Luminescence properties of three structures built from 3-cyano-4-di­cyano­methyl­ene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate and alkaline metals (Na, K and Rb)

The structures of three salts of 3-cyano-4-dicyano­methyl­ene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate with alkali metals (Na, K and Rb) are related to their luminescence properties. The Rb salt, rubidium(I) 3-cyano-4-dicyano­methyl­ene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate, Rb⁺·C₈HN₄O₂^-, is isomorphous with the previously reported potassium salt. For the Na compound, sodium(I) 3-cyano-4-dicyano­methyl­ene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate dihydrate, Na⁺·C₈HN₄O₂^-·2H₂O, two independent sodium ions, located on inversion centers, are coordinated by four water mol­ecules each and additionally by two cyano groups for one and two carbonyl groups for the other. The luminescence spectra in solution are unaffected by the nature of the cation but vary strongly with the dielectric constant of the solvent. In the solid state, the emission maxima vary with structural features; the redshift of the maximum luminescence varies inversely with the distance between the stacked anions.

S1. Comment

Crystal engineering of organic and organometallic molecules involves, among other things, an understanding of the relationship between individual molecules and the properties of their crystals. Such an understanding is necessary in the search for new materials with useful properties (Shirota, 2000; Law, 1993; Hung & Chen, 2002). Luminescent organic and organometallic compounds have attracted attention because of their potential application in organic light emitting devices (OLEDs) (Wang, 2001; Kido & Okamoto, 2002; The Special Issue on Organic Electronics, 2004). Recently, it was shown (Tafeenko et al., 2007) that luminescence of compounds based on the title anion (A) covers a wavelength range from UV to red. Tuning of the emission photon energy can be achieved through changes in intermolecular interactions or/and chemical modification of the anion. The first of these two approaches was used in this work. Some types of intermolecular contacts were found to be of special importance for optics and other electronic properties of organic or metal–organic crystals. In particular, side-by-side (SS, for example, in the case of π-conjugated organic molecules and polymers) and face-to-face contacts (FF, in stacks) are generally recognized as important factors in the control of electron transport and optical properties of molecular crystals. Our previous studies (Tafeenko et al., 2007, and references therein) have shown that the FF interaction is an intrinsic property of anion (A). So, by modifying the distance between neighboring anions, we intended to address the question of how the luminescence maximum depends on the stacking arrangement of (A). Thus, three salts of (A) with alkali metals (Na, K and Rb) were prepared. The structure of the potassium salt, presented earlier (Tafeenko et al., 2003), possesses structural features that we expected would permit a systematic variation of the anion stacking distance. In the potassium salt, all exocyclic heteroatoms of (A) are involved in the formation of a nearly ideal tricapped trigonal prism that encloses the cation, and the anions are arranged in stacks as a result of π–π interactions.

We intended to include cations of different ionic radius into the tricapped trigonal prism, thus varying its volume and with it the distance between adjacent anions in the stack. We succeeded in preparing an isomorphous salt in the case of Rb (Fig. 1 and Table 1) but failed for sodium. For Rb, as with the potassium salt, all external atoms of anion (A) are involved in the formation of the tricapped trigonal prism. Each prism is connected to two neighboring prisms via a common base and to two other prisms via common edges. Thus, double channels are formed along the a axis, in which two rows of rubidium cations are located (Fig. 2). The shortest distance between cations in a given row is 4.2753 (5) Å, while the shortest distance between cations located in different rows is 5.0455 (7) Å. The cation–apex distances in the tricapped prism vary in the range 2.833 (1)–3.173 (2) Å in the potassium salt, while for the rubidium salt the range is 2.964–3.271 (3) Å. The edge lengths in the rubidium salt are also larger, and as a result, the stacking distance for the anions is larger for Rb than for the K salt [3.430 (5) and 3.388 (2) Å, respectively]. The hydrogen bonding between anions (A) also changes. In the potassium salt, anions (A) are connected by an N—H···O hydrogen bond, which is rather weak [H···O = 2.31 (2) Å and N—H···O = 151 (2)°], while for the rubidium salt it is an even weaker contact [H1···O1^vii = 2.49 (5) Å and N1—H1···O1^vii = 150 (4)°; symmetry code: (vii) -x, y + 1/2, -z + 1/2].

