Glycinium semi-malonate and a glutaric acid–glycine cocrystal: new structures with short O—H...O hydrogen bonds

Glycinium semi-malonate, C₂H₆NO₂⁺·C₃H₃O₄⁻, (I), and glutaric acid–glycine (1/1), C₂H₅NO₂·C₅H₈O₄, (II), are new examples of two-component crystal structures containing glycine and carb­oxy­lic acids. (II) is the first example of a glycine cocrystal which cannot be classified as a salt, as glutaric acid remains completely protonated. In the structure of (I), there are chains formed exclusively by glycinium cations, or exclusively by malonate anions, and these chains are linked with each other. Two types of very short O—H...O hydrogen bonds are present in the structure of (I), one linking glycinium cations with malonate anions, and the other linking malonate anions with each other. In contrast to (I), no direct linkages between mol­ecules of the same type can be found in (II); all the hydrogen-bonded chains are heteromolecular, with mol­ecules of neutral glutaric acid alternating with glycine zwitterions, linked by two types of short O—H...O hydrogen bonds.

S1. Comment

Crystalline amino acids and their salts are widely used as biologically active compounds or molecular materials. The studies of the crystal structures of salts of amino acids with carboxylic acids are also of interest for crystal engineering. Amino and carboxylic groups, and in many cases also the side chains of amino acids, are capable of making hydrogen bonds with carboxylic groups of the carboxylic acids, giving rise to a variety of crystal structures. It is of special interest to see in which cases homomolecular fragments (chains, layers etc.) are preserved in these mixed crystal structures, and when the linkages between the molecules of the same type are completely substituted for heteromolecular bonds. This problem is related to understanding the mechanisms of the formation of mixed crystals (cocrystals), as well as to the attempts of using mixed crystals as better soluble forms as compared to individual components.

Glycine is the simplest, and optically inactive, amino acid, but it gives rise to multiple polymorphs as an individual compound, and to a rich variety of crystalline salts. The major part of glycine salts described up to now are formed with inorganic anions [141 compounds in the Cambridge Structural Database (CSD), version 2011; Allen, 2002]. For the salts with carboxylic acids, the structures of two polymorphs of glycinium semi-oxalate (Subha Nandhini et al., 2001; Tumanov et al., 2010), of bis-glycinium oxalate (Chitra et al., 2006) and its solvate (Tumanov et al., 2010), of glycinium hydrogen maleate (Rajagopal et al., 2001) and of glycinium fumarate monohydrate (Natarajan et al., 2009) have been described. In the present paper we report the structures of new two-component crystals of glycine with carboxylic acids [a salt (I) and a cocrystal (II)], which have interesting structural features.

The asymmetric unit of (I) contains a glycinium cation and a malonate anion, whereas the asymmetric unit of (II) contains a neutral glutaric acid and a glycine zwitterion (Figs. 1a and 1b). The intramolecular geometry of glycine in (II) and in the three polymorphs of individual glycine is similar. Glycinium cations in semi-malonate are also similar to those in glycinium oxalate, hydrogen maleate and semi-oxalate (polymorphs I and II). The molecular conformation of glutaric acid in (II) is similar to that in the crystals of individual gutaric acid (Thalladi et al., 2000). (II) is not a salt, since glutaric acid remains completely protonated, and this is a unique example of such a structure for glycine cocrystals. There are 57 structures with glutaric acid in the last version of the CSD, and glutaric acid exists in a diprotonated form in 48%, in monoprotonated form in 33% and in the form of doubly charged anion in 19% of them. Five cocrystals of glutaric acid with amino acids were described. The glutaric acid was monoportonated in four of those (cocrystals with hystidine and lysine) and present as a dianion in the case of bis(l-argininium) glutarate dihydrate. Thus the mixed glutaric acid–glycine crystal is the first example of a cocrystal of an amino acid with glutaric acid, in which glutaric acid is present in the non-ionized form.

