Resonance-stabilized partial proton transfer in hydrogen bonds of incommensurate phenazine–chloranilic acid

Noohinejad, L.; Mondal, S.; Ali, S.I.; Dey, S.; van Smaalen, S.; Schönleber, A.

doi:10.1107/S2052520615004084

research papers

STRUCTURAL SCIENCE
CRYSTAL ENGINEERING
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ISSN: 2052-5206

Volume 71| Part 2| April 2015| Pages 228-234

doi:10.1107/S2052520615004084

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Resonance-stabilized partial proton transfer in hydrogen bonds of incommensurate phenazine–chloranilic acid

Leila Noohinejad,^a Swastik Mondal,^a,^b Sk Imran Ali,^a Somnath Dey,^a Sander van Smaalen ^a ^* and Andreas Schönleber ^a

^aLaboratory of Crystallography, University of Bayreuth, 95440 Bayreuth, Germany, and ^bMax-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
^*Correspondence e-mail: smash@uni-bayreuth.de

Edited by M. Dusek, Academy of Sciences of the Czech Republic, Czech Republic (Received 14 October 2014; accepted 26 February 2015; online 31 March 2015)

The co-crystal of phenazine (Phz) and chloranilic acid (H₂ca) becomes ferroelectric upon cooling through the loss of inversion symmetry. Further cooling results in the development of an incommensurate ferroelectric phase, followed by a lock-in transition towards a twofold superstructure. Here we present the incommensurately modulated crystal structure of Phz-H₂ca at T = 139 K with a symmetry given by the superspace group P2₁(½ σ₂ ½)0 and σ₂ = 0.5139. The modulation mainly affects the positions of the protons within half of the intermolecular hydrogen bonds that are responsible for the spontaneous polarization in all three low-temperature phases. Evidence for proton transfer in part of the hydrogen bonds is obtained from the correlated dependence on the phase of the modulation of the lengths of bonds involved in resonance stabilization of the acidic anion, and much smaller variations of bond lengths of atoms not involved in the resonance mechanism. Incommensurability is explained as competition between proton transfer favored for single hydrogen bonds on the basis of pK_a values and avoiding unfavorable Coulomb repulsion within the lattice of the resulting ionic molecules.

Keywords: protron transfer; ferroelectric materials; incommensurate structure.

B-IncStrDB reference: 10522E4Avuq

CCDC reference: 1051555

1. Introduction

Organic compounds are of interest as ferroelectric materials, because they have a low density and they are potentially cheap to produce (Horiuchi & Tokura, 2008 ). Furthermore, organic compounds offer more possibilities than inorganic compounds for designing properties. Organic materials based on hydrogen-bonded supramolecular chains with a polar space group form one class of ferroelectric materials. The co-crystal of phenazine (Phz) and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (chloranilic acid, H₂ca) is one of several recently discovered hydrogen-bonded organic ferroelectrics (Horiuchi, Ishii et al., 2005 ; Horiuchi et al., 2009 ; Kumai et al., 2006 , 2012 ).

Phz-H₂ca contains chains of alternating Phz and H₂ca molecules connected through O—H⋯N intermolecular hydrogen bonds. At room temperature, all hydrogen bonds are equivalent by the symmetry of the centrosymmetric space group P2₁/n (Z = 2), and the crystal of Phz-H₂ca is paraelectric (PE phase; Horiuchi, Ishii et al., 2005; Kumai et al., 2007 ). Below T_c^I = 253 K the symmetry is reduced to P2₁ (Z = 2), allowing for two inequivalent hydrogen bonds. One of the two bonds exhibits partial proton transfer, which is responsible for the spontaneous polarization (FE-I phase; Horiuchi, Ishii et al., 2005; Kumai et al., 2007; Gotoh et al., 2007 ). Phz-H₂ca has an incommensurately modulated structure between T_c^IC = 147 K and T_c^II = 137 K (FE-IC phase; Saito et al., 2006 ; Horiuchi et al., 2009). Below T_c^II another ferroelectric phase is stable that can be characterized as a twofold superstructure of the room-temperature structure (FE-II phase; Noohinejad et al., 2014 ).

Here we report the crystal structure of the incommensurate phase, employing the superspace formalism applied to single-crystal X-ray diffraction data. The modulation is found to mainly affect the positions of the H atoms within the O—H⋯N intermolecular hydrogen bonds. Evidence for proton transfer in part of these bonds is provided by the correlated variations of bond lengths reflecting resonance stabilization of the anion. A detailed comparison of the various phases reveals that the incommensurate phase has a crystal structure intermediate between the crystal structures of the FE-I and FE-II phases. A mechanism is proposed for the sequence of phase transitions.

2. Experimental

2.1. X-ray diffraction

Single crystals of Phz-H₂ca were obtained by cosublimation of phenazine and chloranilic acid (Horiuchi. Ishii et al., 2005; Noohinejad et al., 2014). A diffraction experiment at T = 139 K was performed on the same crystal as was employed in our previous study on the commensurate FE-II phase (Noohinejad et al., 2014). X-ray diffraction data have been measured at beamline F1 of Hasylab at DESY in Hamburg, Germany, employing a MAR165 CCD detector mounted on a kappa diffractometer. The temperature of the crystal was regulated by a nitrogen gas-flow cryostat. X-ray diffraction data were collected by φ scans and ω scans for various settings of the orientation of the crystal. To better evaluate strong and weak reflections, two measurements were performed with the same measurement strategies but with different exposure times of 20 and 160 s, respectively. Data processing of the measured images has been carried out with the software EVAL15 (Schreurs et al., 2010 ) to index and extract the integrated intensities of Bragg reflections, and with SADABS (Sheldrick, 2008 ) for absorption correction. The latter employed groups of equivalent reflections defined according to the point group 2/m, which appeared as the symmetry of the diffraction. Experimental details are given in Table 1.

Table 1
Experimental details

Crystal data
Chemical formula	C₁₂H₈N₂·C₆H₂Cl₂O₄
M_r	389.2
Crystal system, superspace group	Monoclinic, P2₁(½ σ₂ ½)0
Temperature (K)	139
Wavevector	q = 0.5a* + 0.5139b* + 0.5c*
a, b, c (Å)	12.3720 (2), 3.7649 (5), 16.8315 (2)
β (°)	107.789 (7)
V (Å³)	746.52 (14)
Z	2
Radiation type	Synchrotron, λ = 0.56 Å
μ (mm⁻¹)	0.24
Crystal size (mm)	0.22 × 0.13 × 0.05

Data collection
Diffractometer	Marresearch, mar165 CCD
Absorption correction	Empirical (using intensity measurements) SADABS (Sheldrick, 2008)
T_min, T_max	0.777, 0.991
No. of measured, independent and observed [I > 3σ(I)] reflections	25 001, 15 433, 8092
Main (obs, all)	5607, 5942
Satellites, first order (obs, all)	2485, 9491
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.981

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.071, 2.08
No. of reflections	15 433
No. of parameters	719
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.02
Absolute structure	6649 Friedel pairs used in the refinement
Absolute structure parameter	0.5

Indexing of the diffraction images with EVAL15 resulted in an indexing with four integers on the basis of a monoclinic unit cell closely related to the unit cell of the FE-I phase at 160 K (Horiuchi, Ishii et al., 2005) together with the incommensurate modulation wavevector $[{\bf q}^{\prime} = \textstyle({1 \over 2},\, \sigma_2^{\prime},\, {1 \over 2})]$ , where $[\sigma_2^{\prime}]$ = 0.4861. However, the integration routine of EVAL15 did not accept a modulation wavevector with rational components. Therefore, the integration has been performed within the supercentered setting with $[{\bf q}^{\prime}_{i}]$ = $[(0,\, \sigma_2^{\prime},\, 0)]$ and centering translation $[({1 \over 2},\, 0,\, {1 \over 2},\, {1 \over 2})]$ with respect to the transformed basic structure unit cell $[{\bf A}]$ = $[{\bf a}-{\bf c}]$ , $[{\bf B}]$ = $[{\bf b}]$ , and $[{\bf C}]$ = $[{\bf a}+{\bf c}]$ (Stokes et al., 2011 ). The same setting has been employed in SADABS.

2.2. Choice of the superspace group

The low-temperature superstructure of the FE-II phase at 100 K has been described as a commensurately modulated structure with a basic structure similar to the structure at higher temperatures and the commensurate modulation wavevector $[{\bf q}_{\rm comm} = \textstyle({1 \over 2},\, {1 \over 2},\, {1 \over 2})]$ . The superspace group $[P2_1\textstyle({1 \over 2}\,\sigma_2\,{1 \over 2})0]$ , with $[\textstyle\sigma_2 = {1 \over 2}]$ has been found to describe the symmetry of this phase (Noohinejad et al., 2014).

Presently, the indexing with modulation wavevector $[{\bf q}^{\prime} = \textstyle({1 \over 2},\, \sigma_2^{\prime},\, {1 \over 2})]$ and $[\sigma_2^{\prime} = 0.4861]$ (see §2.1) leads to the superspace group $[P2_1\textstyle({1 \over 2}\, \sigma_{2}^{\prime}\, {1 \over 2})s]$ . The non-centrosymmetric superspace group is established by the lack of inversion symmetry of both the FE-I and FE-II phases (see §1) as well as by measurements of the electrical polarization, indicating a ferroelectric state below T_c^I (Horiuchi, Kumai & Tokura et al., 2005 ). The two superspace groups appear to be alternate settings of superspace group No. 4.1.6.3 with standard setting $[P2_1\textstyle({1 \over 2}\,0\,\sigma_3)0]$ (Stokes et al., 2011). The two settings can be transformed into each other by a shift of the origin. However, this would result in different coordinates of the atoms in the basic structures of the low-temperature and incommensurate phases, which is not desired. The setting with zero intrinsic translation along the fourth coordinate can also be obtained by the choice of a different modulation wavevector for the incommensurate modulation, according to

$[\eqalignno{{\bf q} = \, & {\bf a}^* + {\bf b}^* + {\bf c}^* - {\bf q}^{\prime}\cr =\, & \left({1 \over 2},\,\sigma_2,\,{1 \over 2}\right) &(1)}]$

with

$[\sigma_2 \, = \, 1 - \sigma_2^{\prime} \, = \, 0.5139. \eqno(2)]$

Diffraction data were re-indexed according to this transformation [equations (1) and (2)], and the superspace group $[P2_1\textstyle({1 \over 2}\,\sigma_2\,{1 \over 2})0]$ with $[\sigma_2]$ = 0.5139 has been used for all refinements.

2.3. Structure refinements

Initial values for the parameters of the basic structure have been taken from the basic structure at 100 K (Noohinejad et al., 2014). Anisotropic atomic displacement parameters (ADPs) have been used for all non-H atoms. H atoms were placed at calculated positions with a bond length d(C—H) of 0.96 Å, and they were refined using a riding model with isotropic ADPs equal to 1.2 times the equivalent isotropic ADPs of the bonded C atoms. H atoms of the hydroxyl groups were located in the difference Fourier map. They were then shifted to positions fulfilling the restraints d(O—H) = 0.85 (2) Å and ∠(C—O—H) = 109.5 (2)° (Müller et al., 2006 ; Engh & Huber, 1991 ), while their isotropic ADPs were restricted to 1.5 times the equivalent isotropic ADPs of the adjacent O atoms. Employing JANA2006 (Petricek et al., 2014 ), the positions of all atoms were refined with these restraints in effect. In the last step the restraints were released, resulting in a good fit to the main reflections with R_obs = 0.0412.