It was found to be more difficult to prepare single crystals of the Na salt as well as to index the powder pattern. It appeared that the causa proxima was the simultaneous precipitation of several phases. Slow evaporation of a water–ethanol solution at 323 K yielded a small crystal suitable for X-ray measurements. Two independent Na atoms, Na1 and Na2, occupy inversion centers. Their coordination environments consist of four water molecules plus two cyano (Na1) or two carbonyl (Na2) groups, with similar geometry for both (Table 2). The geometry of (A) is essentially the same as in previously studied structures. The angle between the –C(CN)₂ group and the five-membered ring is 2.1 (1)°. Cation (A) links the two Na atoms via the C9/N4 cyano group and the C5/O2 carbonyl group (Figs. 3 and 4) to form an infinite chain running along [021]. Each anion is linked to its neighbor by N—H···O hydrogen bonds, thus forming a centrosymmetric dimer (Fig. 5 and Table 3). Although adjacent dimers are packed in a fashion similar to that found in the ammonium salt (Tafeenko et al., 2005), the arrangement of the dimers is somewhat different. In the ammonium salt adjacent dimers are connected by (–C—N)···(N—C–) dipole–dipole and π–π interactions, thus forming infinite planar ribbons, while for the sodium salt the packing pattern is mediated by hydrogen bonding between cyano groups of the dicyanomethylene and coordinated water molecules O3 (Fig. 5). The separation between stacked anions is 3.231 (3) Å [for the ammonium salt the distance is larger at 3.358 (2) Å].

Luminescence spectra of the sodium, potassium and rubidium salts were recorded in different solvents and in the solid state. In solution, the spectra are unaffected by the nature of the cation, but vary depending on the dielectric constant of the solvent. The dielectric constants are 19.41, 20.56, 46.45 and 78.30 (Akhadov, 1999) for 2-propanol, acetone, dimethylsulfoxide and pure water, respectively. An increase in the dielectric constant of the solvent results in a redshift of the luminescence from 504 to 539 nm (Fig. 6). In the solid state, the redshift of the luminescence maximum rises sharply for all of the salts studied. As mentioned above, the distances between the anions in the stacks of the sodium, ammonium, potassium and rubidium salts are 3.231 (3), 3.358 (2), 3.388 (2) and 3.431 (5) Å, respectively. The correlation between these values and the luminescence maxima is clear – the smaller the distance, the larger the redshift of the luminescence maximum (Fig. 7).

The energy emission profiles of the salts containing solvent water molecules (ammonium and sodium) differ (Fig. 7) from those without solvates (potassium and rubidium). As mentioned above, the anion packing motifs for the ammonium and sodium salts are similar but differ from that of the mutually isomorphous potassium and rubidium salts. The nature of these similarities and differences in the crystal structures and emission energy profiles are beyond the scope of this paper and require additional investigation.

In conclusion, there are many factors that affect the luminescence properties of the salts in the solid state – hydrogen bonding, the charge on the cation, the π–π interaction details and so on. Thus, the correlation between structural details and emission energies that we observed can be extended to other salts only with caution.

Related literature

For related literature, see: Akhadov (1999); Hung & Chen (2002); Kido & Okamoto (2002); Law (1993); Shirota (2000); Tafeenko et al. (2003, 2005, 2007); Wang (2001).

S2. Experimental

The title salts were obtained by mixing the alkali metal iodide (MI, M = Na and K) in aqueous solution with a suspension of 2,2,3,3-tetracyanocyclopropanecarboxylic acid propan-2-ol, in a molar ratio of 1:1, or by mixing an RbCl and HI aqueous solution with a 2,2,3,3-tetracyanocyclopropanecarboxylic acid propan-2-ol suspension in a molar ratio of 1:1:1. The reactions were carried out at room temperature. The water and propan-2-ol v/v ratio was taken as 1:1. Orange powders were separated from the reaction mixtures by filtration and drying. The resulting clear yellow solutions were left aside at 323 K. Upon slow evaporation with heating over a 7–10 d period, red–orange crystals of the rubidium salt (solvent water), orange crystals of the potassium salt (solvent water–propan-2-ol mixture, v/v 1:1) and yellow [orange according to CIF] crystals of the sodium salt (solvent water–ethanol mixture, v/v 1:1) were grown.

S3. Refinement

For the rubidium and sodium salts, the positions of H atoms were determined from a difference Fourier synthesis and refined freely with the following isotropic displacement parameters: 0.048 (12) Ų for the one H atom in the rubidium salt and in the range 0.051 (11)–0.11 (2) Ų for the H atoms of the sodium dihydrate salt.