The crystal packing in (I) and in (II) is substantially different. In the structure of (I) one can find head-to-tail chains formed exclusively by glycinium cations [C₁¹(5), elongated along the c axis], or exclusively by malonate anions [C₁¹(6), elongated along the b axis], and these chains are linked with each other to form mixed heteromolecular chains [C₂²(11), elongated along the [101] direction] and heteromolecular four-membered cycles [R₂⁴(14), R₄⁴(16)] (Fig. 2) (Bernstein, 2002). Two types of very short O—H···O hydrogen bonds are present in the structure of (I) – one [with an O—O distance of 2.5289 (18) Å] linking glycinium cations with malonate anions, and another [with an O—O distance of 2.5465 (19) Å] linking malonate anions with each other (Table 1). The short O—H···O hydrogen bonds linking malonate anions within the chains are similar to those in other crystal structures containing malonate chains [1,4-butane-diammonium bis(hydrogenmalonate) (Babu et al., 1997), methylammonium hydrogenmalonate (Djinović & Golič, 1991), malonic acid (Thalladi et al., 2000)]. This motif is rather rare for compounds containing malonic acid, semi-malonate or malonate anions (eight structures out of 53 entries in the CSD have this motif), and glycinium semi-malonate is the first example of an amino acid malonate in which semi-malonate anions form chains. Comparing the glycinium semi-malonate structure with other salts of glycine, one can conclude that the chains of semi-oxalate anions are also present in the structure of glycinium semi-oxalate, polymorphs I (Subha Nandhini et al., 2001) and II (Tumanov et al., 2010), but that they are absent in the structure of glycinium hydrogenmaleate (Rajagopal et al., 2001).

In contrast to (I), no direct linkages between the molecules of the same type can be found in (II); all the hydrogen-bonded chains are heteromolecular, with molecules of neutral glutaric acid alternating with glycine zwitterions, linked via two types of short O—H···O hydrogen bonds with O—O distances 2.5377 (17) Å and 2.5671 (16) Å [C₂²(9), C₂²(10), C₂²(11), C₂²(12), C₂²(13)] (Fig. 3, Table 2). These heteromolecular chains are further linked with each other, to form four-membered rings [R₂⁴(8), R₄⁴(18)] (Fig.3). This is the first example of a mixed crystal of an amino acid and a carboxylic acid, which has only heteromolecular contacts.

Related literature

For related literature, see: Allen (2002); Babu et al. (1997); Bernstein (2002); Chitra et al. (2006); Djinović & Golič (1991); Natarajan et al. (2009); Rajagopal et al. (2001); Subha Nandhini et al. (2001); Thalladi et al. (2000); Tumanov et al. (2010).

S2. Experimental

Crystals of the glycinium malonate and glutaric acid–glycine mixed crystal were obtained by slow evaporation of solutions containing stoichiometric amounts of α-glycine and the corresponding carboxylic acid (1:1) at room temperature (298 K). The volume of water was about 3–4 ml.

S3. Refinement

All H atoms were initially located in a difference Fourier map. The positions of all H atoms were subsequently geometrically optimized and refined using a riding model, with N—H = 0.89 Å, O—H = 0.82 Å and C—H = 0.97 Å, and with U_iso(H) = 1.5U_eq(N, O) and 1.2U_eq(C). The tetrahedral ammonium groups were allowed to rotate but not to tip.

Computing details

Data collection: X-AREA (Stoe & Cie, 2006) for (I); CrysAlis PRO (Oxford Diffraction, 2008) for (II). Cell refinement: X-AREA (Stoe & Cie, 2006) for (I); CrysAlis PRO (Oxford Diffraction, 2008) for (II). Data reduction: X-RED (Stoe & Cie, 2006) for (I); CrysAlis PRO (Oxford Diffraction, 2008) for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and X-STEP32 (Stoe & Cie, 2000); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: Mercury (Macrae et al., 2006), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures

	Fig. 1. Displacement ellipsoid plots for (a) (I) and (b) (II), showing the atom-numbering schemes and drawn with 50% probability displacement ellipsoids for non-H atoms. H atoms are shown as arbitrary spheres.
	Fig. 2. The components of the crystal structure of (I), showing (a) homomolecular chains of glycinium cations (blue in the electronic version of the paper) stretching along the c axis and (b) chains of semi-malonate anions (green) stretching along the b axis, with heteromolecular four-membered rings. Hydrogen bonds are shown by dashed lines and H atoms not involved in hydrogen bonding have been omitted. [Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) x, -y+1/2, z-1/2; (iii) -x+2, -y+1, -z+2; (iv) -x+1, y-1/2, -z+3/2.]
	Fig. 3. The components of the crystal structure of (II), showing heteromolecular chains and ring motifs. Hydrogen bonds are shown by dashed lines. H atoms not involved in hydrogen bonding have been omitted. (In the electronic version of the paper, glycine molecules are blue and glutaric acid molecules are green.) [Symmetry codes: (i) -x, y-1/2, -z+1/2; (ii) -x+1, -y+1, -z+1; (iii) x-1 -y+3/2, z-1/2.]

(I) Glycinium semi-malonate

Crystal data

C2H6NO2^+·C3H3O4^−	F(000) = 376
Mr = 179.13	Dx = 1.584 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9108 reflections
a = 10.1431 (19) Å	θ = 2.1–29.6°
b = 8.1729 (11) Å	µ = 0.15 mm^−1
c = 9.260 (2) Å	T = 297 K
β = 101.879 (16)°	Prism, colourless
V = 751.2 (2) Å^3	0.40 × 0.25 × 0.15 mm
Z = 4

Data collection

Stoe IPDS 2 diffractometer	1295 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.038
Plane graphite monochromator	θmax = 26.4°, θmin = 2.1°
Detector resolution: 6.67 pixels mm^-1	h = −11→12
rotation method scans	k = −10→10
10879 measured reflections	l = −11→11
1522 independent 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)] = 0.042	H-atom parameters constrained
wR(F^2) = 0.094	w = 1/[σ^2(Fo^2) + (0.0399P)^2 + 0.3931P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
1522 reflections	Δρmax = 0.31 e Å^−3
113 parameters	Δρmin = −0.26 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: 0.070 (7)

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
C1	0.98011 (17)	0.3350 (2)	0.87357 (18)	0.0237 (4)
C2	0.84642 (19)	0.3000 (2)	0.7718 (2)	0.0298 (4)
H2A	0.8490	0.1925	0.7279	0.036*
H2B	0.7756	0.2999	0.8279	0.036*
C3	0.71424 (17)	0.82832 (19)	0.77731 (18)	0.0215 (4)
C4	0.62937 (17)	0.8377 (2)	0.62129 (18)	0.0244 (4)
H4A	0.5999	0.9498	0.6009	0.029*
H4B	0.6851	0.8083	0.5519	0.029*
C5	0.50793 (18)	0.7282 (2)	0.59661 (18)	0.0247 (4)
N1	0.81672 (15)	0.42421 (18)	0.65443 (16)	0.0276 (4)
H1A	0.7406	0.3982	0.5920	0.041*
H1B	0.8840	0.4280	0.6061	0.041*
H1C	0.8076	0.5216	0.6943	0.041*
O1	1.00899 (14)	0.22244 (15)	0.97738 (14)	0.0311 (3)
H1	1.0759	0.2505	1.0381	0.047*
O2	1.04822 (13)	0.45126 (16)	0.85836 (14)	0.0322 (3)
O3	0.69579 (14)	0.93254 (16)	0.86958 (14)	0.0348 (4)
O4	0.80001 (13)	0.71547 (15)	0.80734 (13)	0.0280 (3)
O5	0.40779 (14)	0.75730 (18)	0.50452 (17)	0.0464 (4)
O6	0.52148 (16)	0.59823 (19)	0.67987 (18)	0.0507 (5)
H6	0.4504	0.5471	0.6649	0.076*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0224 (8)	0.0255 (8)	0.0224 (8)	0.0035 (7)	0.0030 (7)	−0.0009 (6)
C2	0.0280 (10)	0.0268 (9)	0.0304 (9)	−0.0030 (7)	−0.0036 (8)	0.0036 (7)
C3	0.0199 (8)	0.0206 (8)	0.0220 (8)	−0.0018 (6)	−0.0002 (6)	0.0004 (6)
C4	0.0249 (9)	0.0243 (8)	0.0217 (8)	−0.0016 (7)	−0.0008 (7)	0.0037 (7)
C5	0.0249 (9)	0.0254 (8)	0.0218 (8)	0.0001 (7)	−0.0003 (7)	0.0002 (7)
N1	0.0264 (8)	0.0287 (8)	0.0236 (7)	0.0039 (6)	−0.0046 (6)	−0.0007 (6)
O1	0.0288 (7)	0.0302 (7)	0.0287 (7)	−0.0026 (5)	−0.0069 (5)	0.0060 (5)
O2	0.0263 (7)	0.0325 (7)	0.0351 (7)	−0.0043 (6)	0.0005 (5)	0.0047 (5)
O3	0.0341 (8)	0.0353 (7)	0.0299 (7)	0.0112 (6)	−0.0051 (6)	−0.0104 (5)
O4	0.0272 (7)	0.0253 (6)	0.0270 (6)	0.0073 (5)	−0.0052 (5)	−0.0019 (5)
O5	0.0327 (8)	0.0414 (8)	0.0528 (9)	−0.0090 (6)	−0.0197 (7)	0.0146 (7)
O6	0.0385 (9)	0.0493 (9)	0.0532 (9)	−0.0212 (7)	−0.0163 (7)	0.0263 (7)