Three approaches have been chosen for determination of the atomic modulation functions for the incommensurate phase. In one approach, the modulation functions of the model at 100 K (Noohinejad et al., 2014) were used as a starting model. The same superspace group was employed, but with $[\sigma_2 = 0.5139]$ instead of the commensurate value of 0.5. The refinement converged smoothly to a good fit to the combined set of main and satellite reflections, resulting in model A (Table 1). Model A involves one harmonic wave for the displacive modulation of all atoms as well as one harmonic wave for the modulation of ADPs of all non-H atoms. The origin was fixed on the Cl2 atom. Inversion twins are expected to be present, because the IC phase has been reached by phase transitions, starting with the centrosymmetric PE phase at room temperature. Twinning did have a marginal effect on the refinement, while a significant deviation from equal volume fractions of the twin domains was not found. Therefore, equal volume fractions were employed for the final refinements. A model with the alternative symmetry $[P2_1\textstyle({1 \over 2}\,\sigma_2\,{1 \over 2})s]$ did not lead to a good fit to the data.

Starting with the same basic structure, model B was developed by assigning arbitrary but small values to the modulation parameters of the heaviest atom (chlorine). Refinements alternated with the subsequent introduction of modulation parameters for the O, N, C and H atoms, finally resulting in a fit to the diffraction data of equal quality as that of model A (Table 2).

Table 2
R values for the different structure models

Included are R values for observed (obs; defined by I > 3σ) and all (all) reflections. Partial R values are given for the group of main and satellite (sat) reflections. Structure model A is based on the low-temperature commensurate structure; model B has been obtained by refinement with arbitrary but small initial values for the modulation amplitudes; and model C is obtained after refinement of the superflip solution.

Model	A	B	C
GOF^obs	2.78	2.78	2.79
R^obs_F (all)	0.0449	0.0449	0.0451
R^obs_F (main)	0.0411	0.0412	0.0411
R^obs_F (sat)	0.1268	0.1266	0.1301
GOF^all	2.08	2.08	2.08
R^all_F (all)	0.0720	0.0718	0.0720
R^all_F (main)	0.0425	0.0425	0.0425
R^all_F (sat)	0.3661	0.3634	0.3663
No. of parameters	719	719	719

In a completely different approach, charge flipping was applied for the direct solution of the incommensurately modulated structure in superspace (Palatinus & Chapuis, 2007 ; Palatinus, 2013 ). For the solution, the software SUPERFLIP suggested the centrosymmetric symmetry $[P2_1/n\textstyle({1 \over 2}\, \sigma_2 \,{1 \over 2})00]$ . Since we knew that the modulation is non-centrosymmetric, we have chosen the superspace group $[P2_1\textstyle({1 \over 2}\, \sigma_2\, {1 \over 2})0]$ . JANA2006 was subsequently used to extract the basic structure positions and values of the first-order harmonics of the displacive modulation functions for all non-H atoms. Atoms were then named to match Fig. 1. For this model the basic structure coordinates were refined against all reflections, resulting in R_F = 0.3046, R_F^main = 0.2901 and R_F^sat = 0.6184. H atoms were added at calculated positions near C atoms as in model A. Refinement of the atomic coordinates within the riding model resulted in R_F = 0.3037, R_F^main = 0.2892 and R_F^sat = 0.6174. Subsequent refinement of anisotropic ADPs of the non-H atoms resulted in R_F = 0.0680, R_F^main = 0.0430 and R_F^sat = 0.6081. H atoms of the hydroxyl groups were located in the difference-Fourier map and treated as in model A. Refinement of the restrained model gave R_F = 0.0672, R_F^main = 0.0427 and R_F^sat = 0.5993. Refinement of the free model gave R_F = 0.0666, R_F^main = 0.0420 and R_F^sat = 0.5998. Small values were applied to the displacive modulation functions of the H atoms. Refinement of the modulated structure resulted in R_F = 0.0472, R_F^main = 0.0412 and R_F^sat = 0.1787. Finally, modulation parameters were introduced for the ADPs of the non-H atoms, resulting in the final fit of model C to the diffraction data as given in Table 2.

Figure 1
Phenazine C₁₂H₈N₂ and chloranilic acid C₆Cl₂H₂O₄ with the atom labels as employed in the present work.

3. Discussion

3.1. The structure model

The final fit to the diffraction data is excellent for the main reflections (Table 1). The rather high value of R_F^obs(sat) = 0.127 can be completely explained by the weakness of the satellite reflections and the resulting values for $[R_{\sigma}{\rm (sat)} = 0.151]$ , representing the average standard uncertainty over intensity, and R_int(sat) = 0.129 for averaging satellite reflections.

Model A and model B give the same fit to the diffraction data (Table 2). Although modulation parameters are different, these two models are completely equivalent. They differ from each other by a phase shift (Fig. 2). Further support for model A comes from difference-Fourier maps obtained after refinements of model A and of a similar model without the acidic H atoms (see the supporting information ). Model C has been obtained by solving the modulated structure by charge flipping in superspace. The modulation of model C is different from the modulations in models A and B, but R_F^obs(sat) is clearly higher for model C than for the other two models (Table 2). Therefore, model C provides a less good description of the modulation than models A and B do. Difficulties in obtaining the correct structure model by charge flipping are probably related to the pseudo-symmetry of the structure, with deviations from inversion symmetry being mainly the result of rearrangements of H atoms.

Figure 2
Interatomic distances (Å) as a function of phase t of the modulation. The t plot for model B (in blue) is superimposed onto the t plot for model A (in black), after application of a phase shift of −0.5139 in t to model B.

These properties provide strong support that model A (as well as the equivalent model B) is the correct model for the modulated crystal structure of the incommensurate phase. In view of these results, we have restricted the analysis to model A.

3.2. Resonance-stabilized proton transfer

The modulated structure of the incommensurate phase of Phz-H₂ca has been successfully determined at a temperature of 139 K. The magnitudes of the modulation amplitudes of the atoms reveal that the major effect of the modulation is a displacive modulation of the H atom of one of the two hydrogen bonds in which each molecule is involved in. This feature is in complete agreement with the crystal structures of the FE-I and FE-II phases, where also one half of the hydrogen bond is involved in the distortions of the structure.

More precisely, the crystal structure of the FE-I phase contains one crystallographically independent molecule H₂ca with two independent O atoms involved in O—H⋯N hydrogen bonds, denoted by O1 and O2 (Gotoh et al., 2007). The basic structure of the FE-IC phase is the same as the crystal structure of the FE-I phase, so that the FE-IC phase contains modulated atoms O1 and O2. Finally, the FE-II phase represents a twofold superstructure of the structure of the FE-I phase. Together with a reduction of the point symmetry to triclinic, this results in four crystallographically independent molecules H₂ca with atoms O1A through to O1D derived from O1, and atoms O2A through to O2D derived from O2 (Noohinejad et al., 2014). In all three phases, the hydrogen bonds O2—H1o2⋯N2 are not involved in superstructure formation. For the FE-IC structure, Table 3 and Fig. 3(a) show that bond lengths involving the O2, H1o2 and N2 atoms exhibit only a weak dependence on phase t of the modulation. For the FE-I and FE-II structures this property has been previously determined by Gotoh et al. (2007) and Noohinejad et al. (2014), and it is summarized in Table 3. Therefore, the hydrogen bonds O2—H1o2⋯N2 do not play a direct role in the ferroelectricity of this compound.

Table 3
Geometry of the intermolecular hydrogen bonds O1—H1o1⋯N1 and O2—H1o2⋯N2 at different temperatures corresponding to the FE-I, FE-IC and FE-II phases, respectively

Interatomic distances are given in Å and bond angles in degrees. (Max–min) provides the difference between the maximum (max) and minimum (min) separation depending on the phase t of the modulation in the FE-IC phase. The mean gives the value averaged over t. Standard uncertainties are given in parentheses.

	170 K†	139 K		100 K‡
	Distance	Distance	Max–min	Distance
O1—H1o1	1.02 (4)	1.44 (2) (mean)	0.25	0.943 (15) (A)
		1.32 (2) (min)		1.609 (15) (B)
		1.57 (2) (max)		1.066 (14) (C)
				1.467 (14) (D)
O2—H1o2	0.73 (2)	0.91 (2) (mean)	0.06	0.863 (15) (A)
		0.88 (2) (min)		0.796 (15) (B)
		0.94 (2) (max)		0.840 (14) (C)
				0.815 (13) (D)
H1o1—N1ⁱ	1.66 (4)	1.320 (14) (mean)	0.42	1.879 (15) (A)
		1.11 (2) (min)		1.027 (15) (B)
		1.53 (2) (max)		1.700 (14) (C)
				1.205 (14) (D)
H1o2—N2ⁱⁱ	2.15 (2)	1.945 (2) (mean)	0.05	1.908 (14) (A)
		1.92 (2) (min)		2.121 (14) (B)
		1.97 (2) (max)		1.944 (14) (C)
				2.084 (14) (D)
O1—N1ⁱ	2.6446 (16)	2.629 (2) (mean)	0.07	2.6976 (14) (A)
		2.586 (2) (min)		2.5736 (14) (B)
		2.672 (2) (max)		2.5974 (42) (D)
				2.6726 (14) (C)
O2—N2ⁱⁱ	2.7722 (16)	2.763 (2) (mean)	0.09	2.7086 (15) (A)
		2.715 (3) (min)		2.8251 (15) (B)
		2.811 (3) (max)		2.7264 (15) (C)
				2.8062 (15) (D)
O1—H1o1—N1ⁱ	159 (3)	144.8 (15) (mean)	9.9	143.8 (11) (A)
		139.5 (14) (min)		154.4 (11) (B)
		149.7 (16) (max)		149.3 (10) (C)
				152.6 (10) (D)
O2—H1o2—N2ⁱⁱ	145 (2)	149.2 (18) (mean)	5.4	153.7 (11) (A)
		146.4 (17) (min)		147.5 (12) (B)
		152.0 (18) (max)		154.5 (11) (C)
				147.60 (12) (D)
Symmetry codes for N1 and N2 in the structure model at T = 139 K are: (i) x - 1, y, z; (ii) x, y + 1, z.

†From Gotoh et al. (2007

).
‡From Noohinejad et al. (2014

); the labels A, B, C and D refer to the four molecular chains, which have become independent in the crystal structure at low temperatures.

Figure 3
Selected interatomic distances (Å) as a function of phase t of the modulation. (a) The O—H and N—H distances within the two hydrogen bonds. (b) C—C and C—O distances of the resonance system stabilizing the Hca⁻ anion, as well as the C6—O2 distance not involved in resonance. Notice the different length scale on the vertical axes for panels (a) and (b).

The largest variation in bond lengths within the FE-IC phase is found for the hydrogen bond O1—H1o1⋯N1, with a variation of Δd(O1—H1o1) = 0.25 Å and Δd(N1—H1o1) = 0.42 Å (Table 3). All other bonds are much less affected by the modulation, with a maximum variation of 0.06 Å for C3—O1 in H₂ca and of 0.019 Å for C14—C15 in Phz (see the supporting information ). The next largest variations of bond lengths are found for C3—C2, C1—C2 and C1—O4 (Table 4). These bonds are precisely those involved in resonance stabilization of the Hca⁻ ion, as it is obtained after transfer of the proton within the O1—H1o1⋯N1 hydrogen bond. Further evidence for this interpretation comes from t-plots (Fig. 3), which show that an elongation of the O1—H1o1 bond (interpreted as proton transfer) correlates with an elongation of the C3—C2 and C1—O4 bonds, for which resonance represents the admixture of single-bond character into these formally double bonds (Fig. 4). Concomitantly, C1—C2 and C3—O1 have become shorter due to the admixture of double-bond character into formally single bonds. A similar variation of bond lengths is found in the crystal structure of the FE-II phase (Table 4). The results support the model of partial proton transfer (see §3.3).