Computing details

For both compounds, data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008). Molecular graphics: DIAMOND (Brandenburg, 2000) for rb; DIAMOND (Brandenburg, 2000); for na. For both compounds, software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The atom numbering in the rubidium salt, with displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. The packing of the rubidium salt, viewed along the a axis, showing the coordination of the cations by the stacked anions.
	Fig. 3. The atom numbering in the sodium dihydrate salt, with displacement ellipsoids drawn at the 50% probability level. Atoms Na1 and Na2 are located at inversion centres.
	Fig. 4. Part of the crystal structure of the sodium salt, showing infinite anion–cation chains. Adjacent chains are connected by coordinated water molecules and π–π interaction between anions. The shortest distances between atoms of neighboring anions are 3.256 (5) (for C3—C2^i) and 3.272 (4) Å (C6—C4^i) [symmetry code: (i) x + 1, y, z.] ii in table 2
	Fig. 5. Hydrogen bonds (thin lines) in the structure of the sodium salt. For symmetry codes see Table 3.
	Fig. 6. Luminescence spectra of the potassium salt solutions in different solvents: water (filled circles, maximum 539 nm), dimethyl sulfoxide (broken line, maximum 520 nm), acetone (solid line, maximum 510 nm) and 2-propanol (open circles, maximum 504 nm).
	Fig. 7. Luminescence spectra of the rubidium salt (triangles, maximum 539 nm, aqueous solution), the rubidium salt (filled circles, maximum 568 nm, solid state), the potassium salt (solid line, maximum 580 nm, solid state), the ammonium salt (stars, maximum 600 nm, solid state) and the sodium salt (open circles, maximum 645 nm, solid state).

(rb) rubidium(I) 3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate

Crystal data

Rb^+·C8HN4O2^−	F(000) = 520
Mr = 270.60	Dx = 2.034 Mg m^−3
Monoclinic, P21/c	Melting point: 520 K
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.54184 Å
a = 4.2753 (5) Å	Cell parameters from 25 reflections
b = 9.6013 (9) Å	θ = 28–46°
c = 21.614 (2) Å	µ = 7.62 mm^−1
β = 95.215 (9)°	T = 295 K
V = 883.53 (16) Å^3	Prism, orange
Z = 4	0.1 × 0.08 × 0.05 mm

Data collection

Enraf–Nonius CAD-4 diffractometr	1637 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.041
Graphite monochromator	θmax = 74.5°, θmin = 4.1°
non–profiled ω scan	h = −5→5
Absorption correction: ψ scan (North et al., 1968)	k = 0→11
Tmin = 0.518, Tmax = 0.678	l = 0→26
1834 measured reflections	2 standard reflections every 60 min
1787 independent reflections	intensity decay: none

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.072	All H-atom parameters refined
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0377P)^2 + 1.1175P] where P = (Fo^2 + 2Fc^2)/3
1787 reflections	(Δ/σ)max = 0.001
140 parameters	Δρmax = 0.49 e Å^−3
0 restraints	Δρmin = −0.41 e Å^−3

Special details

Experimental. Photoluminescence spectra were recorded using a Perkin Elmer LS 55 spectrometer equipped with 0.75?m grating monochromator. For all samples the excitation wavelength was 410?nm.