Geometric parameters (Å, º)

C1—O2	1.200 (2)	C4—H4A	0.9700
C1—O1	1.319 (2)	C4—H4B	0.9700
C1—C2	1.511 (2)	C5—O5	1.208 (2)
C2—N1	1.472 (2)	C5—O6	1.303 (2)
C2—H2A	0.9700	N1—H1A	0.8900
C2—H2B	0.9700	N1—H1B	0.8900
C3—O3	1.248 (2)	N1—H1C	0.8900
C3—O4	1.259 (2)	O1—H1	0.8200
C3—C4	1.524 (2)	O6—H6	0.8200
C4—C5	1.502 (2)
O2—C1—O1	126.21 (15)	C5—C4—H4B	108.9
O2—C1—C2	122.75 (15)	C3—C4—H4B	108.9
O1—C1—C2	111.04 (15)	H4A—C4—H4B	107.7
N1—C2—C1	110.56 (14)	O5—C5—O6	123.33 (17)
N1—C2—H2A	109.5	O5—C5—C4	122.28 (16)
C1—C2—H2A	109.5	O6—C5—C4	114.37 (14)
N1—C2—H2B	109.5	C2—N1—H1A	109.5
C1—C2—H2B	109.5	C2—N1—H1B	109.5
H2A—C2—H2B	108.1	H1A—N1—H1B	109.5
O3—C3—O4	122.90 (15)	C2—N1—H1C	109.5
O3—C3—C4	118.67 (15)	H1A—N1—H1C	109.5
O4—C3—C4	118.43 (15)	H1B—N1—H1C	109.5
C5—C4—C3	113.57 (14)	C1—O1—H1	109.5
C5—C4—H4A	108.9	C5—O6—H6	109.5
C3—C4—H4A	108.9
O2—C1—C2—N1	1.3 (3)	O4—C3—C4—C5	83.9 (2)
O1—C1—C2—N1	−178.71 (15)	C3—C4—C5—O5	153.67 (18)
O3—C3—C4—C5	−96.1 (2)	C3—C4—C5—O6	−28.0 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O4^i	0.82	1.72	2.5289 (18)	167
O6—H6···O3^ii	0.82	1.73	2.5465 (19)	178
N1—H1A···O5^iii	0.89	2.03	2.859 (2)	154
N1—H1B···O1^iv	0.89	2.27	3.041 (2)	144
N1—H1C···O4	0.89	1.91	2.7926 (19)	171

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

(II) glutaric acid–glycine (1/1)

Crystal data

C2H5NO2·C5H8O4	F(000) = 440
Mr = 207.18	Dx = 1.442 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4462 reflections
a = 4.8954 (4) Å	θ = 2.4–32.8°
b = 20.8944 (14) Å	µ = 0.13 mm^−1
c = 10.8462 (8) Å	T = 297 K
β = 120.648 (6)°	Prism, colourless
V = 954.45 (14) Å^3	0.22 × 0.15 × 0.07 mm
Z = 4