Table 4
Selected bond lengths (Å) at different temperatures corresponding to the FE-I, FE-IC and FE-II phases, respectively

(Max–min) provides the difference between maximum (max) and minimum (min) separation depending on phase t of the modulation in the FE-IC phase. The mean gives the value averaged over t. Standard uncertainties are given in parentheses.

	170 K†	139 K		100 K‡
	Distance	Distance	Max–min	Distance
C3—O1	1.2923 (13)	1.281 (2) (mean)	0.060	1.3200 (14) (A)
		1.251 (2) (min)		1.2536 (14) (B)
		1.311 (2) (max)		1.3054 (14) (C)
				1.2676 (14) (D)
C6—O2	1.3204 (13)	1.312 (3) (mean)	0.004	1.3133 (15) (A)
		1.310 (2) (min)		1.3204 (15) (B)
		1.314 (2) (max)		1.3118 (14) (C)
				1.3214 (14) (D)
C4—O3	1.2269 (15)	1.219 (2) (mean)	0.008	1.2243 (14) (A)
		1.215 (2) (min)		1.2211 (14) (B)
		1.223 (2) (max)		1.2248 (14) (C)
				1.2201 (14) (D)
C1—O4	1.2291 (15)	1.221 (2) (mean)	0.026	1.2183 (14) (A)
		1.208 (2) (min)		1.2385 (14) (B)
		1.234 (2) (max)		1.2210 (14) (C)
				1.2355 (14) (D)
C1—C2	1.4404 (15)	1.428 (3) (mean)	0.043	1.4590 (8) (A)
		1.406 (3) (min)		1.4114 (7) (B)
		1.449 (3) (max)		1.4496 (8) (C)
				1.4207 (8) (D)
C2—C3	1.3713 (16)	1.372 (3) (mean)	0.047	1.3517 (9) (A)
		1.349 (3) (min)		1.3949 (9) (B)
		1.396 (3) (max)		1.3622 (9) (C)
				1.3843 (9) (D)
N1—C12	1.3493 (13)	1.342 (2) (mean)	0.006	1.3451 (11) (A)
		1.339 (2) (min)		1.3465 (11) (B)
		1.345 (2) (max)		1.3468 (14) (C)
				1.3443 (12) (D)
N1—C17	1.3472 (17)	1.344 (2) (mean)	0.005	1.3490 (14) (A)
		1.342 (2) (min)		1.3505 (14) (B)
		1.347 (2) (max)		1.3464 (14) (C)
				1.3526 (14) (D)

†From Gotoh et al. (2007

).
‡From Noohinejad et al. (2014

Figure 4
Schematic representation of resonance within the anion Hca⁻ of chloranilic acid.

3.3. The ferroelectric phase transitions

Ferroelectricity in Phz-H₂ca at low temperatures is the result of intermolecular proton transfer within the O1—H1o1⋯N1 hydrogen bonds (Horiuchi, Kumai & Tokura, 2005; Kumai et al., 2007, 2012; Gotoh et al., 2007; Noohinejad et al., 2014). Consideration of the positions of the H atoms within the O1—H1o1⋯N1 hydrogen bonds of the crystal structures of the three phases leads to the following model for the phase transitions.

At room temperature (PE phase) all hydrogen bonds are equivalent by symmetry of the centrosymmetric space group. Consequently, any dipole moment of the O1—H1o1⋯N1 hydrogen bond will be perfectly compensated by a dipole moment of the O2—H1o2⋯N2 hydrogen bond on the same molecule that points in the opposite direction, because O1 and O2 are related by the inversion center. The ferroelectric phase transition towards the FE-I phase is characterized by loss of inversion symmetry. The O2—H1o2 remains short and should be interpreted as a covalent O—H bond that acts as a hydrogen-bond donor towards N2 (Table 3). The O1—H1o1 bond is clearly elongated compared with a covalent bond, but it is not completely broken. The N1—H1o1 distance is clearly shorter than in the PE phase, but it is not yet the distance of ∼ 1.03 Å of a covalent N—H bond. Therefore, it can be concluded that this structure exhibits partial proton transfer within the O1—H1o1⋯N1 hydrogen bonds.

The low-temperature FE-II has four crystallographically independent O1—H1o1⋯N1 hydrogen bonds. The partial proton transfer of the FE-I phase is replaced in the FE-II phase by complete proton transfer in one half of these hydrogen bonds (B and D), and the absence of proton transfer in the other half (A and C) (Table 3). The FE-I phase transfers into the FE-II phase via the intermediate FE-IC phase. Structurally, the FE-IC phase appears intermediate between the high- and low-temperature ferroelectric phases too. The incommensurate modulations represents a modulation of the O1—H1o1⋯N1 hydrogen bond between one with almost full proton transfer and one which can be characterized as almost no proton transfer (Table 3 and Fig. 3a). Despite an incommensurability of the FE-IC phase, it appears that – on average – one quarter of the hydrogen bonds has full proton transfer in both the FE-IC and FE-II phases, while half of the hydrogen bonds in the FE-I phase are affected by partial proton transfer. These similarities might explain the only marginal effects of the ferroelectric incommensurate and lock-in transitions on the macroscopic electric dipole moment (Horiuchi et al., 2009).

4. Conclusions

The incommensurately modulated structure of the ferroelectric incommensurate (FE-IC) phase of Phz-H₂ca has been successfully determined. It is shown that this structure is intermediate between the ferroelectric FE-I and FE-II phases. Half of the intermolecular hydrogen bonds exhibit partial proton transfer within the FE-I phase. This becomes an incommensurate variation between strong and very weak proton transfer within the FE-IC phase, while in the FE-II phase the active half of the hydrogen bonds splits into a hydrogen bond with complete proton transfer and one without proton transfer. Strong support for proton transfer in part of the hydrogen bonds has been obtained through the variations of the lengths of precisely those bonds that are involved in resonance stabilization of the Hca⁻ ion (§3.2). Proton transfer in only part of the hydrogen bonds has been explained as the result of Coulomb interactions between the resulting ionic species (Kumai et al., 2012). Proton transfer is in line with the acidities of the two molecules with pK_a1 = 1.23 for the proton acceptor Phz, and pK_a1 = 0.76 for the proton donor H₂ca (Albert & Phillips, 1956 ; Molcanov & Prodic, 2010 ). One could thus suggest that the incommensurability will be the result of competition between the inclination towards proton transfer of single hydrogen bonds and avoiding unfavorable Coulomb repulsion within the crystalline lattice of molecules.

Supporting information

B-IncStrDB reference: 10522E4Avuq

CCDC reference: 1051555

Crystal structure: contains datablocks global, I. DOI: 10.1107/S2052520615004084/dk5030sup1.cif

Structure factors: contains datablock block. DOI: 10.1107/S2052520615004084/dk5030Isup2.hkl

Extra tables and figures. DOI: 10.1107/S2052520615004084/dk5030sup3.pdf

Computing details top

Data collection: Eval15; cell refinement: Eval15; data reduction: Eval15; program(s) used to refine structure: Jana2006; molecular graphics: DIAMOND Version 3; software used to prepare material for publication: Jana2006.

Figures top

(I) top

Crystal data top

C₁₂H₈N₂·C₆H₂Cl₂O₄	Z = 2
M_r = 389.2	F(000) = 396
Monoclinic, P21(1/2β1/2)0†	D_x = 1.731 Mg m⁻³
q = 0.500000a* + 0.513900b* + 0.500000c*	Synchrotron radiation, λ = 0.56 Å
a = 12.3720 (2) Å	µ = 0.24 mm⁻¹
b = 3.7649 (5) Å	T = 139 K
c = 16.831 (2) Å	Platelet, dark brown
β = 107.789 (7)°	0.22 × 0.13 × 0.05 mm
V = 746.52 (14) Å³

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂+1/2, −x₃, −x₁−x₃+x₄.

Data collection top

Marresearch, marCCD 165 diffractometer	8092 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.019
ω and ϕ scans	θ_max = 33.3°, θ_min = 1.9°
Absorption correction: empirical (using intensity measurements) SADABS;Sheldrick,2008	h = −10→16
T_min = 0.777, T_max = 0.991	k = −7→7
25001 measured reflections	l = −33→32
15433 independent reflections

Refinement top

Refinement on F	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.045	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
wR(F²) = 0.071	(Δ/σ)_max = 0.001
S = 2.08	Δρ_max = 0.17 e Å⁻³
15433 reflections	Δρ_min = −0.02 e Å⁻³
719 parameters	Absolute structure: 6649 of Friedel pairs used in the refinement
0 restraints	Absolute structure parameter: 0.5
0 constraints

Crystal data top

C₁₂H₈N₂·C₆H₂Cl₂O₄	β = 107.789 (7)°
M_r = 389.2	V = 746.52 (14) Å³
Monoclinic, P21(1/2β1/2)0†	Z = 2
q = 0.500000a* + 0.513900b* + 0.500000c*	Synchrotron radiation, λ = 0.56 Å
a = 12.3720 (2) Å	µ = 0.24 mm⁻¹
b = 3.7649 (5) Å	T = 139 K
c = 16.831 (2) Å	0.22 × 0.13 × 0.05 mm

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂+1/2, −x₃, −x₁−x₃+x₄.

Data collection top

Marresearch, marCCD 165 diffractometer	15433 independent reflections
Absorption correction: empirical (using intensity measurements) SADABS;Sheldrick,2008	8092 reflections with I > 3σ(I)
T_min = 0.777, T_max = 0.991	R_int = 0.019
25001 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.071	Δρ_max = 0.17 e Å⁻³
S = 2.08	Δρ_min = −0.02 e Å⁻³
15433 reflections	Absolute structure: 6649 of Friedel pairs used in the refinement
719 parameters	Absolute structure parameter: 0.5
0 restraints