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
Rb	0.85400 (7)	0.61111 (3)	0.099159 (12)	0.03042 (11)
O1	0.0499 (6)	0.0669 (3)	0.26210 (10)	0.0453 (6)
O2	0.3638 (6)	0.4087 (2)	0.13365 (11)	0.0382 (5)
N1	0.1623 (7)	0.2642 (3)	0.20524 (12)	0.0347 (6)
N2	0.8185 (7)	−0.0916 (3)	0.05139 (13)	0.0387 (6)
N3	0.7256 (7)	0.3503 (3)	0.00909 (13)	0.0423 (7)
N4	0.3972 (8)	−0.2081 (3)	0.16641 (14)	0.0456 (7)
C2	0.1682 (7)	0.1210 (3)	0.21929 (13)	0.0300 (6)
C3	0.3402 (7)	0.0560 (3)	0.17206 (12)	0.0274 (6)
C4	0.4371 (6)	0.1569 (3)	0.13198 (12)	0.0237 (5)
C5	0.3224 (7)	0.2942 (3)	0.15540 (12)	0.0268 (5)
C6	0.6053 (7)	0.1475 (3)	0.08070 (12)	0.0249 (5)
C7	0.6686 (7)	0.2623 (3)	0.04222 (13)	0.0288 (6)
C8	0.7244 (7)	0.0157 (3)	0.06310 (12)	0.0266 (6)
C9	0.3744 (7)	−0.0896 (3)	0.16909 (13)	0.0297 (6)
H1	0.090 (10)	0.318 (5)	0.2227 (19)	0.048 (12)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Rb	0.04368 (18)	0.01500 (15)	0.03357 (17)	0.00173 (10)	0.00887 (11)	0.00158 (9)
O1	0.0621 (15)	0.0417 (13)	0.0346 (12)	−0.0065 (12)	0.0181 (11)	0.0021 (10)
O2	0.0559 (14)	0.0146 (10)	0.0455 (12)	0.0038 (9)	0.0123 (10)	0.0003 (8)
N1	0.0525 (16)	0.0248 (13)	0.0281 (12)	0.0047 (11)	0.0112 (11)	−0.0056 (10)
N2	0.0594 (17)	0.0206 (13)	0.0370 (14)	0.0078 (11)	0.0089 (12)	−0.0002 (10)
N3	0.0666 (19)	0.0211 (12)	0.0417 (15)	0.0007 (12)	0.0189 (13)	0.0039 (11)
N4	0.0631 (19)	0.0205 (14)	0.0546 (17)	0.0046 (12)	0.0129 (14)	0.0094 (12)
C2	0.0397 (15)	0.0256 (14)	0.0247 (13)	0.0000 (11)	0.0029 (11)	−0.0003 (10)
C3	0.0419 (15)	0.0165 (13)	0.0238 (12)	0.0007 (11)	0.0028 (11)	0.0020 (10)
C4	0.0349 (13)	0.0135 (11)	0.0221 (12)	0.0004 (10)	−0.0008 (10)	−0.0009 (9)
C5	0.0379 (14)	0.0154 (12)	0.0268 (13)	0.0030 (10)	0.0009 (11)	−0.0032 (10)
C6	0.0403 (14)	0.0112 (11)	0.0233 (12)	0.0007 (10)	0.0035 (10)	−0.0008 (9)
C7	0.0436 (16)	0.0157 (12)	0.0277 (13)	0.0033 (11)	0.0070 (11)	−0.0029 (10)
C8	0.0421 (15)	0.0160 (13)	0.0216 (12)	0.0026 (11)	0.0028 (11)	0.0008 (9)
C9	0.0422 (16)	0.0196 (14)	0.0273 (14)	−0.0011 (11)	0.0033 (11)	0.0056 (10)

Geometric parameters (Å, º)

Rb—O2^i	2.964 (2)	N1—C2	1.408 (4)
Rb—O2	3.001 (2)	N1—H1	0.72 (4)
Rb—O1^ii	3.020 (2)	N2—C8	1.142 (4)
Rb—N2^iii	3.035 (2)	N3—C7	1.148 (4)
Rb—N4^iii	3.075 (3)	N4—C9	1.144 (4)
Rb—N3^iv	3.099 (3)	C2—C3	1.452 (4)
Rb—N4^v	3.147 (3)	C3—C4	1.388 (4)
Rb—N3	3.189 (3)	C3—C9	1.408 (4)
Rb—N3^vi	3.271 (3)	C4—C6	1.378 (4)
O1—C2	1.211 (4)	C4—C5	1.510 (3)
O2—C5	1.216 (3)	C6—C7	1.421 (4)
N1—C5	1.359 (4)	C6—C8	1.428 (4)
C5—N1—C2	112.1 (2)	C3—C4—C5	106.0 (2)
C5—N1—H1	122 (3)	O2—C5—N1	126.8 (3)
C2—N1—H1	126 (3)	O2—C5—C4	126.7 (3)
O1—C2—N1	125.6 (3)	N1—C5—C4	106.5 (2)
O1—C2—C3	128.8 (3)	C4—C6—C7	124.1 (2)
N1—C2—C3	105.6 (2)	C4—C6—C8	119.8 (2)
C4—C3—C9	128.8 (3)	C7—C6—C8	116.1 (2)
C4—C3—C2	109.7 (2)	N3—C7—C6	176.5 (3)
C9—C3—C2	121.4 (3)	N2—C8—C6	177.3 (3)
C6—C4—C3	131.6 (2)	N4—C9—C3	178.9 (4)
C6—C4—C5	122.4 (2)

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

(na) sodium(I) 3-cyano-4-dicyanomethylene-5-oxo-4,5-dihydro-1H-pyrrol-2-olate dihydrate