Data collection

Oxford Gemini R Ultra CCD diffractometer	1953 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1543 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
Detector resolution: 10.3457 pixels mm^-1	θmax = 26.4°, θmin = 2.4°
ω scans	h = −6→6
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2008)	k = −26→26
Tmin = 0.882, Tmax = 0.991	l = −13→13
14842 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)] = 0.038	H-atom parameters constrained
wR(F^2) = 0.102	w = 1/[σ^2(Fo^2) + (0.0492P)^2 + 0.2277P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
1953 reflections	Δρmax = 0.18 e Å^−3
131 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: 0.020 (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 F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > σ(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ 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
C1	0.2704 (3)	0.55863 (7)	0.22253 (17)	0.0335 (4)
C2	0.0167 (3)	0.51180 (7)	0.20531 (16)	0.0338 (4)
H2A	−0.1758	0.5352	0.1806	0.041*
H2B	−0.0308	0.4827	0.1271	0.041*
C3	0.1860 (3)	0.63895 (7)	0.48997 (17)	0.0358 (4)
C4	0.4071 (4)	0.69532 (8)	0.54316 (19)	0.0450 (4)
H4A	0.6216	0.6803	0.5778	0.054*
H4B	0.4019	0.7142	0.6237	0.054*
C5	0.3296 (4)	0.74628 (8)	0.43215 (18)	0.0424 (4)
H5A	0.1158	0.7617	0.3980	0.051*
H5B	0.3337	0.7275	0.3513	0.051*
C6	0.5566 (4)	0.80251 (7)	0.48766 (17)	0.0386 (4)
H6A	0.5810	0.8169	0.5778	0.046*
H6B	0.7631	0.7888	0.5058	0.046*
C7	0.4422 (4)	0.85718 (7)	0.38376 (17)	0.0350 (4)
N1	0.1161 (3)	0.47454 (6)	0.33676 (14)	0.0376 (3)
H1A	−0.0250	0.4437	0.3187	0.056*
H1B	0.1279	0.5002	0.4048	0.056*
H1C	0.3056	0.4571	0.3662	0.056*
O1	0.5369 (2)	0.55443 (5)	0.33346 (12)	0.0435 (3)
O2	0.1965 (3)	0.59744 (6)	0.12309 (14)	0.0545 (4)
O3	0.2685 (3)	0.58448 (5)	0.53315 (12)	0.0420 (3)
O4	−0.1056 (3)	0.65332 (6)	0.39428 (16)	0.0574 (4)
H4	−0.2157	0.6210	0.3721	0.086*
O5	0.1779 (3)	0.85897 (5)	0.27942 (13)	0.0493 (3)
O6	0.6355 (3)	0.90550 (5)	0.40882 (14)	0.0504 (4)
H6	0.8077	0.8980	0.4807	0.076*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0302 (8)	0.0299 (7)	0.0411 (9)	0.0012 (6)	0.0185 (7)	0.0005 (6)
C2	0.0283 (7)	0.0343 (8)	0.0355 (8)	−0.0025 (6)	0.0139 (6)	−0.0008 (6)
C3	0.0326 (8)	0.0338 (8)	0.0389 (8)	0.0002 (6)	0.0167 (7)	0.0048 (7)
C4	0.0379 (9)	0.0364 (9)	0.0472 (10)	−0.0048 (7)	0.0117 (8)	0.0078 (7)
C5	0.0397 (9)	0.0336 (8)	0.0434 (9)	−0.0043 (7)	0.0135 (7)	0.0045 (7)
C6	0.0335 (8)	0.0311 (8)	0.0419 (9)	−0.0011 (6)	0.0124 (7)	0.0041 (7)
C7	0.0355 (8)	0.0268 (7)	0.0398 (8)	0.0000 (6)	0.0171 (7)	−0.0021 (6)
N1	0.0332 (7)	0.0331 (7)	0.0407 (7)	−0.0085 (5)	0.0145 (6)	0.0002 (6)
O1	0.0319 (6)	0.0421 (7)	0.0463 (7)	−0.0084 (5)	0.0124 (5)	0.0055 (5)
O2	0.0414 (7)	0.0546 (8)	0.0595 (8)	0.0003 (5)	0.0199 (6)	0.0242 (6)
O3	0.0402 (6)	0.0298 (6)	0.0480 (7)	0.0024 (5)	0.0167 (5)	0.0028 (5)
O4	0.0321 (6)	0.0377 (7)	0.0776 (9)	−0.0042 (5)	0.0099 (6)	0.0156 (6)
O5	0.0386 (6)	0.0377 (7)	0.0497 (7)	0.0013 (5)	0.0067 (6)	0.0082 (5)
O6	0.0480 (7)	0.0349 (6)	0.0526 (8)	−0.0097 (5)	0.0144 (6)	0.0063 (5)