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl2	0.39426 (2)	0.759355	0.425664 (9)	0.01637 (8)
Cl1	0.10334 (2)	1.36699 (6)	0.076472 (9)	0.01630 (8)
O1	0.01710 (6)	1.0198 (3)	0.20084 (4)	0.0187 (2)
O2	0.47869 (6)	1.1115 (3)	0.30175 (3)	0.0182 (2)
O3	0.14288 (6)	0.7382 (3)	0.34754 (4)	0.0199 (2)
O4	0.35598 (6)	1.3761 (3)	0.15557 (3)	0.0189 (2)
N1	0.85572 (7)	0.6962 (3)	0.24458 (4)	0.0134 (2)
N2	0.64611 (7)	0.4400 (3)	0.25095 (4)	0.0135 (2)
C1	0.30168 (9)	1.2333 (3)	0.19627 (4)	0.0138 (3)
C2	0.18097 (9)	1.2022 (3)	0.17186 (4)	0.0135 (3)
C3	0.12546 (9)	1.0428 (3)	0.22157 (4)	0.0140 (3)
C4	0.19362 (9)	0.8866 (3)	0.30527 (4)	0.0135 (3)
C5	0.31591 (8)	0.9219 (3)	0.33025 (4)	0.0125 (3)
C6	0.36782 (8)	1.0814 (3)	0.27986 (4)	0.0124 (3)
C7	0.81178 (9)	0.5094 (3)	0.10230 (4)	0.0152 (3)
C8	0.73694 (9)	0.3530 (3)	0.03492 (4)	0.0167 (3)
C9	0.63221 (9)	0.2204 (3)	0.03867 (4)	0.0162 (3)
C10	0.60119 (9)	0.2457 (3)	0.10984 (4)	0.0154 (3)
C11	0.67723 (9)	0.4113 (3)	0.18154 (4)	0.0136 (3)
C12	0.78295 (8)	0.5441 (3)	0.17721 (4)	0.0123 (3)
C13	0.69135 (9)	0.6285 (3)	0.39302 (4)	0.0155 (3)
C14	0.76521 (9)	0.7854 (3)	0.46057 (4)	0.0172 (3)
C15	0.87021 (9)	0.9210 (3)	0.45697 (5)	0.0162 (3)
C16	0.90122 (9)	0.8951 (3)	0.38591 (5)	0.0145 (3)
C17	0.82595 (9)	0.7284 (3)	0.31464 (4)	0.0129 (3)
C18	0.71946 (9)	0.5983 (3)	0.31757 (4)	0.0132 (3)
H7	0.883405	0.595476	0.099163	0.0183*
H8	0.755844	0.332715	−0.016126	0.0201*
H9	0.581407	0.109597	−0.009819	0.0194*
H10	0.529556	0.153698	0.111502	0.0185*
H13	0.620244	0.538221	0.396235	0.0186*
H14	0.745931	0.804454	0.511489	0.0207*
H15	0.920655	1.033441	0.505363	0.0194*
H16	0.972721	0.988108	0.384193	0.0174*
H1o1	−0.0461 (11)	0.765 (4)	0.2321 (8)	0.0281*
H1o2	0.5251 (11)	1.158 (4)	0.2704 (8)	0.0273*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl2	0.01737 (18)	0.01914 (12)	0.01152 (7)	−0.00017 (11)	0.00280 (9)	0.00293 (6)
Cl1	0.01772 (18)	0.01883 (12)	0.01129 (7)	0.00005 (11)	0.00285 (9)	0.00285 (6)
O1	0.0117 (4)	0.0259 (4)	0.0183 (2)	−0.0023 (4)	0.0042 (3)	0.0039 (3)
O2	0.0132 (4)	0.0252 (4)	0.0169 (2)	−0.0030 (4)	0.0056 (3)	0.0055 (3)
O3	0.0167 (4)	0.0272 (4)	0.0177 (2)	−0.0030 (5)	0.0081 (3)	0.0054 (3)
O4	0.0160 (4)	0.0254 (4)	0.0165 (2)	−0.0021 (5)	0.0067 (3)	0.0054 (3)
N1	0.0132 (5)	0.0140 (3)	0.0123 (2)	0.0001 (4)	0.0029 (3)	0.0007 (2)
N2	0.0133 (5)	0.0142 (3)	0.0127 (2)	−0.0009 (4)	0.0037 (3)	0.0005 (2)
C1	0.0165 (6)	0.0137 (4)	0.0114 (2)	−0.0004 (5)	0.0044 (3)	0.0002 (3)
C2	0.0144 (6)	0.0152 (4)	0.0107 (2)	−0.0016 (4)	0.0035 (3)	0.0005 (2)
C3	0.0145 (6)	0.0152 (4)	0.0122 (2)	−0.0001 (5)	0.0039 (3)	0.0000 (3)
C4	0.0143 (6)	0.0150 (4)	0.0120 (2)	−0.0011 (5)	0.0050 (3)	−0.0004 (3)
C5	0.0125 (6)	0.0137 (4)	0.0110 (2)	−0.0009 (4)	0.0029 (3)	0.0007 (2)
C6	0.0110 (6)	0.0137 (4)	0.0118 (2)	−0.0009 (4)	0.0028 (3)	0.0002 (2)
C7	0.0159 (6)	0.0159 (4)	0.0142 (3)	−0.0004 (5)	0.0051 (3)	−0.0009 (3)
C8	0.0187 (6)	0.0179 (4)	0.0139 (2)	0.0045 (5)	0.0055 (3)	0.0000 (3)
C9	0.0166 (6)	0.0165 (4)	0.0138 (3)	0.0015 (5)	0.0022 (3)	−0.0020 (3)
C10	0.0148 (6)	0.0164 (4)	0.0137 (2)	−0.0047 (5)	0.0023 (3)	−0.0020 (3)
C11	0.0161 (6)	0.0119 (4)	0.0118 (2)	0.0000 (4)	0.0028 (3)	0.0008 (2)
C12	0.0112 (5)	0.0127 (4)	0.0130 (2)	0.0023 (4)	0.0038 (3)	0.0018 (2)
C13	0.0159 (6)	0.0180 (4)	0.0135 (2)	0.0018 (5)	0.0060 (3)	0.0012 (3)
C14	0.0200 (6)	0.0177 (4)	0.0143 (3)	0.0006 (5)	0.0057 (3)	−0.0027 (3)
C15	0.0160 (6)	0.0168 (4)	0.0143 (3)	0.0002 (5)	0.0024 (3)	−0.0028 (3)
C16	0.0126 (6)	0.0144 (4)	0.0144 (2)	0.0010 (5)	0.0009 (3)	−0.0006 (3)
C17	0.0144 (6)	0.0124 (4)	0.0124 (2)	0.0018 (4)	0.0050 (3)	0.0009 (2)
C18	0.0151 (6)	0.0117 (4)	0.0117 (2)	−0.0009 (4)	0.0023 (3)	0.0007 (2)

Geometric parameters (Å, º) top

	Average	Minimum	Maximum
Cl2—C5	1.7153 (15)	1.7131 (15)	1.7178 (15)
Cl1—C2	1.7155 (15)	1.7119 (15)	1.7190 (15)
O1—C2	2.329 (3)	2.320 (3)	2.339 (3)
O1—C3	1.281 (2)	1.251 (2)	1.311 (2)
O1—C4	2.401 (2)	2.391 (2)	2.411 (2)
O1—H1o1	1.44 (2)	1.32 (2)	1.57 (2)
O2—C1	2.405 (2)	2.400 (2)	2.410 (2)
O2—C5	2.321 (3)	2.316 (3)	2.325 (3)
O2—C6	1.312 (3)	1.310 (2)	1.314 (2)
O2—H1o2	0.91 (2)	0.88 (2)	0.94 (2)
O3—C3	2.362 (2)	2.350 (2)	2.374 (2)
O3—C4	1.219 (2)	1.215 (2)	1.223 (2)
O3—C5	2.351 (3)	2.344 (3)	2.358 (3)
O3—H1o1	2.546 (17)	2.399 (17)	2.697 (17)
O4—C1	1.221 (2)	1.208 (2)	1.234 (2)
O4—C2	2.357 (3)	2.352 (3)	2.362 (3)
O4—C6	2.333 (2)	2.327 (2)	2.338 (2)
O4—H1o2	2.513 (17)	2.492 (17)	2.535 (17)
N1—C7	2.394 (2)	2.386 (2)	2.402 (2)
N1—C11	2.392 (2)	2.370 (2)	2.413 (2)
N1—C12	1.342 (2)	1.339 (2)	1.345 (2)
N1—C16	2.392 (2)	2.382 (2)	2.401 (2)
N1—C17	1.344 (2)	1.342 (2)	1.347 (2)
N1—C18	2.398 (3)	2.382 (3)	2.415 (3)
N1—H1o1ⁱ	1.32 (2)	1.11 (2)	1.53 (2)
N2—C10	2.383 (2)	2.376 (2)	2.391 (2)
N2—C11	1.342 (2)	1.338 (2)	1.345 (2)
N2—C12	2.418 (3)	2.414 (3)	2.421 (3)
N2—C13	2.391 (2)	2.390 (2)	2.392 (2)
N2—C17	2.413 (2)	2.403 (2)	2.423 (2)
N2—C18	1.3470 (19)	1.342 (2)	1.352 (2)
N2—H1o2ⁱⁱ	1.94 (2)	1.92 (2)	1.97 (2)
C1—C2	1.428 (3)	1.406 (3)	1.449 (3)
C1—C3	2.453 (3)	2.444 (3)	2.462 (3)
C1—C5	2.500 (2)	2.491 (2)	2.509 (2)
C1—C6	1.508 (2)	1.505 (2)	1.510 (2)
C2—C3	1.372 (3)	1.349 (3)	1.396 (3)
C2—C4	2.503 (2)	2.487 (2)	2.519 (2)
C2—C6	2.508 (2)	2.494 (2)	2.521 (2)
C3—C4	1.522 (2)	1.507 (2)	1.537 (2)
C3—H1o1	2.42 (2)	2.26 (2)	2.58 (2)
C4—C5	1.447 (3)	1.438 (3)	1.456 (3)
C4—C6	2.435 (3)	2.427 (3)	2.443 (3)
C5—C6	1.351 (3)	1.346 (3)	1.356 (3)
C6—H1o2	2.02 (2)	1.99 (2)	2.05 (2)
C7—C8	1.360 (2)	1.355 (2)	1.364 (2)
C7—C9	2.411 (3)	2.406 (3)	2.416 (3)
C7—C11	2.458 (3)	2.450 (3)	2.466 (3)
C7—C12	1.417 (3)	1.415 (3)	1.420 (3)
C7—H7	1.0 (13)	1.0 (13)	1.0 (13)
C7—H8	2.0 (15)	2.0 (15)	2.0 (15)
C7—H1o1ⁱ	2.543 (17)	2.450 (17)	2.640 (17)
C8—C9	1.408 (3)	1.403 (3)	1.413 (3)
C8—C10	2.422 (3)	2.414 (3)	2.431 (3)
C8—C12	2.397 (2)	2.383 (2)	2.410 (2)
C8—H7	2.0 (10)	2.0 (10)	2.0 (10)
C8—H8	1.0 (18)	1.0 (18)	1.0 (18)
C8—H9	2.1 (10)	2.0 (10)	2.1 (10)
C9—C10	1.368 (3)	1.364 (3)	1.373 (3)
C9—C11	2.407 (2)	2.406 (2)	2.408 (2)
C9—H8	2.1 (16)	2.1 (16)	2.1 (16)
C9—H9	1.0 (12)	1.0 (12)	1.0 (12)
C9—H10	2.0 (17)	2.0 (17)	2.0 (17)
C10—C11	1.427 (2)	1.420 (2)	1.434 (2)
C10—C12	2.459 (3)	2.451 (3)	2.467 (3)
C10—H9	2.0 (16)	2.0 (16)	2.0 (16)
C10—H10	1.0 (13)	1.0 (13)	1.0 (13)
C11—C12	1.423 (3)	1.420 (3)	1.426 (3)
C11—C18	2.298 (2)	2.292 (2)	2.304 (2)
C11—H10	2.1 (10)	2.1 (10)	2.1 (10)
C12—C17	2.316 (2)	2.291 (2)	2.341 (2)
C12—H7	2.1 (17)	2.1 (17)	2.1 (17)
C12—H1o1ⁱ	2.197 (19)	2.009 (18)	2.391 (19)
C13—C14	1.357 (2)	1.351 (2)	1.363 (2)
C13—C15	2.411 (3)	2.406 (3)	2.415 (3)
C13—C17	2.449 (3)	2.446 (3)	2.452 (3)
C13—C18	1.420 (3)	1.417 (3)	1.423 (3)
C13—H13	1.0 (13)	1.0 (13)	1.0 (13)
C13—H14	2.0 (15)	2.0 (15)	2.0 (15)
C14—C15	1.414 (3)	1.405 (3)	1.424 (3)
C14—C16	2.423 (3)	2.421 (3)	2.426 (3)
C14—C18	2.403 (2)	2.398 (2)	2.409 (2)
C14—H13	2.0 (10)	2.0 (10)	2.0 (10)
C14—H14	1.0 (18)	1.0 (18)	1.0 (18)
C14—H15	2.1 (10)	2.1 (10)	2.1 (10)
C15—C16	1.367 (3)	1.361 (3)	1.372 (3)
C15—C17	2.401 (2)	2.391 (2)	2.410 (2)
C15—H14	2.1 (16)	2.1 (16)	2.1 (16)
C15—H15	1.0 (12)	1.0 (12)	1.0 (12)
C15—H16	2.0 (17)	2.0 (17)	2.0 (17)
C16—C17	1.420 (2)	1.417 (2)	1.424 (2)
C16—C18	2.459 (3)	2.451 (3)	2.468 (3)
C16—H15	2.0 (16)	2.0 (16)	2.0 (16)
C16—H16	1.0 (13)	1.0 (13)	1.0 (13)
C17—C18	1.421 (3)	1.417 (3)	1.424 (3)
C17—H16	2.1 (10)	2.1 (10)	2.1 (10)
C17—H1o1ⁱ	2.41 (2)	2.21 (2)	2.61 (2)
C18—H13	2.1 (17)	2.1 (17)	2.1 (17)
H7—H8	2.316	2.3116	2.3206
H7—H1o1ⁱ	2.2 (15)	2.2 (15)	2.3 (15)
H8—H9	2.3483	2.3375	2.3591
H9—H10	2.3259	2.3213	2.3308
H13—H14	2.3115	2.3035	2.3196
H13—H1o2ⁱⁱ	2.5 (12)	2.5 (12)	2.6 (12)
H14—H15	2.3585	2.3424	2.3748
H15—H16	2.3252	2.3154	2.335