Crystal data

Na^+·C8HN4O2^−·2H2O	Z = 2
Mr = 244.15	F(000) = 248
Triclinic, P1	Dx = 1.556 Mg m^−3
Hall symbol: -P 1	Melting point: 530 K
a = 3.6549 (8) Å	Cu Kα radiation, λ = 1.54184 Å
b = 10.1920 (12) Å	Cell parameters from 25 reflections
c = 14.8401 (16) Å	θ = 31–46°
α = 108.849 (12)°	µ = 1.45 mm^−1
β = 94.079 (12)°	T = 296 K
γ = 91.58 (2)°	Prism, orange
V = 521.09 (14) Å^3	0.04 × 0.01 × 0.01 mm

Data collection

Enraf–Nonius CAD-4 diffractometr	Rint = 0.077
Radiation source: fine-focus sealed tube	θmax = 64.9°, θmin = 3.2°
Graphite monochromator	h = −4→4
non–profiled ω scan	k = −11→11
1794 measured reflections	l = 0→17
1721 independent reflections	2 standard reflections every 60 min
1212 reflections with I > 2σ(I)	intensity decay: none

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)] = 0.052	All H-atom parameters refined
wR(F^2) = 0.144	w = 1/[σ^2(Fo^2) + (0.0793P)^2 + 0.0504P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
1721 reflections	Δρmax = 0.30 e Å^−3
178 parameters	Δρmin = −0.24 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.011 (2)

Special details

Experimental. Photoluminescence spectra were recorded using a Perkin Elmer LS 55 spectrometer equipped with 0.75?m grating monochromator. For all samples the excitation wavelength was 410?nm.

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
Na1	0.5000	0.0000	0.0000	0.0481 (6)
Na2	0.5000	1.0000	0.5000	0.0476 (6)
O2	0.4265 (7)	0.7657 (2)	0.39509 (16)	0.0442 (6)
O1	0.1066 (6)	0.3364 (2)	0.40524 (15)	0.0393 (6)
O3	1.0052 (8)	−0.1169 (3)	0.0466 (2)	0.0507 (7)
O4	0.0070 (8)	0.9473 (3)	0.5946 (2)	0.0524 (7)
N1	0.2217 (7)	0.5660 (3)	0.42007 (18)	0.0341 (6)
N2	0.7957 (10)	0.3975 (3)	0.0521 (2)	0.0574 (9)
N3	0.7784 (11)	0.8305 (4)	0.2227 (2)	0.0604 (10)
N4	0.4828 (10)	0.1678 (3)	0.1643 (2)	0.0565 (9)
C2	0.2217 (9)	0.4240 (3)	0.3718 (2)	0.0321 (7)
C3	0.3745 (9)	0.4065 (3)	0.2827 (2)	0.0313 (7)
C4	0.4667 (8)	0.5359 (3)	0.2763 (2)	0.0307 (7)
C5	0.3757 (9)	0.6407 (3)	0.3694 (2)	0.0332 (7)
C6	0.6205 (9)	0.5770 (3)	0.2066 (2)	0.0338 (7)
C7	0.6996 (10)	0.7183 (4)	0.2171 (2)	0.0410 (8)
C8	0.7155 (9)	0.4789 (4)	0.1207 (2)	0.0383 (8)
C9	0.4316 (9)	0.2742 (3)	0.2169 (2)	0.0364 (8)
H1	0.152 (10)	0.608 (4)	0.482 (3)	0.051 (11)*
H31	1.007 (13)	−0.096 (5)	0.107 (4)	0.085 (17)*
H32	0.994 (14)	−0.211 (6)	0.014 (4)	0.102 (19)*
H41	0.041 (12)	1.000 (5)	0.644 (3)	0.067 (16)*
H42	−0.034 (15)	0.867 (6)	0.601 (4)	0.11 (2)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Na1	0.0557 (13)	0.0428 (11)	0.0421 (11)	0.0047 (9)	0.0160 (9)	0.0061 (9)
Na2	0.0529 (12)	0.0362 (11)	0.0497 (12)	0.0023 (9)	0.0064 (9)	0.0079 (9)
O2	0.0600 (16)	0.0297 (13)	0.0398 (13)	0.0010 (11)	0.0130 (11)	0.0055 (10)
O1	0.0531 (15)	0.0322 (12)	0.0350 (12)	0.0013 (10)	0.0116 (10)	0.0126 (10)
O3	0.0706 (19)	0.0457 (16)	0.0383 (15)	0.0047 (13)	0.0153 (13)	0.0150 (12)
O4	0.070 (2)	0.0398 (16)	0.0447 (17)	0.0021 (14)	0.0070 (14)	0.0096 (14)
N1	0.0435 (16)	0.0300 (14)	0.0263 (13)	0.0013 (11)	0.0097 (12)	0.0044 (11)
N2	0.078 (2)	0.052 (2)	0.0418 (18)	0.0087 (17)	0.0241 (16)	0.0096 (16)
N3	0.090 (3)	0.045 (2)	0.0474 (19)	−0.0072 (18)	0.0180 (18)	0.0151 (15)
N4	0.076 (2)	0.0392 (18)	0.0471 (19)	0.0039 (16)	0.0152 (17)	0.0016 (15)
C2	0.0365 (18)	0.0320 (17)	0.0261 (15)	0.0006 (13)	0.0037 (13)	0.0071 (13)
C3	0.0379 (18)	0.0300 (17)	0.0243 (14)	0.0025 (13)	0.0072 (13)	0.0055 (12)
C4	0.0304 (17)	0.0338 (17)	0.0271 (15)	0.0043 (13)	0.0020 (12)	0.0086 (13)
C5	0.0393 (18)	0.0319 (19)	0.0272 (15)	0.0029 (14)	0.0042 (13)	0.0074 (13)
C6	0.0383 (18)	0.0355 (18)	0.0278 (16)	0.0012 (14)	0.0061 (13)	0.0101 (13)
C7	0.047 (2)	0.043 (2)	0.0350 (18)	0.0017 (16)	0.0099 (15)	0.0151 (16)
C8	0.0399 (19)	0.043 (2)	0.0348 (18)	0.0005 (15)	0.0075 (14)	0.0152 (16)
C9	0.0405 (19)	0.038 (2)	0.0291 (16)	0.0001 (14)	0.0045 (14)	0.0091 (15)