Geometric parameters (Å, º)

C1—O2	1.2465 (19)	C5—H5A	0.9700
C1—O1	1.2479 (18)	C5—H5B	0.9700
C1—C2	1.516 (2)	C6—C7	1.498 (2)
C2—N1	1.473 (2)	C6—H6A	0.9700
C2—H2A	0.9700	C6—H6B	0.9700
C2—H2B	0.9700	C7—O5	1.2097 (19)
C3—O3	1.2186 (18)	C7—O6	1.3141 (18)
C3—O4	1.3018 (19)	N1—H1A	0.8900
C3—C4	1.501 (2)	N1—H1B	0.8900
C4—C5	1.504 (2)	N1—H1C	0.8900
C4—H4A	0.9700	O4—H4	0.8200
C4—H4B	0.9700	O6—H6	0.8200
C5—C6	1.515 (2)
O2—C1—O1	125.42 (14)	C4—C5—H5B	108.9
O2—C1—C2	117.08 (14)	C6—C5—H5B	108.9
O1—C1—C2	117.49 (13)	H5A—C5—H5B	107.7
N1—C2—C1	112.11 (12)	C7—C6—C5	112.03 (13)
N1—C2—H2A	109.2	C7—C6—H6A	109.2
C1—C2—H2A	109.2	C5—C6—H6A	109.2
N1—C2—H2B	109.2	C7—C6—H6B	109.2
C1—C2—H2B	109.2	C5—C6—H6B	109.2
H2A—C2—H2B	107.9	H6A—C6—H6B	107.9
O3—C3—O4	122.39 (14)	O5—C7—O6	118.93 (14)
O3—C3—C4	123.52 (14)	O5—C7—C6	122.60 (14)
O4—C3—C4	114.08 (13)	O6—C7—C6	118.46 (13)
C3—C4—C5	114.17 (14)	C2—N1—H1A	109.5
C3—C4—H4A	108.7	C2—N1—H1B	109.5
C5—C4—H4A	108.7	H1A—N1—H1B	109.5
C3—C4—H4B	108.7	C2—N1—H1C	109.5
C5—C4—H4B	108.7	H1A—N1—H1C	109.5
H4A—C4—H4B	107.6	H1B—N1—H1C	109.5
C4—C5—C6	113.35 (13)	C3—O4—H4	109.5
C4—C5—H5A	108.9	C7—O6—H6	109.5
C6—C5—H5A	108.9
O2—C1—C2—N1	−172.18 (14)	C3—C4—C5—C6	−179.62 (15)
O1—C1—C2—N1	9.1 (2)	C4—C5—C6—C7	−170.06 (15)
O3—C3—C4—C5	147.53 (17)	C5—C6—C7—O5	10.5 (2)
O4—C3—C4—C5	−33.4 (2)	C5—C6—C7—O6	−170.71 (15)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O5^i	0.89	2.00	2.7643 (17)	143
N1—H1B···O3	0.89	2.13	2.9581 (17)	155
N1—H1C···O3^ii	0.89	1.99	2.8727 (17)	169
O6—H6···O2^iii	0.82	1.74	2.5377 (17)	165
O4—H4···O1^iv	0.82	1.75	2.5671 (16)	175

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