C2—O1—C3	29.71 (9)	29.63 (9)	29.79 (9)
C2—O1—C4	63.86 (7)	63.39 (7)	64.34 (7)
C2—O1—H1o1	151.4 (8)	145.0 (8)	157.4 (7)
C3—O1—C4	34.16 (9)	33.67 (9)	34.68 (9)
C3—O1—H1o1	125.7 (7)	118.9 (8)	132.2 (6)
C4—O1—H1o1	93.6 (7)	87.6 (7)	99.2 (6)
C1—O2—C5	63.84 (7)	63.57 (7)	64.12 (7)
C1—O2—C6	34.00 (9)	33.74 (9)	34.26 (9)
C1—O2—H1o2	97.4 (11)	94.7 (11)	100.1 (11)
C5—O2—C6	29.85 (9)	29.81 (9)	29.88 (9)
C5—O2—H1o2	157.2 (11)	154.8 (11)	159.6 (11)
C6—O2—H1o2	130.2 (11)	127.4 (11)	133.1 (11)
C3—O3—C4	34.44 (9)	34.09 (9)	34.80 (9)
C3—O3—C5	65.34 (7)	65.00 (7)	65.66 (7)
C3—O3—H1o1	58.9 (5)	56.9 (5)	60.8 (5)
C4—O3—C5	30.89 (9)	30.74 (9)	31.05 (9)
C4—O3—H1o1	92.9 (5)	90.5 (5)	95.3 (5)
C5—O3—H1o1	123.5 (5)	120.9 (5)	125.8 (5)
C1—O4—C2	29.54 (9)	28.60 (8)	30.48 (8)
C1—O4—C6	35.11 (9)	34.48 (9)	35.74 (9)
C1—O4—H1o2	84.1 (5)	82.6 (5)	85.5 (5)
C2—O4—C6	64.65 (7)	64.33 (7)	64.96 (7)
C2—O4—H1o2	113.5 (5)	112.8 (5)	114.1 (5)
C6—O4—H1o2	49.1 (5)	48.2 (5)	50.1 (5)
C7—N1—C11	61.82 (7)	61.44 (7)	62.19 (7)
C7—N1—C12	30.73 (11)	30.19 (11)	31.28 (11)
C7—N1—C16	178.51 (9)	177.48 (10)	179.40 (8)
C7—N1—C17	149.90 (12)	148.23 (12)	151.54 (13)
C7—N1—C18	119.15 (8)	118.13 (8)	120.16 (8)
C7—N1—H1o1ⁱ	80.6 (8)	78.4 (9)	82.6 (8)
C11—N1—C12	31.09 (11)	30.20 (10)	31.98 (11)
C11—N1—C16	119.12 (10)	118.10 (9)	120.13 (9)
C11—N1—C17	88.09 (11)	86.76 (11)	89.40 (11)
C11—N1—C18	57.34 (7)	56.67 (6)	58.00 (7)
C11—N1—H1o1ⁱ	141.9 (8)	140.0 (9)	143.7 (8)
C12—N1—C16	150.19 (15)	148.29 (14)	152.08 (15)
C12—N1—C17	119.17 (16)	116.96 (16)	121.35 (16)
C12—N1—C18	88.42 (12)	86.87 (12)	89.96 (12)
C12—N1—H1o1ⁱ	111.2 (8)	108.8 (9)	113.3 (8)
C16—N1—C17	31.04 (9)	30.71 (9)	31.37 (9)
C16—N1—C18	61.79 (7)	61.43 (7)	62.13 (7)
C16—N1—H1o1ⁱ	98.5 (8)	96.4 (9)	100.5 (8)
C17—N1—C18	30.75 (9)	30.08 (9)	31.41 (9)
C17—N1—H1o1ⁱ	129.3 (8)	126.9 (9)	131.6 (8)
C18—N1—H1o1ⁱ	159.5 (8)	157.5 (8)	161.3 (8)
C10—N2—C11	31.66 (9)	31.59 (9)	31.73 (9)
C10—N2—C12	61.62 (7)	61.45 (7)	61.79 (7)
C10—N2—C13	179.22 (9)	178.94 (9)	179.44 (8)
C10—N2—C17	118.92 (9)	118.24 (9)	119.59 (9)
C10—N2—C18	149.11 (14)	148.37 (14)	149.85 (14)
C10—N2—H1o2ⁱⁱ	92.5 (6)	91.0 (6)	93.9 (6)
C11—N2—C12	29.96 (9)	29.73 (9)	30.19 (9)
C11—N2—C13	148.55 (12)	147.85 (12)	149.25 (12)
C11—N2—C17	87.26 (11)	86.63 (11)	87.89 (11)
C11—N2—C18	117.45 (16)	116.74 (16)	118.18 (16)
C11—N2—H1o2ⁱⁱ	122.9 (6)	121.4 (6)	124.4 (6)
C12—N2—C13	118.60 (8)	117.91 (8)	119.28 (8)
C12—N2—C17	57.30 (7)	56.62 (7)	57.98 (7)
C12—N2—C18	87.50 (12)	86.80 (12)	88.20 (12)
C12—N2—H1o2ⁱⁱ	150.6 (6)	149.3 (6)	151.9 (6)
C13—N2—C17	61.30 (7)	61.10 (7)	61.49 (7)
C13—N2—C18	31.10 (10)	31.08 (10)	31.13 (10)
C13—N2—H1o2ⁱⁱ	87.2 (6)	85.8 (6)	88.6 (6)
C17—N2—C18	30.20 (10)	30.00 (10)	30.40 (10)
C17—N2—H1o2ⁱⁱ	145.5 (5)	144.3 (5)	146.8 (5)
C18—N2—H1o2ⁱⁱ	117.4 (6)	116.0 (6)	118.7 (6)
O2—C1—O4	88.01 (12)	86.51 (10)	89.51 (11)
O2—C1—C2	146.45 (13)	145.95 (13)	146.97 (13)
O2—C1—C3	118.25 (8)	118.05 (8)	118.45 (8)
O2—C1—C5	56.44 (7)	56.39 (6)	56.50 (6)
O2—C1—C6	29.12 (9)	28.99 (9)	29.25 (9)
O4—C1—C2	125.53 (14)	124.49 (13)	126.58 (14)
O4—C1—C3	153.73 (12)	152.44 (12)	155.03 (11)
O4—C1—C5	144.45 (13)	142.98 (12)	145.91 (12)
O4—C1—C6	117.13 (17)	115.75 (15)	118.50 (15)
C2—C1—C3	28.21 (9)	27.90 (8)	28.52 (9)
C2—C1—C5	90.01 (12)	89.52 (12)	90.50 (12)
C2—C1—C6	117.33 (16)	116.93 (16)	117.75 (16)
C3—C1—C5	61.80 (7)	61.62 (7)	61.98 (7)
C3—C1—C6	89.13 (12)	89.03 (12)	89.23 (12)
C5—C1—C6	27.33 (9)	27.24 (9)	27.41 (9)
Cl1—C2—O1	91.62 (9)	91.12 (8)	92.13 (8)
Cl1—C2—O4	93.57 (9)	93.15 (9)	93.99 (9)
Cl1—C2—C1	118.48 (14)	118.17 (14)	118.80 (14)
Cl1—C2—C3	119.18 (14)	118.25 (14)	120.13 (14)
Cl1—C2—C4	151.05 (12)	150.68 (12)	151.43 (12)
Cl1—C2—C6	150.76 (12)	150.30 (12)	151.22 (12)
O1—C2—O4	174.70 (8)	173.87 (8)	175.52 (8)
O1—C2—C1	149.89 (12)	149.10 (12)	150.67 (12)
O1—C2—C3	27.57 (9)	26.31 (9)	28.84 (9)
O1—C2—C4	59.47 (7)	58.86 (7)	60.08 (7)
O1—C2—C6	117.62 (8)	116.76 (8)	118.47 (8)
O4—C2—C1	24.93 (8)	24.81 (8)	25.05 (8)
O4—C2—C3	147.25 (12)	146.67 (12)	147.82 (12)
O4—C2—C4	115.37 (8)	115.00 (8)	115.72 (8)
O4—C2—C6	57.21 (6)	57.10 (6)	57.32 (7)
C1—C2—C3	122.33 (14)	121.64 (14)	123.02 (14)
C1—C2—C4	90.44 (10)	90.07 (10)	90.80 (10)
C1—C2—C6	32.28 (8)	32.07 (9)	32.49 (9)
C3—C2—C4	31.90 (9)	31.24 (9)	32.54 (8)
C3—C2—C6	90.05 (11)	89.55 (10)	90.54 (10)
C4—C2—C6	58.16 (7)	57.86 (7)	58.45 (7)
O1—C3—O3	90.71 (12)	90.57 (12)	90.86 (13)
O1—C3—C1	152.17 (12)	151.65 (12)	152.72 (12)
O1—C3—C2	122.72 (14)	121.42 (14)	124.04 (14)
O1—C3—C4	117.63 (17)	117.46 (16)	117.79 (17)
O1—C3—H1o1	28.7 (4)	26.8 (4)	30.7 (5)
O3—C3—C1	117.12 (8)	116.52 (8)	117.72 (8)
O3—C3—C2	146.56 (13)	145.14 (13)	147.99 (13)
O3—C3—C4	26.94 (9)	26.87 (9)	27.00 (9)
O3—C3—H1o1	64.3 (4)	62.5 (4)	65.9 (4)
C1—C3—C2	29.46 (9)	28.64 (8)	30.29 (9)
C1—C3—C4	90.19 (12)	89.54 (11)	90.84 (12)
C1—C3—H1o1	169.9 (5)	169.0 (5)	170.9 (5)
C2—C3—C4	119.65 (17)	118.19 (16)	121.11 (16)
C2—C3—H1o1	147.9 (4)	147.4 (4)	148.4 (5)
C4—C3—H1o1	90.9 (4)	89.0 (5)	92.7 (4)
O1—C4—O3	90.42 (11)	90.13 (12)	90.72 (12)
O1—C4—C2	56.67 (6)	56.45 (6)	56.88 (6)
O1—C4—C3	28.21 (10)	27.58 (10)	28.85 (10)
O1—C4—C5	146.08 (13)	145.99 (13)	146.17 (13)
O1—C4—C6	117.68 (9)	117.37 (8)	117.98 (8)
O3—C4—C2	147.05 (13)	146.56 (13)	147.54 (13)
O3—C4—C3	118.62 (16)	118.20 (16)	119.04 (17)
O3—C4—C5	123.49 (14)	123.13 (14)	123.85 (14)
O3—C4—C6	151.89 (12)	151.63 (12)	152.16 (12)
C2—C4—C3	28.46 (10)	27.65 (10)	29.26 (10)
C2—C4—C5	89.44 (12)	89.29 (12)	89.60 (12)
C2—C4—C6	61.02 (7)	60.56 (7)	61.47 (7)
C3—C4—C5	117.89 (16)	117.23 (16)	118.54 (16)
C3—C4—C6	89.47 (12)	89.12 (12)	89.82 (12)
C5—C4—C6	28.43 (8)	28.11 (8)	28.74 (8)
Cl2—C5—O2	91.46 (8)	91.33 (8)	91.59 (8)
Cl2—C5—O3	93.13 (9)	92.86 (8)	93.39 (8)
Cl2—C5—C1	151.16 (11)	150.77 (11)	151.54 (11)
Cl2—C5—C4	118.73 (14)	118.20 (13)	119.26 (14)
Cl2—C5—C6	120.36 (13)	120.11 (13)	120.60 (13)
O2—C5—O3	175.30 (8)	175.01 (8)	175.58 (8)
O2—C5—C1	59.71 (7)	59.39 (6)	60.03 (7)
O2—C5—C4	149.81 (12)	149.34 (12)	150.28 (12)
O2—C5—C6	28.90 (8)	28.75 (8)	29.05 (8)
O3—C5—C1	115.71 (8)	115.58 (8)	115.85 (8)
O3—C5—C4	25.62 (8)	25.34 (8)	25.90 (8)
O3—C5—C6	146.51 (12)	146.37 (12)	146.65 (12)
C1—C5—C4	90.10 (10)	89.95 (10)	90.26 (10)
C1—C5—C6	30.81 (9)	30.63 (8)	30.99 (8)
C4—C5—C6	120.91 (14)	120.58 (14)	121.25 (14)
O2—C6—O4	89.12 (11)	87.99 (11)	90.24 (11)
O2—C6—C1	116.88 (16)	116.49 (16)	117.27 (16)
O2—C6—C2	147.27 (13)	146.44 (13)	148.09 (13)
O2—C6—C4	151.91 (12)	151.75 (12)	152.07 (12)
O2—C6—C5	121.25 (14)	121.11 (14)	121.40 (14)
O2—C6—H1o2	20.1 (5)	18.9 (5)	21.2 (5)
O4—C6—C1	27.76 (9)	27.02 (9)	28.52 (9)
O4—C6—C2	58.14 (6)	57.84 (6)	58.45 (6)
O4—C6—C4	118.96 (8)	117.98 (8)	119.97 (8)
O4—C6—C5	149.62 (13)	148.61 (13)	150.64 (13)
O4—C6—H1o2	70.1 (5)	69.2 (5)	71.0 (5)
C1—C6—C2	30.38 (10)	29.93 (9)	30.83 (9)
C1—C6—C4	91.20 (12)	90.96 (11)	91.45 (11)
C1—C6—C5	121.86 (17)	121.60 (16)	122.13 (16)
C1—C6—H1o2	97.7 (5)	96.6 (5)	98.7 (5)
C2—C6—C4	60.82 (7)	60.13 (7)	61.52 (7)
C2—C6—C5	91.48 (12)	90.77 (12)	92.20 (12)
C2—C6—H1o2	127.8 (5)	126.9 (5)	128.8 (5)
C4—C6—C5	30.66 (9)	30.64 (9)	30.68 (9)
C4—C6—H1o2	169.1 (6)	168.2 (6)	169.9 (6)
C5—C6—H1o2	140.1 (5)	138.9 (5)	141.2 (6)
N1—C7—C8	148.24 (16)	147.13 (16)	149.37 (16)
N1—C7—C9	118.28 (10)	117.41 (10)	119.15 (10)
N1—C7—C11	59.05 (7)	58.29 (7)	59.82 (7)
N1—C7—C12	28.94 (8)	28.41 (8)	29.47 (8)
N1—C7—H7	91.41	90.58	92.23
N1—C7—H8	172.78	171.83	173.72
N1—C7—H1o1ⁱ	30.8 (5)	26.4 (5)	35.0 (5)
C8—C7—C9	29.97 (11)	29.71 (11)	30.22 (11)
C8—C7—C11	89.19 (13)	88.83 (13)	89.54 (13)
