
N2A—H3NA	0.898 (14)	C1B—C3B	1.3934 (15)
N2A—H4NA	0.893 (13)	C2B—C3B^i	1.3857 (15)
C1A—C2A	1.3958 (15)	C2B—H2B	0.9300
C1A—C6A	1.3957 (14)	C3B—H3B	0.9300
C2A—C3A	1.3864 (14)	N1C—C1C	1.4068 (14)
C2A—H2A	0.9300	N1C—H1NC	0.901 (16)
C3A—C4A	1.3974 (14)	N1C—H2NC	0.914 (14)
C3A—H3A	0.9300	C1C—C3C	1.3897 (16)
C4A—C5A	1.3943 (15)	C1C—C2C	1.3943 (15)
C5A—C6A	1.3901 (14)	C2C—C3C^ii	1.3832 (15)
C5A—H5A	0.9300	C2C—H2C	0.9300
C6A—H6A	0.9300	C3C—H3C	0.9300
C1A—N1A—H1NA	113.8 (8)	C1B—N1B—H1NB	111.9 (9)
C1A—N1A—H2NA	112.2 (8)	C1B—N1B—H2NB	117.4 (9)
H1NA—N1A—H2NA	111.3 (12)	H1NB—N1B—H2NB	108.1 (13)
C4A—N2A—H3NA	111.7 (8)	C2B—C1B—C3B	117.57 (10)
C4A—N2A—H4NA	110.6 (8)	C2B—C1B—N1B	121.08 (10)
H3NA—N2A—H4NA	110.9 (11)	C3B—C1B—N1B	121.22 (10)
C2A—C1A—C6A	117.68 (9)	C3B^i—C2B—C1B	121.45 (10)
C2A—C1A—N1A	120.96 (10)	C3B^i—C2B—H2B	119.3
C6A—C1A—N1A	121.25 (10)	C1B—C2B—H2B	119.3
C3A—C2A—C1A	121.31 (9)	C2B^i—C3B—C1B	120.98 (10)
C3A—C2A—H2A	119.3	C2B^i—C3B—H3B	119.5
C1A—C2A—H2A	119.3	C1B—C3B—H3B	119.5
C2A—C3A—C4A	121.03 (10)	C1C—N1C—H1NC	113.6 (9)
C2A—C3A—H3A	119.5	C1C—N1C—H2NC	111.7 (9)
C4A—C3A—H3A	119.5	H1NC—N1C—H2NC	114.7 (13)
C5A—C4A—C3A	117.73 (10)	C3C—C1C—C2C	118.04 (10)
C5A—C4A—N2A	120.95 (9)	C3C—C1C—N1C	120.79 (10)
C3A—C4A—N2A	121.22 (10)	C2C—C1C—N1C	121.03 (11)
C6A—C5A—C4A	121.20 (9)	C3C^ii—C2C—C1C	120.81 (11)
C6A—C5A—H5A	119.4	C3C^ii—C2C—H2C	119.6
C4A—C5A—H5A	119.4	C1C—C2C—H2C	119.6
C5A—C6A—C1A	121.04 (10)	C2C^ii—C3C—C1C	121.15 (10)
C5A—C6A—H6A	119.5	C2C^ii—C3C—H3C	119.4
C1A—C6A—H6A	119.5	C1C—C3C—H3C	119.4

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1A—H1NA···N1B	0.902 (13)	2.336 (14)	3.2366 (14)	176.1 (11)
N2A—H4NA···N1C^iii	0.893 (13)	2.271 (13)	3.1609 (14)	174.1 (11)
N1B—H2NB···N2A^iv	0.904 (14)	2.512 (13)	3.2074 (13)	134.1 (11)
N1C—H2NC···N1A	0.914 (14)	2.347 (14)	3.2218 (14)	160.0 (12)
N1A—H2NA···CgA^iv	0.905 (15)	2.57 (2)	3.361 (2)	146 (2)
N2A—H3NA···CgA^iii	0.898 (14)	2.53 (2)	3.311 (2)	145 (2)
N1B—H1NB···CgC^v	0.869 (15)	2.95 (2)	3.666 (2)	151 (2)

Symmetry codes: (iii) −x+2, y+1/2, −z+3/2; (iv) −x+1, y−1/2, −z+3/2; (v) x−1, y, z.