Geometric parameters (Å, º)

Na1—O3^i	2.401 (3)	N1—C5	1.367 (4)
Na1—O3	2.404 (3)	N1—C2	1.391 (4)
Na1—N4	2.491 (3)	N1—H1	0.94 (4)
Na1—Na1^i	3.6549 (8)	N2—C8	1.149 (4)
Na2—O2	2.388 (2)	N3—C7	1.147 (5)
Na2—O4^ii	2.421 (3)	N4—C9	1.143 (4)
Na2—O4	2.510 (3)	C2—C3	1.431 (4)
Na2—Na2^ii	3.6549 (8)	C3—C4	1.387 (4)
O2—C5	1.211 (4)	C3—C9	1.417 (4)
O1—C2	1.231 (4)	C4—C6	1.382 (4)
O3—H31	0.85 (5)	C4—C5	1.514 (4)
O3—H32	0.93 (6)	C6—C8	1.415 (4)
O4—H41	0.76 (5)	C6—C7	1.417 (5)
O4—H42	0.87 (6)
O3^i—Na1—O3	99.04 (10)	C4—C3—C2	109.2 (3)
O3—Na1—N4	93.04 (11)	C9—C3—C2	122.7 (3)
O2—Na2—O4	89.06 (9)	C6—C4—C3	132.7 (3)
O4^ii—Na2—O4	95.64 (10)	C6—C4—C5	121.4 (3)
H31—O3—H32	114 (5)	C3—C4—C5	105.9 (3)
H41—O4—H42	108 (5)	O2—C5—N1	126.1 (3)
C5—N1—C2	111.2 (3)	O2—C5—C4	127.8 (3)
C5—N1—H1	122 (2)	N1—C5—C4	106.2 (3)
C2—N1—H1	126 (2)	C4—C6—C8	121.4 (3)
C9—N4—Na1	152.8 (3)	C4—C6—C7	122.5 (3)
O1—C2—N1	122.6 (3)	C8—C6—C7	116.0 (3)
O1—C2—C3	130.0 (3)	N3—C7—C6	176.4 (4)
N1—C2—C3	107.4 (3)	N2—C8—C6	178.5 (4)
C4—C3—C9	128.0 (3)	N4—C9—C3	179.0 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H32···N2^iii	0.93 (6)	2.03 (6)	2.901 (4)	155 (5)
O3—H31···N3^iv	0.85 (5)	2.28 (5)	2.998 (4)	142 (4)
O4—H41···N3^v	0.76 (5)	2.21 (5)	2.955 (5)	170 (5)
O4—H42···O1^vi	0.87 (6)	2.05 (6)	2.911 (4)	171 (5)
N1—H1···O1^vi	0.94 (4)	1.91 (4)	2.827 (3)	165 (3)

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