C8—C7—C12	119.31 (17)	118.70 (17)	119.91 (17)
C8—C7—H7	120.35	120.05	120.65
C8—C7—H8	24.55	24.39	24.71
C8—C7—H1o1ⁱ	175.0 (5)	172.5 (5)	176.9 (4)
C9—C7—C11	59.23 (7)	59.12 (7)	59.33 (7)
C9—C7—C12	89.34 (12)	88.98 (12)	89.71 (12)
C9—C7—H7	150.3	150.23	150.38
C9—C7—H8	54.52	54.42	54.61
C9—C7—H1o1ⁱ	148.7 (5)	143.5 (5)	153.8 (5)
C11—C7—C12	30.12 (9)	29.86 (9)	30.38 (9)
C11—C7—H7	150.46	150.38	150.53
C11—C7—H8	113.74	113.54	113.93
C11—C7—H1o1ⁱ	89.6 (5)	84.5 (5)	94.7 (5)
C12—C7—H7	120.35	120.04	120.65
C12—C7—H8	143.85	143.41	144.29
C12—C7—H1o1ⁱ	59.6 (5)	54.7 (5)	64.4 (5)
H7—C7—H8	95.8	95.65	95.95
H7—C7—H1o1ⁱ	60.85	55.7	66.07
H8—C7—H1o1ⁱ	156.43	151.23	161.7
C7—C8—C9	121.19 (18)	120.64 (17)	121.74 (17)
C7—C8—C10	92.40 (13)	91.86 (13)	92.95 (13)
C7—C8—C12	31.05 (11)	30.70 (11)	31.38 (11)
C7—C8—H7	24.19	24.12	24.25
C7—C8—H8	119.4	119.13	119.68
C7—C8—H9	145.24	144.66	145.82
C9—C8—C10	28.79 (9)	28.53 (9)	29.05 (9)
C9—C8—C12	90.15 (12)	89.91 (12)	90.39 (12)
C9—C8—H7	145.37	144.87	145.87
C9—C8—H8	119.4	119.13	119.68
C9—C8—H9	24.05	23.87	24.23
C10—C8—C12	61.36 (7)	61.14 (7)	61.58 (7)
C10—C8—H7	116.59	116.1	117.07
C10—C8—H8	148.19	147.87	148.52
C10—C8—H9	52.84	52.74	52.94
C12—C8—H7	55.23	54.95	55.51
C12—C8—H8	150.44	150.32	150.56
C12—C8—H9	114.2	113.96	114.44
H7—C8—H8	95.22	95	95.44
H7—C8—H9	169.4	168.86	169.94
H8—C8—H9	95.36	95.02	95.69
C7—C9—C8	28.84 (9)	28.54 (9)	29.15 (9)
C7—C9—C10	92.66 (11)	91.96 (11)	93.37 (11)
C7—C9—C11	61.37 (8)	61.09 (8)	61.64 (8)
C7—C9—H8	52.83	52.63	53.03
C7—C9—H9	148.09	147.68	148.5
C7—C9—H10	116.65	116.14	117.17
C8—C9—C10	121.50 (14)	120.78 (15)	122.22 (15)
C8—C9—C11	90.20 (11)	89.88 (11)	90.54 (11)
C8—C9—H8	23.99	23.86	24.12
C8—C9—H9	119.25	118.89	119.61
C8—C9—H10	145.49	144.96	146.03
C10—C9—C11	31.30 (9)	30.86 (9)	31.74 (9)
C10—C9—H8	145.49	144.73	146.26
C10—C9—H9	119.25	118.89	119.61
C10—C9—H10	23.99	23.79	24.19
C11—C9—H8	114.19	113.86	114.53
C11—C9—H9	150.54	150.4	150.69
C11—C9—H10	55.29	55.05	55.53
H8—C9—H9	95.26	94.84	95.67
H8—C9—H10	169.48	168.92	170.04
H9—C9—H10	95.26	95.08	95.43
N2—C10—C8	118.69 (9)	118.10 (9)	119.27 (9)
N2—C10—C9	148.39 (13)	147.35 (13)	149.42 (14)
N2—C10—C11	29.57 (10)	29.31 (10)	29.83 (10)
N2—C10—C12	59.89 (7)	59.59 (7)	60.18 (7)
N2—C10—H9	172.87	171.94	173.76
N2—C10—H10	91.02	90.38	91.67
C8—C10—C9	29.71 (9)	29.24 (9)	30.17 (9)
C8—C10—C11	89.12 (13)	88.77 (13)	89.47 (13)
C8—C10—C12	58.81 (7)	58.39 (7)	59.22 (7)
C8—C10—H9	54.21	53.84	54.58
C8—C10—H10	150.29	150.17	150.41
C9—C10—C11	118.83 (17)	118.04 (17)	119.61 (17)
C9—C10—C12	88.51 (12)	87.70 (12)	89.32 (12)
C9—C10—H9	24.51	24.41	24.59
C9—C10—H10	120.59	120.2	120.98
C11—C10—C12	30.32 (10)	30.19 (10)	30.44 (10)
C11—C10—H9	143.33	142.63	144.03
C11—C10—H10	120.59	120.2	120.98
C12—C10—H9	113.02	112.29	113.75
C12—C10—H10	150.9	150.47	151.32
H9—C10—H10	96.08	95.78	96.39
N1—C11—N2	92.82 (10)	92.30 (10)	93.34 (10)
N1—C11—C7	59.13 (7)	58.69 (7)	59.56 (7)
N1—C11—C9	118.54 (10)	118.04 (10)	119.03 (10)
N1—C11—C10	148.41 (15)	147.95 (15)	148.87 (15)
N1—C11—C12	29.14 (9)	28.41 (9)	29.87 (9)
N1—C11—C18	61.48 (7)	61.25 (7)	61.71 (7)
N1—C11—H10	171.73	171.29	172.18
N2—C11—C7	151.94 (12)	151.52 (13)	152.35 (13)
N2—C11—C9	148.64 (13)	148.01 (14)	149.28 (14)
N2—C11—C10	118.77 (17)	118.47 (18)	119.07 (18)
N2—C11—C12	121.95 (14)	121.56 (14)	122.34 (14)
N2—C11—C18	31.34 (8)	30.99 (8)	31.69 (8)
N2—C11—H10	95.43	94.93	95.95
C7—C11—C9	59.41 (7)	59.19 (7)	59.63 (7)
C7—C11—C10	89.28 (12)	89.16 (13)	89.41 (13)
C7—C11—C12	29.99 (9)	29.64 (9)	30.34 (9)
C7—C11—C18	120.60 (9)	120.37 (9)	120.83 (9)
C7—C11—H10	112.62	112.52	112.72
C9—C11—C10	29.88 (10)	29.53 (10)	30.22 (10)
C9—C11—C12	89.40 (12)	88.87 (12)	89.92 (12)
C9—C11—C18	179.42 (10)	179.16 (10)	179.71 (9)
C9—C11—H10	53.21	53.1	53.34
C10—C11—C12	119.27 (17)	119.00 (16)	119.55 (16)
C10—C11—C18	150.11 (16)	149.88 (15)	150.34 (15)
C10—C11—H10	23.34	23.11	23.56
C12—C11—C18	90.61 (11)	90.11 (11)	91.11 (11)
C12—C11—H10	142.61	142.19	143.03
C18—C11—H10	126.78	126.5	127.06
N1—C12—N2	91.69 (13)	90.24 (12)	93.14 (12)
N1—C12—C7	120.33 (17)	119.26 (16)	121.39 (17)
N1—C12—C8	149.98 (15)	148.65 (15)	151.30 (15)
N1—C12—C10	150.17 (15)	148.72 (15)	151.64 (15)
N1—C12—C11	119.77 (17)	118.16 (17)	121.39 (17)
N1—C12—C17	30.44 (10)	29.41 (10)	31.48 (10)
N1—C12—H7	96.8	95.64	97.95
N1—C12—H1o1ⁱ	33.9 (6)	31.2 (6)	36.4 (5)
N2—C12—C7	147.98 (12)	147.49 (12)	148.46 (12)
N2—C12—C8	118.33 (9)	118.04 (9)	118.62 (9)
N2—C12—C10	58.50 (7)	58.37 (7)	58.62 (7)
N2—C12—C11	28.09 (9)	27.91 (9)	28.27 (9)
N2—C12—C17	61.25 (7)	60.79 (7)	61.71 (7)
N2—C12—H7	171.49	171.1	171.92
N2—C12—H1o1ⁱ	125.3 (6)	121.2 (6)	129.2 (5)
C7—C12—C8	29.65 (9)	29.39 (9)	29.91 (9)
C7—C12—C10	89.48 (11)	89.03 (11)	89.92 (11)
C7—C12—C11	119.89 (14)	119.28 (14)	120.50 (14)
C7—C12—C17	150.77 (13)	150.67 (13)	150.87 (13)
C7—C12—H7	23.53	23.45	23.62
C7—C12—H1o1ⁱ	86.6 (6)	83.0 (5)	90.4 (6)
C8—C12—C10	59.83 (7)	59.64 (7)	60.03 (7)
C8—C12—C11	90.24 (11)	89.89 (11)	90.60 (11)
C8—C12—C17	179.48 (11)	179.25 (11)	179.86 (11)
C8—C12—H7	53.18	53.01	53.36
C8—C12—H1o1ⁱ	116.2 (6)	112.4 (5)	120.2 (6)
C10—C12—C11	30.41 (9)	30.25 (9)	30.58 (9)
C10—C12—C17	119.75 (11)	119.31 (10)	120.19 (11)
C10—C12—H7	113.01	112.65	113.37
C10—C12—H1o1ⁱ	173.6 (5)	170.9 (5)	175.6 (5)
C11—C12—C17	89.33 (12)	88.73 (12)	89.94 (12)
C11—C12—H7	143.42	142.89	143.94
C11—C12—H1o1ⁱ	153.2 (6)	148.9 (6)	157.1 (5)
C17—C12—H7	127.24	127.1	127.38
C17—C12—H1o1ⁱ	64.3 (6)	60.5 (6)	67.8 (5)
H7—C12—H1o1ⁱ	63.11	59.44	67.01
N2—C13—C14	149.20 (16)	148.50 (16)	149.91 (16)
N2—C13—C15	118.99 (10)	118.59 (10)	119.38 (10)
N2—C13—C17	59.79 (7)	59.49 (7)	60.09 (7)
N2—C13—C18	29.35 (8)	29.16 (8)	29.53 (8)
N2—C13—H13	90.72	90.35	91.1
N2—C13—H14	173.72	173.03	174.41
C14—C13—C15	30.22 (11)	29.81 (11)	30.64 (11)
C14—C13—C17	89.41 (13)	88.76 (13)	90.08 (13)
C14—C13—C18	119.86 (18)	119.15 (17)	120.58 (18)
C14—C13—H13	120.07	119.71	120.43
C14—C13—H14	24.52	24.48	24.57
C15—C13—C17	59.20 (7)	58.95 (7)	59.44 (7)
C15—C13—C18	89.64 (12)	89.31 (12)	89.97 (12)
C15—C13—H13	150.29	150.18	150.4
C15—C13—H14	54.74	54.36	55.14
C17—C13—C18	30.45 (9)	30.32 (9)	30.58 (9)
C17—C13—H13	150.51	150.2	150.82
C17—C13—H14	113.94	113.3	114.58
C18—C13—H13	120.07	119.71	120.42
C18—C13—H14	144.39	143.69	145.09
H13—C13—H14	95.55	95.2	95.89
C13—C14—C15	120.90 (18)	120.42 (18)	121.38 (18)
C13—C14—C16	92.08 (13)	91.52 (13)	92.64 (13)
C13—C14—C18	30.82 (11)	30.53 (11)	31.10 (11)
C13—C14—H13	24.32	24.12	24.53
C13—C14—H14	119.55	119.31	119.79
C13—C14—H15	144.83	144.15	145.5
C15—C14—C16	28.82 (9)	28.71 (9)	28.93 (9)
C15—C14—C18	90.08 (12)	89.85 (12)	90.31 (12)
C15—C14—H13	145.22	144.93	145.51
C15—C14—H14	119.55	119.31	119.79
C15—C14—H15	23.93	23.74	24.12
C16—C14—C18	61.26 (7)	60.97 (7)	61.55 (7)
C16—C14—H13	116.41	116.04	116.76
C16—C14—H14	148.37	148.04	148.69
C16—C14—H15	52.75	52.61	52.89
C18—C14—H13	55.14	55.06	55.22
C18—C14—H14	150.37	150.27	150.47
C18—C14—H15	114.01	113.59	114.42
H13—C14—H14	95.23	95.15	95.31
H13—C14—H15	169.15	168.66	169.62
H14—C14—H15	95.62	95.19	96.05
C13—C15—C14	28.88 (9)	28.81 (9)	28.95 (9)
C13—C15—C16	92.38 (11)	91.82 (11)	92.93 (11)
C13—C15—C17	61.19 (7)	61.17 (7)	61.22 (7)
C13—C15—H14	52.75	52.62	52.87
C13—C15—H15	148.25	147.94	148.56
C13—C15—H16	116.41	116.13	116.69
C14—C15—C16	121.26 (15)	120.76 (15)	121.74 (15)
C14—C15—C17	90.07 (11)	90.02 (11)	90.12 (11)
C14—C15—H14	23.87	23.67	24.06
C14—C15—H15	119.37	119.13	119.62
C14—C15—H16	145.29	145.06	145.51
C16—C15—C17	31.19 (9)	30.64 (9)	31.73 (9)
C16—C15—H14	145.12	144.44	145.79
C16—C15—H15	119.37	119.13	119.62
C16—C15—H16	24.03	23.76	24.31
C17—C15—H14	113.93	113.79	114.08
C17—C15—H15	150.56	150.26	150.85
C17—C15—H16	55.22	54.94	55.49
H14—C15—H15	95.51	95.08	95.95
H14—C15—H16	169.15	168.74	169.55
H15—C15—H16	95.34	95.28	95.4
N1—C16—C14	118.20 (9)	117.23 (9)	119.19 (9)
N1—C16—C15	148.12 (14)	146.75 (14)	149.52 (14)
N1—C16—C17	29.20 (10)	28.95 (10)	29.46 (10)
N1—C16—C18	59.25 (7)	58.55 (7)	59.95 (7)
N1—C16—H15	172.59	171.26	173.93
N1—C16—H16	91.34	90.51	92.15
C14—C16—C15	29.92 (9)	29.52 (9)	30.34 (9)
C14—C16—C17	89.00 (13)	88.27 (13)	89.74 (13)
C14—C16—C18	58.97 (7)	58.68 (7)	59.26 (7)
C14—C16—H15	54.4	54.03	54.78
C14—C16—H16	150.46	150.29	150.62
C15—C16—C17	118.93 (18)	117.79 (18)	120.08 (18)
C15—C16—C18	88.89 (12)	88.20 (13)	89.59 (13)
C15—C16—H15	24.48	24.43	24.53
C15—C16—H16	120.54	119.96	121.1
C17—C16—C18	30.04 (10)	29.59 (10)	30.50 (10)
C17—C16—H15	143.41	142.31	144.52
C17—C16—H16	120.54	119.96	121.1
C18—C16—H15	113.37	112.71	114.04
C18—C16—H16	150.57	150.43	150.71
H15—C16—H16	96.06	95.52	96.59
N1—C17—N2	91.84 (10)	90.42 (10)	93.27 (10)
N1—C17—C12	30.39 (8)	29.24 (8)	31.56 (8)
N1—C17—C13	150.74 (12)	149.36 (12)	152.14 (12)
N1—C17—C15	149.64 (13)	148.44 (13)	150.81 (13)
N1—C17—C16	119.76 (17)	119.18 (17)	120.33 (17)
N1—C17—C18	120.32 (13)	118.95 (13)	121.72 (14)
N1—C17—H16	96.33	95.54	97.11
N1—C17—H1o1ⁱ	25.0 (4)	22.9 (4)	26.9 (4)
N2—C17—C12	61.45 (7)	61.18 (7)	61.73 (7)
N2—C17—C13	58.91 (7)	58.79 (7)	59.04 (7)
N2—C17—C15	118.52 (10)	118.20 (10)	118.84 (10)
N2—C17—C16	148.40 (15)	147.52 (15)	149.27 (15)
N2—C17—C18	28.48 (8)	28.35 (8)	28.62 (8)
N2—C17—H16	171.8	171.17	172.42
N2—C17—H1o1ⁱ	116.6 (4)	113.2 (4)	119.6 (4)
C12—C17—C13	120.36 (9)	120.06 (9)	120.67 (9)
C12—C17—C15	179.66 (10)	179.46 (9)	179.82 (11)
C12—C17—C16	150.14 (16)	149.50 (16)	150.78 (16)
C12—C17—C18	89.93 (10)	89.64 (10)	90.24 (10)
C12—C17—H16	126.71	126.3	127.13
C12—C17—H1o1ⁱ	55.3 (4)	52.2 (4)	58.1 (4)
C13—C17—C15	59.61 (7)	59.37 (7)	59.85 (7)
C13—C17—C16	89.49 (12)	88.65 (12)	90.33 (12)
C13—C17—C18	30.43 (8)	30.41 (8)	30.46 (8)
C13—C17—H16	112.92	112.3	113.53
C13—C17—H1o1ⁱ	173.8 (5)	171.4 (5)	175.6 (4)
C15—C17—C16	29.88 (10)	29.27 (11)	30.49 (11)
C15—C17—C18	90.04 (12)	89.82 (12)	90.26 (12)
C15—C17—H16	53.31	52.91	53.7
C15—C17—H1o1ⁱ	124.8 (4)	122.0 (4)	127.8 (4)
C16—C17—C18	119.92 (17)	119.09 (17)	120.73 (17)
C16—C17—H16	23.43	23.2	23.65
C16—C17—H1o1ⁱ	95.0 (4)	92.7 (4)	97.5 (5)
C18—C17—H16	143.34	142.74	143.93
C18—C17—H1o1ⁱ	145.0 (4)	141.7 (5)	147.9 (4)
H16—C17—H1o1ⁱ	71.65	69.15	74.35
N1—C18—N2	92.39 (12)	91.64 (12)	93.14 (12)
N1—C18—C11	61.19 (8)	60.76 (7)	61.62 (7)
N1—C18—C13	148.03 (12)	147.23 (12)	148.81 (12)
N1—C18—C14	118.72 (9)	118.37 (9)	119.08 (9)
N1—C18—C16	58.97 (7)	58.62 (7)	59.32 (7)
N1—C18—C17	28.93 (8)	28.20 (8)	29.65 (8)
N1—C18—H13	171.56	170.87	172.25
N2—C18—C11	31.20 (10)	30.82 (10)	31.58 (10)
N2—C18—C13	119.55 (17)	119.36 (17)	119.74 (17)
N2—C18—C14	148.86 (15)	148.40 (15)	149.33 (15)
N2—C18—C16	151.35 (15)	150.92 (15)	151.79 (15)
N2—C18—C17	121.32 (16)	120.99 (17)	121.64 (17)
N2—C18—H13	95.94	95.7	96.19
C11—C18—C13	150.74 (14)	150.41 (14)	151.07 (14)
C11—C18—C14	179.10 (9)	178.66 (9)	179.52 (10)
C11—C18—C16	120.15 (11)	120.07 (10)	120.23 (10)
C11—C18—C17	90.12 (12)	89.82 (12)	90.41 (12)
C11—C18—H13	127.14	126.92	127.36
C13—C18—C14	29.32 (9)	28.88 (9)	29.75 (9)
C13—C18—C16	89.09 (11)	88.65 (10)	89.51 (11)
C13—C18—C17	119.11 (14)	118.97 (14)	119.26 (14)
C13—C18—H13	23.61	23.48	23.73
C14—C18—C16	59.77 (7)	59.75 (7)	59.79 (7)
C14—C18—C17	89.80 (10)	89.43 (10)	90.17 (10)
C14—C18—H13	52.93	52.61	53.24
C16—C18—C17	30.04 (9)	29.66 (8)	30.42 (8)
C16—C18—H13	112.7	112.38	113.01
C17—C18—H13	142.72	142.62	142.81
C7—H7—C8	35.47	35.23	35.7
C7—H7—C12	36.12	35.91	36.33
C7—H7—H8	59.85	59.66	60.03
C7—H7—H1o1ⁱ	97.2	91.01	103.49
C8—H7—C12	71.59	71.14	72.04
C8—H7—H8	24.38	24.32	24.44
C8—H7—H1o1ⁱ	132.57	126.16	139.09
C12—H7—H8	95.96	95.57	96.36
C12—H7—H1o1ⁱ	61.16	55.19	67.23
H8—H7—H1o1ⁱ	156.83	150.49	163.27
C7—H8—C8	36.05	35.93	36.16
C7—H8—C9	72.65	72.38	72.93
C7—H8—H7	24.35	24.31	24.4
C7—H8—H9	96.67	96.34	97
C8—H8—C9	36.61	36.45	36.76
C8—H8—H7	60.4	60.24	60.56
C8—H8—H9	60.63	60.4	60.85
C9—H8—H7	97	96.68	97.33
C9—H8—H9	24.02	23.89	24.16
H7—H8—H9	121.02	120.64	121.4
C8—H9—C9	36.7	36.52	36.88
C8—H9—C10	72.94	72.5	73.4
C8—H9—H8	24.02	23.89	24.15
C8—H9—H10	97.17	96.78	97.57
C9—H9—C10	36.24	35.98	36.52
C9—H9—H8	60.72	60.43	61.01
C9—H9—H10	60.47	60.26	60.69
C10—H9—H8	96.96	96.41	97.52
C10—H9—H10	24.23	24.16	24.3
H8—H9—H10	121.19	120.7	121.69
C9—H10—C10	35.42	35.23	35.61
C9—H10—C11	71.5	71.13	71.86
C9—H10—H9	24.27	24.22	24.31
C10—H10—C11	36.08	35.91	36.24
C10—H10—H9	59.69	59.45	59.93
C11—H10—H9	95.76	95.35	96.17
C13—H13—C14	35.61	35.46	35.76
C13—H13—C18	36.32	36.09	36.56
C13—H13—H14	60.04	59.8	60.28
C13—H13—H1o2ⁱⁱ	110.69	109.8	111.58
C14—H13—C18	71.93	71.54	72.32
C14—H13—H14	24.43	24.34	24.52
C14—H13—H1o2ⁱⁱ	145.15	144.28	146.01
C18—H13—H14	96.36	95.89	96.84
C18—H13—H1o2ⁱⁱ	75.05	74.05	76.06
H14—H13—H1o2ⁱⁱ	165.89	164.95	166.84
C13—H14—C14	35.93	35.71	36.14
C13—H14—C15	72.51	72.24	72.77
C13—H14—H13	24.42	24.31	24.52
C13—H14—H15	96.41	95.96	96.86
C14—H14—C15	36.58	36.53	36.64
C14—H14—H13	60.34	60.22	60.46
C14—H14—H15	60.48	60.24	60.72
C15—H14—H13	96.93	96.76	97.09
C15—H14—H15	23.9	23.71	24.09
H13—H14—H15	120.83	120.46	121.18
C14—H15—C15	36.7	36.63	36.76
C14—H15—C16	72.85	72.58	73.1
C14—H15—H14	23.9	23.7	24.09
C14—H15—H16	97.08	96.94	97.22
C15—H15—C16	36.15	35.94	36.35
C15—H15—H14	60.59	60.35	60.83
C15—H15—H16	60.39	60.31	60.47
C16—H15—H14	96.74	96.29	97.19
C16—H15—H16	24.24	24.11	24.37
H14—H15—H16	120.98	120.66	121.3
C15—H16—C16	35.43	35.14	35.73
C15—H16—C17	71.47	70.83	72.12
C15—H16—H15	24.27	24.16	24.38
C16—H16—C17	36.04	35.69	36.39
C16—H16—H15	59.7	59.3	60.11
C17—H16—H15	95.74	94.99	96.5
O1—H1o1—O3	80.5 (8)	73.2 (7)	88.2 (9)
O1—H1o1—N1ⁱⁱⁱ	144.8 (15)	139.5 (14)	149.7 (16)
O1—H1o1—C3	25.6 (4)	21.1 (3)	30.5 (5)
O1—H1o1—C7ⁱⁱⁱ	104.1 (9)	102.3 (9)	106.6 (9)
O1—H1o1—C12ⁱⁱⁱ	131.0 (10)	127.7 (10)	134.1 (11)
O1—H1o1—C17ⁱⁱⁱ	140.5 (12)	138.5 (13)	142.8 (12)
O1—H1o1—H7ⁱⁱⁱ	84.85	81.58	88.16
O3—H1o1—N1ⁱⁱⁱ	123.0 (11)	119.6 (10)	126.6 (12)
O3—H1o1—C3	56.8 (4)	53.4 (4)	60.4 (5)
O3—H1o1—C7ⁱⁱⁱ	150.7 (9)	146.9 (9)	153.6 (9)
O3—H1o1—C12ⁱⁱⁱ	147.8 (9)	143.7 (9)	151.6 (9)
O3—H1o1—C17ⁱⁱⁱ	99.6 (7)	98.5 (7)	101.0 (7)
O3—H1o1—H7ⁱⁱⁱ	137.69	130.72	144.42
N1ⁱⁱⁱ—H1o1—C3	165.0 (13)	163.4 (13)	166.6 (14)
N1ⁱⁱⁱ—H1o1—C7ⁱⁱⁱ	68.6 (7)	63.5 (6)	74.1 (8)
N1ⁱⁱⁱ—H1o1—C12ⁱⁱⁱ	34.9 (5)	31.3 (4)	39.0 (6)
N1ⁱⁱⁱ—H1o1—C17ⁱⁱⁱ	25.6 (5)	23.0 (4)	28.7 (6)
N1ⁱⁱⁱ—H1o1—H7ⁱⁱⁱ	90.38	84.13	96.94
C3—H1o1—C7ⁱⁱⁱ	119.5 (8)	114.8 (8)	123.9 (9)
C3—H1o1—C12ⁱⁱⁱ	152.2 (9)	148.9 (10)	155.2 (9)
C3—H1o1—C17ⁱⁱⁱ	144.2 (8)	141.0 (8)	147.4 (9)
C3—H1o1—H7ⁱⁱⁱ	97.66	92.08	103.21
C7ⁱⁱⁱ—H1o1—C12ⁱⁱⁱ	33.8 (3)	32.3 (2)	35.3 (3)
C7ⁱⁱⁱ—H1o1—C17ⁱⁱⁱ	94.2 (7)	86.8 (6)	102.1 (7)
C7ⁱⁱⁱ—H1o1—H7ⁱⁱⁱ	21.95	20.74	23.06
C12ⁱⁱⁱ—H1o1—C17ⁱⁱⁱ	60.4 (5)	54.4 (5)	67.1 (7)
C12ⁱⁱⁱ—H1o1—H7ⁱⁱⁱ	55.72	53.03	58.31
C17ⁱⁱⁱ—H1o1—H7ⁱⁱⁱ	116.03	107.42	124.96
O2—H1o2—O4	89.1 (12)	86.8 (12)	91.4 (12)
O2—H1o2—N2^iv	149.2 (18)	146.4 (17)	152.0 (18)
O2—H1o2—C6	29.7 (7)	28.0 (7)	31.5 (7)
O2—H1o2—H13^iv	80.6	78.12	83.17
O4—H1o2—N2^iv	101.3 (8)	100.1 (8)	102.5 (8)
O4—H1o2—C6	60.8 (5)	60.2 (5)	61.3 (5)
O4—H1o2—H13^iv	121.59	120.99	122.21
N2^iv—H1o2—C6	154.2 (12)	153.0 (12)	155.5 (11)
N2^iv—H1o2—H13^iv	69.26	68.66	69.84
C6—H1o2—H13^iv	103.12	101.58	104.7

Symmetry codes: (i) x₁+1, x₂, x₃, x₄; (ii) x₁, x₂−1, x₃, x₄; (iii) x₁−1, x₂, x₃, x₄; (iv) x₁, x₂+1, x₃, x₄.

Experimental details

Crystal data
Chemical formula	C₁₂H₈N₂·C₆H₂Cl₂O₄
M_r	389.2
Crystal system, space group	Monoclinic, P21(1/2β1/2)0†
Temperature (K)	139
Wave vectors	q = 0.500000a* + 0.513900b* + 0.500000c*
a, b, c (Å)	12.3720 (2), 3.7649 (5), 16.831 (2)
β (°)	107.789 (7)
V (Å³)	746.52 (14)
Z	2
Radiation type	Synchrotron, λ = 0.56 Å
µ (mm⁻¹)	0.24
Crystal size (mm)	0.22 × 0.13 × 0.05

Data collection
Diffractometer	Marresearch, marCCD 165 diffractometer
Absorption correction	Empirical (using intensity measurements) SADABS;Sheldrick,2008
T_min, T_max	0.777, 0.991
No. of measured, independent and observed [I > 3σ(I)] reflections	25001, 15433, 8092
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.981

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.071, 2.08
No. of reflections	15433
No. of parameters	719
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.02
Absolute structure	6649 of Friedel pairs used in the refinement
Absolute structure parameter	0.5

† Symmetry operations: (1) x₁, x₂, x₃, x₄; (2) −x₁, x₂+1/2, −x₃, −x₁−x₃+x₄.

Computer programs: Eval15, Jana2006, DIAMOND Version 3.

Acknowledgements

Single crystals were grown by Alfred Suttner at the Laboratory of Crystallography in Bayreuth. The help of Carsten Paulmann with diffraction experiments with synchrotron radiation at beamline F1 of Hasylab at DESY, Hamburg, is gratefully acknowledged. Beamtime has been awarded under proposal No. II-20100019. The research of LN has been made possible through financial support by the German Academic Exchange Service (DAAD).

References

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Volume 71| Part 2| April 2015| Pages 228-234

doi:10.1107/S2052520615004084

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research papers\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Resonance-stabilized partial proton transfer in hydrogen bonds of incommensurate phenazine–chloranilic acid

1. Introduction

2. Experimental

2.1. X-ray diffraction

2.2. Choice of the superspace group

2.3. Structure refinements

3. Discussion

3.1. The structure model

3.2. Resonance-stabilized proton transfer

3.3. The ferroelectric phase transitions

4. Conclusions

Supporting information

Acknowledgements

References

research papers